Studies on genotype – environmental interaction in onion

Abstract

Fifteen onion genotypes comprising nine varieties and six elite genotypes were tested under twelve environments generated by the manipulation of nutrition and different sowing seasons. Nineteen characters which involved yield and yield components were studied for stability. The genotypes and environments differed significantly for all the nineteen characters, where as genotype environment interaction was significant for most of the characters except fresh weight of bulb per plant, number of leaves per plant, firmness of bulb, undersized bulb percentage, TSS percent and neck thickness. These characters remained unaffected with the change in environment and can be grouped as most stable characters. On the basic of stability statistics, mean (μi), regression coefficient (bi), deviation from regression (S2 di), UD-103 was identified as a stable genotype for estimated bulb yield, total bulb yield, marketable bulb yield per plot, split bulb percentage, bolting percentage & polar bulb diameter. Arka Niketan was stable for estimated bulb yield, total bulb yield per plot, bolting percentage, split bulb percentage, marketable & unmarketable bulb yield per plot, per cent dry matter, rotten bulb percentage, single centered bulb percentage & equatorial bulb diameter. Among other varieties IHR-396 was stable for 12 characters & N-2-4-1 was stable for 10 characters including bulb yield. These four genotypes were well adapted to all the environments with above average estimated bulb yield.