The lychee (Litchi chinensis Sonn) an important sub-tropical evergreen fruit crop belonging to family Sapindaceae, is believed to have originated in China, where it has been grown in Southern Guangdong state for thousand of years. It is highly specific to climatic requirements and probably due to this reason its cultivation is restricted to few countries in the world. In India, lychee was introduced in the 18th century through Burma, and from there, it spread to many countries. India and China account for 91 percent of the world lychee production but it is mainly marketed locally. In India, 428,900 metric tonnes of lychee is produced annually from 56,200 hectares. Lychee being exacting in climatic requirement is confined to a few states with 74 percent of production recorded in Bihar. In this state, lychee is the livelihood for millions of people as it provides both on-farm and off-farm employment. Small and marginal farmers get additional income from lychee plants in their homesteads. Thus, lychee cultivation is the livelihood security for a large population, especially in the state of Bihar.
The lychee tree is handsome, dense, round-topped and slow growing with evergreen leaves having 6-9 elliptic oblong and lanceolate abruptly pointed leaves. Colour of leaves varies from light green to dark green. Greenish white or yellowish flowers are borne in clusters. Fruits are round or heart shaped having thin, leathery skin. The colour of fruits varies with cultivar, and is red or rose or pinkish. The edible portion or fruit is the aril, which is immediately beneath the skin. Flavour of the aril varies with cultivar, which is distinctive. Seeds are bold but in some cultivars seeds are partially developed, due to failure of pollination, referred to as ‘chicken-tongue’ seed. The trees with small seeded fruits are prized because of the greater portion of pulp.
Considering the importance of this fruit crop in the region, efforts are made to provide technological support through research and promoting production, post-harvest management and marketing, including export, through development programmes. Lychee has also been identified as an important crop for export. Currently, Indian export of lychee remains quite small due to expanded domestic market. The product for export and distant domestic markets is typically packed in 2 kg cartons after pre-cooling and sulphuring. Domestic marketing generally receives lychee in 10 kg wooden cages or 15 to 18 kg baskets. The growing of lychee in different states under various climatic conditions has advantages in terms of earliness and extended harvest. With a narrow genetic base, under given climatic conditions, fruits are available only for 3-4 weeks. However, due to the spread of cultivation over a wide range of climate there is possibility for extending the cropping period from the first week of May to the first week of July. Evidently, with an expanding market, there is ample potential for increasing area and production with improved production technology and efficient post-harvest management and storage. This paper deals with the current status and identifies the constraints which are required to be addressed.
2. PRESENT SITUATION OF LYCHEE CULTIVATION IN THE COUNTRY
Area and Production
In India, lychee ranks 7th in area and 9th in production among fruit crops (Table 1), but in value terms, it ranks sixth. At national level banana and mango are the most important fruit but in Bihar state, lychee is considered to be the most important fruit as it contributes significantly to its total fruit production.
Table 1. Area and Production of Major Fruit Crops in India
Crops
|
Area (000 ha)
|
Production (000 tonnes)
| ||||
| 1991-92 | 1996-97 | 1998-99 | 1991-92 | 1996-97 | 1998-99 | |
| Apple |
195.00
|
222.70
|
231.00
|
1148.00
|
1308.37
|
1380.00
|
| Banana |
384.00
|
424.66
|
464.00
|
7790.00
|
10014.14
|
15073.00
|
| Citrus |
387.00
|
474.73
|
488.00
|
2822.00
|
4456.16
|
4575.00
|
| Grapes |
32.00
|
429.39
|
43.00
|
668.00
|
1134.66
|
1083.00
|
| Guava |
94.00
|
150.89
|
151.00
|
1095.00
|
1601.24
|
1800.00
|
| Lychee |
49.00
|
51.22
|
56.00
|
244.00
|
377.65
|
429.00
|
| Mango |
1078.00
|
1344.87
|
1401.00
|
8751.00
|
9981.25
|
9785.00
|
| Papaya |
45.00
|
63.05
|
68.00
|
805.00
|
1299.29
|
1582.00
|
| Pineapple |
57.00
|
68.73
|
74.00
|
769.00
|
924.58
|
1006.00
|
| Sapota |
27.00
|
45.67
|
50.00
|
396.00
|
588.49
|
668.00
|
| Others |
522.00
|
304.09
|
694.00
|
4144.00
|
8774.17
|
6659.00
|
| Total |
2870.00
|
3580.00
|
3720.00
|
28632.00
|
40460.00
|
44040.00
|
There has been substantial increase in area and production of lychee in the last 50 years. Area has increased from 9,400 hectares in 1949-50 to 56,000 hectares in 1998-99. The contribution of lychee to total area under fruit has increased from 0.75 percent to 1.5 percent. Increase in area between 1991-92 and 1998-99 (7 years) has been 14.28 percent, while production increase during the same period is to the tune of 75 percent. Productivity also recorded an increase of 52.91 percent during the same period. Evidently, production and productivity of lychee is constantly increasing in the country.
Lychee being exacting in climatic and soil requirements has limited distribution. It is grown in the states of Bihar, Tripura, West Bengal, Uttar Pradesh, Punjab and Haryana. Of the total production of lychee in India, 74 percent is contributed by Bihar. The second largest lychee producing state is West Bengal followed by Tripura and Assam (Table 2). Productivity is highest in Bihar followed by West Bengal. An interesting feature of distribution of lychee in India is that maturity commences first in Tripura, followed by West Bengal then Bihar. The first and second week of May is the time for harvest in the eastern region, while lychee of Bihar matures in the 3rd -4thweek of May and continues up to the first week of June. Lychee in Uttar Pradesh and Punjab is ready for harvest during the 2nd - 3rd week of June. In Himachal Pradesh, lychee of the same cultivar is harvested in the last week of June. Interestingly, in most of the states the best lychee orchards are seen along the rivers, big or small.
Table 2. Area and Production of Lychee in different States
State
|
Area (000 ha)
|
Production (in 000 MT
| ||||
91-92
|
96-97
|
98-99
|
91-92
|
96-97
|
98-99
| |
| Assam |
3.96
|
4.10
|
4.00
|
11.92
|
17.60
|
16.80
|
| Bihar |
19.14
|
23.50
|
25.80
|
191.15
|
282.40
|
309.60
|
| Orissa |
-
|
2.10
|
3.20
|
-
|
7.30
|
8.60
|
| Punjab |
1.52
|
2.20
|
2.30
|
9.13
|
13.00
|
13.20
|
| Tripura |
11.87
|
3.50
|
4.70
|
5.65
|
22.10
|
26.60
|
| Uttar Pradesh |
9.12
|
8.70
|
8.80
|
10.89
|
13.20
|
13.70
|
| W. Bengal |
3.25
|
3.40
|
3.70
|
14.49
|
17.90
|
36.00
|
| Others |
0.42
|
3.70
|
3.70
|
0.58
|
4.10
|
4.40
|
| Total |
49.28
|
51.20
|
56.20
|
243.81
|
377.60
|
428.90
|
Varieties
Lychee varieties grown in India are highly variable under different climate and soil conditions. Singh (1954) described 33 varieties and classified them into 15 groups varieties of lychee grown in India have also been subsequently described (Singh, 1998). When distinguishing the cultivar, the shape of skin segments and protuberances are the reliable and stable genetic characteristics. Fruit size, shape and taste are also variables but are influenced by other than genetic factors. Indian cultivars vary greatly in vegetative flushing pattern, flush colour and flowering ability. Based on these characteristics, cultivars were classified in five groups (Singh, 1998). Group A, which has 7 cultivars is the early group, B and C groups are mid-season, and group D is the late group. Only one cultivar, which is very late, is under group E and its cultivation is confined to Muzaffarpur. Yield and physicochemical characteristics of important cultivars are given in Table 3. The cultivars also show variation in yield, cracking, and physico-chemical quality. Shahi among the early group and China among the mid-season groups appeared to be promising in Jharkhand state (Babita, Personal communication).
