Improvement in the Stability and Yield Performance of a Snap Bean Cultivar

ABSTRACT The genetic analysis of crop yield potential includes three main components that are controlled by groups of genes: (i) genes that control yield/plant, which are selected by the entry mean of individual plant yields; (ii) genes that confer tolerance to the biotic and abiotic stresses, which are defined by the CV of individual plant yields; and (iii) genes that control responsiveness to inputs, which are defined by the progeny standardized selection differential (SSD). This paper evaluates the efficiency of a breeding program applied to improve the stability, the yield and the product uniformity of a snap bean cultivar following these three components. The selection was based on the following criteria: (i) comparisons on the basis of whole-genome phenotypic evaluation should expand among progeny lines and among individual plants within lines; (ii) selection should be applied across the target area of adaptation from the earliest generations and during all stages of the breeding program; (iii) honeycomb designs should be used to sample effectively for environmental diversity and exploit the genotype-by-environment inter-action for the development of “homeostatic cultivars.” The changes in the three components through the honeycomb pedigree selection showed: (i) the entry mean of earliness increased by 54.1–79.8%, while the entry mean of yield followed stabilizing trends, which means improvement in early harvest; (ii) the CV of earliness and yield decreased by 49.2–65.9% and 27.5–35%, respectively, which means improvement in performance stability; and (iii) the SSD of earliness and yield followed different trends in the different offsprings, i.e., the responsiveness to inputs was family dependent. The breeding program provides the possibility of incorporating desirable genes in improved cultivars of green bean.