Assessment of Russian Wheat Aphid (Homoptera: Aphididae) Resistance in Barley Seedlings in Mexico uri icon

abstract

  • Resistance to the Russian wheat aphid, Diuraphis noxia (Mordvilko), was assessed in five genotypes of barley, Hordeum vulgare L. The barley genotypes were API/CM67//AGER/3/GLORIA/COME/4/79W40762 (S4), BARBEROUSSE/P.STO//GLORIA/COPAL (S6), RHODES/CI14100//LIGNEE527 (S8), GLORIA/COME (S13), and 'ESPERANZA' (S16). Field screening indicated S4, S6, S8, and S13 were resistant to D. noxia, and S16, a recently released Mexican barley variety, was susceptible. Correlation between D. noxia damage scored in the field and in the greenhouse was good. Of the five genotypes in the greenhouse, the height and weight of S8 and S13 plants were least affected by D. noxia and were the most tolerant genotypes. Root weight was unaffected by D. noxia. The methods used to assess antibiosis were nymph counts on whole plants and excised leaves, colony size (aphid numbers and colony weight), and embryo counts. Mean nymph production was significantly higher on plants than on excised leaves, but the data were correlated. Neither nymph production on excised leaves nor on whole plants was correlated with aphid numbers, colony weights, or embryo counts. Aphid numbers, colony weights, and embryo counts should be used cautiously to assess antibiosis to D. noxia in barley seedlings because tolerance effects may confound the results. S13 was shown to be less preferred (more antixenotic) than the other genotypes and S4 most preferred. Taking antibiosis, tolerance, and antixenosis into account, S8 was the most resistant genotype and S16 the least. S8 is a good agronomic type, is resistant to several fungal pathogens, and represents a new source of resistance to D. noxia in barley.

publication date

  • 1992
  • 1992