Leaf colour along with shape and size of the leaves is of importance in varietal identification. The leaf of Rose Scented is boat-shaped while China has a distinctive twist along the length curved upward from the midrib and down along its length. Small leaflets of Bedana are oval shaped. The fruit shape of the lychee is very distinguishing. The round shape of Bedana is distinguished from the oblong shape of China or Shahi. The fruit is smooth and pulp is even or uneven. The apex of the fruit can be round, obtuse, blunt as in Shahi, or pointed as in China. The varieties can also be distinguished depending upon the colour of the new flush and season of flushing. Shahi produces very light coloured flush while China has pinkish flush. Bedana has very dark pink flush. Emergence of the panicle and its shape also differs. Singh and Singh (1954) distinguished the cultivars based on panicle characteristics. Shahi has long panicles while Bedana produces short and compact panicles. The colour of the lychee fruit is pinkish brown or dark red depending on the cultivar. Colour of the skin varies and is also influenced by growing conditions.
Table 3. Physicochemical characteristics of important cultivars
Varieties
|
Cracking (%)
|
Estimated Fruit Yield (Kg/ plant)
|
Length (cm)
|
Shape Index
|
Fruit Weight (g)
|
Pulp (%)
|
TSS 00 Brix
|
Acidity (Citric Acid-100g)
|
Total Sugar (g/100g)
|
| Ajhauli |
27.58
|
72.42
|
3.48
|
1.15
|
15.29
|
63.13
|
20.22
|
0.3
|
12.53
|
| Bedana |
0.24
|
32.75
|
3.32
|
0.94
|
16.33
|
70.68
|
19.33
|
0.28
|
10.2
|
| China |
0.33
|
95.33
|
3.4
|
1.1
|
14.77
|
58.46
|
20.22
|
0.29
|
10.95
|
| Dehra Dun |
14.27
|
67
|
2.82
|
1.17
|
16.77
|
71.74
|
20.75
|
0.41
|
11.87
|
| Dehra Rose |
10.01
|
74.87
|
3.34
|
1.13
|
19.63
|
74.12
|
21.27
|
0.37
|
12.19
|
| Deshi |
13.63
|
83.03
|
3.5
|
1.18
|
15.94
|
66.65
|
22.82
|
0.37
|
13.48
|
| Green |
24.44
|
84.72
|
3.57
|
1.27
|
16.7
|
61.35
|
21.42
|
0.33
|
11.55
|
| Kasba |
0
|
37
|
3.78
|
1.12
|
25.93
|
72.23
|
20.23
|
0.4
|
11.24
|
| Late Bedana |
0
|
54.22
|
3.36
|
1.06
|
16.7
|
75.08
|
18.17
|
0.27
|
10.38
|
| Longia |
0
|
63.85
|
3.17
|
1.16
|
13.84
|
67.51
|
19.27
|
0.28
|
11.5
|
| Purbi |
0.95
|
80.65
|
3.31
|
1.07
|
20
|
71.73
|
20.1
|
0.29
|
11.04
|
| Rose Scented |
8.85
|
88.05
|
3.63
|
1.16
|
19.39
|
69.05
|
20.37
|
0.37
|
12.98
|
| Shahi |
12.25
|
100.3
|
3.4
|
1.21
|
19.47
|
74.78
|
22.3
|
0.38
|
12.97
|
| Trikolia |
12.03
|
42.37
|
3.37
|
1.14
|
17.35
|
70.83
|
22.43
|
0.36
|
12.7
|
| CD (5%) |
7.45
|
9.71
|
0.17
|
0.09
|
1.73
|
3.07
|
0.48
|
0.03
|
0.18
|
Skin thickness depends on the cultivars. Bedana and China have very thick skin. Rose Scented and Shahi have very thin skin. Skin surface at maturity also varies being smooth, swelling, sharp and pointed. Protuberances of the skin (pericarp) can be smooth and sharply pointed. Bedana has very smooth protuberances while Shahi has very distinct protuberances. The presence and absence of seed as well as structure and size of seeds also vary from cultivar to cultivar, although it is influenced by environmental conditions. In Rose Scented and Bedana, a high proportion of chicken-tongued, seeds (aborted seeds) are observed while China has bold seeds. In a recent selection cv. Swarna Rupa, a high proportion of fruits have small seeds (Singh and Yadav 1992). Although lychee has short duration not exceeding 30-40 days, cultivars can be distinguished based on season and maturity, provided they are grown at same location. Accordingly, cultivars can be grouped into three categories namely, early, medium and late season. Fruit maturity also varies slightly and relatively from year to year depending upon prevailing weather conditions. The maturity period of the fruit also varies depending upon agro-climatic regions. Some of the varieties in West Bengal come to maturity earlier, while the same varieties can be late in Uttar Pradesh. Due to the production of lychee in varying agro-climatic conditions, maturity, fruit colour, shape and size are reported to be varying. Thus, there has been much confusion in the names of varieties. As a result, the same variety is called by different names at different locations (Ray et al. 1984). Varieties grown in India are given in Table 4 and a few selected varieties are described.
Table 4. Varietal Distributions of Lychee in Different States in India
| States |
Varieties
|
| Bihar | Deshi, Purbi, China, Kasba, Bedana, Early Bedana, Late Bedana, Dehra Rose, Shahi, Manragi, Maclean, Longia, Kaselia and Swarna Rupa |
| Uttar Pradesh | Early Large Red, Early Bedana, Late Large Red, Rose Scented, Late Bedana, Calcuttia, Extra Early, Gulabi, Pickling, Khatti, Dehra Dun, Piyazi |
| West Bengal | Bombai, Ellaichi Early, China, Deshi, Purbi and Kasba |
| Haryana / Punjab | Early Seedless, Late Seedless, Seedless-1, Seedless-2 |
Shahi
This is the most popular cultivar grown in North Bihar, Jharkhand, Uttaranchal and Uttar Pradesh regions of India. Besides having high quality fruit it has a distinct rose aroma and hence is called ‘Rose Scented’. It is known as Shahi in Bihar, Rose Scented in Uttaranchal and Muzaffarpur in Western Uttar Pradesh. The vegetative flush of this cultivar is light, and fruit weight ranges from 20-25 g. This cultivar is earliest in maturity, and ripens during the second week of May to the first week of June at various locations. It matures on 12-15 May in Jharkhand, the 25th May in North Bihar and by the first week of June in the Terai region of Uttaranchal. Trees of this cultivar are very vigorous and produce fruits ranging from 100-150 kg per plant. Mature fruits are prone to cracking in zones with low humidity and poor moisture content in the soil. Fruits are globous-heart or obtuse in shape having rose madder and fuchsia purple background with red tubercles at ripening. Pulp is greyish-white, soft, moderately juicy and sweet, and TSS ranges from 19.00 to 22° brix. Seed size varies. On the same plant larger fruits have big seeds while seeds in small fruits are shrunken. The fruits are known for excellent aroma and quality. This cultivar occupies a major area under lychee in India.
