Allelic differentiations and effects of the Rf3 and Rf4 genes on fertility restoration in rice with wild abortive cytoplasmic male sterility

Abstract

To reveal the allelic differentiations at the two genes for fertility restoration (Rf) on chromosomes 1 (Rf3) and 10 (Rf4), 15 chromosome single segment substitution lines (SSSLs) with the Rf3 locus and 18 SSSLs with the Rf4 locus were crossed with Bobai A (BbA), a cytoplasmic male sterility line with wild abortive type of cytoplasm (WA-CMS), respectively. Based on the pollen and seed fertility of the F 1 hybrids, the Rf3 and Rf4 genes were each classified into four alleles, namely Rf3-1, Rf3-2, Rf3-3, and Rf3-4 for Rf3, and Rf4-1, Rf4-2, Rf4-3, and Rf4-4 for Rf4. Out of the 33 SSSLs, an SSSL W23-19-06-06-11 carrying the genotype Rf3-4Rf3-4/Rf4-4Rf4-4 possessed the strongest restoring ability for BbA. To determine the genetic effects of Rf3 and Rf4 for WA-CMS, one BC 3 F 2 population possessing the genetic background of W23-19-06-06-11 was generated from the cross between W23-19-06-06-11 and BbA by backcrossing and marker-assisted selection. In the BC 3 F 2 population, the plants carrying the Rf3Rf3/Rf4Rf4, Rf3Rf3/rf4rf4, and rf3rf3/Rf4Rf4 genotypes were selected and their phenotyping for pollen and spikelet fertility were evaluated. The result showed that under the genetic background of SSSL W23-19-06-06-11, the effect of Rf4 appeared to be slightly larger than that of Rf3 and their effects were additive for WA-CMS system. These studies will lead to the transfer of Rf genes into adapted cultivars through marker-assisted selection in active hybrid rice breeding programs.

Frequency and fertility restoration efficiency of Rf3 and Rf4 genes in Indian rice

“…Cai et al. () also reported similar results where the IR64 (effective restorer) carrying Rf3Rf4 alleles and Basmati 370 (partial restorer) carrying rf3Rf4 alleles showed 85.4% and 59.3% spikelet fertility, respectively. The analysis of variance among the four groups ( rf3rf4, Rf3Rf4, Rf3rf4 and rf3Rf4 ) pooling WA and Kalinga CMS‐based F 1 populations showed significant differences revealing the occurrence of substantial variability of spikelet fertility restoration due to different Rf allele combinations.…”

“…Further, presence of same functional WA352 gene indicated the common mechanism of fertility restoration in both the CMS. The greater genetic association of Rf4 as compared to Rf3 in WA CMS has also been reported earlier (Yao et al 1997, Zhuang et al 2001, Ahmadikhah and Karlov 2006, Sattari et al 2008and Cai et al 2013). Cai et al (2013) also reported similar results where the IR64 (effective restorer) carrying Rf3Rf4 alleles and Basmati 370 (partial restorer) carrying rf3Rf4 alleles showed 85.4% and 59.3% spikelet fertility, respectively.…”

Mapping QTLs for Fertility Restoration of Different Cytoplasmic Male Sterility Types in Rice Using Two Oryza sativa ×O. rufipogon Backcross Inbred Line Populations

“…Similar results were reported for WA-type CMS in that the effect of Rf4 appeared to be larger than that of Rf3 and inheritance of both Rf genes resulted in compounded effects [18, 46, 48, 49]. The mitochondrial gene WA352 was recently described in wild rice and is associated with WA-, ID-, and DA-type CMS, suggesting that Rf3 ( qRf1.1 ) and Rf4 ( qRf10.2 ) are effective for restoring the fertility of DA-, ID-, and WA-type CMS [8].…”

Conversion of partial restorer Swarna into restorer by transferring fertility restorer Rf gene(s) through marker assisted back cross breeding (MABB) in rice

“…The hybrids produced using converted Swarna breeding lines with Rf3 gene showed 15-20% of more pollen and spikelet fertility than the partial restorer Swarna. This clearly demonstrates that that Rf3 gene may be contributing 15 to 30% for the fertility restoration trait of WA-CMS and Rf4 may be contributing about 70% for the same trait and presence of both the genes can bestow complete fertility restoration 13,[33][34][35][36][37][38] .…”