Relationship between Rps 1k gene and resistance to Pythium ultimum and P. irregulare in soybean

ABSTRACT In soybean Pythium spp. produces seed and root rot and “damping off”. The aim of this study was to verify the relationship between resistant gene Rps 1k to Phytophthora sojae with Pythium ultimum and P. irregulare. Four genotypes of soybean were sown on inoculated soil, two of them with gene Rps 1k and the other two without it. Genotypes without the gene did not differ among themselves, no matter whether they were inoculated or not. On the other hand, Rps1k genotypes differed from each other, whether or not they were inoculated. SE+2 presented 95% of emergence whereas SE+1 presented 78.35% of emergence, but in both cases the emergence decreased when genotypes were inoculated with 63.35% and 34.15% respectively. Under the assayed conditions the gene Rps1k resistant to Ph. sojae did not show a greater number of emerged seedlings against the tested strains of P. ultimum or P. irregulare.摘要：在大豆种植体系中，腐霉属（Pythium）病原菌可引发种子腐烂、根腐病及猝倒病。本研究旨在明确抗大豆疫霉菌（Phytophthora sojae）的Rps1k基因与终极腐霉（Pythium ultimum）、不规则腐霉（P. irregulare）之间的关联。本试验选取4个大豆基因型，播种于接种病原菌的土壤中，其中2个携带Rps1k基因，另外2个不携带该基因。不携带Rps1k基因的大豆基因型之间，无论是否接种病原菌，出苗情况均无显著差异。而携带Rps1k基因的大豆基因型之间，无论是否接种病原菌，出苗情况均存在显著差异。其中SE+2的出苗率为95%，SE+1的出苗率为78.35%；但接种病原菌后，二者的出苗率分别降至63.35%和34.15%。在本试验设定的条件下，抗大豆疫霉菌的Rps1k基因，针对供试的终极腐霉与不规则腐霉菌株，并未表现出提升出苗数量的效果。