Improved Tolerance to Increased Temperatures During Grain Filling in a Winter Wheat (Triticum aestivum L.) Line Selected from a Cross Involving Aegilops speltoides Tausch

Progress in breeding for heat tolerance could be enhanced by diversification of gene sources for tolerance to high temperatures. At the National Agricultural Research and Development Institute Fundulea, Romania, Aegilops speltoides has been used as a source for introduction of more diversity in the winter wheat (Triticum aestivum L.) breeding program. Two of the lines selected from a cross Favorit/Aegilops speltoides//3*Favorit were tested for response to enhanced high temperatures induced in the field by covering the plants with transparent cellophane paper. Line G557-6 showed a smaller reduction of grain weight, despite flowering 3-4 days later than the heat susceptible sister line and than most other tested cultivars. Molecular analysis identified three markers located on chromosome 2B, which differentiated G557-6 together with the Aegilops speltoides parent from its sister line and from the recurrent parent Favorit. To our knowledge this is the first report of heat tolerance gene(s) transfer from Aegilops speltoides to hexaploid wheat, and the identified line might contribute to diversification of gene sources in breeding for heat tolerance. Further studies are necessary to indicate which of the three identified markers could be best for marker assisted selection in crosses with this line.