Naz Farkhanda, Arif Muhammad, Shuangfei Sun, Jiyu Zhang, Dachuan Wang, Kai Zhou, Fangming Zhao (Rice Research Institute, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, CHINA).
Disciplinary: Agriculture & Agronomy (Rice Research), Biotechnology.
Keywords: Hybrid rice; Chromosome Segment Substitution Line (CSSLs); Rice grain size; Restorer line; Additive and epistatic effect; Z436; Xihui18; F2 plant; Quantitative Trait Loci (QTL); QTL mapping; QTL pyramiding; DSSL; Secondary Substitution Lines (SSSL); Marker-assisted selection (MAS); Rice breeding; Pyramided genotype; Fertility-restoring gene; Rice genetics.
Grain size is essential in rice agronomic traits. Rice chromosomal segment substitution lines (CSSLs) are perfect resources for QTL mapping and gene pyramid breeding of important rice traits. Here, a novel rice short-wide grain CSSL-Z436 was isolated from advanced-generation backcross population BC3F7 based on the hereditary backgrounds of indica restorer line Xihui 18. Z436 contained 8 substitution segments (average length 4.49Mb) from donor Huhan 3. Eleven (QTLs) for grain size-associated traits were identified using a secondary F2 segregation population constructed by the cross between Xihui 18/Z436. The grain length in Z436 was mainly controlled by two major QTLs, qGL5 and qGL11. The additive effects of qGL5 and qGL11 reduced the grain length. The grain width in Z436 was mainly controlled by qGW2, qGW5, and qGW9. The QTL qGW2 had an additive effect of reducing the grain width, while qGW5 and qGW9 had an additive effect of increasing the grain width. Then, seven SSSLs and eight DSSLs were generated by MAS containing the target QTLs. Five QTLs (qGL11, qGW5, qRLW5, qRLW11, and qGWT5) were verified by the SSSLs, indicating that these QTLs are stable genetically. Distinct epistatic effects and phenotypes were created by pyramiding different QTLs. In general, the additive effect value of a single QTL and the numerical total of the additive and epistatic effects of QTLs in the pyramidal line determined gene efficiency after pyramiding. We may use this approach to anticipate the phenotype of novel pyramided genotypes and choose appropriate genotypes for molecular breeding based on specific breeding. Also, the fertility-restoring genes Rf1~Rf4 were not altered in either Z436 or the seven SSSLs, enabling them to be used as new restorer lines to create innovative hybrid rice cultivars.
Paper ID: 13A2N
Cite this article:
Farkhanda, N. et. al.(2022). Identification and Pyramiding of QTLs for Rice Grain Size Based on Short-Wide Grain CSSL-Z436 and Seven SSSLs & Eight DSSLs. International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, 13(3), 13A2N, 1-17. http://TUENGR.COM/V13/13A2N.pdf DOI: 10.14456/ITJEMAST.2022.45