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Artículo de publicación ISIBackground: The genetic diversity and structure of 31 popcorn accessions of the germplasm bank of the State University of Maringa were assessed using 30 microsatellite primers. Results: 127 alleles were identified from 30 evaluated loci. The number of alleles per locus ranged from two to eight. The overall mean of the polymorphic loci averaged 79.89%. The primers UMC1549 and UMC1072 detected polymorphism in all accessions analyzed. The mean observed heterozygosity ranged from 0.07 to 0.30 and the highest proportion of heterozygous plants was observed in accession BOZM 260 (Ho = 0.30). The analysis of molecular variance revealed that 60% of the total genetic variation was found within accessions and 40% was found between accessions. The Bayesian clustering approach grouped the 31 accessions into two genetically differentiated clusters. The dendrogram revealed that accessions TATU 2 and ARZM 05 083 are genetically less similar than the others. Conclusions: The analysis allowed to identify microsatellite lociwith high levels of heterozygosity (UMC1549 and UMC1072). These loci can be indicated as promising for detecting polymorphisms in popcorn accessions and in the monitoring of genetic improvement programs. Moreover, allowed to identify heterozygous accessions (BOZM 260), this accession showed allelic variation at all analyzed microsatellite loci and can be recommended for crosses with plants that have desirable agronomic characteristics, with a view to the broadening of the genetic base of popcorn accessions and developing new cultivars.CNPq (National Council for Scientific and Technological Development) 140802/2009-

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In this study, we aimed to estimate general and specific combining abilities (GCA and SCA, respectively) and to verify genetic divergence (Rogers distance, Unweighted Pair-Group Method Using Arithmetic Average - UPGMA) using microsatellite markers in maize inbred lines. Using a partial diallel scheme, a total of 19 inbred lines were crossed as (9 x 10), which were derived from the single hybrids SG6015 and P30F53, respectively. The 90 hybrids were evaluated in an incomplete randomized block design with common checks and three replications during the 2017-2018 growing season. Flowering time, average plant height, ear height insertion, average ear diameter, ear length, number of lodged and broken plants, mass of 100 grains and grain yield were measured. According to the analysis of variance, GCA, and SCA were significant (p < 0.05) in all the measured traits; inbred line B as well as 1 and 8, derived from the single hybrids SG6015 and P30F53, respectively, were selected due to their higher GCA values in grain yield to be used in crosses as testers, while the single cross hybrid (B x 1) was selected due to their higher SCA value in grain yield to be used in future breeding programs. The molecular marker analysis divided the inbred lines into two groups, where the highest dissimilarity (0.74) was observed between lines A and 9; however, these did not result in a high SCA value, therefore the hybrids obtained by such crossings were not selected for grain yield.

Our objectives were to evaluate general and specific combining ability (SCA) and genetic divergence among tropical maize inbred lines using single sequence repeat (SSR) markers. Thirteen inbred lines were crossed based on a complete diallel scheme. Hybrids and three checks were evaluated in a lattice experimental design. Silk and anthesis flowering, average plant height, average ear height, white spot (Pantoea ananatis) and gray leaf spot (Cercospora zeae-maydis) severity, and grain yield were evaluated. Significant differences (p < 0.05) for general and specific combining abilities were observed for all traits. Based on additive effects, inbred lines 1 (Flash) and 12 (SG 6015) were selected to reduce the flowering period and plant and ear height. Inbred lines 2 (CD 303) and 3 (AG 8080) were selected to reduce disease severity. For the simultaneous increase in grain yield and reduced severity of diseases, line 11 (AG 9090) as a parent or tester in topcross schemes is recommended. According to non-additive effects, crosses 2 (CD 303) × 13 (DKB 747) and 11 (AG 9090) × 12 (SG 6015) were selected for grain yield and future breeding programs. Six groups were identified using SSR markers; a major group contained six inbred lines. Because of the minor relationship between genetic divergence and SCA effects on grain yield limits, the use of the groups for future divergent crosses is recommended.