Alien chromosome substitution of durum wheat: Substitution of the chromosome e7 of Elytrigia elongata for chromosome 4A of Stewart durum

Four monosomic substitution lines of the Elytrigia elongata (=Agropyron elongatum) chromosomes, e2, e3, e6 and e7 for chromosome 4A of durum wheat were produced by the cross between monosomic 4A and the corresponding disomic addition lines of Stewart durum. Among them the monosomic substitution line e7(4A) was the most vigorous and fertile. Although this line showed a chromosome configuration of 13″+2′ at the first meiotic metaphase, it had 14 bivalents at diakinesis in most of its pollen mother cells. The fertilization rate of the four types of the egg cells produced by this monosomic substitution suggested a 50% elimination of both e7 and 4A univalents during the meiosis of durum wheat. Male transmission behavior indicated that chromosome e7 compensates for the function of chromosome 4A in the certation. A disomic substitution line was selected from the progeny of the monosomic substitution line e7 (4A). Plants of this line were vigorous and completely fertile. Chromosome e7 was found to have a structural gene for alcohol dehydrogenase; in wheat this gene is known to be located on the three chromosomes of homoeologous group 4. It was thus concluded that chromosome e7 of E. elongata belongs to homoeologous group 4. A comparison of the morphology of the substitution, addition and monosomic lines with those of the normal Stewart durum, showed that chromosome e7 carried genes for awn suppression, culm thickness and ear laxness.