Identification And Selection Of Clones With Low Reducing Sugar Contents In Progenies Of Neo-tuberosum

It has been proved that strong heterosis always come out of hybrids derived from crosses between Neotuberosum and Solanum tuberosum ssp. tuberosum. In conventional breeding programs, introduction of Neotuberosum is an effective tool to improve yields and quality of potatoes. It has been verified that some favorable characteristics, such as low reducing sugar, high starch contents and resistance to some diseases, were found in Neotuberosum, which are important genetic resources for germplasm enhancement and breeding aimed at low reducing sugar contents. Nowadays, varieties used specially for processing are scarce and insufficient supply of suitable tubers is still constraining potato processing industry in China. Therefore, breeding aimed at processing is still one of major purposes of potato breeding programs in China.How to choose clones with lower reducing sugar and high yields accurately and efficiently in early generations is an crucial method for speeding up breeding programs and germplasm innovation aimed at fry-processing. In this experiment, tuber yields and reducing sugar contents of nine hybrid families derived from Neotuberosum were identified. Again, reducing sugar and dry matter contents of clones with high yields and low reducing sugar contents (<0.4%) selected form hybrid families were tested under changeable temperature conditions. The results were as followed:Through comprehensive evaluation on yield components, 16 selections of high yields were identified, in which 4 selections derived from N03-3 family, 4 selections come from N03-9 family, which meant both families N03-3 and No03-9 are potential for high yields and could be used as promising crosses.Tests of reducing sugar contents of 175 clones from nine crosses were made firstly by glycosuric test paper, and 67 clones were identified as low reducing sugar content selections. Then accurate tests by means of colorimetry of 3,5-dinitrosalicylic acid were made on the 67 selections. 64 selections out of 67 clones were identified as clones with lower reducing sugar contents (<0.3%). It certified that glycosuric test is available for preparatory selection of lower sugar contents.Tests of reducing sugar contents were also made on 55 selections under recondition after low temperature storage. The results showed that thoes 55 selections possess characteristics tolerant to low temperature storing and recovered. Clone 4-30 is the best for tolerance to low...