Registration of Partially Converted Germplasm from 44 Accessions of the USDA-ARS Ethiopian and Sudanese Sorghum Collections
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Forty-four sources of late-maturing sorghum [Sorghum bicolor (L.) Moench] germplasm registered with National Plant Germplasm System as genetic stocks (Reg. No. GS-655, PI 665639 to Reg. No. GS-698, PI 665682) were converted to early-maturing, dwarf-height F3 families and were released by the National Sorghum Foundation, the United Sorghum Checkoff Program, the USDA-ARS, and MMR Genetics in 2012. The sorghum working groups represented in these partially converted materials include zerazera, caudatum, caudatum-kafr, caudatum-guineense, caudatum-nigricans, caudatum-durra, nandyal, durra, durra-kafr, and durra-bicolor. Conversion was accomplished by crossing photoperiod-sensitive tropical accessions to elite line BTx406 during the winter in Puerto Vallarta, Mexico with selection of early-maturing, short (generally 2- or 3-dwarf) genotypes within F2 segregating populations under long-day, summer conditions in Vega, TX. Early-flowering short F2 selections were genotyped by sequencing, and five F2 plants with the greatest proportion of the exotic genome from each accession were selfed in Puerto Vallarta. The resulting F2:3 germplasm families, RSC02-3sel(bulk) to RSC149-3sel(bulk), represent new sources of germplasm from the USDA-ARS collection of a height and maturity readily usable to temperate-zone areas of the world. This germplasm will be useful in breeding programs by providing new genetic diversity from tropical accessions currently not available for use in hybrids. Crop Science Society of America.