CLIMATIC ADAPTABILITY AND REQUIREMENTS OF GRAPE

1. CLIMATIC ADAPTABILITY AND REQUIREMENTS OF GRAPE Next End

2. Climate and Soil Temperature, humidity and light are important for grapes. Hot and dry climate is ideal. Areas with high rainfall are not suitable. The climate requirements of vinifera are different from those of labrusca grapes. Mild temperature, not exceeding 350C in summers, impairs the fruiting of vinifera grapes, particularly, in Thompson Seedless Higher night temperatures (above 250C) during ripening hamper the colour development in coloured grapes. Cool nights and hot days even though congenial for coloured grapes, pink pigmentation development in green grapes if the diurnal differences are more than 200C during ripening. (cont)… Next Previous End

3. Grape vines are deciduous under temperate conditions and do not show dormancy under tropical and sub tropical conditions. Basically, it is a sun­ loving plant. Excepting coastal humid regions with high rainfall, climatic conditions varying from temperate to subtropical and tropical are suitable for grape culture. Temperature, light and humidity are the climatic conditions playing significant roles in vine growth and development. High humid conditions result in excessive vegetative growth, in turn affecting yield and quality. Ripening of berries will be affected and incidence of pests and diseases will be more. Vinifera varieties prefer long, warm to hot, dry summers and cool winters. (cont)… Next Previous End

4. They need about 60 days of rest in winter, with an average daily mean temperature below 10°C and some freezing temperatures. • Shoot growth begins in spring. • Bright sunny days help in development of sugar in berries. • Maturity and ripening in grapes are influenced by degree-days - heat unit summation. • Heat units are calculated by multiplying the mean daily temperature over and above 10°C by the number of days. • Certain amount of heat units is to be attained specific to varieties for berry ripening and this requirement varies from 1600 to 3500 degree days. • Distribution of rain is important in grape culture. • Rains at blooming time reduce fruit set and during ripening time result in spoilage of crop. (cont)… Next Previous End

5. Vines tolerate low temperature or frost during dormancy period but during spring season, frost damages sprouting buds. • Humidity is a limiting factor for vinifera grape culture, due to disease susceptibility. • Vinefera varieties cannot tolerate high humidity or rain during harvest. • Internal quality is reduced, fruit cracks when swollen with water, and fungal diseases are far worse. • Thick-skinned, disease tolerant muscadines grow much better in humid climates. • Viticulture is prevalent in semi-arid irrigated regions of North India and Central, Southern and Coastal tropical regions of other parts of country as well. • Vines exhibit dormancy during winter in Northern India and under tropical conditions vines exhibit luxurious continuous vegetative growth. Next Previous End

6. Grape vines have strong root system and grow on a wide variety of soils. • A well-drained sandy loam soil with good water holding capacity and a pH of 6.7-7.5 is the ideal one for best results. • Vines tolerate moderate salt concentrations but presence of excess salts, especially sodium and free calcium is detrimental for growth. • Electrical conductivity of soil extract should not be more than 4 mmhos/ cm and exchangeable sodium content should be less than 15% for successful viticulture. • Free calcium concentration value exceeding 12% results in severe iron deficiency to vines. • High proline content in leaves is attributed to survival of vine under low to moderate salt stress conditions. • Exogenous application of proline or cytokinins in initial stages of growth reduces damage by salt stress. Next Previous End (cont)…

7. A number of rootstocks are identified to impart salt resistance to commercial grape varieties. • They include Degrasset, Dogridge, Salt Creek, ARG No.1 and Vitis riparia. Degrasset and Dogridge are tolerant up to 6.8 and 6.5 dSm-1 under sodium salinity respectively. • Soil moisture content has influence on yield and quality of grapes. • Moisture stress during first three weeks after anthesis has direct adverse effect on berry set and size, resulting in poor yield. • Delayed maturity, poor colour development and reduced berry size are results of soil moisture stress during berry development period. • Selective use of rootstocks contributes to successful cultivation in moisture stress soils. • Dogridge is a suitable rootstock for such conditions. Next Previous End

