Identification of photo insensitive genotypes(s) of winged bean (Psophocarpus tetragonolobus (L.) DC.)

Abstract

The present investigation entitled “Identification of photoinsensitive genotype(s) of winged bean (Psophocarpus tetragonolobus (L.) DC.)” was conducted at the Department of Olericulture, College of Agriculture, Vellayani, during 2013-2014. The study envisaged identification of photo insensitive, high yielding and year round fruiting genotype(s) of winged bean suitable for cultivation in Kerala. Twenty one genotypes of winged bean were collected from different parts of Kerala, state agricultural universities and available germplasm of the Department of Olericulture, College of Agriculture, Vellayani were grown in the field in RBD with three replications. Analysis of variance showed significant difference between the genotypes for almost all the characters studied. Among the genotypes, PT 21 recorded earliness for flowering, flowering commences in June (75 DAS) and had highest yield (2703.33 g) and pods per plant (154.49). This is followed by PT 14 and PT 19. Also the genotypes PT 21, PT 1 and PT 4 showed prolonged harvest up to February, irrespective of photoperiod and temperature. The genotypes PT 18 and PT 7 showed typical short day nature i.e., the flowering was recorded in October. High phenotypic and genotypic coefficients of variation were observed for most of the yield contributing characters. High heritability coupled with high genetic advance was observed for characters like primary branches per plant, days to first flowering, days to 50 per cent flowering, days to first harvest and yield per plot, pod weight, seeds per pod and 100 seed weight. The highest phenotypic and genotypic correlation with yield was observed for pods per plant. The path analysis revealed that pods per plant exhibited the highest positive direct effect on pod yield followed by pod length and pod girth. The twenty one genotypes were grouped in to five clusters based on Mahalanobis D2 analysis. Cluster III was the largest with six genotypes followed by cluster I and II with five genotypes each. Cluster IV had only one genotype and cluster V with four genotypes. The intercluster distance was maximum between cluster II and cluster V where as it was minimum between the cluster I and cluster III. The selection indices were worked out for twenty one genotypes based on yield and yield attributing characters. Genotype PT 21 (Nemom collection) was ranked first followed by PT 6 (local collection, Munnar), PT 1 (Parassala collection), PT 4 (Anchal collection) and PT 7 (local collection, Palakkad). Genotypes PT 21, PT 1, and PT 4 showed photoinsensitivity i.e., flowering and fruiting irrespective of photoperiod and had long fruiting period. On the basis of the present study PT 21, PT 1 and PT 4 were identified as the high yielding, photoinsensitive genotypes suitable for year round cultivation and can be utilized for further crop improvement programmes.