Inheritance and combining ability studies of pod physical and biochemical quality traits in vegetable pigeonpea (Cajanus cajan L. Millsp)

Abstract

Pigeonpea (Cajanus cajan L. Millsp) is a popular vegetable crop in the Caribbean, grown for its immature green peas. Although breeding programmes, in the past, have made considerable strides in improving yield in a relatively photoperiod insensitive genetic background, the quality of peas continue to affect consumer acceptance. The mode of inheritance of a number of quality traits (physical and biochemical) known to affect consumer acceptance of pigeon peas was investigated in this study using a 6 × 6 half-diallel mating design and a M × N (5 × 6) mating design analysed using Griffing’s Method II Model I approach and the North Carolina design-II approach, respectively. The results showed that pod length, pod width, seeds per pod, shelling percentage and phenolic content were under the control of additive genetic effects with the non-additive effects generally being either not significant or much smaller compared to the additive genetic effects. Hundred seed weight was controlled by both additive and non-additive effects, while pod biochemical characteristics viz. sugar content, starch content and protein content, were governed by a preponderance of non-additive genetic effects. The strong genetic correlation between pod length, pod width and seed number indicates that these characteristics could be simultaneously improved in breeding programmes. The best general and specific combiners for the various characteristics were identified, and a method of improvement of quality in pigeonpea is discussed.