8. PRESENT STATUS OF GRAPE CULTIVATION IN THE COUNTRY Grape is grown under a variety of soil and climatic conditions in three distinct agro-climatic zones, namely, sub-tropical, hot tropical and mild tropical climatic regions in India. Sub-tropical Region: This region covers the northwestern plains corresponding to 28° and 32° N latitude including Delhi; Meerut district of Uttar Pradesh; Hissar and Jind districts of Haryana; and Bhatinda, Ferozpur, Gurdaspur and Ludhiana districts of Punjab. Cont… Next Previous End

9. Vines undergo dormancy and bud break starts in the first week of March while the rains arrive in the first week of June, and therefore, only 90-95 days are available from the initiation of growth to harvest. Consequently, ‘Perlette’ is the only early ripening variety grown in this region. Rain damage is a problem with Thompson Seedless in this region. Single pruning and a single harvest is the accepted practice here. Hot Tropical Region: This region covers Nashik, Sangli, Solapur, Pune, Satara, Latur and Osmanabad districts of Maharashtra; Hyderabad, Ranga Reddy, Mahbubnagar, Anantapur and Medak districts of Andhra Pradesh; and Bijapur, Bagalkot, Belgaum, Gulberga districts of northern Karnataka lying between 15° and 20° N latitude. This is the major viticulture region accounting for 70 percent of the area under grapes in the country. Vines do not undergo dormancy and double pruning and a single harvest is the general practice in this region. Cont… Next Previous End

10. Maximum and minimum temperature is 42°C and 8°C, respectively. The major problems in this region are soil and water salinity and drought. Berry growth is impaired and in certain locations pink blush sometimes develops on green berries due to temperatures that drop to a low of 8°C. Thompson Seedless and its clones (Tas-A-Ganesh, Sonaka), Anab-e-Shahi, Sharad Seedless and Flame Seedless are the varieties grown in this region. Mild Tropical Region: An area covered by 10° and 15° N latitude including Bangalore and Kolar districts of Karnataka; Chittoor district of Andhra Pradesh and Coimbatore; and Madurai and Theni districts of Tamil Nadu fall in this region. Maximum temperatures in a year seldom exceed 36°C, while the minimum is about 12°C.Principal varieties are Bangalore Blue (Syn. Isabella), Anab-e-Shahi, Gulabi (Syn. Muscat Hamburg), and Bhokri. Thompson Seedless is grown only with limited success. Except for Thompson Seedless, two crops are harvested in a year. \Vinifera varieties susceptible to mildew suffer losses due to unprecedented rains during flowering and fruit set in both hot and mild tropical regions. Next Previous End

11. Assessment: • 1. Higher night temperatures required for coloured grapes (True/ False) • 2.Bright sunny days help in development of _________ in berries. • a). Sugar b). Acid c). Alkaloids • _____________ content in leaves is attributed to survival of vine under low to moderate salt stress conditions. (High proline). • 4. _____________ is a suitable rootstock for moisture stress soils. • (Dogridge) • 5. pH range for grapes cultivation __________ • a). 6.7-7.5 b). 5.0- 6.0 c). 8.0-9.0 Next Previous End

12. References: • Sawant, S.D. and I.S. Sawant. 1999. Effect of essential oils in controlling post - harvest pathogens. Annual Report (1998-99) of National Research Centre for Grapes. pp. 35. • Somkuwar, R.G., S.D. Ramteke and S.D. Shikhamany. 1999. Effect of growth regulators on productivity and quality of grapes. Annual report (1998-99) of National Research Centre for Grapes, Pune. pp. 21. • Singh, P.V. 1999. Note on effect of thiourea on breaking of dormancy of grapevine buds. India, J. Hort.56(4): 312 – 3. • Pramanick, P.K., V.P. Sharma, P.C. Jindal, S.K. Saxena and S.K. Singh. 2001. Effect of different bud-breaking chemicals for hastening maturity in Pusa Seedless grape (Vits vinifera L.). Indian J. Hort.,58(3): 232 - 238. Previous