Variation within and among Ladino white clover ecotypes for agronomic traits

One set of 285 genotypes from three landraces and one natural population and a second set of 165 genotypes from two landraces and one natural population were evaluated in separate trials. Variation among populations was mostly accounted for by the difference between landrace and natural population genotype groups, the former showing features related to higher seed yield and short-term aerial dry matter (DM) yield and to lower persistence, cold tolerance and protein content. Compared to variance among ecotypes, that within ecotypes was never lower and it was at least four-fold higher for important traits such as aerial and total (aerial plus stolen) DM yield, stolen density, production of seed heads and cold tolerance. Landraces and natural populations showed similar levels of intra-population variation for all traits except cold tolerance, for which landraces tended to somewhat greater variation. Trait associations were less definite at the genotype level than what previously found in terms of mean values of the ecotypes. This finding and the relatively high broad sense heritability which was observed for all components of DM and seed yield can support the breeding activity on this clover. The level of variation and of heritability found for protein content do not suggest the routine evaluation of this trait in breeding programmes.