Detection and Estimation of Genetic and Environmental Parameters through Model Fitting of Ten Bulb Yield Contributing Traits in Onion

Two onion varieties P2 and P3 and their products F1 and F2 were evaluated in summer and winter seasons for this investigation. Estimated mean values of different traits showed variations from generation to generation in each season. Values of six-parameters viz., m ̂, [d], [h], e1, gd1, gh1 for all the characters were significant except gd1 for a number of leaves, leaf length and bulb volume and also [d] for leaf length and neck length. Overall means ‘m ̂’ had the highest magnitude than [d], [h], e1, gd1 and gh1 for all the characters. Environmental parameter ‘e1’ also exhibited higher magnitude than [d], gd1 and gh1. As the values of [d] and gd1 were found to be non-significant, 4-parameter model was considered for leaf length only. Five-parameter model was considered for neck length, number of leaves and bulb volume and for rest of the traits 6-parameter model was considered. The goodness of fit test showed that 4, 5 and 6-parameter models were not adequate except bulb length and neck length. Therefore, for the development of these two traits in consideration of genotype × environment (G × E) interaction proper design and analysis needs to be done. Due to significant 2 values for other characters the situations becoming more complex as G × E interaction model is inadequate, so for their exact genetic explanation G × E model needs to be extended to include linkage and non-allelic parameters.