China
The origin of this cultivar is not known but the name indicates that it was selected for its superiority and named ‘China’. It is tolerant to hot waves and fluctuations in soil moisture, which cause fruit cracking. It is known as Purbi, Calcuttia, Bengalia, Bombaiya and Manragi in different regions. This is a medium-late season cultivar. Fruits ripen during the end of May in West Bengal, the first week of June in Jharkhand and North Bihar and the third week of June in Uttar Pradesh. Trees are comparatively dwarf and high yielders but it is prone to alternate bearing. Rains at the time of fruit bud differentiation cause emergence of vegetative flush resulting in loss of crop. It bears fruits in cluster of 12-18. In some cases more than 30 fruits per cluster are also recorded. The plants bear less fruit in eastern and southern directions. Fruits are large in size, medium-heavy in weight, oblong in shape, and tyrant rose in colour with dark tubercles at maturity. The aril is creamy-white, soft, juicy, sweet having 18 to 17° brix TSS, 11 percent total sugar and 0.43 percent titratable acidity. Seeds are glaucous, dark chocolate in colour, oblong to concave or planoconvex in shape, medium in size (2.9 cm length and 1.5 cm diameter), and average in weight (3.49 g/seed). The ratio of rind:pulp:seed by weight is 16.42 : 69.22 : 14.36 (Pandey and Sharma, 1989). The flavour of the pulp is not pleasant like Shahi, but owing to its high yield and no cracking this cultivar is popular. This cultivar cannot be distinguished from Manraji and Purbi grown in the eastern part of Bihar state.
Early Bedana
It is also known as Early Seedless in Punjab because of its early ripening and small seeds. This cultivar has distinguishing leaf and flower characters. The cultivar is very much popular in Uttar Pradesh and Punjab. Trees are medium, attaining an average height of 5.0 m and spread of 6.2 m. It is a medium yielding cultivar (50-60 kg/tree) but bears fruits regularly. Fruits are medium in size and weight ranges from 15 to 18 g having oval or heart shape, rough surface with uranium green skin covered with carmine red tubercles at maturity. Aril is creamy white, soft, juicy and sweet containing 17.2 to 19.80 brix TSS. Seed is very small, shrunken, glamorous, dirty chocolate in colour. The overall fruit quality of the cultivar is good.
Late Bedana
This cultivar is also known as Late Seedless. This is a late maturing cultivar, which usually ripens, in the last week of June in Uttaranchal, the end of May in Jharkhand and in first the week of June in Muzaffarpur. The trees are vigorous having an average height of 5.5 m and spread of 7.0 m., with yield ranging from 60-80 kg/tree. Although the fruit size is medium the pulp content is high. The fruits are conical in shape and vermilion to carmine in colour having dark blackish brown tubercles at maturity. The pulp is creamy white, soft, juicy, sweet having 18 to 2° brix TSS, but acidity is low. Seeds are very small, shrunken, glamorous, and chocolate in colour with fusiform shape. The new flush is dark pink in colour and its leaf can be distinguished from other cultivars. The panicle is compact.
Ajhauli
This is an early maturing variety selected from Ajhauli village. It yields about 80-100 kg fruit from a sixteen year old tree. Fruits are red in colour weighing 15 to 18 g and have big seeds. It cannot be distinguished from Shahi on vegetative characteristics as it has many similarities. This variety is highly prone to cracking but under irrigated condition cracking is minimized.
Bombai
This is an important cultivar in West Bengal. It is a vigorous cultivar attaining a height of 6-7 m and spread of 7-8 m. The cultivar matures early (second week of May) and gives 80-90 kg fruit yield per tree. Fruits are large in size (3.5 cm long and 3.2 cm diameter), obliquely heart shaped, and weigh 15-20 g. The colour of ripe fruit is an attractive carmine red with uranium green skin background. Like the Chinese cultivar ‘Nuomici’, this cultivar also has a tiny under-developed fruit attached to the fruit stalk of each fully developed fruit. The pulp is greyish white, soft, juicy, sweet, containing 17° brix TSS, 11 percent total sugar and 0.45 percent acidity. The elongated, smooth and shining seed of light chocolate colour is 2.3 cm long, 1.6 cm in diameter and weighs 3.4 g. This cultivar is akin to China grown in other states.
Dehra Dun
This is an important cultivar of Uttar Pradesh and Punjab where it is grown with the name of Dehra Rose. The fruits start ripening by the third week of June in Uttar Pradesh but in Jharkhand it matures with Shahi. It is a medium vigorous tree (5 m height and 7 m spread) which produces medium to high yield. Fruits are medium to large in size, measuring 3.7 cm in length, 3.5 cm in diameter, weighing 15.2 g and having oblique-heart to conical shape. Bright rose-pink coloured fruits of Dehra Dun look very attractive at ripening. The pulp of this cultivar is greyish-white, soft, moderately juicy with 18° brix TSS, 10.4 percent sugar and 0.44 percent acidity. Seeds remain small, light, shrunken, mostly oblong in shape and dark chocolate in colour. Under rainfed conditions this cultivar is highly prone to cracking. The name of the cultivar suggests that it is a selection made in Dehra Dun.
Gulabi
This is another late maturing cultivar of North India in which ripening takes place by the fourth week of June. Early rain hampers the quality of fruits. The medium vigorous tree of cultivar Gulabi bears profusely and regularly with medium to large sized fruits. The shape of the fruit is variable from oblong-oval to heart shaped whereas the rind colour at ripening varies from shrimp red to carmine red with mandarin red tubercles. The pulp is firm, greyish white, sweet with 18.2° brix TSS, 10.7 percent total sugar and 0.49 percent titratable acidity. The seed is rather big, heavy, oblong-cylindrical in shape with a shining chocolate seed coat.
Ellaichi
This is an important cultivar in West Bengal having brighter prospects for commercialization. The trees are moderately vigorous, attaining an average height of 5-6 m and spread of 6-7 m. It is a mid season cultivar which ripens in the first week of June. The cultivar yields 50-60 kg fruits annually. Fruits are conical, marigold-orange red in colour with an average weight of 12-15 g. The pulp is creamy white in colour, sweet, soft and juicy with agreeable flavour. The cultivar has 18° brix TSS, 11.5 percent total sugar and 0.45 percent acidity, and 6.91 :1 pulp:stone ratio at ripening. Seeds are relatively small, shining, and weigh 1.5 - 2.0 g. Fruits are less susceptible to sunburn and cracking. This cultivar has not assumed commercial success.
Longia
This cultivar is well distributed in North Bihar, and is preferred for late maturity. The tree is medium in size, leaves are small and light in colour and it has compact panicles. Fruits are medium in size and the aril has an excellent aroma. Due to shy bearing habit, there is a declining preference for this cultivar.
