Near-Isogenic Barley Lines with Genes for Resistance to Powdery Mildew

Kølster, P. and Munk, L. and Støle, O. and Løhde, J. (1986) Near-Isogenic Barley Lines with Genes for Resistance to Powdery Mildew. Crop Science, 26 (5). pp. 903-907.

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Near-isogenic lines differing in resistance genes were developed to study the effects of genes in barley (Hordeum vulgare L.) giving specific resistance to powdery mildew (Erysiphe graminis DC f.sp. hordei Em. Marchal). This paper describes breeding techniques, degree of similarity between isolines, and resistance genes present in the isolines. Twenty-four donors of resistance genes were crossed and backcrossed five times to the spring barley cv. ‘Pallas’, and homozygous resistant BC5F2 plants were selected. Resistant lines were evaluated and selected for phenotypic similarity with the recurrent parent in the BC5F3, through BC5F7 generations. To select for genetic similarity in the region of the resistance locus Ml-a, two linked hordein loci, Horl and Hor2, were studied in the BC5F4 generation. The resulting 24 near-isogenic lines originated from single BC5Fs4 plants in each of 24 different progenies. With a few exceptions, the near-isogenic lines were similar to the recurrent parent in morphological and physiological characteristics. Tests with the hordein genes indicated that double crossing-over occurred very close to the resistance locus Ml-a in five of the isogenic lines. With 22 powdery mildew isolates, 22 lines were similar to their donors in resistance reaction, while two lines gave reactions that indicated that they have lost a second resistance gene. The 24 near-isogenic lines comprised 14 lines with one resistance gene each, and 10 lines with two or more resistance genes. All the isogenic lines differ in resistance. The degree of genetic similarity between the 24 isogenic lines and the recurrent parent Pallas is high according to the morphological and physiological observations and may be even higher than theoretically expected in lines with double recombination in the region of locus Ml-a. These near-isogenic barley lines are recommended for both practical and theoretical research work in the barley-powdery mildew system.

Item Type: Article
Uncontrolled Keywords: Hordeum vulgare L., Erysiphe graminis DC f.sp. hordei Em. Marchal, Specific resistance, Hordein genes.
Author Affiliation: Graduate research assistant, Dep. of Plant Breeding and Crop Husbandry The Royal Veterinary and Agric. Univ., Copenhagen, Denmark
Subjects: Crop Improvement
Divisions: General
Depositing User: Mr Siva Shankar
Date Deposited: 26 Mar 2013 04:41
Last Modified: 26 Mar 2013 04:41
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