Authors: D E Obert A K Fritz J L Moran Sukhwinder Singh Jackie C Rudd M A Menz
Publish Date: 2005/04/07
Volume: 110, Issue: 8, Pages: 1439-1444
Abstract
Hostplant resistance is the most economically viable and environmentally responsible method of control for Puccinia triticina the causal agent of leaf rust in wheat Triticum aestivum L The identification and utilization of new resistance sources is critical to the continued development of improved cultivars as shifts in pathogen races cause the effectiveness of widely deployed genes to be short lived The objectives of this research were to identify and tag new leaf rust resistance genes Forty landraces from Afghanistan and Iran were obtained from the National Plant Germplasm System and evaluated under field conditions at two locations in Texas PI 289824 a landrace from Iran was highly resistant under field infection Further evaluation revealed that PI 289824 is highly resistant to a broad spectrum of leaf rust races including the currently prevalent races of leaf rust in the Great Plains area of the USA Eight F1 plants 176 F2 individuals and 139 F23 families of a cross between PI 289824 and T112 susceptible were evaluated for resistance to leaf rust at the seedling stage Genetic analysis indicated resistance in PI 289824 is controlled by a single dominant gene The AFLP analyses resulted in the identification of a marker P39 M48367 linked to resistance The diagnostic AFLP band was sequenced and that sequence information was used to develop an STS marker TXW200 linked to the gene at a distance of 23 cM The addition of microsatellite markers allowed the gene to be mapped to the short arm of Chromosome 5B The only resistance gene to be assigned to Chr 5BS is Lr52 The Lr52 gene was reported to be 165 cM distal to Xgwm443 while the gene in PI 289824 mapped 167 cM proximal to Xgwm443 Allelism tests are needed to determine the relationship between the gene in PI 289824 and Lr52 If the reported map positions are correct the gene in PI 289824 is unique
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