Altitudinal Air Temperature Variations and its Relationship with Phenological Stages of Apple Fruit Crop in North West Himalayan Region
The present study was undertaken to assess the effect of weather variations on phenological cycle of apple fruit crop, different altitudinal gradients in respective growing pockets were selected. The altitudinal wise weather variations were utilized as natural laboratory to assess the effect of changing climate in the selected fruit crops. The field experiments were laid in Randomized Block Design (factorial) where cultivars/fruit species and altitudinal gradients were considered as treatments and replicated three times. Three altitudinal gradients (1000-1200, 12000-1400, 1400-1600 m above mean sea level) and five cultivars namely, Scarlet Spur, Royal Delicious, Red Delicious, Vance Delicious and Red Chief in Kullu and Shimla district of apple growing regions were selected. The maximum and minimum temperature in respective sites was recorded during the growing seasons of crops and data was analyzed for its altitudinal variations. The observations of phenophasic developmental stages were compared and correlated with respect to change in weather between altitudinal gradients and growing seasons. It was concluded that all phenological stages have started to be affected by increase in average air temperature and Growing Degree Days (GDD) for the phenophasic duration. Warming in the spring season by 2-4ºC at 100-1200 m caused an advancement of the phenophases by 7-13 days in apple crop. All phenophases were significant and negatively correlated to the average air temperature from January to April and GDD thereby signifying that the processes involved in bud development, i.e. cell division and growth are temperature dependent and are enhanced by rise in temperature. Thus, indicating that productivity will be affected by changing weather conditions in years to come. The lower altitude of 1000-1200 m above mean sea level of apple growing regions has now become vulnerable for its production due to rise in temperature.