Genetics of Fertility Restoration in A₄‐Based, Diverse Maturing Hybrids of Pigeonpea [Cajanus cajan (L.) Millsp.]

Abstract

Recently, a breeding technology for hybrid pigeonpea [Cajanus cajan (L.) Millsp.] based on cytoplasmic‐nuclear male sterility (CMS) and partial natural outcrossing was developed at ICRISAT. The limited number of experimental hybrids tested has shown the presence of a considerable amount of hybrid vigor for seed yield. In the present study, one extra‐early‐ (120 d), two early‐ (150 d), and two late‐maturing (180 d) pigeonpea hybrids were studied to generate information on the genetics of fertility restoration of the A4 CMS system. In the extra‐early‐maturing hybrids, pollen fertility was controlled by a single dominant gene, whereas in the early‐ and late‐ maturing hybrids, male fertility was governed by two duplicate dominant genes. It was also observed that hybrids with two dominant genes produced a greater pollen load and expressed greater stability as compared with those carrying a single dominant gene. The information on the inheritance of fertility restoration will help in designing strategies for breeding elite hybrid parents, and it was concluded that for breeding hybrids with stable fertility restoration, the presence of two dominant genes is essential.

Exploitation of the Leaf Variants in CGMS System Derived from A2 Cytoplasm in Pigeonpea [Cajanus cajan (L.) Millsp.]

“…In the first generation (F 1 ) these four leaf types were found recessive in expression against lanceolatus leaf. Recessive gene expression for Obcordifoliate leaf shape was observed by Cruz et al, (1971), Deokar et al, (1972), Chopde et al, (1979) and Saxena et al, (2011). Most of the F 1 plants were found sterile as CMS line; it indicated that the factor for male fertility is located in cytoplasm of four recurrent parents.…”

“…In addition, different hybrid combinations were made to identify fertility restorer gene and heterotic combiner parents from new leaf type CMS lines. Recently, Saxena et al, (2011) incorporated obcordifoliate leaf shape into A 4 cytoplasm based CMS lines for use as naked eye polymorphic markers. The success of hybrid technology largely dependent on the provision of quality F 1 seeds to the farmers.…”

“…Some modifier genes present in the nucleus and cytoplasm could be the reason for incomplete penetrance and expressivity of the fertility restoring genes (Hossain et al, 2010). For getting effective fertility restoration Saxena et al, (2011) postulated that the selection for both the dominant fertility restoring genes in one line is essential that will increase the restoration in the hybrids. Two restorers AKPR-249 and AKPR-319 were identified best for fertility restoration in four leaf type CMS lines.…”

Identification of new fertility restorers for development of early maturing pigeonpea hybrids

“…A perusal of published reports on the genetics of fertility restoration of A 4 CMS system in the medium maturing pigeonpea (Table 2) showed that either one or two dominant genes controlled the fertility restoration with variable gene action. Saxena et al (2011a) reported that the fertility restoration in the early maturing pigeonpea was stable across environments only when both the dominant genes were present together in a single genotype; and the hybrids carrying either of the dominant genes were also fertile but not in all the environments. Dalvi et al( 2008) and Saxena et al(2014a) examined over 2000 testers from pigeonpea germplasm across the maturities and reported that, in compaison to early maturing germplasm, the fertility restoring genes were more frequent in the medium maturing pigeonpea germplasm.…”

Male Sterility Systems in Major Field Crops and Their Potential Role in Crop Improvement

“…In most crops one or two dominant fertility restorer genes have been reported to control the pollen fertility (Kaul 1988 ). Saxena et al ( 2011 ) reported that in pigeon pea two dominant genes were responsible for fertility restoration of A 4 cytoplasm. However, the hybrids with a single dominant gene were also fertile, but they produced less quantity of pollen and also showed a lot of instability with respect to fertility restoration in diverse environments.…”