Azerbaijan is one of the centers of origin and concentration of cereals. More than 14 species of wheat, including wild species Tboeoticum Boiss and Turartu Thum. ex Gandil., which are now considered as donors of the first genome (A) for tetra- and hexaploid wheats, are concentrated here. Wild wheat Tararaticum Jakubz is also widely spread in Azerbaijan. Together with wheat, several species of Aegilops: Ae. umbellulata Zhuk., Ae.biuncialis Vis.,Ae.kotschyi (Boiss.) Bowden, Ae triunciallis L., Ae.triaristata Willd., Ae.cylindrica Host, Ae.crassa Boiss., are also widely distributed across a broad environmental range, as well asAe.tauschii Coss., characterized by intraspecific heterogeneity and considered as the donor of D-genome of bread wheat. The crops of wheat are almost ubiquitously infested by weed rye (Secale segetale Roshev), which develops straw of about 2 meters and over. In Talish Mountains the population ofrye, which grows as high as 120-130 cm in height is commonly utilized by the local dwellers. This rye easily crosses with wheat. The Absheron peninsula is rich in a different species ofrye (S. sylvestre Host.) It is a strictly self-pollinating species. Besides, about seven species of barley are identified in Azerbaijan Co-existence of different species of wheat, aegilops and rye in the same plant communities facilitates formation of spontaneous hybrids due to their systematic affinity and parallel variability. Natural hybrids of wheat and rye (sterile) and of individual species of wheat and aegilops set favorable conditions for the exchange of genes, facilitating creation of variability. A wide diversity of cereals made it possible to conduct research in many directions of genetics and breeding. Intergeneric hybrids were developed and used further as sources of the richest set of genes enhancing the introgression process. One of the obtained intergeneric amphidiploids had A- genome of wild wheat Tboeoticum Boiss. and D- genome of Ae.tauschii Coss. This amphidiploid with a genome structure AADD was further crossed with the prospective donor of B-genome of wheat - Ae.speltoides Tausch. The hybrid plants have, through the natural polyploidy, produced the spelt- type wheat (2n=42), phenotypically sÍmilarto its Iraqi ecotype. By crossing the amphidiploid (Tdurum x Ae.tauschii) with rye (S. segetale Roshev) a trigeneric hybrid was produced. A dwarfish constant line having 42 chromosomes was selected from progeny ofthis hybrid generation. The investigations showed that this line has an incomplete chromosome set of wheat, rye and aegilops, being further named as the trigeneric incomplete amphidiploid -Aegilotriticale (with the genome structure ABDR). Using this hybrid in crosses showed it to be a very strong generator of variability. In the present report the example of incomplete trigeneric amphidiploid [(Tdurum x Ae.tauschii) x S.segetaleJ (2n=42) demonstrates neoplastic potential in its crosses with Tcompactum Host and with bread wheat cultivar Chinese Spring under the Absheron peninsula conditions. The hybrid plants of the first generation generally had an intermediate phenotype. A structure of chromosome has a mosaic character due to the unbalanced meiotic process. In the second generation of hybrid plants the spectrum of segregation repeatedly grows. In these hybrid combinations, fractions reach 89 and 149 units, accordingly. Among these plants, phenotypes of triticale, spelt forms, persicoids, durocompactoids, emmer, etc. are found. Branch-spike plants and many other forms are also met. The fraction- forming plants differed not only in the form ofthe spike, but also in height. By plant height, all plants were divided into 4 groups: dwarf(30-40 cm), short-stem (50- 70 cm), normal-stem (80-110 cm) and long-stem (higher than 120 cm). Their further study showed that the segregation by growth, especially among dwarf and shot-stem forms, stabilizes from the third generation. It is interesting to note that the quantity of chromosomes in the first and second generations varied from 28 to 42 and more. As the plant phenotype stabilized, the number of chromosomes in somatic cells also strictly stabilized at 2n=42, rarely at 2n=28. Very likely, it was promoted by normalization of the meiotic process in hybrid plants. On the basis of a wide set of phenotypically and cytogenetically stable forms, a collection of dwarf and short-stem lines with 28 and 42 chromosomes has been developed. The data provides evidence that the genetic resources of cereals in Azerbaijan, due to the concentration of a large number of dominant and recessive genes, possess strong neoplastic potential. Their utilization in the genetics and breeding programs will facilitate development of high-yielding wheat cultivars. Institute of Genetic Resources is currently implementing a purpose-oriented program of collection, study, storing and sustainable restoration of cereals.

English

0407|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection