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COUNTERFEIT HYBRIDS BETWEEN TRIPSACUM AND ZEA (GRAMINEAE)
Author(s) -
Wet J. M. J.,
Newell C. A.,
Brink D. E.
Publication year - 1984
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1984.tb12510.x
Subject(s) - biology , hybrid , ploidy , pollen , parthenogenesis , meiosis , apomixis , genome , chromosome , botany , genetics , gene , embryo
Diploid (2 n = 36) Tripsacum australe Cutler and Anderson var. hirsutum de Wet and Timothy, T. cundinamarce de Wet and Timothy, T. dactyloides (L.) L. var. dactyloides and var. meridonale de Wet and Timothy, and T. laxum Nash were crossed with Zea mays L. (2 n = 20) as the pollen parent. True hybrids combine the cytologically nonreduced genome of Tripsacum (36 chromosomes) with the haploid (10 chromosomes) or more rarely diploid (20 chromosome) genome of Zea. Maternal offspring with 2 n = 36 Tripsacum chromosomes commonly result from parthenogenetic development of cytologically nonreduced eggs. Some individuals with 2 n = 36 Tripsacum chromosomes, however, resemble true hybrids in phenotype. These counterfeit hybrids incorporated Zea genetic material into their Tripsacum genomes without true fertilization having taken place. Offspring of counterfeit hybrids that were grown to maturity resembled their mothers in phenotype, and must have originated parthenogenetically. It is proposed that counterfeit hybrids are also produced in nature, and that this process contributes to origins of variation in gametophytic apomicts, and perhaps also in sexually reproducing species.