Crotalaria ochroleuca Susceptibility to Heterodera glycines Races

Abstract

The aim of the study is to assess Crotalaria ochroleuca susceptibility to six Heterodera glycines races. To this, C. ochroleuca seedlings and two soybean cultivars were transplanted and individually inoculated with nematode races 1, 2, 3, 5, 6 and 14. Plants were collected and assessed 30 and 60 days after inoculation. Crotalaria ochroleuca reduced the number of females and the total number of eggs of the races 1, 2, 5 and 6. The reproduction of race 3 in crotalaria was equal to that of soybean cultivars in both assessment periods, whereas race 14 only reduced the reproduction in crotalaria to 60 days. Races 1 and 6 (30th day) and races 6 and 14 (60th day) showed number of eggs female-1 smaller than the controls. According to female index (FI), C. ochroleuca was resistant to races 1, 2 and 5, susceptible to race 3, and showed varying reactions to races 6 and 14.

Population dynamics of the nematodes Heterodera glycines and Pratylenchus brachyurus in a succession crop of soybean and chickpea

“…The increase in the number of nonviable cysts, the reduction of viable cysts, and the reduction in the number of these PPN in the soil may be due to the hatching of juveniles of H. glycines race 5 and the absence of a host plant in the area for a period that prevented the reinfection and continuity of its life cycle (Cardoso et al, 2019). This result shows that chickpea is not a host of H. glycines race 5 and that it can be indicated for crop rotation or succession with soybeans in the areas infested with this race.…”

“…Poromarto and Nelson (2010) found that the chickpea was not an efficient host of H. glycines race 3, although it allowed the multiplication of a small number of this nematode. However, Cardoso et al (2019), who evaluated the resistance of rattlepod (Crotalaria ochroleuca) to races 1, 2, 3, 5, 6, and 14 of H. glycines, found that this plant species was resistant to races 1, 2, and 5 but was susceptible to race 3 and showed varied reactions to races 6 and 14.…”

“…Poromarto and Nelson (2010) verified that chickpea was a poor host of H. glycines race 3; however, there are no studies on H. glycines race 5. Cardoso et al (2019) evaluated the resistance of Crotalaria ochroleuca to races 1, 2, 3, 5, 6, and 14 of H. glycines, and verified that it was resistant to races 1, 2 and 5, but was susceptible to race 3 and showed varied reactions to races 6 and 14. Due to the increase in the cultivated areas of chickpea in succession to soybeans in the Brazilian Midwest, research on these two PPN species becomes important.…”