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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #355497

Research Project: Cereal Rust: Pathogen Biology and Host Resistance

Location: Cereal Disease Lab

Title: Adult plant leaf rust resistance derived from the wheat landrace cultivar Americano 44d is conditioned by interaction of three QTL

item Kolmer, James
item Garvin, David
item HAYDEN, M - Centre For Agriculture & Biosciences International (CABI)
item SPIELMEYER, W - Commonwealth Scientific And Industrial Research Organisation (CSIRO)

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2018
Publication Date: 3/2/2018
Citation: Kolmer, J.A., Garvin, D.F., Hayden, M., Spielmeyer, W. 2018. Adult plant leaf rust resistance derived from the wheat landrace cultivar Americano 44d is conditioned by interaction of three QTL. Euphytica. 214:59.

Interpretive Summary: Americano 44d is an old wheat cultivar that orignated from Uruguay in 1918 and it has had good resistance to an important disease of wheat called leaf rust that is caused by a fungus called Puccinia triticina. The objective of this study was to determine what genes in Americano 44d have provided the good leaf rust resistance for so long. The results indicated that there are three genes on different chromosomes that provide the leaf rust resistance. The genes individually do not provide much resistance, but combinations of two or three genes give good resistance to the leaf rust disease. The genes are likely genes that have not yet been chararcterized by wheat researchers. These genes are useful to wheat breeders and plant pathologists can be be used for the development of new wheat cultivars with good resistance to leaf rust.

Technical Abstract: Americano 44 is a landrace derived wheat cultivar from Uruguay that has had long lasting resistance to the leaf rust pathogen Puccinia triticina. A population of 100 recombinant inbred lines (RIL) derived from the cross 'Thatcher*3/Americano 44d' was evaluated for segregation of adult plant leaf rust resistance in four field plot tests and two greenhouse tests. A genetic map was constructed with 381 Diversity Array Technology (DArT) markers, five simple sequence repeat markers (SSR), and 11 kompetitive allele specific PCR (KASP) markers. Significant effects for reduction of leaf rust severity were found for quantitative trait loci (QTL) on chromosomes 3AS, 3DS and 6DS. Individually the 3AS and 3DS regions did not lower leaf rust severity in any of the tests compared to the susceptible parent, yet strongly interacted when present in the same genotype to lower leaf rust severity equal to the resistant parent. Genotypes with only the 6DS region had significantly lower leaf rust severity compared to the susceptible parent in three of the field plot tests. The 6DS QTL also interacted with the 3DS QTL to lower leaf rust severity. Major QTLs on chromosome 3AS and 3DS may be encoded by homoeoalleles.