State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Triticeae Research Institute, Sichuan Agricultural University, Chengdu, China.
Crop Characteristic Resources Creation and Utilization Key Laboratory of Sichuan Providence, Mianyang Academy of Agricultural Science, Mianyang, China.
Theor Appl Genet. 2024 Sep 25;137(10):232. doi: 10.1007/s00122-024-04745-3.
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. 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 aestivum L.), 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, with QSFS.sau-MC-5A for SFS and QSFPs.sau-MC-5A for 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 both TraesCS5A03G1247300 and TraesCS5A03G1250300. The locus of QSFS.sau-MC-5A/QSFPs.sau-MC-5A showed 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 of QSFS.sau-MC-5A/QSFPs.sau-MC-5A and be instrumental in strategies to increase KNS, thereby enhancing wheat yield.
一个与穗部不育小穗数和不育小花数相关的主效和稳定的 QTL 被鉴定出来，它被定位在 5AL 染色体上的一个 2.22Mb 区间内，并使用两个具有不同遗传背景的分离群体进行了验证。穗部每小穗的可育小花数（FFS）和每穗的不育小花数（SFS）对小麦（Triticum aestivum L.）的最终产量有显著影响，两者之间存在理论上的权衡。为了提高作物产量，小麦育种家历来集中于 FFS、小穗数和穗长等易于测量的性状。其他具有重要农艺性状的性状，包括 SFS 和每小穗的不育小花数（SFPs），在很大程度上被忽视了。在本研究中，基于重组自交系（RIL）群体的评估，研究了 SFS 和 SFPs 的遗传基础。RIL 群体是通过与品种川农 16 杂交，自发突变体（msf）与川农 16 杂交而开发的。共鉴定到 10 个数量性状位点（QTL），其中 QSFS.sau-MC-5A 与 SFS 相关，QSFS.sau-MC-5A 与 SFPs 相关，是主要和稳定的，它们在 5A 染色体的长臂上共定位。该位点位于一个 2.22Mb 的区间内，并在基于紧密连锁 Kompetitive Allele-Specific PCR（KASP）标记 K_sau_5A_691403852 的两个额外群体中进一步得到验证。在 TraesCS5A03G1247300 和 TraesCS5A03G1250300 两个亲本之间观察到表达差异和启动子序列变异。QSFS.sau-MC-5A/QSFPs.sau-MC-5A 位点与穗长、中间小穗小花数和每穗小花总数呈显著正相关，但与穗粒数（KNS）或穗粒重（KNS）无关。适当的施氮肥可降低 SFS 并增加 KNS，这与氮肥对小麦穗和小花发育的积极影响的先前报道结果一致。基于这些结果，我们提出了一种有前途的方法来培育每穗多育小花的小麦品种，这可以增加穗粒数，从而有可能提高产量。总之，这些发现将有助于进一步精细定位 QSFS.sau-MC-5A/QSFPs.sau-MC-5A，并有助于提高 KNS 的策略，从而提高小麦产量。
