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Cytology and Reproduction of Reciprocal Backcrosses Between Pearl Millet and Sexual and Apomictic Hybrids of Pearl Millet ✕ Pennisetum squamulatum 1
Author(s) -
Dujardin Michel,
Hanna Wayne
Publication year - 1985
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1985.0011183x002500010016x
Subject(s) - apomixis , biology , pennisetum , pollen , hybrid , pearl , ploidy , botany , sexual reproduction , reciprocal cross , agronomy , genetics , philosophy , theology , gene
Interspecific hybrids ( 2n = 41) between pearl millet, Pennisetum americanum L. Leeke ( 2n = 4x = 28), and P. squamulatum Fresen ( 2n = 6x = 54) were used ~s pollen and maternal parents and backcrossed (BC) to pearl mi}let to determine the potential for germplasm exchange and for transfer of apomixis to pearl millet. Backcrosses to diploid pearl millet ( 2n = 14) resulted in 12 28‐ or 27‐chromosome male and female‐sterile plants from more than 600 pollinated inttorescences. Backcrosses to tetraploid pearl millet ( 2n = 4x = 28) resulted in 2830 BC 1 progenies (crossability 91%). These BC 1 progenies had somatic chromosome numbers ranging from 2n = 32 to 2n = 39 with a mode of 2n = 35 chromosomes. They were perennial and more closely resembled pearl millet in morphological characteristics than did the original interspecific hybrids. Meiosis was irregular with a mean of 4.88 bivalents. Univalents, trivalents, quadrivalents, and other multivalents were present in all microsporocytes. Eightyfour percent of these plants did not shed pollen and the remaining 16% were semi‐sterile with pollen stainability ranging up to 6.6%. Among 177 semi‐sterile BC 1 plants resulting from crosses with highly apomictic F 1 hybrids as pollen parents, 55 progenies showed only apomictic t:mbryo sac development. Seed set ranged from 0 to 14 seed per head under open‐pollination. Similar chromosome behavior and fertility as above were observed in progeny from reciprocal backcrosses between the sexual interspecific hybrids and diploid or tetraploid pearl millet. The production of partially male‐fertile apomictic BC 1 plants should make it possible to continete gene transfer from P. squamulatum to pearl millet in succeeding generations.