Cytological and phenological characterization of adapted genetic stocks derived from: Triticum aestivum/ thinopyrum bessarabicum

Abstract

The diploid maritime grass Thinopyrum bessarabicum (2n=2x=14, EbEb) hybridized with bread wheat (Triticum aestivum L., 2n=6x=42, AABBDD) yielding a self-sterile F1 intergeneric hybrid (2n=4x=28, ABDEb). By back or top crossing, the hybrid with bread wheat cultivars, individual disomic Th. bessarabicum chromosome addition lines were produced with 44 chromosomes (2n=6x=42 + 2 = 44; AABBDD + 1Eb1Eb to 7Eb7Eb). Also, earlier produced by using F1 hybrid clones were the colchicine induced amphiploids (2n=8x=56; AABBDDEbEb). These genetic stocks were produced and maintained by the wide cross program at National agriculture research center (NARC) and studied cytologically and phenologically. The disomic chromosome additions are a conduit towards providing information on trait associations with grass chromosomes after stress screening, followed by cytogenetic manipulations to effect subtle alien chromatin transfers into homoeologous chromosomes of wheat. Each addition line was stable at 44 chromosomes, possessed regular bivalent meiosis and high fertility. The amphiploid was also cytologically normal. Phenological details permitted some additions to be readily characterized as follows: tapering spike = group 2Eb2Eb, solid stem = group 3 EbEb, blue aleurone seed = group 4 EbEb and club shaped spike = group 5 EbEb. The seed repository in Pakistan is the wide cross program in NARC, Islamabad.