The character association and path coefficient analysis studies were carried out for 18 yield and morpho-physiological traits in 40 foxtail millet (Setaria italica (L.) P. Beauv.) germplasm accessions. The phenotypic and genotypic correlation analyses revealed strong positive associations of grain yield per plant with straw yield (rp=0.848**, rg=0.900**), chlorophyll fluorescence (rp=0.606**, rg=0.878**), SPAD chlorophyll meter reading (rp=0.569**, rg=0.735**), number of productive tillers (rp=0.594**, rg=0.560**) and harvest index (rp=0.566**, rg=0.517**) among the traits under study and indicating their potential as selection criteria for yield accompanied with photosynthetic efficiency. Genotypic correlations were generally higher than phenotypic, suggesting strong intrinsic genetic relationships despite environmental influences. Path coefficient analysis showed straw yield (P=0.7935, G=0.7349) and harvest index (P=0.5102, G=0.3225) exerted the highest positive direct effects on grain yield, while traits like specific leaf area and protein content had negative direct effects. High positive indirect effects via straw yield were noted for most of the traits, reinforcing its role in yield enhancement. Low residual effects (P=0.0116, G=0.0069) indicated a robust model fit. The study identified plant height, number of productive tillers per plant, panicle length, net photosynthetic rate, chlorophyll fluorescence, SCMR, straw yield per plant, and harvest index as key traits with significant positive direct effects on grain yield per plant. Photosynthetic efficiency in terms of high SCMR, chlorophyll fluorescence, net photosynthetic rate; low specific leaf area and canopy temperature indicates direct correlation with harvest index and yield enhancement. Hence future breeding programmes in foxtail millet, may be targeted for increasing photosynthetic efficiency coupled with grain yield.
Ram et al. (2025) studied this question.