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United States Department of Agriculture

Agricultural Research Service

Research Project: Small Fruit and Ornamental Genetic Research for the Mid-South

Location: Southern Horticultural Research

Title: Analysis and mapping of Rhizoctonia root rot resistance traits from the synthetic wheat (Triticum aestivum L) line SYN-172

Author
item Mahoney, Aaron
item Babiker, Ebrahiem
item Okubara, Patricia
item See, Deven
item Paulitz, Timothy
item Hulbert, Scot

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/10/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rhizoctonia root rot disease is one of the main obstacles to adoption of reduced tillage in the Pacific Northwest regions. In previous efforts to find root rot resistance, a CIMMYT synthetic wheat line, SYN-172 was found to have little to no seedling stunting from disease and lower root disease scores. To identify chromosomal regions associated with this resistance, 689 polymorphic markers were used to genotype a population of plants developed by crossing the resistant line SYN-172 with a susceptible cultivar ‘Lousie’. The population was evaluated for seedling stunting in field green bridge and growth chamber environments. With this method we found that there are five regions for resistance on chromosome arms 1AL, 2AL, 5BL, 7DS, and 7DL. The 2AL was consistently detected in all four of the environments tested. The 7DL was found consistently in all three of the field environments. Both the 2AL and 7DS have not been previously reported, and will be useful for breeding root rot resistance germplasm.

Technical Abstract: The prevalence of root disease after planting in cold spring soils has hindered the adoption of reduced or no-tillage cereal cropping systems in the Pacific Northwest. In particular, Rhizoctonia solani AG8, a necrotrophic root pathogen, can cause significant damage to wheat stands under these conditions. In previous efforts to find root rot resistance, a CIMMYT synthetic wheat line, SYN-172 was found to have little to no seedling stunting from disease and lower root disease scores. To identify trait-maker associations, a population consisting of 150 BC1F5 recombinant inbred lines from a cross of ‘Louise’, a typically susceptible PNW cultivar, and SYN-172 was created. 689 polymorphic markers were used identify trait-marker associations for seedling stunting in field green bridge and growth chamber environments. In total five quantitative trait locius (QTL) were found on chromosome arms 1AL, 2AL, 5BL, 7DS, and 7DL. One QTL on chromosome 2AL was consistently identified detected in all four of the environments tested. A second QTL on 7DL was found consistently in all three of the field environments. The QTL on 2AL and 7DS have not been previously reported, and will be useful root rot resistance genes when transferred into the PNW spring wheat germplasm.

Last Modified: 09/25/2017
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