Inheritance and QTL Analysis of Field Resistance to Ashy Stem Blight in Common Bean

Authors

Phillip N. Miklas, USDA-ARSFollow
Valerie Stone, Whitehead Institute
Carlos A. Urrea, University of Nebraska-LincolnFollow
E. Johnson, North Carolina State University
James S. Beaver, University of Puerto RicoFollow

Date of this Version

7-1998

Citation

Published in Crop Sci. 38:916-921 (1998).

Comments

U.S. government work.

Abstract

Ashy stem blight [caused by Macrophomina phaseolina (Tassi) Goid.] can be a serious disease of common bean (Phaseolus vulgaris L.) under drought and high temperature conditions in some regions. The mode of inheritance of valuable sources of resistance is lacking. We studied inheritance of field resistance to ashy stem blight in a recombinant inbred population (’Dorado’ × XAN 176) consisting of 119 F_5:7 recombinant inbred lines (RILs) tested in replicated experiments across 2 yr. A score from 1 to 9 (no disease to severe disease) was used to measure disease reaction. Moderate H_Ns (0.53 and 0.57) and near-normal frequency distribution of RILs for mean disease score each year indicated a lack of discrete segregation classes. The phenotypic variation across a subgroup composed of 79 RILs was further investigated with 165 randomly amplified polymorphic DNA (RAPD) markers by one-way analyses of variance and interval mapping. Five quantitative trait loci (QTL), explaining 19, 15, 15, 13, and 13% of the phenotypic variation for disease score, were detected in 1993. Three of these QTL, explaining 15,12, and 12% of the variation in disease reaction, were detected in 1994. Multiple QTL regression models (P < 0.01) explained up to 47% (four loci) of the phenotypic variation for disease score in 1993 and 28% (three loci) in 1994. The five QTL, all derived from XAN 176, generally showed additive effects. These QTL-linked RAPD markers may prove useful for indirect selection of field resistance to ashy stem blight derived from XAN 176.