Functional molecular markers (EST-SSR) in the full-sib reciprocal recurrent selection program of maize (Zea mays L.)

Abstract

ABSTRACT. This study aimed to improve grain yield in the full-sib reciprocal recurrent selection program of maize from the North Fluminense State University. In the current phase of the program, the goal is to maintain, or even increase, the genetic variability within and among populations, in order to increase heterosis of the 13th cycle of reciprocal recurrent selection. Microsatellite expressed sequence tags (EST-SSRs) were used as a tool to assist the maximization step of genetic variability, targeting the functional genome. Eighty S 1 progenies of the 13th recurrent selection cycle, 40 from each population (CIMMYT and Piranão), were analyzed using 20 EST-SSR loci. Genetic diversity, observed heterozygosity, information content of polymorphism, and inbreeding coefficient were estimated. Subsequently, analysis of genetic dissimilarity, molecular variance, and a graphical dispersion of genotypes were conducted. The number of alleles in the CIMMYT population ranged 7345 EST-SST markers in the maize breeding program ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (3): 7344-7355 (2015) from 1 to 6, while in the Piranão population the range was from 2 to 8, with a mean of 3.65 and 4.35, respectively. As evidenced by the number of alleles, the Shannon index showed greater diversity for the Piranão population (1.04) in relation to the CIMMYT population (0.89). The genic SSR markers were effective in clustering genotypes into their respective populations before selection and an increase in the variation between populations after selection was observed. The results indicate that the study populations have expressive genetic diversity, which corresponds to the functional genome, indicating that this strategy may contribute to genetic gain, especially in association with the grain yield of future hybrids.

Inference of genetic diversity in popcorn S3 progenies

“…In population genetic studies, the estimate of F is considered one of the most important parameters. F estimates the balance between homozygotes and heterozygotes, and the mean values obtained are related to the allelic richness observed in the populations (Galvão et al, 2015). In breeding programs aimed at strain development, the analysis of F allows us to infer important information about genotype homozygosis level.…”

“…This broadens the possibilities in terms of exploratory potential of this population, and indicates the potential for significant genetic gains with the composition of future hybrids among S 3 progenies with strains obtained from the four testers. Galvão et al (2015) evaluated the genetic diversity within and between populations of field corn (populations Cimmyt and Piranão) and obtained Shannon index estimates > 1, with an average of 1.04, for the Piranão population. These high values illustrate the efficiency of this index in studies aimed at increasing the genetic diversity of the target population.…”

Genome size, cytogenetic data and transferability of EST-SSRs markers in wild and cultivated species of the genus Theobroma L. (Byttnerioideae, Malvaceae)

“…Coming from coding regions, these markers are more conserved among populations of the same species and congeners, thus, enabling cross-amplification and allowing the characterization of molecular marker sets for species which have not been well characterized genetically [ 18 – 22 ]. Several EST-SSR markers have been identified for a diverse range of crops, such as maize [ 23 ] and tomato [ 24 ], arboreal crops as coffee [ 25 , 26 ], cacao [ 27 ] and, the first work involving EST-SSR from T . grandiflorum [ 28 ].…”

Molecular Variability of Old Maize (Zea Mays L.) Based on Gene Specific Markers

“…For the analysis of genetic diversity of maize genotypes were used several dominant molecular markers: amplified fragment length polymorphism (AFLP) (Roy and Kim, 2016), random amplified polymorphic DNA (RAPD) (Balážová et al, 2016;Vivodík et al, 2017a), start codon targeted (SCoT) (Vivodík et al, 2017b), inter-simple sequence repeat (ISSR) (Žiarovská et al, 2013) and sequence-related amplified polymorphism (SRAP) (Abd El-Azeem et al, 2015). And codominant molecular markers were also used for the analysis of maize genotypes: simple sequence repeat (SSR) (Shiri et al, 2014), expressed sequence tag (EST)-SSR (Galvão et al, 2015) and using protein markers (SDS-PAGE) (Vivodík et al, 2017c).…”