Stability of Heterodera glycines (Tylenchida: Heteroderidae) juvenile hatching from eggs obtained from different sources of soybean, Glycine max

Abstract

AbstractThe hatching behaviours of Heterodera glycines second-stage juveniles (J2) from eggs obtained from laboratory and glasshouse cultures, and from the field, were examined in vitro using large scale (Baermann funnel) and small-scale (depression slide) assay designs. Hatching of J2 from cultured eggs was robust, whereas J2 from field eggs hatched very poorly in vitro (<1% total cumulative percentage hatch). Qualitative aspects of hatch were stable as hatching of J2 from eggs from all sources was linear from 2 through to 8-10 days. By contrast, quantitative aspects were more variable. Total cumulative percentage hatch typically ranged from 45 to 70% but approached 90% depending upon the source of the cultured eggs. Egg density (eggs/cm2) affected hatch of J2 in the large scale in vitro system, with total cumulative percentage hatch significantly greater at 3100 eggs/cm2 than at 420 eggs/cm2. The poor hatch of J2 from field eggs was lost after two generations in culture and replaced by the typical hatch characteristics of J2 from eggs from an established culture. This included both qualitative and quantitative elements. Stability of H. glycines hatching behaviour and its reflection of dormancy and diapause of J2 are discussed.