Cytological And Molecular Characterization Of Four Common Wheat-Agropyron Cristatum Derivative Lines

Distant hybridization is an effective way to provide new germplasm for wheat genetic improvement. Agropyron cristatum(L.) Gaertn not only carries the fertility genes, but also possesses resistance to cold, drought, powdery mildew and rust disease of wheat. In this study, the derivatives II-13, II-23 and the disomic addition lines II-7-1, II-8-1 were identified by in situ hybridization, molecular markers and investigation of agronomic traits. The results are shown as follows:1. Chromosome composition of wheat- A. cristatum derivative lines II-13, II-23. The cytological results of root tip cells and pollen-mother cells showed that both II-13 and II-23 had 44 chromosomes, in which II-13 contained two pairs of P chromosomes whereas II-23 carried three pairs of P chromosomes. The detection of fluorescence in situ hybridization and specific molecular markers further indicated that 7D chromosomes were absent and 2P, 7P added in II-13. II-23 did not have 4B and 7A chromosomes, but carried 2P, 4P and 7P chromosomes. Therefore, II-13 was 7D(7P) substitution line and 2P addition line, while II-23 was 4B(4P) and 7A(7P) substitution line and 2P addition line.2. The acquirement of wheat- A. cristatum alien disomic addition lines and substitution lines. Some novel alien disomic addition lines were obtained among the progeny between II-13, II-23 and recurrent parent Fukuho. The plants 2-57, 2-72 were wheat- A. cristatum 2P addition lines, the plants 4-7, 4-11, 4-12 were wheat- A. cristatum 4P addition lines, and the plant 7-7 was wheat- A. cristatum 7P addition line. In addition, five plants were identified as wheat- A. cristatum substitution lines, including 4P substitution lines(4-6, 4-8), 7P substitution lines(7-49, 7-64, 7-65), in which 7-64, 7-65 were 7D(7P) substitution lines.3. Morphology evaluation of wheat- A. cristatum derivatives. The lines II-13 and II-23 exhibited narrow flag leaves, compared with Fukuho. Powdery mildew investigation showed that II-23 was highly resistant to powdery mildew.4. Cytological identification and powdery mildew evaluation of the lines II-7-1 and II-8-1. GISH and molecular results showed that II-7-1 and II-8-1 were wheat- A. cristatum 2PS telosomic alien addition lines. They were both susceptible to powdery mildew, indicating that 2PS did not carry powdery mildew resistance genes.5. The acquirement and detection of wheat- A. cristatum 2P translocation lines. Wheat- A. cristatum 2PS telosomic addition lines II-7-1 and II-8-1 were irradiated by 60Co-γ rays to induce alien translocation lines. The GISH and STS markers results showed that two wheat- A. cristatum 2P translocation lines were detected in M1 progenies of II-7-1, and the frequency of translocation was 3.6%; nine translocation lines were found in M1 progenies of II-8-1 and the frequency of translocation was 8.5%.