Mao Zuyuan, Di Xinyan, Xia Saisai, Chen Qian, Ma Xiaohui, Chen Mei, Yang Zhenglin, Zhao Fangming, Ling Yinghua
Chongqing Key Lab of Application and Safety Control of Genetically Modified Crops, Engineering Research Center of South Upland Agriculture, Ministry of Education, Rice Research Institute, Southwest University, Chongqing, China.
Front Plant Sci. 2022 Dec 16;13:1020847. doi: 10.3389/fpls.2022.1020847. eCollection 2022.
Plant height and grain length are important agronomic traits in rice, exhibiting a strong effect on plant architecture and grain quality of rice varieties.
Methods: A novel rice chromosomal segment substitution line (CSSL), i.e., CSSL-Z1357, with significantly increased plant height (PH) and grain length (GL) was identified from CSSLs constructed by using Nipponbare as a receptor and a restorer line Xihui 18 as a donor. Seven agronomic traits of PH, PL, GL, GW, GPP, SPP, and TGW were phenotyped, and REML implemented in HPMIXED of SAS were used to detect the QTL for these traits. Secondary CSSLs were screened out via marker-assisted selection (MAS) to estimate the additive and epistatic effects of detected QTLs, evaluating the potential utilization of pyramiding the target QTLs for yield and quality improvement of rice varieties.
Results and Discussion: CSSL-Z1357 carried nine segments from Xihui 18 with an average segment length of 4.13 Mb. The results show that the long grain of CSSL-Z1357 was caused by the increased number of surface cells and the length of the inner glume. Thirteen quantitative trait loci were identified via the F2 population of Nipponbare/CSSL-Z1357, including three each for GL (qGL-3, qGL-6, and qGL-7) and PH (qPH-1, qPH-7, and qPH-12I), among which qGL-3 increased GL by 0.23 mm with synergistic allele from CSSL-Z1357. Additionally, three single (S1 to S3), two double (D1, D2), and one triple segment (T1) substitution lines were developed in F3 via MAS. Results show that pyramiding the segments from Chr.3 (qGL-3 and qPH-3), Chr.6 (qGL-6 and qPH-6), and Chr.7 (Null and qPH-7) tended to result in better phenotype of increased GL and PH and decreased grain width, providing a potential basis for enhancing grain yield and quality in rice breeding.
株高和粒长是水稻重要的农艺性状，对水稻品种的株型和籽粒品质有显著影响。
以日本晴为受体、恢复系西恢18为供体构建染色体片段代换系（CSSL），从中鉴定出一个株高（PH）和粒长（GL）显著增加的新型水稻染色体片段代换系CSSL-Z1357。对PH、PL、GL、GW、GPP、SPP和TGW这7个农艺性状进行表型分析，并使用SAS软件的HPMIXED过程中的REML方法检测这些性状的QTL。通过分子标记辅助选择（MAS）筛选次级CSSL，以估计检测到的QTL的加性和上位性效应，评估将目标QTL聚合用于水稻品种产量和品质改良的潜在利用价值。
CSSL-Z1357携带了来自西恢18的9个片段，平均片段长度为4.13 Mb。结果表明，CSSL-Z1357的长粒是由颖壳表面细胞数量增加和内稃长度增加引起的。通过日本晴/CSSL-Z1357的F2群体鉴定出13个数量性状位点，其中粒长相关的有3个（qGL-3、qGL-6和qGL-7），株高相关的有3个（qPH-1、qPH-7和qPH-12I），其中qGL-3来自CSSL-Z1357的增效等位基因使粒长增加了0.23 mm。此外，通过MAS在F3中培育出3个单片段（S1至S3）、2个双片段（D1、D2）和1个三片段（T1）代换系。结果表明，将来自第3染色体（qGL-3和qPH-3）、第6染色体（qGL-6和qPH-6）和第7染色体（空片段和qPH-7）的片段聚合，倾向于产生粒长和株高增加、粒宽减小的更好表型，为水稻育种中提高籽粒产量和品质提供了潜在依据。
