Study of correlation, path coefficient and linkage of flower colour and hairiness with yield controlling quantitative traits in segregating population of cluster bean

Abstract

Cluster bean or guar [Cyamopsis tetragonoloba (L.) Taub] is a multipurpose legume crop of the arid regions of the Indian subcontinent. This industrially important crop is primarily used as a food and feed; and cultivated mainly for its galactomannan enriched seed. There is a lack of information on the genetics of important traits including flower colour and pubescence/hairiness and its correlation with the quantitative trait like yield and under-standing the co-segregation of these traits may be helpful in yield improvement. Therefore, the current study was performed using 235 F2 segregating lines of guar generated from two diverse parents differing in many traits. Phenotyping of population was carried out for 13 agronomic traits, flower colour and hairiness. Results indicated that both parents of the population were diverse for both qualitative and quantitative traits except pods per plant. The heritability of various quantitative traits ranged from 32.68 % (seeds per pod) to 97.73 % (pods per plant). A significant positive correlation (0.40 * * ) between days to maturity and plant height was observed. Yield demonstrated significant positive correlations with all traits except days to flowering. The path coefficient analysis showed that merely two characters, namely pods per plant (0.87) and pods per clusters (0.19) exerted a significant positive direct effect on seed yield per plant. The scrutiny of principal components revealed that the first four components described a cumulative variability of 73.4 %. The scattering of F2 plants in bi-plot confirmed our earlier observations that both parents were genetically dissimilar and quite diverse for the traits under study. A significant linkage of flower colour with pods per cluster, cluster on the main stem, pod length and seed per pod was observed. Likewise, hairiness displayed linkage with leaf area, plant height and days to flowering. The R2 value ranged from 1.7 % (seed per pod) to 3.8 % (days to flowering). The result suggested that subtle influence of hairiness and violet flower on yield and yield attributing traits have favoured their se-lection in the released varieties in the past. The future breeding strategies may emphasize combining pod length and leaf area with pods per plant in a smooth (hairless) genotype