Kasba
This is a large fruited cultivar selected from Kasba village for its attractive fruit size and colour. The tree is large and compact having broad and elongated leaves. Fruit weighs between 23-27g, perhaps the heaviest fruit among the known varieties, but the number of fruit is less. Interestingly, the cultivar performs better in marginal soils as it has the capacity to absorb more nutrients (Personal Communication, S. Babita).
Kaselia
This is later maturing cultivar found growing in isolation. The tree is medium in size and fruits mature very late. Fruit attain a pink red colour. The pulp content is comparatively low and the seed is big. This cultivar is also known as ‘khatti’ or ‘pickling’. The cultivar has not assumed commercial success.
Swarna Roopa
This is a late maturing, cracking resistant cultivar of lychee selected at the Central Horticultural Experiment Station (CHES), Ranchi. The fruits are a attractive red colour with small seed and high aril percentage. Leaves are similar to Bedana in shape and size. New flush is pink and mature leaves are dark in colour. The cultivar has 18.5-22.5 cm long, compact panicles. Fruits are medium in size weighing 12-15 g and have a high pulp content. The pulp contains high TSS and low acidity. Total sugar content in the fruit is 13 percent out of which 8.5 percent is reducing sugar. The cultivar is suitable for extended harvest as it matures after China and is prized for its attractive fruit colour. This cultivar is recommended for commercial production.
CHES-2
This is a late maturing selection from the population of the China group. It bears fruits both at the outer and inner canopy, which helps in reducing the sunburn as well as fruit cracking. The fruits are deep red, conical shaped and appear in a cluster of about 15-20. The fruit has an average weight of 21.3 g containing 3.8 g seed and 16.1 g pulp. Vegetative characteristics are similar to China however flowering and fruiting is earlier.
The cultivars described above can be grouped based on the flush colour, shape of the leaf, panicle, fruit, pulp colour and flavour and maturity. Accordingly a key to important cultivars of lychee has been prepared and is presented in the Table 5. All the major cultivars fall into five groups.
Table 5. Key to Important Cultivars of Lychee
| 1. Flush pink, leaf boat-shaped, dark green, panicle long, fruits oblong with round apex. | |
| -Colour of fruit deep pink | Shahi/Tirkolia |
| -Rose flavour | Rose scented |
| -Colour of fruit light and greenish | Green |
| -High cracking and big seed | Ajhauli |
| -Late in Maturity | Dehra Dun |
| 2. Deep pink flush, leaf with twist along the length, curved upward from the midrib and down along their length, panicle long, fruit oblong with pointed apex | |
| -Color of fruit pink | China |
| -Fruits deep pink | Purbi/Manraji |
| -Fruits in bunches | Bombaia/ Calcuttia |
| -Early maturity | CHES-2 |
| 3. Dark pink flush, oval shaped leaves, compact and small panicles, Fruit round, smooth, chicken tongue seed (aborted seed) | |
| -Early maturing | Early bedana or Early seedless |
| -Late maturing | Late seedless/Late Bedana |
| -Deep pink colour | |
| -Mid season maturity | Swarna Rupa |
| 4. Deep pink flush, boat-shaped and dark green long leaves, panicle long, largest size fruit, deep in colour | Kasba |
| 5. Small elongated leaves, light green in colour, panicle compact, fruit medium in size, very late maturity. | |
| -Pulp sweet and excellent flavour | Longia. |
| -Pulp sour | Kaselia/Khatti. |
Climate and Soil
Since, flower bud differentiation, flowering, fruit set, fruit quality and flavour development in Lychee is influenced significantly by temperature and humidity, it has adapted well in the sub-tropics where summer months are hot and wet and winter months are dry and cool. Hot summers free from hot wind and winters free from frost are essential.
Lychee cultivation is highly successful in areas having minimum temperature of 10°C from December to February and 38°C from April to June. However, temperature of 32° C during these months is considered to be optimum. It is highly specific to climatic requirement for its establishment, plant growth and fruiting, and consequently spread of area. A moist atmosphere, occasional rainfall, cool dry winter free from frost and hot winds are ideal for its cultivation. In lychee growing areas in India the temperature varies from 21° C to 37.8°C during flowering and fruiting. It has been observed that flower initiation in lychee requires comparatively low temperature. Seasonal variation in temperature is favourable for proper fruiting. A dry climate, free from rains for about 2 months before flowering induces flower bud differentiation, blossom and consequently give high production. In Chotanagpur, the fog free dry winter, mild sub-tropical summer and intermittent pre-monsoon showers during April-May have been observed to be highly favourable for blossoming, better aril development and improvement in fruit quality. The sub-tropical to mild temperate climate in the foothills and valleys of the Himalayas are also suitable for lychee cultivation. Depending upon the temperature rise after winter the time of flowering and maturity is determined. No fruiting has been recorded when lychee has been grown in tropical conditions. However, on hills in southern states flowering is observed and harvesting commences in November-December.
In India, lychee is grown successfully on a wide range of soil types, which include sandy loams, laterite, alluvial sand, and calcareous soil, but the best lychee orchards are seen in alluvial sandy loam soils with good drainage and access to the water table. The performance of orchards is very poor on clay soil with poor drainage. Lychee grown in sandy soils have a root system network, while trees grown in clay soil have very poor root distribution. The pH of soils in North Bihar ranges from 7.5 to 8, while in Jharkhand lychee grows well at a pH of 6 to 6.5. It grows well even in calcareous soil with 30 percent free lime content. However, in acidic soil of Jharkhand mycorrhizal activity is minimal which affects fruit yield and quality (Pandey and Mishra, 1975). The taxonomy, morphology and mycotrophic habit of mycorrhiza association with lychee was described by Pandey and Misra (1975) and their work also confirmed that lychee requires mycorrhiza to grow and produce better quality of fruits. Thus, it is often suggested that new orchards should be grown with the introduction of soil from old orchards.
3. PRODUCTION OF PLANTING MATERIAL
Lychee is generally multiplied by vegetative methods of propagation as plants raised through sexual method (by seed) grow slowly, have a long juvenile period and do not produce fruit true to the type. However, earlier introduction in different parts of the country was perhaps through seeds, which enabled the selection of superior types and perpetuation the cultivar through vegetative means. The most commonly practiced method of vegetative propagation is air-layering, though cutting, grafting and budding have been found to be successful.
Air-layering
Air-layering, known as ‘marcottage’ in China and ‘goottee’ in India, is commercially practiced for large scale multiplication both in public sector and private sector nurseries. When and how this practice was adopted is not documented but the process of development and modification in the method of layering suggests that the method has gone through transformation. Earlier layering was done using clay soil having provision of watering, however, the air-layer practiced now uses growth hormone and nutrient mixed media of peat moss or coir pith, which is covered with polythene. For preparation of the air-layer a healthy terminal branch receiving good sunshine with a thickness of about 1.2-1.5 cm is selected and a 2.5 cm ring is made by removal of bark about 45-50 cm below the apical growth. The cambium layer is rubbed off and the woody portion is exposed. Rooting hormone (1000 ppm IBA) is used as paste or powder. A layer of moist sphagnum moss or coir pith is placed and wrapped with a piece (20 x 25 cm) of 400 gauge polythene sheet and tied properly at both ends to ensure supply of proper moisture which facilitates the development of roots. It is advised to enrich the rooting medium using organic nutrients. After about 50-60 days, the adequate root system develops from the upper end of the ring, which is visible through the polythene film. The layer is removed by making a sharp cut about 5 cm below the lower end of the ring, preferably in 2-3 stages. The detached layers are planted in partial shade. Success in rooting of the layer is determined by temperature and humidity. When night-time temperature falls to less than 20°C the root becomes brittle. Thus, June is considered to be best time for air-layering. In order to enhance the success of the detached layer, defoliation of leaves up to 50 percent is advocated. At the time of planting excess vegetative growth may be removed to maintain balance between the top and newly developed root system. Regular irrigation and weeding is done to facilitate better establishment and growth. Beds are kept weed free. Lychee layers become ready for field planting in 4-5 months. Growing of layers in the greenhouse has been found to enhance success.
