Response to Selection for Winter Survival and Yield in Different Populations of Synthetic Hexaploid Wheats (Triticum dicoccum/Aegilops tauschii)

Pureline selection was applied in Synthetic Hexaploid Wheat populations (SHW), obtained from irradiated seeds with 150 Gy gamma rays and compared with their corresponding controls. The selection was performed in progenies of 20 initial plants from three amphiploids (8 from SHW32, 4 - SHW106 and 8 - SHW107) generating 19 M1-3 and 19 C2-5 lines. Two families did not survive winter in the first year. All selected lines expressed high germination, intermediate type of growth in winter and good seed set in the field conditions. The irradiation of seeds did not influence the germination and winter survival of the SHW plants. The response to direct selection was based on the mean performance of progenies for grain number and kernel weight per main spike and the selected elite plants in M3 and C4-5 generations. The coefficient of heritability and genetic advance for these traits were highest in SHW106, followed by SHW32. SHW107 displayed the largest morphological variability and sterility during the investigated period. All synthetics formed long, but sparse ears with seed fertility being lower than their tetraploid parents, but elite plants of SHW32 and 106 were equaled to tetraploid parent No 45432 on grain weight per major spike in 2013. Seed irradiation with 150 Gy gamma rays did not cause any effects on the two investigated traits. The selected subset of 10 lines from the three amphiploids represents a source of spike productivity for use in wheat breeding programs to enhance yield potential.