| Morphology, cytology and molecular markers were adopted to identify the dwarf line WB29 and the big spike line WB13 selected from the progenies of common wheat cv. 7182 × Two-rowed barley. Meanwhile, molecular marker technique and GA treatment were used to detect the distribution of dwarfing genes in 21 India wheat cultivars. The results were as following:(1) WB13 contained barley 4H and 7H chromosomes, it mainly showed large panicle and large grain in the field, and its comprehensive agronomic characters were good. To take advantage of this material, more work had been done to study on it. 130 pairs of SSR markers were used to detect the genetic background of WB13, the results showed that the geneticsimilarity coefficient was 97.0% between WB13 and 7182. On the basis of former researches on this material, we can confirm that the large spike and grain characters of WB13 were inherited from barley. With 35 sets of SSR markers distributed among barley 4H and 7H chromosomes to detect WB13 and its parents, a marker MGB396 located in barley 4H chromosome which had been identified may link with a QTL related with thousand-grain weight by previous research amplified a specific band in WB13.Combined with former research we were sure that WB13 was an introgression line, it had 4H barley chromosomes, and the 4H chromosome may had some genes related with thousand-grain weight which may contribute to the large spike and grain characters of WB13.(2)The new WB29 was a dwarf line of wheat, in spite of dwarf, its comprehensive character was good. Cytology identification showed that root-tip cell chromosome number ofBC1F1 and F2 population were derived by crossing between WB29 and Chinese spring, and the WB29 was 2n=42, no obvious hybridization signal was observed in genomic in situHybridization(GISH) with two-rowed barley genomic DN A acted as a probe. STS markers of barley ABG459(2HS) could amplify specific barley bands from WB29. Ten pairs of specific molecular markers for wheat dwarfing genes(Rht) were applied to identify two-rowed barley,7182, WB29 and Chinese spring, the results showed that 7182 and WB29 had Rht-D1 b while none of the 10 wheat dwarfing genes(Rht) were detected in barley and Chinese spring.The results above had defined that WB29 contain the barley 2HS chromosome and the dwarfing gene in WB29 had played an important role in reducing its plant height.(3)The result showed that all of the 21 India wheat cultivars contained two or more dwarfing genes, in which Rht8 and Rht4 had been utilized with the highest percentage atamong which the coleoptile length of 13 cultivars weresignificantly longer than Chinese spring, the plant height data showed that the plant height of these cultivars were significantly lower than Chinese spring. statistical analysis of these two derived populations indicated the dwarf traits of WB29 wascontrolled by one pair of incomplete dominance gene. Gibberellic acid reaction pointed that WB29 was a gibberellic- insensitive type of wheat. STS of barley A BG459(2HS) and the primer of Rht-D1 b were used to evaluate F2 population, and a linkage analysis was carried out which showed that ABG459 was closely linked to the main dwarfing gene of WB29 at a genetic distance of 7.0 c M, while Rht-D1 b was not linked to this main dwarfing gene. 66.7% and 61.9 %, respectively, while Rht5 and Rht-B1 b was utilized slightly lesser than these two at a percentage of 57.1 % and 52.4 %, respectively, none contained Rht12 and Rht13; only 3 cultivars had 4 dwarfing genes, and 13 cultivars had 3 dewarfing genes. Test on response to GA3 of these cultivars revealed that only 4 cultivars were senstive to GA3. The results of coleoptile length investigation indicated that most coleoptile length of the cultivars were longer than Chinese spring. |
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