Pot layering
Some nurseries practice, pot layering wherein a lower branch of mature wood is cinctured and the cut surface is buried in a pot or container filled with rooting medium. The pot is watered regularly. The roots develop in the cinctured portion of the branch in about 2 months. Then the branch is detached from the main plant by giving sharp cut, preferably in 2-3 stages. No repotting is required before transplanting in the field. Application of IBA (2000-5000 ppm) improves rooting and survival of the layers.
Stooling
For large scale multiplication stooling is also recommended. In this method, planting is done closely at 1 x 2 m. Once the plant attains the required growth it is headed back to the stump during January-February which permits new shoot (stools) emergence from the stump within two months. A ring of 2 cm is made at the base of the newly emerged shoots and rooting hormone is applied. Then a mound of soil is raised around the shoots to encourage rooting and watering is done regularly. Profuse rooting occur in the stools within two months. These stools are detached and kept in the nursery for hardening and become ready for transplanting in July-August. In stooling, one must be careful not to allow the soil mound to dry, otherwise the rooting process is affected adversely. Therefore, the stool beds should be irrigated at weekly intervals from April-June.
Cuttings
Although this method is advocated it has not been practiced by nurserymen on a commercial scale. The propagation of lychee has also been tried through cutting under mist conditions. A high percentage of rooting was also obtained from the cutting treated with IBA and planted in April-May under mist. But this has not been adopted commercially.
Grafting and budding
Grafting in lychee is mainly practiced for changing scion cultivar or seedling tree or unproductive and old orchards by top working. The apical, side and approach grafting are mainly practiced. In apical grafting 10 cm long scion wood (non-terminal) with at least 2 slightly swollen buds gives better results. The technique of splice or tongue grafting is successful. Apical grafting has not been commercially used for large scale multiplication. Grafting appears to be promising provided seedling growth and percent germination improves. Yadav and Singh (1988) observed that the highest germination of lychee seeds could be obtained if fruits are harvested one week before maturity. A higher rate of growth in seedlings is possible under greenhouse conditions. Softwood grafting has been found to be successful in many nurseries. Budding of lychee has also been successful. However, much more work is required to be done before these methods become accepted practices.
Since, air-layering is a commercial practice, a large number of private nurseries have come forward for large scale multiplication of plants especially in lychee growing regions. It is estimated that about 300,000 lychee plants of different cultivars are produced annually. The regulatory framework to ensure the quality of plants is not in place, thus the creditability of public institutes or private nurseries determine the preference of growers. The cost of plants also becomes a factor in determining the preference of farmers.
4. ESTABLISHMENT OF ORCHARDS
Orchard establishment is a highly specialized activity, which requires proper planning, selection of site, land preparation, layout, planting of saplings, as well as orchard protection and management.
Selection of site and soil
Lychee can be cultivated in a wide range of soils, starting from sandy to clay loam with good drainage and rich in organic matter. However, well-drained deep sandy loam soils having good moisture holding capacity, rich in organic matter and calcium content have been found ideal for lychee cultivation. The well-drained soils of North Bihar rich in calcium content have been observed to be most suitable for better growth and quality fruits. The rolling uplands of Chotanagpur have also been found to be suitable. Soils with poor physical conditions, lacking in available nutrients can be improved for lychee cultivation by adding sufficient quantities of decomposed farmyard manure (FYM), compost and green manure. Lychee growth is restricted in clay soil, thus the site selected should have the above characteristics. When selecting the site climate is also given due consideration. Lychee should not been grown in excessively humid regions when winter temperature is not below 12°C. Also when selecting a site the source of water and transport facilities should be given due consideration.
Planting
Before layout the land is cleared of bushes and other weedy vegetation and is leveled with a mild slope in the opposite direction of the water source. To improve the fertility of the soil organic matter is added. A green manure crop is grown and incorporated into the soil, which improves its fertility, moisture holding capacity and physical condition.
Pits 90 x 90 x 90 cm in dimension are dug at the spacing decided for the orchard. Pit opening is normally recommended in April-May to have a sterilization effect for about 3 days. Before the onset of monsoon pits are filled with topsoil mixed with about 40 kg decomposed compost, 2 kg neem/karanj cake, 1 kg bone meal/single super phosphate and 200-300 g muriate of potash. Incorporation of about 2 baskets of soil from the root zone of old lychee trees encourages the mycorrhiza growth. Then the soil is allowed to settle with the first few rains and leveled properly. Planting is done during June to July. At the time of planting a hole the size of ball of earth is made in the centre of the pit at the marked point where the plant is fixed and the soil is pressed to remove air. Watering is done immediately after planting for proper establishment. Subsequently the plant is regularly irrigated till it is properly established.
Spacing and planting system
Lychee is an evergreen spreading tree, which attains the height of about 10-12 m at its full growth and development. Light penetration of its canopy is also desirable for proper fruiting, hence planting in square system at a distance of 9-10 m within and between the rows has been practiced. However, in an experiment conducted at the Central Horticultural Experiment Station, Ranchi, planting of lychee in a double hedgerow system at a distance of 4.5 x 4.5 x 9 m accommodating 329 plants/ha has been found to be the best and gave higher yield of equally good quality fruits up to 16 years of plantation. High density planting adopting a double row system has also been found to be superior at other locations in terms of yield and quantity of fruits. Through appropriate canopy management high density planting accommodating about 1,200 plants per hectare could also be done as has been found successful in mango. However, this would need further investigation.
Training and pruning
Training of the plant in the initial stage is essential to provide the required framework. Unwanted branches should be pruned to provide definite shape and to promote growth of the trunk and crown of the tree. Three to four branches 60-75 cm from ground opposite to each other are allowed to form the proper frame of the tree. Further, crowded and crisscross branches are removed to facilitate better growth. The branches with narrow angles are also avoided as they are prone to breakage. Non-fruiting unproductive branches inside the canopy in growing and mature trees should also be pruned. Dried, diseased and scissors-shaped branches should also be periodically removed. Light pruning after harvest has been found congenial for better growth, fruiting and yield. While harvesting the fruit the panicle is plucked along with 8-10 cm of twig to promote new flush and better bearing for the succeeding year.
