Identification of quantitative trait loci involved in the response to cold stress in maize (Zea mays L.)

The effect of low temperature on the physiology of maize has been well studied, but the genetics behind cold tolerance is poorly understood. To better understand the genetics of cold tolerance we conducted a quantitative trait locus (QTL) analysis on a segregating population from the cross of a cold-tolerant (EP42) and a cold-susceptible (A661) inbred line. The experiments were carried under cold (15 A degrees C) and control (25 A degrees C) conditions in a phytotron. Cold temperature reduced the shoot dry weight, number of survival plants and quantum yield of electron transport at photosystem II (I broken vertical bar PSII) and increased the anthocyanin content in maize seedlings. Low correlations were found between characteristics under low and optimum temperature. Ten QTLs were identified, six of them at control temperatures and four under cold temperatures. Through a meta-QTL analysis we identified three genomic regions in chromosomes 2, 4 and 8 that regulate the development of maize seedlings under cold conditions and are the most promising regions to be the target of future marker-assisted selection breeding programs or to perform fine mapping to identify genes involved in cold tolerance in maize.