Identification Of A Dwarf Line Deriving From Wheat-Thinopyrum Intermedium Progenies By Molecular Cytogenetic Techniques

The high-yield and lodging resistance have been the important target traits in the wheat breeding.All the lodging resistance,good response to fertilizer and high harvest index are the advantage of the dwarf varieties.The dwarf varieties have been the main target traits in the high-yield wheat and super-high-yield breeding of the wheat.However, the simple phenomenon of the dwarf genes is very serious.The important way to solve this shortcoming is constantly searching for identification of the new dwarf germplasm resources to use.Thinopyrum intermedium,one of species in Thinopyrum of Triticeae, has excellent characteristics,such as drought resistance,cold resistance,tolerance to bad environments,big spike and multi-spikelet.It is easy to cross with wheat,and many desirable genes in Th.intermedium have been transferred into wheat.In this experiment,the morphology,cytogenetics and situ hybridization method were used to identify a wheat dwarf line 08-725 which derived from the progenies of common wheat and Th.intermedium.The reaction of 08-725 with GA3 was also carried out.The results were as follows:1.Line 08-725 could be normal growth and grain.The most important characteristic of the line is far shorter than the height of its wheat parent Chuanmai 107 which inferred that a gene or chromosome fragment could be existed to reduce the plant height in line 08-725.2.The number of chromosomes with root tip of line 08-725 was counted.The results indicated that the chromosome number were 2n = 42.3.The chromosome pairing configuration of line 08-725 was 2n=20.52â…¡+0.27â… +0.14â…¢+0.07â…£through pollen mother cell meiosisâ… checked.The result demonstrated that line 08-725 might be cytologically stable.However,there were still a small number of univalent,trivalent and quadrivalent,and log chromosomes and chromosomal bridge were also observed in PMC AI Combination of root tip chromosome number and structure analysis,wheat - Thinopyrum intermedium translocation or chromosome structure modification might be occurred in line 08-725. 4.Genomic in situ hybridization results showed that one arm of the 2 chromosomes showed yellow-green(hybridization signal),while the other arms showed red hybridization signal among the 42 chromosomes.It is apprarently that line 08-725 is a fragment translocation between wheat and E.intermedium chromosomes,and the fragment translocation might be carried one dwarf gene which has strongly reduced the plant height.5.The results of gibberellic acid reaction indicated that the first leaf length and coleoptile length had little difficences,but no significant differences were found in wheat variety Nonglin 10 and line 08-725.However,drooping on leaves of Chuanmai 107 was observed when the seedling of Chuanmai 107 was treated by different GA3 solutions,and significant differenc was recorded by t-test.Those results suggested that gene to reduce plant height in line 08-725 might not be sensitive to the GA₃,and it might be the pleiotropic role of the dwarf gene.