Commercial viability of alternative cytoplasmic-nuclear male-sterility systems in pearl millet

Commercial viability of three cytoplasmic-nuclear male sterility (CMS) syst ems (A(4), A(5) and A(v)) as potential alternatives to the most widely used A(1) system in pearl millet ( Pennisetum glaucum (L.) R.Br.) was evaluated in terms of stability of complete male sterility of four isonuclear A-line s (81A(1), 81A(4), 81A(5) and 81A(v)) and the level and stability of male f ertility restoration of their 44 single-cross hybrids. Lines 81A(4) and 81A (5) had no pollen shedders (PS), and there were very low frequency of non-P S plants of these A-lines that had a maximum of 1-5% selfed seedset (SSS). In 81A(1) and 81A(v), there were, albeit low frequency (<1%) of PS plants, and relatively higher frequency of the non-PS plants in these two lines, th e more so in 81A(v), had 1-5% and even greater SSS. Some hybrids made on ea ch of the three A-lines (81A(1), 81A(4) and 81A(v)) had high and stable mal e fertility, while others made on the same three A-lines displayed large va riation in SSS across the environments, the more so in case of hybrids made on 81A(v). These results indicate that the A(4) CMS system provides a bett er alternative to the A(1) CMS system, while the A(v) system does not. On t he basis of highly stable male sterility and the highest frequency of polli nators behaving as maintainers, the A(5) CMS system appeared to be the best for A-line breeding. The commercial viability of this CMS system in breedi ng R-lines of grain hybrids, however, still remains to be ascertained as no hybrid on it was fully male fertile in any environment.