Sugar Content Of Sweet Sorghum F₅ Populations And The SCAR Analysis Of High Sugar Genes

As a new energy crop, sweet sorghum is famous for its high sugar content. The using of fule ethanol can not only ease the energy crisis but also has a very broad prospect for food security. Learn the prograss of glucose metabolism and the changes of related enzyme activity have important significance for choosing high sugar content varieties and improving the sugar conent in sweet sorghum. The research for this thesis used female 1331B(sweet sorghum), paternal 7009B(ordinary sorghum) and their hybrids F5 as the model material to study the content of total sugars and sucrose to learn the sucrose phosphate synthase(SPS) and sucrose synthase(SS) activity, used molecular marker technology to analyse high sugar gene, clone the target bands and transfer the RAPD to SCAR molecular markers, the main findings are as follows:1. In 100 F5 plants, 70 of the total sugar content was similar to female 1331B(sweet sorghum),30 of the total sugar content was similar to paternal 7009B(ordinary sorghum). By using HPLC, we determined the sucrose content of male, female and F5 individuals, the results showed that 64 of the sucrose content was similar to female 1331B(sweet sorghum) in 70 individuals, 36 of the sucrose content was similar to paternal7009B(ordinary sorghum).2. This experiment determined sucrose phosphate synthase(SPS) and sucrose synthase(SS) activity, the results showed that 62 of the SPS activity were similar to female 1331B(sweet sorghum) in above 64 individuals, 38 of the SPS activity were similar to paternal 7009B(ordinary sorghum), but the change of SS activity was not similar to the total sugar and the sucrose, so according to the change of the total sugar,sucrose and SPS, we established those 62 individuals as a high sugar gourps, the other as a low sugar gourps.3. 120 RAPD primers were used to analyse female 1331B(sweet sorghum), paternal 7009B(ordinary sorghum) and their hybrids F5, the results showed that 95 of 120 pairs amplified products, 25 of them did not amplify products, so the amplification rate reached 79%. The recombination rate of S512 and high sugar genes was 7%, and the genetic distance was 7.05 c M in F5 populations. S512 amplified polymorphic bands were recovered, cloned and sequenced, its bands length was 441 bp. According to the sequence, we transferred the RAPD to SCAR molecular markers and designed SCAR primer. We got the same amplification results with the RAPD in specific amplification prograss of sweet sorghum F5 populations, thus the RAPD transfered to SCAR successfully, we called this SCARS512-441.