20. Potassium-induced resistance of cotton against boll-rottening, thrips and mealybugs
Abstract
Understanding the role of potassium (K) to increase crop stress tolerance is very important, and hence, explored in cotton (Gossypium hirsutum L.). The field experiment was conducted on a non-saline, alkaline, poorly fertile, K-deficient, sandy clay loam soil, following randomized complete block split-plot design, repeated thrice. Eight cotton genotypes, Sindh-1, Hari Dost, NIAB-78, CRIS-134, CRIS-142, CRIS-121, Sadori and Chandi-95 received two K doses, i.e. 0 (deficient-K) and 72 (adequate-K) kg K2O ha-1. Adequate-K increased sympodia (40%), bolls (36%), stem-diameter (23%), seed-cotton yield (37%) and K concentration (109%), while decreased boll-rottening (61%), thrips (77%) and mealybugs (88%). Maximum increase in sympodia was observed for NIAB-78 (79%) while minimum for Chandi-95 (13%). Maximum increase in bolls was recorded for NIAB-78 (67%) while minimum for Chandi-95 (17%). Maximum increase in stem-diameter was noted for NIAB-78 (69%) while minimum for Chandi-95 (4%). Maximum increase yield of seed cotton was observed for NIAB-78 (73%), while minimum for Chandi-95 (15%). K concentration was found highest for NIAB-78 (164%) while minimum for Chandi-95 (52%). Maximum decrease in boll-rottening was observed in case of CRIS-142 (79%) while minimum decrease was noted in case of Chandi-95 (17%). Maximum decrease in thrips was observed for Chandi-95 (81%), while minimum decrease for Hari-Dost (72%). Mealybugs were 100% less at adequate-K, while CRIS-121 was completely safe. In crux, adequate-K increased growth and yield of cotton genotypes by enhancing their stress tolerance. NIAB-78 was the most K-deficiency cotton genotype while Chandi-95 was the most tolerant, with highest and lowest response to K-nutrition, respectively.
Keywords: Boll-rottening; Cotton; Cotton yield; CRIS-121, Mealybug; NIAB-78, Potassium; Thrips
