Genetic recombination in Sorghum bicolor × S. macrospermum interspecific hybrids

Kuhlman, L.C. and Burson, B.L. and Klein, P.E. and Klein, R.R. and Stelly, D.M. and Price, H.J. and Rooney, W.L. (2008) Genetic recombination in Sorghum bicolor × S. macrospermum interspecific hybrids. Genome, 51 (9). pp. 749-756.

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Sorghum has been improved by public and private breeding programs utilizing germplasm mostly from within the species Sorghum bicolor. Until recently, cross-incompatibilities have prevented hybridization of S. bicolor with most other species within the genus Sorghum. Utilizing germplasm homozygous for the iap allele, hybrids were readily produced between S. bicolor (2n = 20; AAB1B1) and S. macrospermum (2n = 40; WWXXYYZZ). These hybrids were intermediate to the parents in chromosome number (2n = 30) and overall morphology. Meiosis in both parents was regular; S. bicolor had 10 bivalents per pollen mother cell (PMC) and S. macrospermum had an average of 19.96 bivalents per PMC. Six hybrids were studied cytologically and meiosis was irregular, with the chromosomes associating primarily as univalents and bivalents. There was an average of 3.54 bivalents per PMC, with a range of 0–8 bivalents, most of which were rods (98%). Using FISH (fluorescent in situ hybridization), moderate levels (2.6 II per PMC) of allosyndetic recombination were observed. Genomic relationships were sufficient to assign S. macrospermum the genomic formula AAB1B1YYZZ (Y and Z remain unknown). Allosyndetic recombination in the interspecific hybrids indicates that introgression through genetic recombination should be possible if viable backcrosses can be recovered.

Item Type: Article
Author Affiliation: Department of Soil and Crop Sciences, Texas A&M Univeristy, College Staiton, TX 77843, USA
Subjects: Crop Improvement > Genetics/Genomics
Crop Improvement > Plant Breeding
Divisions: Sorghum
Depositing User: Sandhya Gir
Date Deposited: 14 Dec 2010 16:25
Last Modified: 29 Dec 2010 19:47
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