Manure and fertilizer
Among the several factors associated with production of lychee, balanced nutrition is considered to be the most important which determines productivity and quality. Lychee responds to exogenously applied manure and fertilizers and response varies depending upon cultivar (Kotur and Singh, 1993), climatic conditions and soil types. A survey conducted in the Doon valley indicated that 80 percent of orchards are low in N and P and need N and P application (Kunwar and Singh, 1993). In West Bengal, NPK was reported to be below the optimum level (Rao et al, 1985). However in Punjab N, K, Mg, Zn and Mn are reported to be in deficit range. Recently, a survey conducted by Babita (Personal Communication) has clearly shown that low yield and poor quality fruits in lychee are associated with a sub-optimal range of nutrients. Variation in nutrient content was also observed among varieties.
Field experiments conducted on different cultivars at different locations have clearly demonstrated the effect of a graded dose of NPK on growth, yield and quantity of fruits. Application of 600-800 g N, 200-300 g P2O5 and 400-600 g K2O per plant is recommended for 12-15 year old trees. Nitrogen and Potassium should be applied in 2-3 splits and P2O5 in two splits. Excessive application of nitrogenous fertilizer before flowering should be avoided. Phosphorus application at the time of flower bud differentiation improves flowering and fruiting. Application of cakes and manure is generally practiced to get better quality fruits. In general, lychee orchards maintained with higher doses of organic manure have better yield and quality as compared to orchards maintained with chemical fertilizers.
Additional application of Ca, Zn, B, Cu and Mn is recommended. Application of 0.6 percent Ca as calcium chloride improves fruit weight and quality. Zn is applied in the form of 0.5 percent zinc sulphate hydrated with lime, which helps in reducing fruit drop and enhancing fruit yield and quality. Boron in the form of borax (600 ppm) enhances fruit setting and reduces fruit cracking.
In acidic soil application of 10-15 kg lime/tree once in 3 years has been found to increase the yield. In general, application of FYM, potassic and phosphoric fertilizers in major lychee growing areas of the country is done during June-July, just after harvesting of the crop. However, in heavy rainfall areas like West Bengal, Uttaranchal, and Uttar Pradesh, manure and fertilizers are applied in the month of September-October just before the end of monsoon. The nitrogen is applied in two equal spilt doses. The first dose is applied after fruit set, in the month of March-April while the remaining half dose is applied immediately after harvesting of the crop. After application of fertilizer, irrigation of the tree is essential to maintain proper soil moisture. The total requirement of nitrogen, phosphorus and potash is applied through basal application. However 2 percent urea spray is practiced once or twice during the period of fruit growth as needed.
Foliar application of zinc sulphate (0.1 percent) is done twice, 10-15 days before flowering for improving sex ratio and to reduce fruit drop. If a deficiency of zinc and magnesium is observed, application of 150-200 g ZnSO4 and 150-200 g MgSO4, respectively per plant during September has been found to be beneficial. Foliar application of 0.1 percent borax, 2-3 times during the period of fruit growth and development of the trees enhances fruit retention, minimizes cracking, improves fruit colour and sweetness, and advances maturity. Other micronutrients like Fe (Ferrous sulphate), Cu (Copper sulphate), Mg (Magnesium sulphate) are applied if deficiency symptoms are observed. Two to three spray in a year is sufficient to maintain the trees in good health.
Foliar application of the plant bio-regulator, NAA (20 ppm) at an interval of 10-15 days during the period of fruit growth and development, twice or thrice, has been found to be useful for minimizing the fruit drop. IAA may be substituted for NAA if the latter is not available. Spraying plain water four to six times in the early morning hours of the day during the advanced stage of fruit growth and development have been found to be highly effective for achieving better growth with minimized fruit cracking.
Monitoring of plant nutrients is done arbitrarily although some farmers get their soil analyzed for pH and nutrients content once in a while. However, it is advocated to use leaf nutrients as diagnostics for monitoring nutrient needs (Kotur and Singh, 1993). Application of fertilizer based on leaf analysis values, though holding promise, is not yet a reality. Babita (Personal Communication) observed that the critical value of nutrients could be used as a guide to determine the nutritional needs, and could economize on fertilizer and provide higher yields of quality fruits.
Irrigation, mulching and water conservation
Lychee being an evergreen plant, the maintenance of optimum soil moisture is critical for growth, development and fruit production. If the rainfall is evenly distributed lychee is grown successfully and supplementary water requirement depends upon cultivar and evaporation demand. Water requirement ranges from 600-800 mm. Investigations carried out to determine the irrigation needs have clearly indicated that irrigation is critical at the fruit development stage to get better yield and quality of fruits. Interestingly, differential management of water in the vegetative phase and reproductive phase is also suggested. To achieve faster growth of the plant no water stress should be permitted, while in the reproductive phase water stress is beneficial at the time of fruit bud differentiation. Light irrigation during summer and winter months and cleaning of the basin is advocated. Irrigation at the intervals of 2-3 days during the initial stage of plant establishment is considered essential. Further, the young plants should be irrigated during dry periods and winter months at intervals of 3-5 days. For young plants mulching with dry leaves or residues in the basin help in better moisture conservation. Experiments conducted at Ranchi indicated that irrigation of plants at alternate day intervals, 6 weeks before harvesting improves fruit retention, encourages better fruit development, and minimizes the cracking, apart from the quality of fruits. Certain physiological disorders like poor sex ratio, poor fruit set, heavy fruit drop and high fruit cracking, besides sunburn of the fruits can be minimized with proper water management. The basin or flood method of irrigation is normally practiced. However, adoption of drip irrigation has been found to be effective in the economic use of water and enhanced growth, especially in an area where water availability is not satisfactory.
Moisture conservation through mulching using dried weeds or black polythene sheet has been found useful. Trials have also been conducted to conserve moisture using farm residues and polythene sheets. Through adoption of mulching, frequency of irrigation is reduced. In a trial conducted at Ranchi mulching with 3 irrigations was effective in reducing cracking and enhancing yield and quality of fruits (Singh, 1986). To check fruit cracking mulching with 3-4 irrigations during fruit growth has been found to be satisfactory.
Filler plant and intercropping
Lychee is a slow growing plant and takes about 15-16 years to develop canopy and cover the area. During the initial period of establishment, the space between the plants can be utilized for planting of filler plants/intercrops. The planting of guava, custard apple, lime/lemon in the centre, between and within the rows of lychee have been found to give additional income in the initial stage of planting without competing with the main crop. Papaya is also planted as filler plant at the spacing of 2.5 x 2.5 m. In between the plants in the initial stage, cowpea, french bean, okra, brinjal or other suitable crops of the regions are grown as intercrops. In the mature lychee orchards, cultivation of partial shade loving plants (ginger, turmeric, elephant foot yam) is practiced successfully, which provides additional income.
Control of pests, diseases and physiological disorders
Lychee plants and fruits are affected by insect pests and diseases, which causes considerable losses, if not managed. Lychee plants as compared to many fruit bearing species are least affected by diseases. A few leaf spot diseases have come to light that are caused by fungal pathogens. No bacterial or viral infections have been reported so far. Powdery mildew (Oidium spp.), anthracnose or leaf spot (Botryodiplodia theobormae Pat, Colletotrichum gloeosporioides Penz) and red rust (Cephalexros mycoides) are some diseases which cause some damage to the lychee crop, but severity varies from season to season even in the same locality. Their control measures consist of 1-2 applications of proper fungicides, while for red rust sulphur washes in September-October and February-March is sufficient.
Although about 40 insect and mite pests are reported to affect lychee trees and fruits at different stages of growth, erinose mite, lychee bug and fruit borer are the insect pests of most concern.
