توليد و بررسي ساختار كروموزومي و باروري ژنوتيپ هاي ثانويه تريتي پايرم

Production and Assessment of Chromosomal Constitution and Fertility of Secondary Tritipyrum

Tritipyrum (2n=6x=42; AABBEbEb) is a new synthetic allohexaploid created through crossing durum wheat (2n=4x=28; AABB) and Thinopyrum bessarabicum (2n=2x=14; EbEb) and subsequently doubling the hybrid plant chromosomes. Secondary Tritipyrum is referred to the progenies of wheat and Tritipyrum crosses, obtained during segregating generations. The study of chromosomal constitution and fertility is very important in the assessment of hybrids derived from wheat and wild relative crosses. Navid cultivar of bread wheat (AABBDD; 2n=6x=42) was crossed with Tritipyrum (AABBEbEb; 2n=6x=42) the Fi progenies being produced. F2 seeds were obtained by selfing Fj plants and their chromosome number determined. The F2 plants possessing 42 chromosomes were selected for the study of their meiotic behavior. In spite of high chromosomal stability and fertility of the parents (wheat and Tritipyrum), these characteristics in F2 plants were observed as low probably due to the different chromosomal compositions and a lack of chromosome homology of D and Eb genomes and consequently the formation of univalents in pollen mother cells of F2 plants. The results of meiotic analysis of F2 plants confirmed the accessibility of different chromosomal composition and the production of either the addition or substitution lines in the progenies of segregating generations.