DefinePK

Abstract

Heat stress in a major obstacle in cucumberproduction in the Punjab province of Pakistan. To savecucumber production from heat stress, a study wasdesigned to evaluate chitosan on cucumber genotypes foryield enhancement under three sowing dates. Fourcucumber genotypes, two tolerant (L3466 and Desicucumber) and two susceptible (Suyo Long and Poinsett),were screened in a previous experiment under fieldconditions during 2016. The 1st sowing date was 15thMarch, followed by 1st April, and 15th April, respectivelywith four replications. Chitosan level (200 ppm) wasapplied as foliar spray at 30 days post-sow and thenapplied two times after a week interval. During presentresearch, the highest summer temperature was 47.5 °C recorded in May, 48°C in June, and 46.1°C in July. Chitosanimproved the enzymatic antioxidants and osmolytes inenhancing the ability of cucumber to tolerate heat stress.Enhancement in biochemical characteristics (Superoxidedismutase, peroxidase, catalase, and protein content) wereobserved in chitosan treated plants as compared with nontreated plants. It was revealed that yield per plant was highestin L3466 (2.12 kg) and Desi-cucumber (2.10 kg) with chitosanapplication on the 1st sowing date, while yield per plant wasreduced in Suyo Long (0.31 kg) and Poinsett (0.29 kg) on thethird sowing date with chitosan application. However, in 3rdsowing date Suyo Long and Poinsett could not survive at thefruiting stage without the chitosan application. L3466 andDesi-cucumber could be a benefit to farmers with chitosanapplication and breeders for further studies for heat stresstolerance. © 2020 Department of Agricultural Sciences, AIOU