Genetics of fertility restoration of ‘Wild Abortive’ cytoplasmic male sterility in rice, Oryza sativa L.

Abstract

Genetics of fertility restoration 2 in six varieties and breeding lines of rice was studied in 'Wild Abortive' cytoplasmic genetic male sterility system using cytoplasmic male sterile lines V 20 A and IR 54752 A. Fertility evaluation of the plants in F2 and testcross populations of the crosses of V 20 A with PR 103, PR 106 and PAU 502-94-1, and IR 54752 A with PAU 1124-36-1 and PAU 1126-1-1 revealed that fertility restoration in PR 103, PR 106, PAU 502-94-1, PAU 1124-36-1 and PAU 1126-1-1 was controlled by two independently segregating dominant genes. The two genes appeared to have additive effects; one of them being stronger than the other in imparting fertility restoration. Data on spikelet fertility of the plants in F2 and testcross populations of V 20 A/UPR 82-1-1 cross showed that fertility restoration in UPR 82-1-1 was controlled by two independently segregating dominant genes which exhibited recessive epistatic interaction.

Effects of Rf-1, Rf-3 and Rf-6(t) Genes on Fertility Restoration in Rice (Oryza sativa L.) with WA- and BT-type Cytoplasmic Male Sterility

“…I observed that the Rf-1 gene was more or less effective on both cytoplasm types: the Rf-1 derived from IR36 restored pollen fertility in a gametophytic manner in BT-type CMS (Table 1), and partially restored pollen fertility in WA-type CMS (Table 2). These results are consistent with those obtained in previous studies using indica and japonica varieties (Young and Virmani 1984, Raj and Virmani 1988, Bharaj et al 1991, 1995, Teng and Shen 1994, Yao et al 1997, Akagi et al 2004, Komori et al 2004, Wang et al 2006. At present, it is remains to be determined whether the partial restoration of pollen fertility in WA-type CMS is a pleiotropic effect of Rf1a or Rf1b (Wang et al 2006), or is due to the clustering of multiple Rf genes of the Rf-1 locus.…”

“…Genetic studies on Rf genes using indica variety are complicated due to the inconsistency of the number and map position of the Rf genes involved , Raj and Virmani 1986, 1988, Bharaj et al 1991, 1995, Teng and Shen 1994, Zhu et al 1996, Yao et al 1997, Tan et al 1998, Jing et al 2001. I suggested that this phenomenon was associated with the indica genetic background which may contain unidentified genes that influence the pollen fertility.…”

“…Although fertility can be restored by the dominant restorer genes, reports on the number, positions and effects of these Rf genes are inconsistent. The presence of one Rf gene has been reported in some studies and of two in others (Raj and Virmani 1988, Bharaj et al 1991, 1995, Teng and Shen 1994, Tan et al 1998, Jing et al 2001. Raj and Virmani (1986) reported that an appropriate combination of two of eight restorer genes fully restored fertility in F 1 hybrids with WA-type CMS.…”

INHERITANCE OF FERTILITY RESTORATION INVOLVING WILD ABORTIVE CYTOPLASMIC MALE STERILITY SYSTEM IN RICE (Oryza sativa L.)

“…Assuming that two dominant fertility restoring genes involved in this action but one of the two genes appeared more effective than the other. The F 2 ratio of 9:3:4 involving supplementary or epistasis with recessive gene action has been reported earlier by Bharaj et al, (1991) and Hossain et al, (2010) in WA type sources of CMS lines. Again when the CMS lines crossed with the restorer line BR7013-62-1-1R, the F 2 segregation for pollen fertility showed semi-epistasis ratio 9:6:1 (FF: SF: CS).…”

Untitled

“…However, conclusions regarding the number of nuclear genes controlling fertility restoration depend on the materials and methods used. The genetics of fertility restoration in WA-CMS lines has been shown to follow monogenic 4,5 , digenic 6 , digenic with different types of interaction [7][8][9][10] , trigenic [10][11][12] , and trigenic interactions 13 . Nevertheless, most of the investigations tend to indicate that fertility restoration of the WA cytosterility system is controlled by two nuclear genes.…”