Lychee mite
Lychee mite (Aceria litchi) is a serious pest in all the lychee growing regions in the country. The tiny nymph and adults stick to the under-surface of the leaf and suck the cell sap. Consequently, the young leaf turns yellow to greyish-yellow and a velvety growth develops on lower surfaces, which subsequently turn brown. The affected mature leaf develops continuous to scattered brown patches with curling, twisting and leathery structure, which ultimately result in blister-like gall formations. It spreads fast under favourable conditions and reduces the photosynthesis activity and increases leaf drop. As a result the tree becomes weak, and yield and quality of the fruit is severely affected. The pest is well studied. It is suggested to prune the affected twigs/branches and burn to avoid spread. Two sprays of karathene 0.05 percent at 7-10 days interval during the attack of the insect has been found to effectively control the pest. Application of neem cake has also been found to reduce the incidence of this pest.
Shoot borer
In lychee orchards incidence of shoot borer is reported. The caterpillar bore inside the newly growing shoot and feed on inner parts resulting in drying of the twigs. In the case of severe infestation the sap movement is interrupted and the tree ceases to flush. Pruning and burning of affected twigs minimize the infestation.
Bark eating caterpillar and trunk borer
The caterpillar (Inderbela sp.) bore inside the trunk/main stem. During the night they come out and feed on the bark protected by the large silken webs usually during July-September. The branch ceases growth and the stem becomes weak and may ultimately fall to the ground. The presence of the insect can be known by seeing the excreta and silky web. This pest has become a very serious problem in Bihar state where yield and quality of fruits have been adversely affected. Cleaning of the infested area and plugging holes with petrol, nuvacron or formaline soaked material is advocated.
Fruit Borer
This pest becomes serious especially in humid conditions at the time of ripening. The small caterpillars bore through the stalk end of the fruit, and feed on the seed and skin. As a result fruits become unfit for consumption. The excreta of the caterpillar is seen near the stalk end of the fruit. High humidity and intermittent rains favour the infestation.
Besides the important pests described above, lychee are often affected by leaf eating caterpillars, leaf miners, bugs and aphids. Birds, bats and squirrels also cause damage to lychee fruits.
Weeds
Weeds Compete for water and nutrients during the initial year of growth. Depending upon location more than 25 species of weeds are reported to be present in lychee orchards. Inter-culture operation and mulching suppress the weeds. Herbicides, although found effective for the control, are rarely applied. In mature orchards the weed problem is not encountered due to heavy shade and natural mulching by falling leaves.
Fruit cracking
Fruit cracking is one of the major limiting factors in the cultivation of lychee, especially early cultivars (Singh, 1986). The early varieties are more prone to the problem of fruit cracking in comparison to late cultivars. The low atmospheric humidity, high temperature and hot winds during fruit development and maturity stage favour fruit cracking. Light irrigation to maintain soil moisture and to improve humidity has been found to minimize this problem through maintenance of a better micro-climate. Mulching with farm residues and 3 irrigations significantly reduced the cracking (Singh, 1986) in a trial conducted on the cultivar Shahi. In addition, spraying with either 100 ppm NAA or 0.2 percent borax during the developing stage of the fruits has been found to be highly effective in checking the cracking.
5. HARVESTING OF FRUITS AND YIELDS
Maturity standard
Lychee being a non-climacteric fruit requires to be harvested after attaining full maturity on the tree. Studies have been conducted to determine the maturity standard for different cultivars under different agro-climatic conditions. Fruits have a sigmoid pattern of growth. First the pericarp develops, then the seed and aril is formed and the seed turn from green to brown. During maturity acidity declines and TSS increases which corroborate the appearance and colour on the fruit. Thus, the colour of fruit is an important criteria to decide the harvesting stage (Singh and Yadav, 1988). The red pigmentation in lychee is associated with anthocyanin pigments (cyanindin-3-glucoside, cyanindin-3-galactoside, pelargonidin-3-glucoside and pelargonidin-3, 5-diglucozide), which develop better in the direction of good light penetration. Invariably pericarp colour and smoothness of pubicles are the best indicators (Singh and Yadav, 1988). Depending upon the cultivar, 65-80 days are taken for maturity from fruit set.
Harvesting
The fruits are harvested in bunches along with a portion of the branch and a few leaves. At the time of harvesting care is taken to harvest the selected bunch, which has attained the desirable maturity as determined by colour development and taste of the pulp. For distant market fruits are harvested when TSS attains 19° Brix and acidity 0.3 to 0.4 percent. The fruits are harvested early in the morning when temperature and humidity are congenial, to have longer shelf-life of the fruit. At the time of harvest fruits are collected in a manner so that they do not fall on the ground. Use of mechanical tools for harvesting is practiced. The harvesting period is generally May-June, depending upon cultivar and location. However, in the hills of southern India lychee is harvested in November- December.
Changes in the physicochemical characteristics of lychee after anthesis were observed at two locations. Interestingly, the cultivar Rose Scented had similar patterns of growth at both locations, but the maturity date was one month later in comparison with Muzaffarpur. This phenomenon of maturity at two locations provides an opportunity for extended harvest of fruits. Maturity of fruits at Muzaffarpur was one month earlier than Dhaulakuan (H.P)
Yield
The yield of lychee varies according to the age of the tree, agro-climatic condition and maintenance of the orchard. Usually about 80-150 kg fruit/tree is obtained from 14-16 year old trees. However, from a fully grown tree a yield of 160-200 kg/tree has also been recorded. Apart from a management practice, bee keeping in lychee orchards has been found to increase the yield of quality fruits by 15-20 percent, since lychee needs cross-pollination. Apis mellifera is the commonly used bee in lychee orchards, which also provide additional income from honey.
Post-harvest management
Lychee deteriorates very fast after harvest. Pericarp browning is a major post-harvest problem, which renders the fruit unmarketable. Browning is associated with desiccation. Peroxidase activity coupled with ascorbic acid oxidation enhances anthocyanin degradation. Techniques to reduce browning and maintain the red colour and prolonged storage life include sulphur treatment and packaging in perforated plastic bags and storage under cold conditions. Sulphur dioxide (S02) fumigation is used as a post-harvest treatment to reduce browning. SO2 treated fruits have a bleached pericarp which turns uniformly pink in colour after 2-3 days. Fumigated fruits absorb 30-65 percent of applied SO2. There is increasing concern about the residue of sulphur and the residual limit is only 10 ppm. For sea transportation 600-650g sulphur is recommend for the duration of 50-60 minutes, while for air transport 300-400 g sulphur for 30 minutes are advocated. The Agricultural Produce Export Development Authority (APEDA) has developed a procedure for production of quality lychee. The steps are: production > inspection of farm > harvesting > desolating and sorting > receipt at packhouse > acceptance of produce > sorting and grading > sulphur treatments > packing and cooling > palletization > storage > container loading and transportation.
