A twelve-parental diallel cross including reciprocals was carried out, and the F1 hybrids, F2 generations ant their winter wheat parents were used in a freezing test at -15°C under controlled conditions. The varieties and F1 populations of twelve of the combinations in the diallel cross, chosen because the frost resistance values of the parents differed significantly from each other when frozen at -15°C, were then frozen at four different temperatures (-12 , -14 , -16 and -18°C). It can be seen from the results of diallel analysis that when freezing was carried out at -15°C the dominant genes led to stronger frost resistance and the recessive genes to poorer resistance, i.e. frost resistance proved to be a dominant trait. The results of freezing at four different temperatures, however, indicated that when crossing frost-tolerant and frost-sensitive varieties frost resistance was dominant at a relatively mild freezing temperature (-12°C), while at lower testing temperatures the direction of dominance changed and frost sensitivity became dominant. This proof of the freezing temperature dependence of the direction of dominance explains the contradictory results previously published in the literature on this subject. The direction of dominance also depends on what genotypes are tested and on which types of alleles are present in the greatest proportion in the tested varieties.
|Number of pages||8|
|Publication status||Published - Dec 1 1997|
ASJC Scopus subject areas
- Agronomy and Crop Science