水稻CSSL-Z492单、双片段代换系构建及粒型QTL的遗传解析

doi:10.3864/j.issn.0578-1752.2025.03.001

摘要/Abstract

摘要：

【目的】水稻粒型是由多基因控制的数量性状，将其遗传分解于单片段代换系（SSSL）中，并解析其遗传方式，为后续基因的遗传机制研究和设计育种提供依据。【方法】以日本晴为遗传背景的水稻染色体片段代换系Z492为研究材料，应用混合线性模型（MLM）进行粒型性状QTL的遗传分解和解析。【结果】以日本晴/Z492构建F₂群体，共鉴定出4个粒型QTL，包括粒长qGL6、qGL7和长宽比qRLW7、qRLW12，构建这些QTL的3个单片段代换系（S1—S3）和3个双片段代换系（D1—D3）。利用3个SSSL进一步鉴定出8个粒型性状QTL，包括qGL6、qGL7，以及6个新鉴定的QTL（qGW6、qRLW6、qGW7、qGWT7、qGL12和qGW12）。同时，分析不同QTL在3个DSSL中的遗传模式。结果表明，qGL6（a=0.26 mm）和qGL7（a=0.21 mm）互作产生-0.21 mm的粒长上位性效应，导致D1的粒长遗传效应（0.26 mm）与二者的加性效应相当。因而，D1的粒长（7.98 mm）与含单个QTL的S2和S1粒长（7.89和7.98 mm）无显著差异，而比日本晴的粒长（7.47 mm）显著增加。表明在设计育种中选择qGL6和qGL7聚合对增加粒长无效。qGW6（a=0.07 mm）和qGW12（a=0.06 mm）在D2中独立遗传，二者聚合产生的遗传效应（0.13 mm）使D2的粒宽（3.65 mm）比相应单片段代换系显著增加。因而在设计育种中可选这两个QTL增加粒宽。qGW7（a=0.11 mm）和qGW12（a=0.06 mm）互作则产生-0.10 mm的粒宽上位性效应，导致D3的粒宽遗传效应（0.07 mm）与qGW12的加性效应相当。因而D3的粒宽（3.59 mm）与含qGW12的S3无显著差异，而比日本晴显著变宽（3.44 mm），比携带qGW7的S2显著变窄（3.66 mm）。【结论】以单片段代换系和双片段代换系鉴定不同性状QTL对设计育种是非常必要的。不同QTL聚合会产生不同的遗传模式，有些是独立遗传，有些呈现不同的上位性效应。同时，S1和S3杂交可实现长宽大粒的育种目标，S1和S2杂交可产生比相应单片段代换系更重的籽粒，而S2和S3杂交无实际意义。

关键词: 水稻, 粒型, QTL, 单片段代换系, QTL互作

Abstract:

【Objective】Rice grain size is a quantitative trait controlled by multiple genes. They can be dissected into a single segment substitution line (SSSL), which is of great significance for their genetic mechanism study and breeding by design. 【Method】Z492, a chromosome segment substitution line in the genetic background of Nipponbare, was used as material to dissect QTL for rice grain size by mixed linear model (MLM) method. 【Result】The F₂ population was constructed from Nipponbare/Z492 to identify four QTL for grain size, including qGL6 and qGL7 for grain length and qRLW7 and qRLW12 for rate of grain length to width. Then three single-segment substitution lines (SSSL, S1-S3) and 3 dual-segment substitution lines (DSSL, D1-D3) carrying these QTL were further constructed. And the SSSL were then used to detect eight QTL for grain size, including qGL6, qGL7 and six newly identified QTL (qGW6, qRLW6, qGW7, qGWT7, qGL12, qGW12). Simultaneously, the genetic model of different QTL in 3 DSSL were analyzed. The results showed that interaction of qGL6 (a=0.26 mm) and qGL7 (a=0.21 mm) produced -0.21 mm of grain length epistatic effect, which resulted in the genetic effect (0.26 mm) of D1 equal to the additive effect of each QTL. Thus, the grain length (7.98 mm) of D1 displayed no difference from those (7.89 and 7.98 mm) of S2 with qGL7 and S1 containing qGL6, while significantly longer than that (7.47 mm) of Nipponbare. The result indicated that it is not necessary to pyramid qGL6 and qGL7 in breeding by design for increasing grain length. qGW6 (a=0.07 mm) and qGW12 (a=0.06 mm) belonged to independent inheritance in D2, thus, the genetic effect (0.13 mm) after pyramiding of qGW6 and qGW12 caused the grain width (3.65 mm) of D2 broader significantly than any of the SSSL with the single QTL. So, qGW6 and qGW12 can be selected to increase grain width in breeding by design. Interaction of qGW7 (a=0.11 mm) and qGW12 (a=0.06 mm) yielded -0.10 mm of epistatic effect, causing the grain width genetic effect (0.07 mm) of D3 parallel to the additive effect of qGW12. Thus, the grain width (3.59 mm) of D3 exhibited no difference with that (3.56 mm) of S3 carrying qGW12, while wider significantly than that (3.44 mm) of Nipponbare and narrower significantly than that (3.66 mm) of S2. 【Conclusion】It is very necessary for breeding by design to identify QTL for different important traits using SSSL and DSSL. Pyramiding different QTL produce various genetic models. Some display independent inheritance, and others exhibit various epistatic effects. In addition, to cross with S1 and S3 can realize the goal of longer, wider and heavier rice grain, and to cross with S1 and S2 can reach the target of heavier grain weight, while to cross with S2 and S3 have no any effects in grain size.

Key words: rice, grain size, QTL, single segment substitution lines, QTL interaction

李璐, 谢庄, 谢可盈, 张瀚, 赵卓文, 向奥妮, 李巧龙, 凌英华, 何光华, 赵芳明. 水稻CSSL-Z492单、双片段代换系构建及粒型QTL的遗传解析[J]. 中国农业科学, 2025, 58(3): 401-415.

LI Lu, XIE Zhuang, XIE KeYing, ZHANG Han, ZHAO ZhuoWen, XIANG AoNi, LI QiaoLong, LING YingHua, HE GuangHua, ZHAO FangMing. Construction of Single and Dual-Segment Substitution Lines from Rice CSSL-Z492 and Genetic Dissection of QTL for Grain Size[J]. Scientia Agricultura Sinica, 2025, 58(3): 401-415.

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性状 Trait	QTL	染色体 Chr.	连锁标记 Linked marker	估计效应 Estimated effect	贡献率 Var. (%)	P值 P value
粒长Grain length (mm)	qGL6	6	RM494	0.07	4.97	0.0314
粒长Grain length (mm)	qGL7	7	RM5672	0.15	24.16	<0.0010
长宽比Rate of length to width	qRLW7	7	RM5672	0.03	6.24	0.0208
长宽比Rate of length to width	qRLW12	12	RM491	0.03	4.57	0.0400