DEVELOPMENT AND MOLECULAR-CYTOGENETIC CHARACTERIZATION OF WHEAT-Roegneria ciliaris LINES

¹ Cytogenetics Institute,Nanjing Agricultural University,Nanjing,Jiangsu 210095,P.R.China

² Department of Plant Pathology,Kansas State University, Manhattan,KS66506,USA

Roegneria ciliaris (Agropyron ciliare, 2n=28, S^c S^c Y^c Y^c) is a valuable source for resistance to wheat scab, a devastating disease caused by Fusarium graminearum. In order to transfer this resistance into wheat, effort for developing a set of euplasmic chromosome addition lines derived from the cross T.aestivum c.v. Chinese spring X T. aestivum-R. ciliaris amphiploid is ongoing. The objective of the present study was to determine the genomic affinity and the homeology of the individual R. ciliaris chromosomes in the addition lines. Based on C-banding, meiotic analysis and genomic in situ hybridization, 1 monosomic, 6 disomic, 1 ditelosomic and 1 double disomic addition lines were identified. To determine the genomic affinity of the added R.ciliaris chromosomes, three repeated DNA sequences: pTaq2.5, pTaq4.14 and pEt2 were used. Probes pTaq2.5 and pTaq 4.14 hybridized to 11 and 6 pairs of R. ciliaris chromosomes, respectively and not to any of the wheat chromosomes. pTaq4.14 hybridizes to 6 pairs chromosomes of Pseudoroegneria spicata(2n=14, S^s S^s ). In R. ciliaris pTaq4.14 hybridizes to 6 pairs of chromosomes, and we infer these to be S^c-genome chromosomes. Using this probe, four wheat- R. ciliaris addition lines were assigned to S^cgenome chromosomes. RFLP analysis was used to determine the homeology of the added R. ciliaris chromosomes. The preliminary data suggest that the added R. ciliaris chromosomes belong to group 2,3,4, and 5 respectively.