Identification of resistance to bluegreen aphid and spotted alfalfa aphid in Trigonella species

Abstract The genus Trigonella (Fabaceae, tribe Trifolieae) includes potential new species for pasture legume production in phase farming systems of southern Australia. Performance under biotic stress is an important factor in selecting the most suitable species and genotypes for pasture legume breeding programs. Fifty‐nine accessions representing 26 Trigonella species and two Medicago species (formerly with Trigonella ) were evaluated for resistance to two aphid species, bluegreen aphid ( Acyrthosiphon kondoi Shinji), and spotted alfalfa aphid ( Therioaphis trifolii (Monell) fm. maculata ) in glasshouse experiments. An accession of Trigonella macrorrhyncha (SA 32223) was found to be highly resistant to both the aphids. Accessions of T. coerulescens, T. cylindracea, T. gladiata, T. mesopotamica, T. schlumbergeri and Medicago monspeliaca were found to be resistant to bluegreen aphid, but susceptible to spotted alfalfa aphid. The resistance mechanism in T. macrorrhyncha involved both antixenosis (non‐preference in a choice test) and antibiosis (reduced fecundity). The implications of these results for germplasm improvement are discussed.