Molecular Cytogenetic Identification Of Small Fragment Translocation Line Involving Chromosome Arm 6VS Of Haynaldia Villosa

Wheat production and quality are adversely affected by many biotic and abiotic stresses.The improvement of the resistance to diseases and pests, and the adaptability to various environments are the important objectives of modern wheat breeding. H. villosa (syn. Dasypyrum villosum L.,2n=14, VV) has been proved to be highly resistant to several wheat diseases and pests, tolerant to coldness and drought, so it is considered as an important genetic resource for wheat improvement.In the present study.Genomic in situ hybridization (GISH) at mitosis metaphase of root-tip cell of irradiated materials was used to detect the chromosomes structural changes involving 6VS of H.villosa.20 alien lines containing chromosome structural changes with small segment of 6VS were identified, including 10 interstitial translocation lines,9 terminal translocation lines and 1 deletion line.These small fragments of 6VS are different in both length of fragment and breakage location.They are useful germplasm for fine mapping of Pm21 gene, and construction physical map of 6VS, and they are also the valuable resources for wheat breeding.Eight 6VS specific molecular markers were used to define the fragment of 6VS. The translocation lines YC1-1,YC72-2,YC74-3 and YC24-1 showing high resistance to powdery mildew was involved very small segment of 6VS.The fragment of 6VS in terminal translocation line YC1-1 and YC72-2 was involved in the segment of FL value 0.45-0.58. The break point of the 6VS fragment in translocation line YC74-3 was between FLO.35 to 0.45 and the 6VS fragment was the segment from the breakpoint to FL:1.00. The break point of the 6VS fragment in deletion line YC51-4 was between FL:0.58 to 1.00 and the 6VS fragment was between the centromere to the breakpoint.One homozygous terminal translocation line YC1 with small segment of 6VS(FL0.45-0.58) and a homozygous interstitial translocation line YC24 with a segment of 6VS(FL0.35-0.58) were selected, which showed high resistance to powdery mildew. The Pm21 gene was further located in the region of 6VS from FL:0.45 to FL:0.58 by using these genetic stocks of 6VS and powdery mildew resistance identification.