Transforming Agriculture, Perennially

Scientific Publications


High proportion of diploid hybrids produced by interspecificdiploid 3 tetraploid Sorghum hybridization

Author: Stan Cox, Pheonah Nabukalu, Andrew H. Paterson, Wenqian Kong, Susan Auckland, Lisa Rainville, Sheila Cox, Shuwen Wang.

Publication: Springer Science+Business Media B.V. 2017

A perennial version of grain sorghum [S.bicolor (L.) Moench] would create opportunities for greatly reducing tillage and preventing soil degradation. Efforts to select for perenniality and grain production among progeny of hybrids between S.
bicolor (2n = 20) and the weedy tetraploid perennial S. halepense (L.) Pers. (2n = 40) are complicated in that Fhybrids produced by diploid 9 tetraploid sorghum crosses are usually tetraploid. In 2013, a set of random pollin ations between 19 diploid cytoplasmic male-sterile inbred lines and 43 tetraploid perennial plants produced 165 Fhybrid plants, more than 75% of which had highly atypical plant, panicle, and
seed phenotypes. Phenotypic segregation in Fpopulations derived from atypical hybrids was also anomalous. Examination of mitotic metaphase cells in For Froot tips revealed that 129 of the 165 hybrids were diploid. Parentage of the diploid progenies was conrmed using simple-sequence repeat analysis.  The mechanism by which diploid hybrids arise from diploid 9 tetraploid crosses is unknown, but it may

involve either production of monohaploid (n = 10) pollen by the tetraploid parent or chrom osome elimination during early cell divisions following formation of the triploid zygote. The ability to produce diploigermplasm segregating for S. bicolor and S. halepense alleles could have great utility, both for the development of perennial sorghum and for the improv event of conventional grain sorghum.
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