Seedling and adult plant resistance to Sitobion avenae (Hemiptera: Aphididae) in Triticum monococcum (Poaceae), an ancestor of wheat

Abstract

Cereal aphids are important pests of wheat, Triticum aestivum L. and Triticum durum Desf. Crop resistance is a desirable method for managing cereal aphids in central North America, where the dominant crop, spring-sown wheat, has a low value per unit area. A diploid ancestor of wheat, Triticum monococcum L., is reported to be partially resistant to Sitobion avenae (Fabricius), the most damaging cereal aphid in the region. To identify potential sources of resistance, 42 accessions of T. monococcum and three cultivated wheats were infested with aphids, seedlings for six days and adult plants for 21 days. Overall resistance was estimated by the biomass loss of foliage and spikes in relation to uninfested control plants. Antibiosis was estimated by the gain in biomass of aphids during infestation, and tolerance was estimated as a biomass conversion ratio, overall resistance divided by antibiosis. A few T. monococcum accessions exhibited partial resistance. No relationship was found between seedling and adult plant resistance: the former exhibited primarily antibiosis and the latter primarily tolerance. Two accessions with antibiosis reduced aphid biomass by 60% compared with commercial wheats. Tolerance was correlated with growth potential, and was useful only in accessions with high growth potential. Four accessions exhibited tolerance levels at least 30% greater than commercial wheats. Highly susceptible accessions also were identified, which would be useful for investigating the inheritance of antibiosis and tolerance.

Triticum monococcumlines with distinct metabolic phenotypes and phloem-based partial resistance to the bird cherry-oat aphidRhopalosiphum padi

“…Migui & Lamb (2004) hypothesised that the resistance level of T. monococcum to S. avenae in seedlings could be because of the relative levels of hydroxamic acids (HAs) as reported in Leszczynski et al (1992). Elek et al (2012) observed reduced fecundity by R. padi on some T. monococcum lines.…”

“…Triticum monococcum (L.) lines, in particular, have shown evidence of complete or partial resistance to pathogens and aphids (Spiller & Llewellyn, 1986; Migui & Lamb, 2004; Jing et al , 2007; Elek et al , 2012). Although seldom planted or harvested today, domesticated T. monococcum was an agriculturally important crop in the Neolithic through to the Bronze Age (Salamini et al , 2002).…”

Searching for wheat resistance to aphids and wheat bulb fly in the historical Watkins and Gediflux wheat collections

“…We did not, however, see a difference in average performance of R. padi and S. avenae between the two collections, suggesting that during modern plant breeding, where improvements have focussed mainly on maximising yield, the plant effect on these aphid species has not been altered. In fact it could be inferred that a general loss of resistance traits happened before the rise of landraces, as resistance to aphid species has been reported in a number of diploid ancestors of wheat (Lamb & Migui, 2003; Migui & Lamb, 2004; Radchenko, 2011; Elek et al , 2013). …”

“…This is interesting and suggests that there is a pre‐alighting cue deterring the aphid settlement, which could have important implications for aphid management in wheat production and should be studied further. It also demonstrates differences in aphid preference and performance on older plants in the field compared with seedlings in the laboratory, highlighting the need for phenotyping for aphid resistance at different plant growth stages (Migui & Lamb, 2004). This would be greatly improved by incorporating new technologies which would make field assessments less labour intensive.…”

Field population development of bird cherry-oat aphid and greenbug (Hemiptera: Aphididae) on wheat-alien substitution and translocation lines

“…A few previous studies have assessed the development of aphid populations in field trials on wheat germplasm previously evaluated under controlled conditions, e.g. Randolph et al (2003) for Diuraphis noxia (Mordvilko) and Migui and Lamb (2004) for S. avenae.…”