Identification, pyramid and candidate genes of QTLs for associated traits based on a dense erect panicle rice CSSL-Z749 and five SSSLs, three DSSLs and one TSSL

Abstract Background Seed-set density is an important agronomic trait in rice. However, its genetic mechanism complex. Chromosome segment substitution lines (CSSLs) are ideal materials for studying complex traits. Results A rice CSSL, Z749, with a dense and erect panicle phenotype, was identified among progeny of the recipient parent Nipponbare donor Xihui 18. Z749 carried seven segments (average length 2.12 Mb). Compared Nipponbare, showed significant increases numbers primary (NPB) secondary branches (NSB), number spikelets (SPP) grains per (GPP), seed-set (SSD), decrease (PL). F 2 population derived from cross between used to map quantitative loci (QTLs) associated Fifteen QTLs distributed on chromosomes 5, 7, 8, 10 were detected. The QTL qPL7 might be allele OsFAD8 remaining 14 (e.g., qSSD5 qSSD10 etc.) novel. Fourteen verified using five single-segment (SSSLs). controlled predominantly by one major ( ) two minor qSSD8 ). , fine-mapped intervals 1.05, 1.46, 1.53 Mb 10, respectively. Analysis additive effects indicated that Xihui18 increased 14.10, 11.38, 5.11 cm panicle, epistatic revealed pyramiding produced novel genotypes density. Conclusions Inheritance Then, they Two MAPK genes OsMPK9 OsMPK17 gene (candidate 6) involved auxin metabolism candidate OsSAUR32 qSSD8. Pyramiding enhanced