Abstract:

Banded leaf-sheath blight (BLSB) caused by Rhizoctonia solani Kühn in maize (Zea mays L.) is an important disease in China and Southeast Asia. Knowledge of the identification of quantitative trait loci (QTLs) for tolerance to this disease will facilitate the development of maize cultivars (hybrids) resistant to the disease. A genetic linkage map covered 1 666 cM on total ten chromosomes, with an average interval length of 11.4 cM was constructed using 146 simple sequence repeat (SSR) markers and the software MAPMAKER version 3.0b based on a maize population consisting of 229 F₂ individuals derived from a cross R15 (resistant) × 478 (susceptible). The disease index from the population of 229 F_2:4 lines were evaluated for BLSB resistance under artificial inoculation. With the method of composite interval mapping (CIM) described in QTL Cartographer V2.0 procedure, 9 QTLs controlling resistance to BLSB were identified on chromosomes 1, 2, 3, 4, 5, 6 and 10, accounting for 3.72% to 7.19% of the phenotypic variance. Among them, two QTLs were located in the region of 6.01 of chromosome where the resistance genes were usually located, which will be the important QTLs in the future study.

Key words: Maize, Banded leaf-sheath blight, SSR marker, Quantitative trait loci