Abstract
Soybean cyst nematode, Heterodera glycines Ichinohe, is one of the major phytopathological problems affecting soybeans, Glycine max (L.) Merr., in the major producing countries and the use of resistant cultivars and crop rotation have been the main methods of control adopted to reduce the nematode population in infested soils. Purpose of this study was to evaluate the effect of resistant (BRSGO Ipameri and BRSGO Chapadões) and susceptible (BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR) soybean cultivars on the development of H. glycines males and females during two successive years (2007 and 2008). In the trial of 2008 the plants were divided in three plots, with the last one having the roots stained to count the juveniles and to evaluate survival rate. Resistant cultivars always maintained a small number of females and males, except for cultivar BRSGO Ipameri that had a high count of males. Only cultivars BRS Favorita RR and BRS Silvânia RR had a sex ratio of 1:1. All other susceptible cultivars had, in general, greater number of males than females. Survival rate was nil on both resistant cultivars, and varied from 6.75 to 35.00% on the susceptible cultivars. Key words: Glycine max, cyst nematode, sex ratio, hydroponics.
Highlights
Purpose of this study was to evaluate the effect of resistant (BRSGO Ipameri and BRSGO Chapadões) and susceptible (BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR) soybean cultivars on the development of H. glycines males and females during two successive years (2007 and 2008)
Two experiments were conducted under greenhouse conditions, at Universidade Federal de Goiás (16°35’47.36”S; 49°16’48.01”W; 726 m above sea level), using six commercial soybean cultivars susceptible to H. glycines: BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR and two resistant cultivars: BRSGO Ipameri and BRSGO Chapadões
The commercial cultivars resistant to H. glycines, race 14, BRSGO Ipameri and BRSGO Chapadões, confirmed the expected performance in both experiments, presenting smaller numbers of females (Tables 1 and 2)
Summary
Purpose of this study was to evaluate the effect of resistant (BRSGO Ipameri and BRSGO Chapadões) and susceptible (BRSGO Araçu, BRSGO Jataí, BRSGO Luziânia, BRS Favorita RR, BRS Valiosa RR, BRS Silvânia RR) soybean cultivars on the development of H. glycines males and females during two successive years (2007 and 2008). Those authors found that the greater proportion of males occurred due to differential death of males and females, contributing to the hypothesis that sex determination are a genetic characteristic of nematode H. glycines unaffected by environmental factors.
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