Full-sib reciprocal recurrent selection in the maize populations Cimmyt and Piranão

Abstract

ABSTRACT. We estimated the genetic gains of the 12th cycle of reciprocal recurrent selection for maize traits of agronomic interest. We used 23 ISSR molecular markers in an attempt to maximize genetic variability among and within populations based on selection of S 1 progenies. To this end, 138 full-sib families were evaluated in a randomized block design in two environments (the municipalities of Campos dos Goytacazes and Itaocara, in the State of Rio de Janeiro, Brazil), with replications within sets. Direct selection for grain yield was used for the selection of the families. To assess genetic diversity among and within populations, we examined plants produced from part of the S 1s seeds from the parents that originated the 42 full-sib families that were selected from the agronomic traits. Direct selection for grain yield provided good gains for the traits evaluated, with estimated improvement of -0.87 days for days to flowering, 0.35 plants, 1.79 ears per plot, 0.58 g per 100-grain weight, 308.21 g ear weight per plot, and 261.83 kg/ha grain yield. Application of molecular markers at the stage of superior progeny selection led to increased genetic distance among populations, which is a very important factor for maximizing the ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 11 (3): 3398-3408 (2012) Maize reciprocal recurrent selection 3399 utilization of heterosis and providing greater longevity to the reciprocal recurrent selection program.

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

“…Results presented by Berilli et al (2011), analyzing the tenth RRS cycle, show that 89.84% of the total genetic variance was within the CIMMYT and Piranão populations and only 10.16% was between populations before the selection stage, the latter value increased to 14.27% after selection of the most divergent genotypes. da Cunha et al (2012), evaluating the eleventh RRS cycle, found 88.77% of genetic variance within and 11.23% between the CIMMYT and Piranão populations before selection, and 82.33% within and 17.67% between after selection. Based on these results, it can be observed that one of the main objectives of a program of recurrent selection has been achieved, i.e., the genetic variability within populations has been maintained at satisfactory levels, while the variability between populations has increased over cycles of selection, contributing to the longevity of the breeding program.…”

“…Previous studies involving the use of molecular markers in the same breeding program consisted of analyses using dominant markers, such as RAPDs (Tardin et al, 2007) and ISSRs (Berilli et al, 2011;da Cunha et al, 2012), which had mean values of polymorphic alleles per primer of 5.43, 8.77 and 4.04, respectively. Such markers are multi-locus and have dominant inheritance, with the average number of alleles per primer corresponding to the polymorphism of several loci dispersed randomly in the genome.…”

“…The corn breeding program of the North Fluminense State University (UENF), involving CIMMYT and Piranão populations, has been working on the effectiveness of the FSRRS monitored by molecular markers (Tardin et al, 2007;da Cunha et al, 2012;Berilli et al, 2011Berilli et al, , 2013. This tool was used to aid the FSRRS program in the eighth cycle using RAPD markers (Tardin et al, 2007), followed by AFLP markers in the ninth cycle (Gabriel, 2009), and ISSR markers in the tenth and twelfth cycles (Berilli et al, 2011;da Cunha et al, 2012).…”

“…This tool was used to aid the FSRRS program in the eighth cycle using RAPD markers (Tardin et al, 2007), followed by AFLP markers in the ninth cycle (Gabriel, 2009), and ISSR markers in the tenth and twelfth cycles (Berilli et al, 2011;da Cunha et al, 2012). The effectiveness of this methodology was indicated by the release and registration with the Ministry of Agriculture, Livestock and Supply (MAPA) of two corn hybrids, 'UENF506-6' and 'UENF506-11', recommended for the North/Northwest Fluminense region.…”

Genetic Advance in Grain Yield and Other Traits in Two Tropical Maize Composites Developed via Reciprocal Recurrent Selection

“…Consequently, the probability of selecting elite inbred lines from populations developed through RRS will be higher than from pedigree populations involving recycling of inbred lines to produce outstanding hybrids. Reciprocal recurrent selection has been very effective in improving interpopulation crosses Eyherabide and Hallauer, 1991;Rezende and Souza, 2000;Souza and Pinto, 2000;Santos et al, 2005;da Cunha et al, 2012) and inbred lines and hybrids (Moll et al, 1977;Russell, 1985;Betrán and Hallauer, 1996). These inbreds can also be crossed to inbreds from other breeding programs to diversify the genetic base of new source populations in a sustainable manner (Santos et al, 2007).…”