Study of Genetic Architecture for Yield and Associated Traits in Cowpea [Vigna unguiculata (L.) Walp]

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This experiment was conducted to study the combining ability, heterosis, and inbreeding depression in ten genetically diverse parents of cowpea in two environment viz., irrigated and rainfed conditions at Rajasthan Agricultural Research Institute (SKNAU, Jobner), Durgapura, Jaipur and the parents were crossed in diallel mating design (excluding reciprocals) in Kharif – 2019 and their F1 seeds were advanced in Summer – 2020. The evaluation trial was conducted in Kharif – 2020 in which ten parents along with their 45 F1 and 45 F2 progenies were grown in a randomized block design with three replications. The observations were recorded for different yield attributing traits and protein content. The objective of this study was to identify promising parents and cross combinations for yield under rainfed condition. Major objective of this study was to identify promising parents and cross combinations for yield under rainfed conditions. The present study reveals the existence of sufficient genetic variability for all the studied characters under both the environments. Highly significant GCA and SCA for all the studied characters in both the generations suggested the importance of both additive and non additive gene action. The GCA/SCA variance ratio (predictability ratio) clearly indicated the preponderance of non-additive gene action. An overall assessment showed that the parent Ajmer sel. and IC-2918 appeared as good general combiners and the cross Ajmer sel. x IC 2918 and CPD-119 x IC-8966 appeared as good cross combinations for seed yield per plant along with its component traits in both the environments. Analysis of the genetic components of variance showed that both additive (D) and non-additive components (H1 and H2) were significant for all the studied characters, indicating the involvement of these genetic components in the expression of the traits.The results of graphical analysis showed partial and over dominance for different characters in irrigated and rainfed conditions. The dispersed array point showed the presence of satisfactory diversity among the parents. An overall assessment based on the per se performance, SCA effects, heterosis and heterobeltiosis revealed that the cross IC-8966 x CAZC-10 in both the environments and Ajmer sel. x IC-2918 and CPD 119 x IC-8966 E1 environment were emerged as good specific cross combinations for seed yield per plant and its associated traits. Therefore, these crosses may be considered suitable under particular environment and may be utilized further in specific breeding programmes. An overall assessment of the result of this study suggested that restricted recurrent selection, diallel selective mating and bi-parental mating or multiple crossing may be used as an effective and alternative approaches for the development of superior genotypes and appreciable improvement of cowpea in forthcoming years