LAUSR

A factorial experiment was conducted in Kurdistan-Iraq to identify responses of European wheat varieties to vernalization treatments at 22C, 4C and -18C for two and four weeks in a Complete Randomized Block Design (CRBD) experiment with three replicates. Sabir-beg had the highest and most desired performance for most of the traits studied including grain yield. The highest spike and grain number were recorded for Hereford and Skalnige, respectively. Incubation temperatures had highly significant effects on most of the traits, including grain yield. Two weeks-vernalization at low temperature is satisfactory for vernalization of these wheat varieties. The interaction between varieties and incubation temperature produced varying effects. Grain number is mainly genotype-related. Sabir-beg×two weeks incubations had spent minimum days to flowering, followed by days to maturity. The varieties were persistent in their interaction with the incubation period. The interaction effect of 4C×four weeks incubation advanced flowering, extending flowering-maturation period to give a higher spike number. Harvest index, biomass, and grain yield were highly significant for both interactions of varieties×incubation temperature and varieties×incubation period. The three-factors interaction had a highly significant effect on most traits. The wheat varieties can be developed with more predictable responses to in vitro vernalization as an alternative to early sowing.