Varietal reaction to nutrient and moisture stress in cashew (Aracardium occidentale L.)

Abstract

Five experiments were conducted at Cashew Research Station, Kerala Agricultural University, Madakkathara during 1996-98 to identify drought tolerant varieties of cashew, to study the response of cashew to applied N at different levels of drip irrigation and to assess the tolerance of cashew varieties to N, P and K deficiency in soil. The abstract of the experiments is given below. Exp. I. Varietal variation in drought tolerance The varieties H-1591, M-26/2, V-5 and M-44/3 are drought tolerant and K-22-1 is drought sensitive. Exp. II. Response of cashew to applied N at different levels of irrigation (drip) N application @ 1500 g per tree per year along with irrigation @ 80 litres per tree per day (through drip) is essential in the state of Kerala for obtaining best results from cashew. Exp . lIl. Tolerance of cashew varieties to N dificient soils The varieties H-1591 and M-2612 are efficient for N deficient soils. The N use efficiency of cashew seedlings grown under pot culture was 24.7 per cent. Exp. IV. Tolerance of cashew varieties to P deficient soils H-1591 is an efficient variety for P deficient soils. The P use efficiency of cashew seedlings grown under pot culture was 8.02 per cent.

Exp. V. Tolerance of cashew varieties to K deficient soils The varieties H-1591, M-26/2 and H-1598 are efficient for K deficient soils. The K use efficiency of cashew seedlings grown under pot culture was 12.17 per cent. N, P and K absorption of a six month old cashew seedling was in the order of 151.95 mg N, 21.58 mg P and 49.48 mg K per plant with a nutrient absorption ratio of7: 1:2 (approximately). The variety H-1591 is a super variety capable of tolerating not only drought but also N, P and K deficient soils. The variety M-26/2 is capable of tolerating drought as well as N and K deficiency in soils. The variety K-22-1 is drought sensitive.