title: 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 spikelets in wheat directly affect the kernel number per spike (KNPS). In this study, 220 wheat lines from 18 Chinese provinces and five foreign countries were used as a natural population. Phenotypic analysis showed differences in grain-setting rates between apical and basal spikelets. The broad-sense heritability of grain-setting rate in apical spikelets (18.7-21.0%) was higher than that for basal spikelets (9.4-16.4%). Significant correlations were found between KNPS and grain numbers in apical (R (2) = 0.40-0.45, P < 0.01) and basal (R (2) = 0.41-0.56, P < 0.01) spikelets. Seventy two of 106 SSR markers were associated with grain setting, 32 for apical spikelets, and 34 for basal spikelets. The SSR loci were located on 17 chromosomes, except 3A, 3D, 4A, and 7D, and explained 3.7-22.9% of the phenotypic variance. Four markers, Xcfa2153-1A 202 , Xgwm186-5A 118 , Xgwm156-3B 319 , and Xgwm537-7B 210 , showed the largest effects on grain numbers in apical and basal spikelets. High grain numbers in apical and basal spikelets were associated with elite alleles. Ningmai 9, Ning 0569, and Yangmai 18 with high grain-setting rates carried larger numbers of favorable alleles. Comparison of grain numbers in basal and apical spikelets of 35 Yangmai and Ningmai lines indicated that the Ningmai lines had better grain-setting rates (mean 21.4) than the Yangmai lines (16.5).
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China ; Institute for Chemical Ecology, Shanxi Agricultural University Taigu, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Guo
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute for Chemical Ecology, Shanxi Agricultural University Taigu, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Shi
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China.
authors.forename: Boqiao
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Agricultural Science, School of Veterinary and Life Sciences, Murdoch University Murdoch, WA, Australia.
authors.forename: Jingjuan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Hubei Collaborative Innovation Centre for Grain Industry/College of Agriculture, Yangtze University Jingzhou, China.
authors.forename: Yanhao
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Xueyong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Crop Gene Resources and Germplasm Enhancement, Ministry of Agriculture/The National Key Facility for Crop Gene Resources and Genetic Improvement/Institute of Crop Science, Chinese Academy of Agricultural Sciences Beijing, China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Hao
authors.affiliation: Key Laboratory of Wheat Biology and Genetic Improvement for Low and Middle Yangtze Valley (Ministry of Agriculture), Lixiahe Agricultural Institute of Jiangsu Province Yangzhou, China.
authors.forename: Shunhe
authors.initials: S
authors.lastname: Cheng
keywords: association analysis; bread wheat; grain numbers in apical spikelets; grain numbers in basal spikelets; released cultivars