Correlations based on mixed models as selection criteria for breeding programs targeting seed production and quality in Paspalum nicorae Parodi ecotypes

Abstract To achieve satisfactory genetic gains, breeding programs must identify and prioritize key traits that affect seed production and quality. This study investigated associations among traits related to seed yield and quality in 84 Paspalum nicorae ecotypes. Path analysis based on multitrait best linear unbiased prediction was applied as a selection tool. Ecotypes were evaluated over 3 years in a randomized block design. Pearson correlations showed that seed yield was strongly associated with pure seed yield ( r = 0.90, p < 0.001), number of seeds per inflorescence ( r = 0.45, p < 0.01), number of seeds per raceme ( r = 0.43, p < 0.01), and thousand seed weight ( r = 0.39, p < 0.01). Pure seed yield also correlated with number of seeds per inflorescence ( r = 0.54, p < 0.001), number of seeds per raceme ( r = 0.50, p < 0.001), and thousand seed weight ( r = 0.46, p < 0.01). Claviceps paspali , identified for the first time in P. nicorae in southern Brazil, negatively impacted seed physiological quality, with significant correlations with germination at 7 days ( r = −0.34, p < 0.01), 28 days ( r = −0.35, p < 0.01), and germination speed index ( r = −0.31, p < 0.01). Canonical correlation analysis showed that seed weight increased germination, while physiological quality was negatively affected by pathogen incidence. Path analysis indicated that apparent seed yield and number of seeds per inflorescence were the main determinants of pure seed yield, while number of seeds per raceme and thousand seed weight had secondary effects.