Implications of Changing Climate on Productivity of Temperate Fruit Crops with Special Reference to Apple

Abstract

Winter chill is essential for most of the plants that fall dormant in the winter in order to avoid frost damage and do not resume growth until a certain amount of winter chill has accumulated for fulfilling their chilling requirement. Climate change is likely to affect chilling requirement of temperate fruit crops significantly and therefore, the opportunity to meet this requirement will be reduced as the climate becomes warmer. Increase in average global temperature would move the existing plant species and varieties to new latitudinal belts with favourable climates. It is, therefore, possible that crops that are used to be productive in one area may no longer be so or the other way round. The resultant of these climate changes are clearly apparent in the shifting of apple cultivation from lower elevations to higher altitudes in India. Insufficient chilling greatly influences flower initiation and fruit colouration along with deterioration in fruit texture and taste. Further, the lack of proper chilling is also posing serious problems like scab disease, premature leaf fall and infestation of red spider mite in apple. High temperature and moisture stress is increasing sunburn and cracking in apple, apricots and cherries in the higher altitudes. Insufficient chilling reduces pollination, fruit set and ultimately the yield in walnuts, pistachio and peaches. Advanced flowering has been found in olive, apple and pear. Reduced flower size and pedicel lengths were observed in cherry due to less chilling. The studies regarding impact of climate change on fruit crops is meagre primarily due to lack of data, appropriate modeling and government policies. Development of low chill cultivars with greater tolerance to stresses, use of GIS to match varieties with the projected suitable production locations, development of suitable dormancy and chilling models, altering orchard microclimate and use of rest breaking chemicals are the viable approaches that can be adopted to yield reliable results on regional scale.