Seed parent breeding efficiency of three diverse cytoplasmic-nuclear male-sterility systems in pearl millet

Abstract

Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids, grown widely in India and to some extent in the US, are all based on an A 1 CMS source, leaving the pearl millet hybrids vulnerable to potential disease or insect pest epidemics. A comparison of this CMS system with two additional CMS systems (A 4 and A 5 ) in the present study based on isonuclear A-lines (seed parents) and their isonuclear hybrids showed that A-lines with the A 4 cytoplasm had much fewer pollen shedders and much reduced selfed seed set in visually assessed non-shedding plants as compared to those with the A 1 cytoplasm. A-lines with the A 5 cytoplasm had neither any pollen shedders nor did they set any seed when selfed. This showed that the A 5 CMS system imparts complete and most stable male sterility, followed by the A 4 and A 1 CMS systems. The frequency of maintainers, averaged across a diverse range of 26 populations, was highest for the A 5 CMS system (98%), followed by the A 4 (59%) and the A 1 (34%) system indicating the greatest prospects for genetic diversiWcation of A-lines lies with the A 5 cytoplasm, and the least with the A 1 cytoplasm. Mean grain yield of hybrids with the A 1 cytoplasm was 5% more than the A 4 -system hybrids, while there was no diVerence between the mean grain yield of hybrids based on A 1 and A 5 CMS systems. Based on these results, it is suggested that seed parents breeding eYciency will be the greatest with the A 5 CMS system, followed by the A 4 CMS system, and least with the currently commercial A 1 CMS system.

Inheritance of A1system of cytoplasmic-nuclear male sterility in pearl millet [Pennisetum glaucum(L). R. Br.]

“…Of the three male-sterile lines used in this study, 5054A has been found to be most unstable for its male sterility as reflected in the relatively higher frequency of pollen shedders observed in this line (Rai et al 2008). It gave a 2-gene fit to 15F:1S ratio in the F 2 in both the seasons and to BC 1 ratio of 3F:1S in one season when crossed with L 67B, 3-gene fit to 54F:10S ratio in F 2 in both seasons, but lack of fit to the expected 3F:1S ratio in the BC 1 when crossed with IPC 511, lack of fit to any of these three hypothetical ratios in both populations and both seasons when crossed with IPC 804, and good fit to 3F:1S ratio in the summer season and to 54F:10S ratio in the rainy season in F 2 , but lack of fit to the expected ratios in both seasons in BC 1 when crossed with IPC 1518.…”

Genetics of fertility restoration of the A₄ cytoplasmic-nuclear male sterility system in pearl millet

“…Also, an A 5 CMS system was identified in a pearl millet gene pool (Rai 1995). Among the various CMS systems reported so far, A 4 and A 5 CMS systems were found to have the most stable male sterility (Rai et al , 2001(Rai et al , 2006(Rai et al , 2009. Further, the frequency of maintainers is much higher for the A 4 CMS system than for the A 1 CMS system, and almost all lines are maintainers of the A 5 CMS system (Rai et al 2006).…”

New Sources of Resistance to Multiple Pathotypes of Sclerospora graminicola in the Pearl Millet Mini Core Germplasm Collection

“…P earl millet is grown on 26 million ha in the semiarid tropics of Africa and the Indian subcontinent (Rai et al, 2009). It is a staple food for millions of poor people living in the dry areas of the world where it is difficult to grow any other crop.…”