Genetics of fertility restoration and test for allelism of restorer genes in wheat (Triticum aestivum L.)

Mode of inheritance of fertility restorer (Rf) gene(s) for T type (Triticum timopheevi Zhuk.) sterile cytoplasm in wheat (Triticum aestivum L.) was studied using fertility restorer lines EC368169 and T2003R. A-line 2041A was crossed with EC368169 while another male sterile line 2019A, with T2003R to develop F2 and BC1 (sterile line x F1) populations. The F1’s of all the crosses had more than 60% pollen fertility and 48 to 68 seed set per main spike. Based on the observations recorded on pollen and floret fertility, the F2 and BC1 segregants were categorized into fertile (> 30% pollen fertility and > 5% seed set/spike) and sterile (< 30% pollen fertility and < 5% seed set/spike) classes. The segregation pattern in F2 and BC1 generations showed that both the restorer lines carried a single dominant gene for fertility restoration. However, the frequency distribution of plants in terms of pollen fertility and seed set in the F2 indicated that fertility restoration was affected in complex way by modifiers. Test for allelism between four restorer lines were also conducted to find out the similarity between the genes carried by restorer lines namely, EC 368169, T2003R, PWR4099 and PWR4101.The progenies from three way crosses, [2019A/F1(PWR4101/PWR4099)], [2041A/F1(PWR4101/T2003R)], [2041A/F1(WR4099/T2003R)], 2019A/F1(EC368169R/T2003R)] and [2338A/F1(EC368169R/PWR4099)] did not segregate for male sterility indicating that at least one common fertility restorer gene is present in all the four restorer lines.