Dataset Information

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6.

ABSTRACT:

Background

Grain size affects not only rice yield but is also an important element in quality of appearance. However, the mechanism for inheritance of grain size is unclear.

Results

A rice chromosome segment substitution line Z1392, which harbors three substitution segments and produces grains of increased length, was identified. The three chromosome segments were located on chromosomes 1, 5, and 6, and the average length of the substitution segment was 3.17?Mb. Cytological analysis indicates that the predominant cause of increased grain length in Z1392 could be cell expansion in the glumes. Seven quantitative trait loci (QTLs) for grain size related traits were identified using the secondary F₂ population produced by Nipponbare/Z1392. The inheritance of grain length in Z1392 was mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was localized on a 1.26?Mb region on chromosome 6, and OsARF19 may be its candidate gene. Based on QTL mapping, three single-segment substitution lines (S1, S2, and S3) and two double-segment substitution lines (D1 and D2) were selected, and the mapping accuracy for qGL-5 and qGL-6 was further verified using three single-segment substitution lines. Analysis of QTL additive and epistatic effects revealed that the additive effect of alleles qGL-5 and qGL-6 from 'Xihui 18' was estimated to increase grain length of Z1392 by 0.22 and 0.15?mm, respectively. In addition, a positive epistatic interaction between qGL-5 and qGL-6 was detected, which indicates that the pyramiding of qGL-5 and qGL-6 for grain length produces a novel genotype with longer grains.

Conclusions

Inheritance of grain length in the triple-segment substitution line Z1392 is mainly controlled by two major QTLs, qGL-5 and qGL-6. qGL-6 was found to be located in a 1.26?Mb region on chromosome 6, and OsARF19 may be its candidate gene. A positive epistatic interaction between qGL-5 and qGL-6 results in longer grains. The present results can be used to facilitate cloning of the qGL-5 and qGL-6 genes and contribute to improvement of grain yield in rice.

SUBMITTER: Zhang T

PROVIDER: S-EPMC7290020 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6.

Zhang Ting T Wang Shiming S Sun Shuangfei S Zhang Yi Y Li Juan J You Jing J Su Tian T Chen Wenbo W Ling Yinghua Y He Guanghua G Zhao Fangming F

Rice (New York, N.Y.) 20200611 1

<h4>Background</h4>Grain size affects not only rice yield but is also an important element in quality of appearance. However, the mechanism for inheritance of grain size is unclear.<h4>Results</h4>A rice chromosome segment substitution line Z1392, which harbors three substitution segments and produces grains of increased length, was identified. The three chromosome segments were located on chromosomes 1, 5, and 6, and the average length of the substitution segment was 3.17 Mb. Cytological analys ...[more]

PMID: 32529315

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Project description:BackgroundGrain size is a key determinant of grain weight and a trait having critical influence on grain quality in rice. While increasing evidences are shown for the importance of minor-effect QTL in controlling complex traits, the attention has not been given to grain size until recently. In previous studies, five QTL having small effects for grain size were resolved on the long arm of chromosome 1 using populations derived from indica rice cross Zhenshan 97///Zhenshan 97//Zhenshan 97/Milyang 46. One of them, qTGW1.2c that was located in a 2.1-Mb region, was targeted for fine-mapping in the present study.ResultsFirstly, the qTGW1.2c region was narrowed down into 1.1 Mb by determining genotypes of the cross-over regions using polymorphic markers newly developed. Then, one BC2F9 plant that was only heterozygous in the updated QTL region was identified. A total of 12 populations in generations from BC2F11:12 to BC2F15:16 were derived and used for QTL mapping. Two QTL linked in a 460-kb region were separated. The qGS1-35.2 was delimited into a 57.7-kb region, containing six annotated genes of which five showed nucleotide polymorphisms between the two parental lines. Quantitative real-time PCR detected expression differences between near isogenic lines for qGS1-35.2 at three of the six annotated genes. This QTL affected grain length and width with opposite allelic directions, exhibiting significant effect on ratio of grain length to width but showing little influence on yield traits. The other QTL, qGW1-35.5, was located within a 125.5-kb region and found to primarily control grain width and consequently affect grain weight.ConclusionsOur work lays a foundation for cloning of two minor QTL for grain size that have potential application in rice breeding. The qGS1-35.2 could be used to modify grain appearance quality without yield penalty because it affects grain shape but hardly influences grain yield, while qGW1-35.5 offers a new gene recourse for enhancing grain yield since it contributes to grain size and grain weight simultaneously.

Dataset Information

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6.

Background

Results

Conclusions

Publications

Analysis of QTL for Grain Size in a Rice Chromosome Segment Substitution Line Z1392 with Long Grains and Fine Mapping of qGL-6.

Similar Datasets

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