Effect of cytoplasms and genetic backgrounds of parental lines on fertility restoration in Brassica juncea hybrids

Abstract

Cytoplasm diversification was recognized as one of the most important objective in sustainable exploitation of heterosis. Isonuclear alloplasmic cytoplasmic male sterile (CMS) lines with Moricandia arvensis (mori), Diplotaxis erucoides (eru), Diplotaxis berthautii (ber) cytoplasms were developed in the six diverse Brassica juncea genetic backgrounds (NPJ 112, NPJ 139, LES 1-27, SEJ 8, EC 308575 and Pusa Agarni). Each of these 18 CMS lines were crossed with six locally developed restorers possessing fertility restorer gene from Moricandia arvensis to assess the effect of sterile cytoplasms and nuclear backgrounds of parental lines (A and R) on fertility restoration. Comparison of 108 single cross hybrids, 36 hybrids in each cytoplasm, revealed that the hybrids based on mori cytoplasm was significantly different from the ones possessing ber and eru cytoplasms for mean percent pollen fertility. Further, paired comparisons of the mean per cent pollen fertility of hybrids revealed that the per cent pollen fertility in hybrids was influenced by the genetic backgrounds of parents. However, this effect was not consistent for any cytoplasm or nuclear background of parents. Regression analyses involving percent pollen fertility and seed set in the hybrids, both under open and self pollinated conditions, did not observe any significant association. For diversification of mori based CMS-FR systems eru and ber cytoplasms can be used for sustainable exploitation of heterosis in Indian mustard.