Development of Gray Leaf Spot Resistant Maize Cultivars for Sustainable Maize Production and Food Security in Hills of Nepal, 2010

다국어 초록 (Multilingual Abstract)

Maize (Zeae mays L.) is a second important crop in the country and it is first staple food in high land region. The national average yield is 2.2 t/ha. About 80% maize areas falls in this region. An introduced fungus Gray Leaf Spot (GLS) caused by Cercospora zeae-maydis has caused yield loss an average of 75%. Genetic resistance has been effective control strategy to manage this disease. The main objectives of this work were to develop, evaluate and identify high yielding cultivars tolerant to GLS. Three sets of trials were conducted in Nepal and Korea. GLS evaluation trial-I consisted of 73 genotypes, GLS evaluation trial-II composed of 38 genotypes and mid altitude hybrid evaluation trial-III consisted of 12 genotypes. Exotic, semi exotic and local germplasm of different origins were used. Among these tested genotypes, tolerant genotypes were Thai 717S31-21-3×[TZMi407 × TZMi211-11- 2-1-1-B-B-B-B-B (5.2t/ha), Pioneer12 × MASynVAR-5 F2 (5.0 t/ha) and MA SynVAR-5 F2 × Thai 919 S3 4-5-4 (4.7t/ha) with GLS mean score 2.7, 1.5 and 1 respectively in trial-I. In trial-II, superior genotypes were KYM33 × TZi3 (7.6t/ha), KYM33 × TZi18 (7.5 t/ha) and KYM33 × P45 (7.4 t/ha) with GLS scores 1.4, 2.4 and 2.5 respectively. Similarly in trial-III, high yielding genotypes were MASynVAR-5 (11.0t/ha), and TZMi407×87036- 9-1-1-1-B-B-B/TZMi102×90113-5-3-2-2-B-B-B-B (9.8t/ha). These hybrids and their parents will use to introgress resistant genes to breed better tolerant maize cultivars for Nepal.