Association of Lr 34 gene complex with spot blotch disease resistance at molecular level in wheat (Triticum aestivum L.)

Suneel Kumar; Ravi P. Singh; Arun Kumar Joshi; Marion S. Röder; Parveen Chhuneja; Gurvinder S. Mavi; Uttam Kumar

Suneel Kumar Division of Germplasm Evaluation, ICAR-National Bureau of Plant Genetic Resources, New Delhi 110 012
Ravi P. Singh CYMMYT, NASC Complex, DPS Marg, New Delhi 110 012;
Arun Kumar Joshi CIMMYT, EI Batan, C. P. 56237 Texcoco, Mexico
Marion S. Röder Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), 06466 Gatersleben, Germany
Parveen Chhuneja Punjab Agriculture University, Ludhiana, Punjab 141 004
Gurvinder S. Mavi Punjab Agriculture University, Ludhiana, Punjab 141 004
Uttam Kumar Borlaug Institute for South Asia (BISA), Ludhiana, Punjab 141 004

Keywords: Spot blotch, Lr34, leaf tip necrosis, SSR, AUDPC

Abstract

Leaf rust and spot blotch are among most important wheat diseases causing substantial yield losses in several parts of the world. The studies at phenotypic level suggested that, leaf tip necrosis (LTN) not only associated with multi fungal resistance gene Lr34 but also confer spot blotch resistance. This LTN – spot blotch association has not been tested at molecular level and hardly validated in different genetic backgrounds. A total of 87 near isogenic lines (NILs) segregating for Lr34 gene were evaluated for spot blotch resistance and genotyped with the molecular markers linked to QTL QSb.bhu-7D. A set of 147 advanced breeding lines was also evaluated for spot blotch besides being genotyped with markers belonging to Lr34 genic region. Out of 14 markers located on chromosome 7D, four markers segregated in NILs. The genotypic and phenotypic results indicated that the markers reportedly linked with spot blotch differentiate Lr34+ and Lr34- lines and vice versa. This supports the hypothesis that Lr34, Yr18 and QSb.bhu-7D lies in the same gene region. Hence, the linked markers may be used to select both for Lr34 and spot blotch resistant lines.