Herança da resistência da soja à podridão radicular de fitóftora, em variedades comerciais brasileiras

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/02/2012

RESUMO

The phytophthora root rot (PRR), caused by Phytophthora sojae (Kaufman &Gerdman), is one of the most destructive soybean diseases and can provoke yield losses of up to 100%. PRR has occurred more frequently in Brazil since the season 2005/06, mainly in the South region. There are some resistant commercial varieties but their inheritance remains unknown. All bi-parental crosses involving the resistant soybean varieties BRS 246RR, BRS 260 and BRS 262 among them and between them with the susceptible variety BRS 268 were developed to study the inheritance of resistance to PRR. The F2 populations and the parental varieties used I the crosses were inoculated with the pathogen at V1 soybean stage of development. Evaluations were performed seven days after the inoculation by classifying health plants as resistant and infected and died plants as susceptible. The chi-square test (χ2) was applied to accept or reject the expected Mendelian segregation ratios of resistant and susceptible plants in the F2 population. There exist a single dominant gene determining the resistance of variety BRS 246RR and another single dominant gene, distinct in relation to the first one, determining the resistance to PRR in the variety BRS 260. The variety BRS 262 has two resistance genes to P. sojae, both of them positioned in distinct loci in relation to the two other studied resistance genes. It was possible to conclude that, for this group of three soybean varieties, there are four distinct Rps genes, which can be explored by the breeding programs to develop new varieties resistant to P. sojae.

ASSUNTO(S)

soja - melhoramento genético soja - cultivares - resistência a doenças e pragas soja - doenças e pragas genética vegetal soybean breeding soybean disease and pest resistance soybean diseases and pests plant genetics

Documentos Relacionados