Selection and Reproduction of Soybean Cyst Nematodes on Resistant Soybeans1

Objectives of this work were to select populations of soybean cyst nematodes (SCN, Heterodera glycines Ichinohe) on known resistant soybeans [R‐lines, Glycine max (L.) Merrill] and to compare their reproduction on the various combinations of populations ✕ R‐lines. The original SCN population from a single field soil sample did not reproduce well on the six R‐lines, but after selection, each population reproduced well on the R‐line on which it was selected. A seventh SCN population selected on ‘Pickett’ in North Carolina was included in the comparison of SCN populations on the seven R‐lines and the susceptible cultivar ‘Williams.’ The effects of soybean lines, SCN populations and their interaction were highly significant for females/plant, eggs/plant, and eggs/female. Number of females/plant was the least variable and highly correlated (r = 0.96) with eggs/plant. Eggs/female was the most variable and perhaps the least useful character even though there were significant differences among the soybean‐SCN combinations. ‘Pickett 71’ was as susceptible as Williams to all populations, and the population selected on it reproduced poorly on the other six R‐lines. PI 89772 was a good host only for the population selected on it; which in turn reproduced rather poorly on ‘Cloud’, PI 209332, PI 87631‐1, PI 88788, and PI 90763R. Thus, these five lines have at least some genes in common but different from some genes in Pickett and Pickett 71 and in PI 89772. Phenotypically, PI 90763R is more like PI 88788 than PI 90763.