Study of plant height as a dynamic trait by multistage phenotyping in chickpea under heat stress identifies common as well as stage specific marker–trait associations

Abstract

AbstractPlant height in chickpea is a multivariate, dynamic trait, and shows differences in growth rate at different stages of plant development in different genotypes. In the majority of plant-breeding experiments, the phenotypic data on a quantitative trait measured at a fixed time point (generally at maturity) are used for quantitative trait loci (QTL) mapping. However, this method can result in missing important/major QTLs which are expressed at different time points and are not expressed at maturity. In the current study, using a set of 49 desi chickpea genotypes sown at three different durations for two successive years, we observed that heritability for plant height was highest at the 2 month stage in the normal sown trial, and at the 1 month stage in late-sown trials. However, heritability drastically declines at maturity, particularly due to heat stress with an increase in temperatures during the growing period. In the association analysis, it was also observed that almost all the marker–trait associations (MTAs) identified using endpoint phenotypes were identified using data obtained at different intervals. In addition, some novel and stage-specific MTAs were identified using phenotypic data recorded at monthly intervals. The results highlight the importance of multistage phenotyping for dynamic traits like plant height in germplasm characterization programmes.