Association analysis of grain-setting rates in apical and basal spikelets in bread wheat (Triticum aestivum L.)

Abstract

The rates of grain-setting in apical and basal spike lets in wheat directly affect the kernel number perspike(KNPS). Inthisstudy, 220 wheat lines from 18 Chinese provinces and five foreign countries were used as a natural population. Phenotypic an alysis showed difference singrain-setting rates between apical and basal spike lets. Thebroad-senseher it ability of grain-setting rate in apical spike lets(18.7–21.0%) washigher than that forbasal spike lets(9.4–16.4%). Significant correlations were found between KNPS and grain numbers in apical (R2 = 0.40– 0.45,P<0.01) andbasal (R2=0.41–0.56,P<0.01) spikelets. Seventy two of 106 SSR markers were associated with grain setting, 32 for apical spike lets, and 34 for basalspike lets. The SSR lociwe relocatedon 17chromosomes, except3A, 3D, 4A, and 7D, and explained 3.7–22.9% of the phenotypicvariance. Four markers, Xcfa2153-1A202, Xgwm186-5A118, Xgwm156-3B319,andXgwm537-7B210, showed the largest effects on grain numbers in apical and basal spikelets. Highgra innumbers inapical and basal spikelets were associated with elitealleles. Ningmai9, Ning0569, and Yangmai 18 with high grain-setting rate scarried large rnumbers off avorablealleles. Comparison of grain numbers in basal and apical spike lets of 35 Yangmai and Ningmai lines indicated that the Ningma ilines had better grain-settingrates(mean21.4) than the Yangmai lines(16.5).