Genetic dissection of popping quality traits in tropical popcorn (Zea mays L. var. everta)

Abstract

Mapping quantitative trait loci (QTL) for popping-related traits viz., popping percentage (PP), popping expansion volume (PEV), flake volume (FV) and seed index (SI), is important in popcorn breeding. Therefore, 198 recombinant inbred lines (RILs) developed from a cross of popcorn and field corn lines were phenotyped for popping traits and genotyped using genotyping-by-sequencing (GBS). In the RILs, mean values for PP, FV, PEV and SI ranged from 15.7 to 95.4%, 14.0–484.4 cm, 1.6–21.4 cm and 9.0–28.6 g, respectively. The broad sense heritability (H2%) of the target traits ranged from 82.2 to 96.1% within and 58.9–71.0% between environments. The linkage map based on 6627 filtered single nucleotide polymorphism (SNP) was 2124.30 cM with an average markers interval of 0.33 cM. We mapped four major stable QTLs, one for each SI, PEV, PP and FV on chromosomes 3, 5, 6 and 9, and one minor stable QTL for FV on Chromosome 9 explaining 9.30–29.29% of the phenotypic variance. One major and two minor environment-specific QTLs were mapped on chromosomes 1 and 4 for PEV and SI. In addition, genes involved in kernel endosperm development and metabolic processes were identified and these all can be explored in popcorn improvement.