Fusarium ear rot [caused by Fusarium verticillioides (Sacc.) Nirenberg] is one of the most prevalent diseases of maize (Zea mays L.) worldwide, and has one of the greatest negative economic impacts on this cereal crop globally. Fusarium ear rot is a highly complex trait, under polygenic control with minor effects per gene and moderate heritability, and is strongly influenced by environmental conditions. The aim of this study was to identify genomic regions, including putative candidate genes, associated with resistance to Fusarium ear rot and the starburst pattern caused by F. verticillioides under artificial inoculation. We conducted a genome‐wide association study using phenotypic data from three environments on a panel of 183 inbred lines and a set of 267,525 single‐nucleotide polymorphism (SNPs) generated using genotyping by sequencing. Fourteen SNPs were significantly associated with Fusarium ear rot and two for starburst, some of which were colocalized to previously reported quantitative trait loci regions, and some of which were novel. Four genes linked to the associated SNPs encode defense‐related proteins, including gibberellin 2‐oxidase4, a glucosyltransferase, a Ras‐related protein RHN1, and phosphoribosylanthranilate transferase (PAT). Each of these SNPs explains a considerable proportion of the phenotypic variance, ranging from 15 to 25%. Once these SNPs are validated, they will be useful for marker‐assisted selection and for a better understanding of maize resistance to Fusarium ear rots.

Popcorn is a popular snack food with higher grain value compared with “field corn” maize (Zea mays L.). In general, popcorn germplasm is less improved than common maize cultivars, with less favorable agronomic performance and greater susceptibility to pests, diseases, and lodging, especially in tropical environments. One approach to expanding and improving popcorn germplasm is to introduce favorable alleles for agronomic performance from field corn. If markers tagging quantitative trait loci (QTLs) associated with popping expansion were identified, they could be selected with markers to maintain popping expansion in breeding populations derived from crosses between field and popcorn germplasm. The objectives of this study were to identify single nucleotide polymorphism (SNP) markers and putative candidate genes associated with higher popping expansion in a diverse sample of popcorn and field corns relevant to Brazilian breeding programs. We applied a comprehensive genome‐wide association study (GWAS) for popping expansion, using 165,089 SNP markers in 183 inbred lines with 2 yr of trial data. Four SNPs were significantly associated with popping expansion, three of which were colocalized to previously reported meta‐QTLs, and one that was novel. Annotated genes closely linked to the associated SNPs were identified with functions related with starch content, which plays an important role in popping expansion quality. If these associations can be validated independently, they can be useful for breeders to select agronomically superior genotypes with greater popping expansion.

The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F 1 crosses from a partial diallel scheme, 22 S 1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR), Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956) was applied for the evaluation of the general combining ability (GCA) and specific combining ability (SCA). The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.

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The objective of this study was to evaluate the combining ability and inbreeding depression of commercial maize hybrids for agricultural traits. Twenty-two commercial maize hybrids, 96 F 1 crosses from a partial diallel scheme, 22 S 1 populations and 4 controls were evaluated in a 12x12 simples square lattice experimental setup, totaling 144 treatments, in the municipality of Sabáudia (PR), Brazil, for harvests from 2011/2012 and 2012/2013. Three traits were evaluated: grain yield, plant height and ear height. The Griffing method (1956) was applied for the evaluation of the general combining ability (GCA) and specific combining ability (SCA). The 30B39, 30K64 and 30B30 hybrids showed increased yield, 30F53 and P1630 showed reduced plant height and AG9040 and AG7010 showed reduced ear height. These hybrids can be recommended for the extraction of inbred lines and formation of composites followed by intrapopulation selection. The combinations 30B39 x AG8088, 30B39 x AG9045 and P1630 x AG8021 showed desirable SCA effects for grain yield, plant height and ear height and are recommended for use in reciprocal recurrent selection programs. High magnitudes of inbreeding depression were verified for yield and lower values for inbreeding depression for plant and ear heights. Thus, strategies are recommended for interpopulation breeding accompanied by inbred lines extraction.