Mapping of QTLs conferring high grain length-breadth relative expansion during cooking in rice cultivar Paw San Hmwe

Khin Mar Thi; Yan Zheng; Ei Ei Khine; Ei Ei Nyein; Min Htay Wai Lin; Khin Than Oo; Win Win New; Moe Zin Zi Thet; Moe Moe Khaing; Myat Myat Moe; San San Aye; Weiren Wu

doi:10.1270/jsbbs.20040

Mapping of QTLs conferring high grain length-breadth relative expansion during cooking in rice cultivar Paw San Hmwe

Breed Sci. 2020 Dec;70(5):551-557. doi: 10.1270/jsbbs.20040. Epub 2020 Oct 28.

Authors

Khin Mar Thi^{1

2}, Yan Zheng^{1

2

3}, Ei Ei Khine^{1

2}, Ei Ei Nyein^{1

2}, Min Htay Wai Lin⁴, Khin Than Oo⁴, Win Win New⁴, Moe Zin Zi Thet⁴, Moe Moe Khaing⁴, Myat Myat Moe⁵, San San Aye⁴, Weiren Wu^{1

2}

Affiliations

¹ Fujian Provincial Key Laboratory of Crop Breeding by Design, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
² Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
³ College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
⁴ Department of Botany, Mawlamyine University, Mon State, Mawlamyine, Myanmar.
⁵ Department of Botany, Dagon University, North Dagon, Yangon, Myanmar.

Abstract

Paw San Hmwe (PSH) is a high-quality rice cultivar from Myanmar. PSH has short and broad grains, but the grains become slender after cooking. This desirable feature can be described as a high value of grain length-breadth relative expansion index (GREI). To understand the genetic basis of high GREI in PSH, we crossed PSH with Guang 8B (G8B), a rice cultivar from China with low GREI, to develop an F₂ population and a subsequent F_2:3 population. Based on the phenotypes of these two populations measured in two years and using the method of sequencing-based bulked segregant analysis followed by verification with conventional linkage-based QTL mapping method, we mapped three QTLs for GREI. The three QTLs were located on chromosomes 3, 5 and 12, respectively, with the trait-increasing alleles all from PSH, and could explain a total of 62.5% of the phenotypic variance and 84.1% of the additive genetic variance. The results suggest that the three QTLs would be useful for the genetic improvement of GREI in rice, and the linked markers will facilitate the selection of the favorable alleles from PSH in breeding.

Keywords: QTL mapping; cooking quality; grain expansion; rice.