System-specific Determinants of Seed Yield in Common Bean: Insights from Conventional and Organic Path Analyses

This study aimed to determine the direct and indirect effects of various agronomic traits on seed yield in common bean under contrasting conventional and organic cultivation systems using path coefficient analysis. Field experiments were conducted in 2021 at the research and trial area of Kahramanmaras Sutcu Imam University.

Common bean genotypes were grown under conventional and organic management systems using, a randomized complete block design (RCBD) with three replications. Seed yield (SY) and ten related traits-emergence time (ET), plant height (PH), stem diameter (SD), first pod height (FPH), pod length (PL), pod width (PW), pods per plant (PPP), seeds per pod (SPP), 100-seed weight (HSW) and biomass yield (BY)-were measured.

Correlation coefficients were calculated and path analysis was performed separately for each system to partition correlations into direct and indirect effects on seed yield. Correlation analysis revealed differing significant associations between traits under the two systems. Path analysis identified distinct pathways influencing seed yield. In the conventional system, Emergence Time (ET) exhibited the largest positive direct effect (P=1.143) on seed yield, indicating the importance of rapid establishment. However, Pods per Plant (PPP) showed a strong negative direct effect (P= -1.359), while 100-Seed weight (HSW) also had a notable negative direct effect (P=-0.337). In contrast, under the organic system, Pods per Plant (PPP) exerted the strongest positive direct effect (P=0.567) on seed yield, followed by biomass yield (BY) (P=0.428) and emergence time (ET) (P=0.473). First pod height (FPH) showed the most substantial negative direct effect (P=-0.487) in the organic system. The influence of PPP on seed yield was notably contrasting, shifting from strongly negative under conventional management to strongly positive under organic conditions. The study highlights that the mechanisms determining seed yield in common bean differ significantly between conventional and organic systems. While rapid emergence was paramount in the conventional system, maximizing pods per plant was the key driver under organic conditions, alongside biomass accumulation. These system-specific yield determination pathways suggest that breeding programs and agronomic management strategies should be tailored to the target cultivation environment (conventional or organic) to optimize common bean seed yield.