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2.  Temperature, humidity and light are the important variables influencing growth and development of 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 35 o C in summer, impairs the fruiting of vinifera grapes, particularly, in Thompson Seedless.  Higher night temperature (above 25 o C) during ripening hamper the colour development in coloured grapes. PreviousNextEnd

3.  Cool nights and hot days even though congenial for coloured grapes, pink pigmentation development was found in green grapes if the diurnal differences are more than 20 o C during ripening.  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 variables playing significant roles in vine growth and development. PreviousNextEnd

4.  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.  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. Previous NextEnd

5.  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.  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. Previous NextEnd

6.  The major banana growing areas of the world are geographically situated between the Equator and latitudes 20 o N and 20 o S.  Climatic conditions in these areas are mainly tropical, with comparatively small temperature fluctuation from day to night and from summer to winter.  The banana growing areas of subtropics are situated between 20 o and 30 o North or South of the equator.  The main climatic characteristic in the subtropics are the wide temperature fluctuations between day and night and between summer and winter, the high and the low rainfall which is also poorly distributed. Previous NextEnd

7.  Bananas perform very well under humid tropical conditions but can be cultivated successfully even under humid or semi arid sub-tropical conditions.  The growth and yield of most of the varieties are better at a temperature range of 25-35°C though they can be cultivated at a temperature range of 10-40°C.  A suitable banana climate is a mean temperature of 26.67°C and mean rainfall of 10 cm per month. There should not be more than 3 months of dry season.  Under cooler climates the crop duration is extended. The shooting and bunch development gets affected at temperature less than 10°C. Previous NextEnd

8.  The growth of the banana plant responds quickly, within a matter of an hour or two to changes in air temperature.  All growth ceases as soon as the temperature of the surrounding air falls below 11° C.  As long as the temperature remains 11° C, no growth whatsoever takes place.  As the air temperature rises above 11° C, growth starts and the growth rate increases gradually at first, and then with rising temperatures, more and more rapidly.  The biggest increase in growth rate for every degree that the temperature rise appears to lie between approximately 19° C and 23° C. Previous NextEnd

9.  The daily growth at 23° C is, in fact, about double that at 19° C. With further rise in temperature, the growth continues to increase, but more and more slowly as high levels of temperature are reached.  In the experiments conducted, no falling off or even leveling off of the growth rate was observed. Previous NextEnd

10.  M ango is very well adapted to tropical and subtropical climate. It thrives up to an altitude of 1400 m above mean sea level but fruiting is poor beyond 500 m.  It thrives well from Kanyakumari in Southern India to sub mountainous regions in the North.  The annual mean temperature at which mango thrives best is around 26.7 o. The optimum temperature for mango is 23.9 to 26.7 o C.  The prevailing temperature affects the expression of sex in mango i.e., a close association appears between high temperature and increased percentage of perfect flowers and vice versa.  High temperature by itself is not so injurious to mango, but in combination with low humidity and high winds affects the growth of the trees adversely. Previous NextEnd

11.  Mango thrives in places with good rainfall (75 to 375 cm per annum) and dry season. The distribution of rainfall is more important than quantity of the rainfall.  A dry weather before blossoming is conducive for profuse flowering.  Rain during flowering washes away the pollens, which adversely affects the fruit set, and also encourages greater incidence of mango hoppers, mealy bugs and diseases like powdery mildew and anthracnose that can damage the crop completely.  Cloudy weather with increased humidity in the atmosphere encourages the incidence of pests and diseases and interferes with the activity of pollinating insects, thus adversely affecting fruit set. Previous NextEnd

12.  In areas of excessive rainfall and high humidity, even during the time of fruit maturity, commercial mango growing may not be profitable due to the attack of fruit fly.  If high temperature, rainfall and humidity persist throughout the year, there will not be any distinct phases of vegetative and flowering in the mango tree thus resulting into poor flower production and fruit set.  Temperature, also governs the flowering and ripening of fruits.  In Kanyakumari, some of the varieties flower and fruit twice a year, known as “off season bearing” which is primarily conditioned by the differences in night and day temperatures and humidity.  Strong winds and cyclones during the fruiting season can play havoc as they cause excessive fruit drop. Hot winds during summer have an adverse effect both on fruit and foliage growth. Previous NextEnd