Resistance to root-lesion nematode (Pratylenchus thornei) in Aegilops tauschii Coss., the D-genome donor to wheat

Abstract

Root-lesion nematode (Pratylenchus thornei Sher and Allen) causes substantial loss in yield of wheat in eastern Australia. Central Asian accessions of Aegilops tauschii Coss. were tested to find new sources of resistance to P. thornei for use in wheat-breeding programs. Ae. tauschii (2n = 14, DD genome) is one of the wild progenitors of wheat, Triticum aestivum L. (2n = 42, AABBDD genomes). Resistance was determined by nematode reproduction in the plant roots during 16 weeks of growth in pots in a glasshouse. Thirty-nine of 244 accessions of Ae. tauschii tested in 2 replicated experiments had lower numbers of nematodes than GS50a, a partially resistant line of wheat used as a resistance standard. Resistance to P. thornei was present in accessions of most taxonomic groups within Ae. tauschii, i.e. Ae. tauschii subsp. strangulata (Eig) Tzvel., and Ae. tauschii subsp. tauschii var. typica L. and var. meyeri (Griseb.) Tzvel. Resistance was most common in subsp. strangulata with 20 out of 40 strangulata accessions in the resistant group and none in a highly susceptible group of 43 accessions. Accessions of var. meyeri with the Cre3 gene for effective resistance to cereal cyst nematode (Heterodera avenae Woll.) were also resistant to P. thornei. The results indicate that several resistances to P. thornei are present in Ae. tauschii subspecies and varieties, which could be introgressed into cultivated wheat to help control P. thornei and increase farm profits.