Trait association and path coefficient analysis for seed yield in Niger (Guizotia abyssinica Cass.) across diverse environments

Abstract

The present study assessed 83 germplasm lines of Niger (Guizotia abyssinica Cass.) at the Project Coordinating Unit (Sesame & Niger) within the BSP (Soybean Unit) at JNKVV, Jabalpur (Madhya Pradesh) over four Kharif seasons i.e. 2022 (EI, EII) and 2023 (EIII, EIV) and pooled analysis was conducted to examine the interrelationships between seed yield per plant (SYPP) and associated agronomic traits through correlation and path coefficient analyses. The correlation analysis revealed a strong and significant positive correlation between the number of capitula per plant and seed yield across all environments (r = 0.770-0.840), underscoring its importance in yield enhancement. Other traits, such as the number of primary branches, secondary branches, plant height (PH), and biological yield per plant, also demonstrated strong positive associations, particularly in the early environments (EI and EIII). Conversely, traits like test weight, days to 50% flowering, and days to maturity exhibited weak or environment-dependent relationships with SYPP. Path analysis revealed that biological yield per plant had the highest direct effect on seed yield across environments, with values ranging from 0.494 to 0.846 and a pooled correlation coefficient of r = 0.697. The harvest index also showed significant direct effects (0.444 to 0.596), reinforcing its role in yield enhancement. Additionally, the number of capitula per plant demonstrated moderate to high direct effects (0.360 in EIV and a pooled value of 0.204), confirming its correlation with yield. These findings underscore the critical roles of biological yield, harvest index, and number of capitula per plant as key contributors to seed yield in Niger, suggesting these traits should be prioritized in breeding programs to enhance genetic gains and yield potential.