Quantitative trait loci mapping of the stigma exertion rate and spikelet number per panicle in rice (Oryza sativa L.)

Abstract

ABSTRACT. The stigma exertion rate is a polygenic inherited trait that is important for increased seed yield in hybrid rice breeding. To identify quantitative trait loci (QTL) associated with high stigma exertion rate, we conducted QTL mapping using 134 recombinant inbred lines derived from XieqingzaoB and Zhonghui9308, which have high and low stigma exertion rates, respectively. A total of eight QTLs (qSES6, qSSE11, qDSE1a, qDSE1b, qDSE10, qDSE11, qTSE1, and qTSE11) for single stigma exertion, double stigma exertion, and total stigma exertion were detected. The locations of qSSE11 and qTSE11 have not been previously reported, and the qDSE11 allele from parent XQZB exhibited a positive additive effect. In addition, three QTLs (qSNP1, qSNP3a, and qSNP3b), for spikelet number per panicle were identified. Of note, one QTL (qSNP1) was detected in two different environments (Hainan and Zhejiang). To evaluate the advantage of exerted stigma for cross-pollination, single, dual, and total stigma exertion should be considered separately for future genetic improvement in the production of rice hybrid seeds. In addition, this study provides information for fine mapping, gene cloning, and marker assisted selection, with emphasis on the latter.

Detection of dominant QTLs for stigma exsertion ratio in rice derived from <i>Oryza rufipogon</i> accession ‘W0120’

“…In this study, we screened wild relatives of rice and selected 'W0120' as an ideal accession with clear stigma exsertion. We expected that 'W0120' may have a major dominant QTL, but found that the trait was controlled by several QTLs, similar to previous reports (Li et al 2014, Lou et al 2014, Miyata et al 2007, Rahman et al 2016, Uga et al 2003, Yamamoto et al 2003. An F 1 individual from a cross between 'W0120' and 'Akidawara' showed clear stigma exsertion, which indicated the existence of at least one clearly dominant QTL.…”

“…It has high heritability and can be improved by breeding (Virmani 1994, Yan et al 2009. Many QTLs for this trait have been reported (Li et al 2014, Lou et al 2014, Miyata et al 2007, Rahman et al 2016, Uga et al 2003, Yamamoto et al 2003. The most common and most powerful QTL for stigma exsertion is frequently detected near the centromere in the short arm of chromosome 3 (Li et al 2014, Miyata et al 2007, Yamamoto et al 2003.…”

Genetic Dissection of the Major Quantitative Trait Locus (qSE11), and Its Validation As the Major Influence on the Rate of Stigma Exsertion in Rice (Oryza sativa L.)

“…A total of 134 RILs were used for primary QTLs mapping of the SE rate and 198 SSR markers for genetic linkage map ( Rahman et al, 2016 ). The basis of the linkage map of the CSSL population was the previously established polymorphisms between the parents in this study (XQZB and ZH9308).…”

“…In the previous study, the QTL ( qSE11) was primarily mapped between RM167 and RM5704 on chromosome 11 by using a recombinant inbred population (RIL) derived from a cross between XQZB and Zhonhui9308 ( Rahman et al, 2016 ). The BC 4 F 6 population of the C65 line with the homozygous XQZB alleles, showing uniform SE, and the C65 line were selected for backcrossing with the recurrent parent ZH9308 to produce the F 2 (BC 5 F 2 ) and F 2:3 (BC 5 F 2:3 ) populations.…”

“…Recently, with the progress of genomics and DNA marker technology, a number of QTL mapping studies have been carried out elsewhere for SE in rice by using different populations such as recombinant inbred lines (RILs) and advance backcross (AB) lines. Yamamoto et al (2003) used a RIL of japonica × indica population, another studies by Uga et al (2003) identified two QTLs for SE between a cross of Pei-Kuh (an indica origin), and W1944 ( Oryza rufipogon Griff.) (a wild cultivar).…”