Transfer of germ plasm from the secondary to the primary gene pool in pennisetum.
Germ plasm from the A'-genome of Pennisetum purpureum Schum. (A'A'BB) of the secondary gene pool was transferred to cultivated pearl millet (AA) [P. glaucum (L.) R. Br.] by pollinating cytoplasmicnuclear male-sterile (cms) pearl millet with fertile allohexaploid pearl millet x P. purpureum hybrids (AAA'A'BB). Certain allohexaploids used as pollinators on cms pearl millet resulted in 14-chromosome diploid pearl millet progenies. Three types of diploid pearl millet plants were produced in addition to the expected 28-chromosome AAA'B-genome plants: (1) cms plants with only the A-genome, (2) cms plants with the A- and A'-genomes, and (3) fertile plants with the A- and A'-genomes. The latter group has allowed the utilization of genes for fertility restoration, stiff stalk, maturity, height, and morphological characteristics from the A'-genome of P. purpureum in the pearl millet breeding program. Production of monoploid gametes by the allohexaploids appeared to be genetically controlled.
University of Georgia, Coastal Plain Experiment Station, USDA-ARS, 31793, Tifton, GA, USA.
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