The novel methods of development of the maintainer and cytoplasmic male sterile lines with diferent cytoplasms based on chromosome single-segment substitution lines in rice

Abstract

The present study was carried out with the objective of developing new parental lines of hybrid rice based on chromosomesingle-segment substitution lines (SSSLs), on which the restorer and maintainer genes Rf3 (rf3) and Rf4 (rf4 ) were harbored in rice. Todevelop the new 3-line hybrid, the SSSL W23-19-06-06-11 with the genotype Rf3Rf3/Rf4Rf4 [a strong restorer line for wild abortive(WA), dwarf-wild abortive (DA), and Yegong (Y) cytoplasmic male sterile (CMS) lines] was crossed 4 times as the male parent with4 CMS lines: 2 typical WA-type CMS lines of Bobai A and Zhenshan 97A, 1 typical Y-type CMS line of Y-Huanong A, and 1 typicalDA-type CMS line of Xieqingzao A. In the BC3F 2 populations, the male sterile plants (MSPs) with WA-, Y-, and DA-type CMS sourcesand nuclear background of W23-19-06-06-11 and their maintainer plants (MPs) were developed by backcrossing and marker-assistedselection. All the MSPs showed 100% pollen and spikelet sterility and the panicle length ranged from 20 to 22.6 cm. Te extent ofincomplete panicle exertion in the entries ranged from 40.7 to 48.5. Te pollen grain viability assay with I2KI of the MSPs revealed100% pollen sterility, consisting of both typical and spherical abortive pollen grains. Te MPs showed normal pollen (spikelet) fertility.A genome-wide DNA marker survey revealed that the numbers of the substituted chromosome segments carried by the MSPs and MPswere 0.8 and 0.6, while the lengths of the substituted chromosome segments corresponding to the Rf3 (or Rf4 ) locus were, on average,26.2 cM and 17.0 cM (or 15.3 cM and 15.1 cM).