Identification of gall midge resistant parental lines and validation of fertility restoration linked markers for hybrid rice technology
Keywords: Rice, non aromatic maintainers, fertility restoration, SSR markers, Gall midge resistance, restorers
AbstractThe success of hybrid rice technology depends on the extent of heterosis realized, pest resistance and the grain quality of rice. To identify gall midge resistant, non aromatic maintainers and restorers, 114 germplasm lines were crossed with six CMS lines (2 indigenous and four exotic) to get one hundred fifty five hybrids (Rabi, 2012-13) and evaluated with 10 checks (Kharif, 2013) at Rice Research Station, Regional Agricultural Research Station, Jagtial, Andhra Pradesh. Based on pollen sterility and spikelet fertility studies, 49 maintainers and 31 restorers were identified. Screening hybrids and their parental lines for gall midge incidence indicated the involvement of dominant genes for gall midge resistance. Forty three hybrids, eleven maintainers and eighteen restorers were resistant to gall midge biotype 3. Gall midge resistant maintainers and restorers will be used for new CMS line and hybrid development respectively. The conventional method of restore line identification among rice germplasm pool is time consuming and labor intensive. Molecular mapping of fertility restorer genes in rice have yielded several closely linked DNA markers that can be used in identifying restorer lines. In order to utilize this available information effectively in marker assisted restorer line identification, validation of reported Rf3 and Rf4 gene linked DNA markers was carried out in this study. A total of seven DNA markers reported to be closely linked with two Rf genes of wild abortive CMS (WA-cms) were chosen. These markers were screened among twenty identified restorers and five maintainer lines. The genotypic data set was generated based on the specific PCR product size. Two DNA markers in combination (RM10313 and RM6100) showed 100% selection efficiency in identifying restorers in the germplasm and 90% selection efficiency in differentiating maintainers from restorers. These validated molecular markers linked to Rf genes would save time and money besides adding accuracy in identification of restorers.
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