Discerning the genetic variation of pod wall proportion and pod filling index in cowpea

Cowpea, an important arid legume crop, exhibits wide genetic variation for pod characters. With a view to identifying grain cowpea possessing low pod wall proportion (PWP) and high pod filling index (PFI) with least environmental interaction, fortyone genotypes were field evaluated in three different seasons. Observations on pod length, number of seeds and unfilled locules and mass of pod walls and seeds per pod were recorded. The mass of the seeds supposedly occupying the unfilled locules was worked out, to arrive at corrected PWP that ranged from 11.7% (C 504-1-1) to 31.1% (Harsando) with a mean of 21.1%. PFI was lowest (40.5%) in the cultivar Harsando and highest (101.9%) in the accession EC 394767 with a mean of 75.5%. The additive main effects and multiplicative interactions (AMMI) model identified stable genotypes for PWP and PFI. While the genotype EC 394767 was found promising for most of the pod characters except PWP, C 440 showed the least number of unfilled locules. The genotypes identified with desirable and stable pod characters could be utilized in cowpea breeding for enhancing the grain yield.