Abstract
Distribution of necrosis and chlorosis genes in common wheat, Triticum aestivum L. em. Thell., was further investigated using 73 varieties from Australia, 18 from Tibet, 35 from Sweden, 13 from Norway and 15 from Finland. As to necrosis genes, the Tibetan population contained more Ne1- than Ne2-carriers, just like other Asian populations. The Australian population, also, resembled Asian populations in spite of its origin from European wheat; for this fact preferential selection of spring varieties in Australia was accounted. Spring wheat population in Northern Europe was the purest of all populations analyzed, being almost free from both necrosis genes. A drastic change of population structure seems to have taken place since spring wheat was established there. Regarding chlorosis genes, no remarkable difference was found among all the geographical populations so far studied; more than 90% of varieties had the ch1Ch2 genotype, and the rest had the ch1ch2 genotype. No Ch1-carriers have been found.
