Identification and characterization of QSFS.sau-MC-5A for sterile florets genetically independent of fertile ones per spike in wheat

https://link.springer.com/article/10.1007/s00122-024-04745-3

Theoretical and Applied Genetics，Volume 137, article number 232,25 September 2024

Jieguang Zhou,Yuanjiang He,Wei Li,Bin Chen,Longxing Su,Yuxin Lan,Lei Yan,Ying Wang,Md Nahibuzzaman Lohani,Yanlin Liu,Huaping Tang,Qiang Xu,Qiantao Jiang,Guoyue Chen,Pengfei Qi,Yunfeng Jiang,Chunji Liu,Yong Ren,Youliang Zheng,Yuming Wei&Jian Ma

Key message

A major and stable QTL for sterile florets per spike and sterile florets per spikelet was identified, it was mapped within a 2.22-Mb interval on chromosome 5AL, and the locus was validated using two segregating populations with different genetic backgrounds.

Abstract

Both the number of fertile florets per spike (FFS) and the number of sterile florets per spike (SFS) significantly influence the final yield of wheat (Triticum aestivumL.), and a trade-off theoretically exists between them. To enhance crop yield, wheat breeders have historically concentrated on easily measurable traits such as FFS, spikelets per spike, and spike length. Other traits of agronomic importance, including SFS and sterile florets per spikelet (SFPs), have been largely overlooked. In the study, reported here, genetic bases of SFS and SFPs were investigated based on the assessment of a population of recombinant inbred lines (RILs) population. The RIL population was developed by crossing a spontaneous mutant with higher SFS (msf) with the cultivar Chuannong 16. A total of 10 quantitative trait loci (QTL) were identified, withQSFS.sau-MC-5Afor SFS andQSFPs.sau-MC-5Afor SFPs being the major and stable ones, and they were co-located on the long arm of chromosome 5A. The locus was located within a 2.22-Mb interval, and it was further validated in two additional populations based on a tightly linked Kompetitive Allele-Specific PCR (KASP) marker, K_sau_5A_691403852. Expression differences and promoter sequence variations were observed between the parents for bothTraesCS5A03G1247300andTraesCS5A03G1250300. The locus ofQSFS.sau-MC-5A/QSFPs.sau-MC-5Ashowed a significantly positive correlation with spike length, florets in the middle spikelet, and total florets per spike, but it showed no correlation with either kernel number per spike (KNS) or kernel weight per spike. Appropriate nitrogen fertilizer application led to reduced SFS and increased KNS, supporting results from previous reports on the positive effect of nitrogen fertilizer on wheat spike and floret development. Based on these results, we propose a promising approach for breeding wheat cultivars with multiple fertile florets per spike, which could increase the number of kernels per spike and potentially improve yield. Collectively, these findings will facilitate further fine mapping ofQSFS.sau-MC-5A/QSFPs.sau-MC-5Aand be instrumental in strategies to increase KNS, thereby enhancing wheat yield.