Per se performance of genotypes
In the study, all 20 dolichos bean genotypes exhibited significant differences in pod yield (Table 2). The highest green pod yield per plant in
kharif was from Ankur Gold (487.50 g), while Acc.7 had the lowest (89.59 g). During
rabi, yields ranged from 53.84 to 452.11 g. Pooled data revealed Ankur Gold had the highest yield (469.80 g) and Acc. 6 had the lowest (87.49 g). These results align with
Chattopadhyay and Dutta (2010).
Variability parameters
A wide range of variability was observed among genotypes, with PCV exceeding GCV for all characters, indicating some environmental interaction (Table 3). The narrow gap between PCV and GCV suggests low environmental influence. Plant height showed a higher proportion of genotypic variance and minimal environmental impact, with high heritability and GA supporting its reliability for selection. In contrast, the studies by
Basavarajappa and Byre Gowda (2004) and
Golani et al., (2007) showed low GCV and PCV, moderate heritability with low genetic advance for plant height in dolichos bean. In contrast, the number of primary branches per plant had low genotypic variance and moderate GCV and PCV, indicating limited environmental impact, with high heritability and low GA aligning with
Borah and Shadeque (1992). Minimal differences between phenotypic and genotypic variance for days to first flowering, indicated by a narrow gap between PCV and GCV, suggest low environmental influence, similar to
Nath et al., (2009) in cowpea. High heritability coupled with high genetic advance as per cent of mean observed for 50% flowering character in
kharif. During
rabi, it showed low PCV and GCV with high heritability estimates coupled with moderate genetic advance. Days to 50% flowering showed high PCV and GCV, consistent with
(Pandita et al., 1980; Kabir and Sen, 1987;
Basavarajappa and Gowda, 2004 and
Chattopadhyay and Dutta, 2010). Days to first harvesting were recorded high phenotypic and genotypic coefficients of variability with high heritability estimates coupled with high genetic advance in both
kharif and
rabi aligning with
Rathi and Dhaka (2007) in pea. The higher PCV compared to GCV indicates that environmental factors influence the phenotypic expression of traits. However, a smaller difference between GCV and PCV suggests a minimal environmental impact, emphasizing the stronger role of genetic factors in trait expression. High heritability estimates indicate that phenotypic values are reliable and can be effectively used for trait selection.
High PCV and GCV values for the number of racemes per plant, along with high heritability and genetic gain, indicate additive gene effects, consistent with
Uddin and Newaz (1997) and
Ali et al., (2005). However, Basavarajappa and Byre Gowda (2004) reported moderate heritability coupled with low genetic advance for this trait in lablab. Raceme length showed moderate PCV and GCV with a narrow gap, suggesting suitability for selection, as noted by
Pandita et al., (1980). This trait showed high heritability with moderately low genetic gain depicting suitability for the selection in breeding programme. The number of racemes per plant and flower buds per raceme exhibited high PCV, GCV, heritability and GA, supporting findings by
Uddin and Newaz (1997). However,
Basavarajappa and Byre Gowda (2004) reported moderate heritability coupled with low genetic advance for this trait in lablab.
High phenotypic and genotypic variance, along with elevated PCV and GCV, were recorded for the number of pods per plant, indicating strong selection potential
(Pandita et al., 1980; Borah and Shadeque, 1992). Very high heritability and genetic gain support effective selection (
Joshi, 1971;
Arunachala, 1979;
Uddin and Newaz, 1997). High heritability with high genetic advance indicated these characters were controlled due to considerable additive gene effects (
Panse, 1957). Pod length and width showed high PCV and GCV with high heritability but low GA (
Borah and Shadeque, 1992;
Ali et al., 2005). Hundred green pod weight also had high PCV, GCV and heritability, with moderate GA, suggesting some selection limitations (
Basavarajappa and Gowda, 2004;
Chattopadhyay and Dutta, 2010). Green pod yield per plant and per hectare exhibited high GCV, PCV, heritability and GA, indicating minimal environmental impact and effective selection due to additive gene action. Phenotypic Coefficient of Variation values were usually higher than the Genotypic Coefficient of Variation values indicating the influence of the environment over genotype and phenotypic selection for this trait would be less effective
(Jyothireddy et al., 2018).
