Genetic architecture of lodging resistance revealed by genome-wide association study in maize (Zea mays L)

Lodging is one of key factors influencing biomass yield, restricting planting density and reducing mechanical harvesting productivity in maize. Targeted cultivating lodging resistance varieties with screened lines is an economical and effective approach to improve ability of maize lodging resistance. To accomplish this objective, we performed phenotypic assessment of seven lodging-related traits in a diverse maize population consisting of 290 inbred lines and conducted a genome-wide association study with 201 SSR markers to detected marker-trait associations. Seven lodging-related traits all showed broad phenotypic variations. Through evaluation of stalk pushing resistance in the field for two years, a number of 32 inbred lines featured with strong lodging resistance were selected out. Correlation analysis indicated that stalk pushing resistance had a significantly positive correlation with third internode diameter and fourth internode diameter and a significantly negative correlation with ear height. Furthermore, a total of 27 and 13 significant associations for lodging-related traits were identified in year 2012 and 2013, respectively. Interestingly, three associations on chromosome 4, 5, and 6 were discovered in both years. Thus, this study provides useful information for understanding genetic architecture of lodging resistance in maize and will benefit maize marker-assistant breeding program with improving lodging resistance.