Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/2018
Publication Date: 2/28/2019
Citation: Chen, J., Xin, Z., Echevarria Laza, H.J. 2019. Registration of BTx623dw5 - a new sorghum dwarf mutant. Journal of Plant Registrations. 13:254-257. https://doi.org/10.3198/jpr2018.09.00058crgs.
Interpretive Summary: Dwarf genes are a driving force for the Green Revolution. Although sorghum is an important crop in the United States, improvements in its yield potential have lagged behind other crops like corn, wheat and rice. A reduction in plant height, or semi-dwarfism, has been important to increasing the yields of rice and wheat. While a single dwarf gene is employed in breeding for lodging resistant semi-dwarf varieties in wheat and rice, sorghum breeders need to use a combination of three or four dwarf genes to breed semi-dwarf varieties. Thus, new and efficient dwarf genes are needed to increase breeding efficiency for semi-dwarf grain sorghum. ARS scientists from Lubbock, Texas are registering a new dwarf mutant, dw5, in which the dwarfism is caused by a single gene that is distinct from the previously known dwarf genes. The dw5 mutant provides an alternative approach to sorghum breeders to breed for semi-dwarf grain sorghum.
Technical Abstract: The USDA-ARS has released a new dwarf sorghum [Sorghum bicolor (L.) Moench) mutant BTx623dw5 (PI xxxxxx). Dwarf genes are important driving force for the Green Revolution. In both wheat and rice, single dwarf locus is used to breed high yielding semi-dwarf cultivars. However, in sorghum, any of the known dwarf loci alone is insufficient to breed semi-dwarf grain sorghum fitting for modern farm practices. Therefore, four dwarf genes have been traditionally used collectively in combinations to breed sorghum cultivars of the desired height for machine harvesting. Here we register a new dwarf mutant isolated from a mutagenized BTx623 mutant library that is genetically different in controlling the dwarf phenotype from those of currently known in sorghum. We designate this newly identified dwarf genotype as dwarf 5 (dw5). The dwarf phenotype of dw5 was evaluated in the winter nursery of Puerto Rico under short day and mild temperature conditions and in Lubbock, Texas in summer under long day and hot weather conditions. Presence of dw5 mutation reduced the plant height of BTx623 from 155 to 74 in Puerto Rico and from 113 to 72 in Lubbock. The dwarf phenotype in dw5 mutant is caused by a single nuclear gene mutation and inherited in a recessive manner. It can be easily identified and bred into other sorghum lines through recurrent backcrossing. The dw5 mutation provides a new way to control sorghum height.