Genetic variability, heritability, and trait associations for growth and yield characters in kola [ <i>Cola nitida</i> (Vent) Schott. &amp; Endl.]

Abstract Genetic enhancement of crop plants such as kola [ Cola nitida (Vent) Schott. &amp; Endl.] can be made effective and efficient via estimates of genetic parameters. Our study evaluated genetic parameters to provide insights into heritable variability and character associations in kola to guide variety development. Ten kola clones including two standard varieties were field planted in 2017 following a randomized complete block design with three replicate blocks and assessed for growth and yield characters over a 9‐year period. Analysis showed significant ( p &lt; 0.01) differences between kola clones for trunk cross‐sectional area (TCSA), plant height (HT), and jorquette height (JH), and highly significant ( p &lt; 0.001) differences for yield. Yield, TCSA, HT and JH exhibited high broad‐sense heritability ( H 2 ) together with high genetic advance as a percentage of trait mean, reflecting preponderance of genetic than environmental factors underlying the expression of these traits and high probability for effective selection in trait enhancement efforts. Among the vegetative traits, the significant and largest genetic correlation was observed between TCSA and HT ( r g = 0.93, p &lt; 0.001, 95% CI [0.71, 0.98]). Yield was positively and significantly correlated with canopy span, chlorophyll content, and chlorophyll fluorescence at the phenotypic and genetic levels. Principal component analysis revealed that all traits except JH influenced the variation the most among the assessed clones on the first principal component axis. The top five‐yielding clones (CRK001, CRK002, CRK003, CRK004, and CRK006) are recommended for multilocation testing. Our results highlight substantial variability at the genetic level that can be exploited to improve kola in Ghana.