VARIATION IN SOFT WINTER-WHEAT CHARACTERISTICS MEASURED BY THE SINGLEKERNEL CHARACTERIZATION SYSTEM

Kernel hardness is one of the key grain attributes considered in wheat (Triticum aestivum L.) marketing in the USA. The objective of this re search was to characterize the effects of cultivar, environment, and c ultivar x environment interaction on kernel hardness as measured by th e Single Kernel Characterization System. Kernel weight and width were also studied. Eleven soft winter wheat cultivars were grown in replica ted trials in 19 environments in Michigan. All three traits were signi ficantly (P < 0.01) affected by cultivar, environment, and cultivar x environment interaction. Variation for kernel hardness was large and c ontinuous among cultivars and environments. Huhn's nonparametric stabi lity statistic showed that there were no differences in rank stability of the cultivars. Principal component analysis of the cultivar x envi ronment interaction effects showed that there were no consistent patte rns of behavior for similar cultivars, locations, or seasons. The only significant and large correlation was kernel weight vs. kernel width (r = 0.89). These data suggest that one environment of testing or a co mposite sample of multiple environments may be sufficient to accuratel y rank cultivars for kernel hardness. The large magnitude of the envir onmental effects will make prediction of hardness of a given wheat cro p difficult even when the cultivar is known.