CALCIUM AS A SUPPLEMENTARY NUTRIENT FOR POTATOES GROWN UNDER HEAT STRESS IN SUB-TROPICS

Abstract

A study was conducted for 2 years during early crop (mid-September to mid-November) in 2001 and 2002 at Modipuram to evaluate the effect of supplemental calcium (Ca) on tuber size, tuber yield and calcium accumulation pattern in different plant parts in a commercial potato cultivar Kufri Ashoka and heat tolerant cultivar Kufri Surya. Soil application of calcium resulted in greater Ca content of the root, leaf and tuber in both the varieties, however, the effect was prominent in the leaf and tuber of Kufri Ashoka. Marketable and total yield was higher in Kufri Surya (12.6 and 13.3 t ha-1, respectively) as compared to Kufri Ashoka (8.3 and 10.6 t ha-1) with Ca treatment. The number of non-marketable tubers declined with calcium application in both the varieties. Owing to higher yield potential, higher tuber dry matter (%) and higher basal tuber-Ca content, the calcium harvest was more in Kufri Surya (14.63 kg ha-1) than Kufri Ashoka (11.56 kg ha-1). The results suggest that supplemental Ca application in Ca-responsive cultivars result in increased tuber yield, size and Ca content in short duration, early season potato crop in the sub-tropics.