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

Abstract

Stigma exsertion can enhance the outcrossing fertility in rice. Dominant genes for this trait are expected to be essential for the effective application of a novel outcrossing-based breeding system that uses male sterility in rice, which is normally autogamous. Because reduction of stigma exsertion is a domestication trait, we screened wild rice species as possible donors of genes or QTLs for stigma exsertion. We used in silico image-based screening and selected the Oryza rufipogon accession 'W0120'. A single F 1 individual derived from a cross between the japonica rice cultivar 'Akidawara' and 'W0120' was used to generate F 2 and BC 1 F 1 populations. QTL analysis performed using 114 F 2 individuals detected QTLs on chromosomes 2, 3, 4, 8, and 11. Only two major QTLs on chromosomes 3 and 8 showed higher degrees of dominance. On the other hand, there were no QTLs near GS3, which is well known as a gene for stigma exsertion. Validation of these QTLs using 188 BC 1 F 1 individuals provided clear evidence for their dominance. Genotypes of the markers nearest to the two QTLs were also related to grain length. We expect the genes responsible for these QTLs to be promising tools for improving outcrossing-based breeding in rice.

Substitution mapping of the major quantitative trait loci controlling stigma exsertion rate from Oryza glumaepatula

“…The QTLs were distributed across all 12 chromosomes Zhou et al 2017a;Liu et al 2019). Among of them, a limited number of QTLs for SER were identi ed from the wild Oryza species, O. ru pogon (Xiong et al 1999;Li et al 2001;Uga et al 2003a;Huang et al 2012;Bakti and Tanaka 2019) and O. longistaminata (Li et al 2010). In the present study, we detected 7 QTLs of SER on 5 chromosomes using a set of SSSLs derived from O. glumaepatula ( Figure 5).…”

“…Huang et al (2012) found 8 QTLs for SER using the 271 F 2 lines from the cross between O. sativa, Guangluai-4, and O. ru pogon. Bakti and Tanaka (2019) detected ve QTLs for SER using a F 2 population generated from a cross between the japonica rice cultivar 'Akidawara' and 'W0120' of O. ru pogon. From another wild species, O. longistaminata, several QTLs of SER were identi ed from an introgression line of the wild species in the genetic background of Asian cultivated rice (Li et al 2010).…”

Dissection of closely linked QTLs controlling stigma exsertion rate in rice by substitution mapping

“…The wild rice is the important germplasm resources with strong outcrossing ability (Marathi et al 2015 ; Marathi and Jena 2015 ). Many QTLs for SER were identified from O. rufipogon (Xiong et al 1999 ; Li et al 2001 ; Uga et al 2003a ; Huang et al 2012 ; Bakti and Tanaka 2019 ; Zou et al 2020 ), O. longistaminata (Li et al 2010 ), O. glumaepatula (Tan et al 2020 ), O. barthii and O. meridionalis (Zou et al 2020 ). Many of the QTLs for SER identified from different mapping populations and different mapping methods were found to be position overlapping in rice genome (Tan et al 2020 ).…”

Mapping chromosomal regions associated with anther indehiscence with exerted stigmas in CRI-48 and Jasmine 85 cross of rice (Oryza sativa L)

“…Earlier studies have indicated that efficiency of cross pollination in rice is influenced by floral traits including flowering behaviour, pollen longevity, stigma exertion and spikelet opening angle (Virmani, 1994;Takano-Kai et al, 2011). Among these, stigma exertion is the most important trait since it is directly involved in pollination (Virmani, 1994;Takano-Kai et al, 2011;Lou et al, 2014;Bakti and Tanaka, 2019;Xu et al, 2019).…”