Observations on the occurrence and inheritance in wheat of resistance to the grain aphid Sitobion avenae

Glasshouse screening tests with the aphid, Sitobion avenae, demonstrated resistance or extreme susceptibility in a minority of winter wheat cultivars. Assessments of some, but not all, resistant cultivars were apparently affected by the conditions of the test, and field observations confirmed some, but not all, of the glasshouse results. Rapier and Galahad were the most resistant of the cultivars currently available to British wheat growers. F₄ lines of spring wheat from crosses of wheat stocks resistant to S. avenae were screened by two methods and on average were resistant. Crosses differed in the amount of variability available for further selection, and wide-ranging segregation among the lines indicated that resistance genes differed among the parent stocks.