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Genetic Transfer of Gynomonoecy from Diploid to Triploid Eastern Gamagrass
Author(s) -
Dewald C. L.,
Kindiger B.
Publication year - 1994
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/cropsci1994.0011183x003400050022x
Subject(s) - biology , ploidy , apomixis , plant reproductive morphology , polyploid , reproduction , inflorescence , genetics , sexual reproduction , inbreeding , botany , gene , population , demography , sociology
Seed yields of eastern gamagrass, Tripsacum dactyloides (L.) L. (Andropogoneae), are limited by scarcity of fertile female florets and excessive maleness in its monoecious inflorescence. Gynomonoecious variants, with sex reversal in formerly male spikelets and reactivation of suppressed female florets, are known that have a greater seed production potential than monoecious forms. Sexual reproduction is exclusively observed in diploid eastern gamagrass, whereas facultative apomictic reproduction is the rule in polyploid forms. This study was designed to combine recessive genes for gynomonoecy from diploids with genes for apomixis from polyploids to develop true breeding (apomictic), prolific seed producing (gynomonoecious) lines. Diploid parents with allele(s) for gynomonoecy were used in each of three generations of interploidy matings to transfer gynomonoecy from diploid to triploid eastern gamagrass. A first generation fertile triploid hybrid and a second generation B III derived tetraploid hybrid were used as intermediates for genetic transfer. Ninety triploid progeny from the third generation of cytotype intermatings yielded three gynomonoecious individuals, one with relatively good female fertility and two that failed to set seed. The low percentage (3.3%) of triploid progeny that inherited the gynomonoecions trait indicates a strong selection force against gynomonoecy at the triploid level. The breeding strategy employed is considered a practical method to move genes from diploid to higher ploidy levels for subsequent stabilization by apomixis.