O. sativa と O. glumaepatula との間の雑種に花粉半不稔を生ずる。S23 identified from O. glumaepatula was allelic to S21-gla (Miyazaki et al. 2007). S23 locus was pinpointed to an interval between MM3659 and PSM147 containing three putative genes: ORF4 (Os07g0646500), ORF3 (Os07g0646600) and ORF5 (Os07g0646700). S23 was allelic with qHMS7, and S23-ORF3 was identical to qHMS7-ORF3 (Fang et al. 2019).