Pollen fertilility, seed fertility and efficiency of backcrossing of interspecific hybrids, involving five T. durum varieties and three T. timopheevii forms were studied under conditions of different vegetations. It was shown that variation in the results was determined to a greater extent by genotypical diversity of timopheevii forms used as initial parents. Environmental factors essentially modified the effect of backcrossing regardless of hybrid genotypes.

Key words: durum wheat, timopheevii wheat, interspecific hybrids, backcrossing, pollen fertility, seed fertility, environmental factors, genotype diversity.