Genetic variability, trait association and MGIDI - driven ideotype selection for yield and gum content in guar (Cyamopsis tetragonoloba L. Taub.)

Abstract

Cluster bean (Cyamopsis tetragonoloba L. Taub.) has transitioned from a vegetable crop into a high-value industrial source of galactomannan gum. Twenty-two elite gum type genotypes along with check variety MDU 1 were evaluated for seven agronomic and biochemical traits in randomized block design during Rabi 2023. Analysis of variance revealed highly significant genotypic differences (P < 0.01) for all traits. High heritability and genetic advance for single plant yield, pods per plant, and plant height confirmed additive gene action. Path analysis showed single plant yield was driven directly by pods per plant, while gum content showed negligible direct effect, indicating cumulative yield as the target trait for gum yield per unit area. Principal component analysis captured 75.25 % of total variation, discriminating pod yield from seed quality traits. Through MGIDI at 15 % selection intensity, RGR 18-1, RGR 20-15 and RGC 197 emerged as superior ideotypes, showing significant standard superiority (+44.2 % to +86.4 %) over MDU 1. By developing these guar genotypes into superior gum-type varieties, may replace the cultivation of existing vegetable-type cluster bean for gum purpose. Further, the introduction of new crop to southern districts of Tamil Nadu in the rainfed situation will ultimately help to improve the livelihood and standard of living of the farming community.