Protein content showed low non-genetic influence with moderate GCV and PCV, high heritability and low GA. Carbohydrate content followed similar patterns, while crude fibre content had high variance and heritability, suggesting effective selection with minimal environmental impact. Moderate heritability was exhibited for carbohydrate content coupled with low genetic advance as per cent of mean. These findings supported by
Sarma et al., (2010).
Correlation of green pod yield with quantitative traits
The correlation coefficients for 15 traits studied during the
kharif and
rabi seasons are shown in Table 4 and 5. The analysis revealed a positive and highly significant association between green pod yield per plant and traits such as raceme length, number of flowers per raceme, number of nodes per raceme, number of pods per plant, pod length, pod width, hundred green pod weight and number of seeds per pod in both seasons. The increased green pod yield observed in
kharif season sowing could be attributed to the production of higher amounts of photosynthates. This is likely due to the optimal temperature and greater sunshine hours during the vegetative phase, which is favourable for Dolichos bean, a photosensitive crop
(Venkatesan et al., 2024). These traits are key contributors to yield in lablab bean, aligning with the findings of (
Pandey and Dubey, 1972 and
Golani et al., 2007).
During
kharif, days to first flowering and 50% flowering were positively correlated with raceme length and number of flowers per raceme, but negatively with number of pods per plant. Raceme length positively correlated with multiple traits, including green pod yield, but negatively with days to first harvesting. Number of flower buds per raceme showed positive correlations with raceme length and nodes but negative correlations with days to first harvesting. In
rabi, days to first flowering positively correlated with raceme length and number of flowers per raceme but negatively with other traits. Raceme length correlated positively with nodes, number of pods per plant and green pod yield. Number of flower buds per raceme had mixed correlations, while number of pods per plant was positively associated with several traits but negatively with plant height and flowering days. Strong correlations between number of pods per plant and pod length were noted in both seasons.
The local genotypes with longer duration produced higher green pod yield. This may be due to more vegetative growth and larger duration of flowering and reproductive growth leading to more number of racemes, flowers and pods. In Dolichos bean, early-maturing types accumulate less biomass
(Mass et al., 2003). Positive associations between days to 50% flowering, number of green pods per plant and number of inflorescences with yield have been noted (
Joshi, 1971;
Dahiya et al., 1991; Basavarajappa and Gowda, 2004;
Ali et al., 2005). However, excessive primary branches negatively impact green pod yield due to increased vegetative growth. Thus, selecting genotypes with fewer primary branches but more racemes and pods is recommended. Days to 50% flowering positively correlates with racemes per plant and pods per plant, indicating that longer duration bush types yield better (
Arunachala, 1979;
Dahiya et al., 1991; Basavarajappa and Gowda, 2004;
Ali et al., 2005; Chattopadhyay and Dutta, 2010). Primary branches, however, have no significant positive associations with yield traits and negatively affect green pod yield.
The significant positive association of the number of racemes per plant with green pod yield, number of pods per plant and days to 50% flowering (
Uddin and Newaz, 1997;
Basavarajappa and Gowda, 2004;
Ali et al., 2005; Upadhyay and Mehta, 2010) suggests that selecting plants with more racemes can boost yield. It is evident from the results that the selection for longer duration accessions among bush types results in higher yields. It is mainly because, days to 50 per cent flowering is positively associated with several yield components which are in turn positively associated with yield. The primary branches did not show significant positive association with any of the traits studied. However, it has significant negative association with important yield components. Therefore, it has significant negative association with green pod yield. Raceme length was significantly associated only with the number of flower buds and nodes per raceme, not pod yield
(Baswana et al., 1980; Pandita et al., 1980). Number of nodes per raceme positively correlated with flower buds and raceme length. The number of flower buds per raceme was strongly correlated with green pod yield, number of racemes per plant, number of pods per plant, raceme length and number of nodes (
Uddin and Newaz, 1997). Therefore, selecting genotypes with more racemes and flower buds is recommended. Additionally, the number of pods per plant had a significant positive correlation with days to 50% flowering and number of flower buds (
Joshi, 1971;
Baswana et al., 1980; Uddin and Newaz, 1997;
Basavarajappa and Gowda, 2004;
Chattopadhyay and Dutta, 2010). Hundred green pod weight was positively correlated with both pod width and length.
