Identification of Quantitative Trait Loci for Grain Yield and Other Traits in Tropical Maize Under High and Low Soil‐Nitrogen Environments

Abstract

Low soil Nitrogen (low‐N) is one of the most important abiotic stressors responsible for significant yield losses in maize (Zea mays L.). The development and commercialization of low‐N–tolerant genotypes can contribute to improved food security in developing countries. However, selection for low‐N tolerance is difficult because it is a complex trait with strong interaction between genotypes and environments. Marker‐assisted breeding holds great promise for improving such complex traits more efficiently and in less time, but requires markers associated with the trait of interest. In this study, 150 BC2F1 families of CML 444 × CML 494 were evaluated at two locations for two consecutive seasons to identify SNP markers associated with quantitative trait loci (QTL) for yield and other agronomic traits under low‐ and high‐N environments. A total of 13 QTL were identified with 158 SNP markers, of which nine and four QTL were detected under low‐ and high‐N environments, respectively. Five QTL one each for grain yield (qgy‐1), days to silking (qdts‐1) and anthesis‐ silking interval (qasi‐6), and two for stay green characteristic (qsg‐1 and qsg‐4) were close to their adjacent markers, with an interval of 0.7 to 5.2 cM between them and explained phenotypic variance of 9 to 21%. These QTL would be invaluable for rapid introgression of genomic regions into maize populations using marker‐assisted selection (MAS) approaches. However, further validation of these QTL is needed before use in MAS.

Genetic Dissection of Grain Yield and Agronomic Traits in Maize under Optimum and Low-Nitrogen Stressed Environments

“…Chromosomes 1, 3 and 8 had the highest number of QTL and could be targeted for further QTL studies for GY and related secondary traits under both optimum and low-N stressed conditions. In another study [17], 13 QTL were identified under both low and high N levels. On chromosome 10, overlapping QTL were found for grain yield, ASI, and AD.…”

Breeding Maize for Tolerance to Acidic Soils: A Review

“…The identification of QTL linked to secondary traits correlated with yield performance under conditions of either Fe or Mn toxicity could further enhance the efficiency of maize breeding for tolerance to low soil pH. QTL associated with secondary traits such as days to silking, anthesis-silking interval, and stay green characteristic under stressed environments [142,143] could have the potential to be utilized as indirect molecular predictors of performance of plants exposed to Fe and Mn toxicities. Moreover, it is relevant to check whether any of the previously identified genes or QTL for Al tolerance have pleiotropic effects for tolerance to Fe and Mn toxicities.…”

Identification of QTLs for grain yield and other traits in tropical maize under Striga infestation

“…During the past few years, the recent advances in molecular marker technologies have facilitated the construction of high-density genetic linkage maps and detection of novel QTL associated with quantitative traits in segregating populations and the characterization of the map positions in the genome of crop plants [ 26 – 28 ]. In maize, studies on QTL identification for complex traits have focused mainly on abiotic stresses such as drought [ 29 – 31 ] and low soil nitrogen [ 32 , 33 ] and good progress has been made. Also, significant advances have been made in the identification of QTLs in segregating populations under biotic stresses such as the Maize Lethal Necrosis (MLN), Southern corn rust, and Tar Spot Complex (TSC).…”