Specific Loci in Genome of Wheat Milestone Parent Bima 4 and Their Transmission in Derivatives

Abstract Wheat ( Triticum aestivum L.) cultivar Bima 4 is one of the most important milestone parents in China. The objectives of this study were to reveal the genetic structure of Bima 4 and the transmission of its specific loci in descendents using molecular markers. A total of 1239 simple sequence repeat (SSR), expressed sequence tag derived SSR (EST-SSR), and sequence tagged site (STS) markers covering the whole genome of wheat were screened with the 4 parents of the first generation of Bima 4 progenies, i.e., Bima 4, Early Piemium, Jubileina 2, and Ckopocne ka JI-1. Thirty-three markers were effective to trace the specific loci of Bima 4 in the progenies. Seventy-six derivatives of Bima 4 were genotyped using these markers. Among them, 32 markers except for Xgwm577 could amplify the specific bands of Bima 4 in the first and the second generations derived from Bima 4. Eight and ten loci showed the transmission percentage larger than 50% in the first and the second generations, respectively. In the third and the fourth generations, 29 and 20 specific markers were observed. In these markers, 8 and 4 loci had the transmission rate higher than 50%, respectively. Among the specific loci, Xgwm261, Xedm80, SWES222 , and CFE223 possessed inheritable frequency higher than 50% in all of the 4 generations. Furthermore, 18 loci of Bima 4 were detected in the progenies with genetic contribution ratio higher than 25%. This indicates that some desirable traits, such as yield, grain quality, disease resistance, and adaptability might be associated with these loci or the nearby chromosome regions in Bima 4, which were intensively selected in breeding programs. The important loci detected in this study provide information for understanding the genetic basis of Bima 4 as a milestone parent in wheat breeding.