Estudo genético e validação de marcadores moleculares associados ao nematoide de cisto em populações de soja
Data
2018-04-19
Autores
Azevedo, Cleber Vinicius Giaretta
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Para atender à necessidade de novas cultivares de soja tipo alimento com resistência ao nematoide de cisto da soja (NCS), este trabalho teve como objetivo selecionar progênies superiores e estimar parâmetros genéticos em duas populações de soja F2:3, F3:4 e F4:5 oriundas de cruzamentos entre genótipos tipo alimento x tipo grão. As características avaliadas foram: altura de plantas na maturidade (APM), altura da inserção da primeira vagem (AIV), acamamento (AC), valor agronômico (VA), número de vagens por planta (NV), número de dias para maturidade (NDM), número de ramos (NR), número de nós (NN), peso de 100 sementes (PCS) e produção de grãos por planta (PG). O delineamento experimental utilizado foi o de blocos aumentados e as análises estatísticas foram realizadas utilizando-se a abordagem de modelos mistos (REML/BLUP). As estimativas dos parâmetros genéticos obtidos indicaram alta variância genética na população, em que a herdabilidade apresentada foi alta para a maioria dos caracteres avaliados e os coeficientes de variação ambiental, em sua maioria, foram baixos. Além destas avaliações, foi realizada a identificação de marcadores moleculares do tipo microssatélites (SSR) associados à resistência ao NCS (raça 3). Esta etapa foi realizada utilizando-se progênies F2 dos cruzamentos entre soja tipo grão x tipo alimento, as quais foram previamente fenotipadas quanto a resistência ao NCS. Foram identificados 2 pares de primers SSR flanqueando 2 genes associados à resistência ao NCS, sendo Satt275 e Satt309 no cromossomo 18 ligados ao gene rhg1 e dois no cromossomo 8, Sat_162 e GMES6186, associados ao gene Rhg4. Em conjunto, estes marcadores podem ser utilizados de maneira eficaz na seleção assistida de progênies superiores para a resistência ao NCS.
To meet the need of new food-type soybean cultivars with resistance to soybean cyst nematode (SCN), this work aimed to select superior progenies and to estimate genetic parameters in two soybean populations F2:3, F3:4 e F4:5 originated from crosses between genotypes type food x grain type. The evaluated traits were: height of plants at maturity (APM), height of first pod insertion (AIV), lodging (AC), agronomic value (VA), number of pods per plant (NV), number of days to maturity ND), number of branches (NR), number of nodes (NN), weight of 100 seeds (PCS) and grain yield per plant (PG). The experimental design used was the augmented blocks and the statistical analyses were performed using mixed model REML/BLUP. The genetic parameters estimates indicated a high genetic variance in the population, the heritability presented was high for most of the evaluated traits and the coefficients of environmental variation were mostly low. In addition, the identification of molecular markers of the microsatellite type (SSR) associated with resistance to SCN (race 3). This step was performed using F2 progenies of the crosses between grain type soybean x food type, which were previously phenotyped for resistance to NCS. Two pairs of SSR primers flanking 2 genes associated with resistance to the SCN were identified, with Satt275 and Satt309 on chromosome 18 linked to the rhg1 gene and two on chromosome 8, Sat_162 and GMES6186, associated with the Rhg4 gene. Together, these markers can be used effectively in the assisted selection of higher progenies for resistance to NCS.
To meet the need of new food-type soybean cultivars with resistance to soybean cyst nematode (SCN), this work aimed to select superior progenies and to estimate genetic parameters in two soybean populations F2:3, F3:4 e F4:5 originated from crosses between genotypes type food x grain type. The evaluated traits were: height of plants at maturity (APM), height of first pod insertion (AIV), lodging (AC), agronomic value (VA), number of pods per plant (NV), number of days to maturity ND), number of branches (NR), number of nodes (NN), weight of 100 seeds (PCS) and grain yield per plant (PG). The experimental design used was the augmented blocks and the statistical analyses were performed using mixed model REML/BLUP. The genetic parameters estimates indicated a high genetic variance in the population, the heritability presented was high for most of the evaluated traits and the coefficients of environmental variation were mostly low. In addition, the identification of molecular markers of the microsatellite type (SSR) associated with resistance to SCN (race 3). This step was performed using F2 progenies of the crosses between grain type soybean x food type, which were previously phenotyped for resistance to NCS. Two pairs of SSR primers flanking 2 genes associated with resistance to the SCN were identified, with Satt275 and Satt309 on chromosome 18 linked to the rhg1 gene and two on chromosome 8, Sat_162 and GMES6186, associated with the Rhg4 gene. Together, these markers can be used effectively in the assisted selection of higher progenies for resistance to NCS.
Descrição
Palavras-chave
Glycine max, Heterodera glycines, REML/BLUP, SSR, Componentes de variância, Parâmetros genéticos