Aril breakdown or softening of the aril involves a loss of turgidity and translucency where fruits become blunt in taste. The disorder starts near the pericarp and is prevalent at the end of the stem. Post-harvest decay also occurs due to bacteria, yeast and fungi. Lychee browning and fungal contamination is prevented by dipping fruits in hot benomyl. Since this chemical is being restricted from use, alternative methods are desirable. Irradiation of fruit is considered to reduce browning and post-harvest losses. Storage temperature of 2-5°C is considered to extend the shelf-life. Use of perforated polythene bags and storage at 3°C have also been reported to increase shelf-life. Controlled atmosphere storage is considered better for maintenance of the freshness of the fruits. Thus, to have better post-harvest life of fruits, careful harvesting, pre- cooling, transportation in cool van, sulfuring and storing at 2-3°C would be essential.
Processing
Processing of lychee is done in different forms. Canning of pulp, aseptic packing and ready to serve lychee juice are common. Dried lychee processing is not in practice. Pulp of lychee is aseptically packed and stored at 2-3°C for preparing lychee juice.
6. MARKETING
A substantial amount of lychee produced in the country is consumed locally. Lychee, being highly perishable, is available for very short duration. Marketing of fruits is done in different forms. Growers rent their orchards to contractors, who in turn harvest and sell to local markets. Different market chains prevalent are given in Figure 1.
In chains of marketing increased numbers of middlemen reduces the share of growers in the price of produce paid by consumers. Generally, for the domestic market lychee is packed in 10 kg boxes or baskets having a lining of lychee leaves. There has been considerable importance given to the packing of lychee for niche domestic markets. Now lychee is packed in 2-2.5 kg boxes and transported in cool-chain.
In the last few years serious attempts have been made to export lychee from India. Test consignments were initially sent by air and the technology for sea transport has also been perfected. The exportable lychee is packed in 2 to 2.5 kg or 5 to 6 kg boxes after sulphur treatment. Quality standards are managed as per the standard developed by APEDA. The strong cooperative marketing and infrastructure facilities developed are expected to promote marketing of lychee.
7. POTENTIAL FOR LYCHEE PRODUCTION DEVELOPMENT
With increased market base, there is an ample opportunity for increasing the area under lychee as prevailing agro-climatic conditions have not been fully exploited. Extended area under different situations could be exploited for extended harvest. Based on the fruiting behaviour, quality development and area under cultivation, the lychee growing districts could be grouped in a manner to take full advantage of climatic variability. However, to increase production and productivity, concerted efforts would be required for technological support and development of infrastructure. The foothills of the Himalayas free from frost offer good scope for plantation of lychee. Experience has indicated that lychee cultivation can be done up to an altitude of 1,000 m above mean sea level. In these foothills, fruits mature late and ensure the availability of fruits late in the season. Interestingly, the lychee crop in India matures early in comparison to other lychee growing countries and offers better domestic and export markets. Accordingly there is potential for an additional 100,000 hectares to be brought under lychee cultivation. However, to achieve targeted growth in production, strategic planning, including improved production systems and infrastructure for post-harvest management, is needed.
8. CONSTRAINTS IN LYCHEE PRODUCTION DEVELOPMENT
Despite the fact that the lychee is one of the finest fruits and has a growing demand in national and international markets, productivity continues to be low and a gap exists between potential and existing yield. The ratio in yield between the best managed orchards and national productivity ranges between 2 to 4 times at different locations. The probable reasons for low yield are the narrow genetic base of the crop, non-availability of suitable superior cultivars, traditional production systems, poor technological support and incidence of insect pests, coupled with poor post-harvest management. The shortage of genuine planting material coupled with the long juvenile period of lychee are also the constraints. The low female/male flower ratio, premature fruit drop, and fruit cracking due to non scientific water and nutrient management also add to low productivity and production of poor quality fruits.
The lychee tree has luxuriant vegetative growth, which causes problems in harvesting. Thus, canopy management to achieve the required plant architecture is essential. Lack of scientific information on critical stages for flower bud differentiation, and requirements of water and nutrients also significantly reduces the yield. The lychee has a short shelf-life. Practices that can enhance post-harvest life of fruits would be useful to achieve higher productivity.
9. GOVERNMENT POLICIES AND PLANS FOR RESEARCH AND DEVELOPMENT OF LYCHEE
The research support for varietal and production technology improvement is provided through the All India Coordinated Research Project on Sub-tropical Fruits, which has four centres located in lychee growing regions. The Central Horticultural Experimental Station CHES), Ranchi, Jharkhand, RAU, Pusa, Samastipur, Bihar, G.B.Pant University of Agriculture and Technology, Pantnagar, Udhamsingh Nagar, Uttaranchal and BCKVV, Mohitnagar, Nadia, West Bengal are engaged in research. The main thrust of research is on augmentation of germplasm, varietal evaluation, orchard management, propagation studies and development of fruit production technologies for higher yield and improved shelf-life. A network project for improving productivity of lychee has also been initiated. A National Research Centre on Lychee has been started for strategic and basic research on lychee.
The state Governments of Bihar, Jharkhand, Bengal, Tripura, Uttar Pradesh, Chattisgarh, and Uttaranchal also having programmes for the propagation of planting material to meet the requirements. Bihar has special focus on lychee development. The Government of India is implementing a programme on ‘Integrated Development of Fruits’ that includes lychee. Under this programme, support is provided for production of planting material, expansion of area under improved cultivars, rejuvenation of old orchards, transfer of technology, micro-irrigation etc. APEDA is making efforts for improving the export of lychee through the creation of infrastructure and enhancing capabilities.
10. CONCLUSIONS
Lychee, a climate specific, evergreen fruit plant, introduced in the country in the 18th Century has adapted well to the climate in Eastern India, i.e. Bihar, Jharkhand, West Bengal, Tripura, Uttar Pradesh, Uttaranchal, Chattisgarh, Punjab and Himachal Pradesh. Due to its increasing demand the area under cultivation has increased manifold. However, there is need for improving productivity and also widening the genetic base. Concerted research efforts and effective linkages are essential. Suitable cultivars are needed for various climatic conditions. It is also essential to develop promising lines/hybrids, which have larger fruit size, small/chicken-tongued seeds, tolerance to pericarp splitting, and having various maturity groupings. Suitable agro-techniques particularly for source and sink management, micronutrients, post-harvest technology and effective marketing need due attention. In this context exchange of information among countries would be beneficial. The following points need due consideration:
- Lychee has a very narrow genetic base, which needs to be widened through selection of genotypes from the existing population. Target oriented programmes must be launched so that germplasm is conserved and used.
- A systematic approach for the description of cultivars is needed. Thus, a lychee descriptor needs to be developed.
- Faster multiplication techniques for the production of quality planting material need attention.
- There is need to develop propagation technology for faster multiplication of quality plants.
- The development of nutrition management to maintain tree health and encourage successful flowering, fruiting and quality in sustainable manner, requires attention.
- Monitoring of nutrition in lychee through leaf analysis would be an approach for efficient fertilizer use.
- Integrated management of nutrient and water with efficient monitoring mechanisms would improve input use efficiency.
- Through effective recycling of residues coupled with organic manure, it is possible to improve soil health. Thus, there is an immense potential for organic production of lychee through effective management.
- Integrated management of insect pests and diseases is required to improve productivity and reduce the cost of production.
- Infrastructure for post-harvest management requires emphasis to reduce risk.
- The lychee product range has to be widened for effective utilization.
- Cooperation among lychee growing countries for the exchange of information and cultivars is vital. Starting of a network programme on lychee would boost the production and ensure livelihood security of the people.
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