Correlation and path coefficient analysis for yield and its component characters in rice bean [Vigna umbellata (Thunb.) Ohwi and Ohashi] landraces of Nagaland in different environments

The analysis of variance revealed significant differences among genotypes for all the characters studied, indicating high degree of variability in the material. The magnitude of genotypic correlation tended to be higher than phenotypic correlation for most of the characters. This suggested a strong genetic association between these traits. Correlation studies indicated that yield/plant was significantly positively associated with pod length, number of seeds per pod, 100 seed weight at both phenotypic and genotypic level indicating that selection through these traits would be effective. Negative significant correlation was recorded for 50% flowering with seed yield per plant. Genotypic Path analysis revealed that the maximum positive direct effect on seed yield has been shown by number of primary branches, number of pods per plant, plant height followed by 80% maturity and 100 seed weight. Primary branches and plant height exhibited positive direct effect and also showed significant positive correlation with yield at genotypic level indicating a true relationship between the characters. This suggests that while selection emphasis should be given on primary branches and plant height in increasing seed yield. The residual effect estimated was 0.2488 indicating that the characters under study are not sufficient to account for variability and there might be a few more characters other than those studied in the present investigation and thus inclusion of some more characters is required. Inclusion of some characters like leaf area index, chlorophyll content etc. could be considered important in order to derive a much clear picture of casual relationship. The present study suggested that while selection emphasis should be given on primary branches and plant height for improvement in seed yield.