Seleção genômica ampla e novos métodos de melhoramento do milho / Genome wide selection and new methods of maize breeding

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

29/04/2011

RESUMO

The evaluation for nutrient efficiency use (UE) generally use destructive methods of the plant, not allowing, depending on the population genetic structure, using those identified as superior in hybridizations. Consequently, there is a reduction in the potential gains with selection. Additionally, some conventional breeding methods, such as the recurrent selection, are very laborious and have low gains with selection per unit time. The genome wide selection (GWS) was proposed to increase the efficiency of breeding. With the GWS, the prediction and selection can be performed on early plant stages, thus accelerating the process. Given the above, the objectives of this work were: i) verify the effectiveness of the GWS method in maize breeding for nutritional stress conditions, ii) propose new methods to maize breeding based on GWS. For this, 41 single crosses were evaluated in two experiments in high and low availability of N and P, using complete blocks design with two replications, in two-way scheme (single crosses x levels of N and P). The experiments were conducted in a greenhouse (2045 14 "S; 4252 53"W), at the Federal University of Viçosa, during the month of October 2010. The plants were harvested at the V6 stage. From the material collected, were estimated the two components of N or P UE. The data were subjected to statistical analysis by REML / BLUP, to obtain the variance components and genetic parameter estimates. In genotyping of estimation population, were used 80 microsatellite markers (SSR). The prediction of genomic breeding values of the single crosses were obtained by RR-BLUP/GWS. For the traits that GWS showed higher selective accuracy values than the phenotypic, it was compared with the methods of intra and interpopulation recurrent selection. With a cycle of GWS per year, it was possible to increase the efficiency of selection in relation to recurrent selection methods for the traits EA and EUt in low (LP) and shoot dry mass (SDM) in high P (HP) of 1028.01%, 960.21% and 1240,86% respectively. When was considered the possibility of two GWS cycles per year, these values changed to 3317.05%, 3098.27% and 4003,85%, respectively. In the experiment of N, with a cycle of GWS per year, for the traits EA in low N (LN), EA, EUt and SDM in high N (HN), the increase in efficiency was 306.98%, 393.84%, 816.99% and 363.82%, respectively. With the possibility of two cycles of GWS per year, these values changed to 990.53%, 1270.80%, 2636.15% and 1173,92%, respectively. Thus, we conclude that with the GWS is a significant increase in selective accuracy, earnings per unit of time and process improvement. Therefore, the recurrent selection genomic methods proposed in this work can modify significantly the way as done the selection in breeding programs

ASSUNTO(S)

zea mays l. estresse abiótico ssr seleção assistida por marcadores melhoramento vegetal abiotic stress marker-assisted selection ssr zea mays l.

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