马铃薯转基因研究进展

简要介绍马铃薯转基因技术方法,着重对已获得的转抗真菌病基因、抗病毒基因、抗虫基因、改良品质基因的马铃薯的特征特性,以及将马铃薯作为植物生物反应器来生产有用蛋白质和疫苗等方面的研究成果进行了综述,同时还对转基因马铃薯的生物安全性作了评价和展望。     

Composition of sulfited potatoes: Comparision with fresh and frozen potatoes

The content in moisture, fat, protein, carbohydrate, fibre and vitamin C was analyzed in three commercial types of potatoes: sulfited (treated with E223), frozen potatoes (pre-fried) and fresh potatoes (not processed). The composition of sulfited potatoes does not usually appear in food composition tables. Our results showed significant differences in the content of carbohydrates and fibre between sulfited and fresh potatoes. The content of vitamin C in sulfited potatoes, which is similar to that of frozen potatoes, was shown to be approximately half of that found in fresh potatoes.     

Chemical weed control in potatoes

Nine herbicide treatments were applied to potatoes grown at three locations in each of 3 years. The locations were characterized by widely different soil types—silty clay loam, sandy loam, and muck—and by differences in rainfall and temperatures during the growing season. None of the herbicide treatments applied pre-emergence gave adequate weed control at all locations and/or in all years. EPTC at 6 lb per acre (6.72 kg/ha) gave excellent weed control on both mineral soils but not on muck. Metabromuron at 4 lb per acre (4.48 kg/ha gave excellent weed control only on the low organic matter sandy loam. Propachlor at 6 lb. (6.72 kg/ha) and 2 lb amiben plus 3 lb propachlor (2.24 plus 3.36 kg/ha) gave variable control. Four herbicides: 1 lb paraquat (1.12 kg/ha), 2 lb linuron (2.24 kg/ha), 6 lb dinoseb (6.72 kg/ha) and 6 lb dinoseb plus 2.25 dalapon (6.72 plus 2.52 kg/ha) applied at potato plant emergence, when weeds were in the 2–6 leaf stage, also gave variable control but as a group generally gave better control than the pre-emergence herbicides, particularly on muck soil. The effectiveness of herbicides applied at potato plant emergence was less affected by soil type than those applied pre-emergence but was affected by the degree of weed emergence. On muck soil, weeds generally emerged well before “at emergence” herbicide treatments were applied. Tuber yields were not directly affected by the herbicides, but were reduced where weed control was inadequate. Tuber specific gravity and chip color were unaffected by the herbicides.     

Sugar-end in Russet Burbank potatoes

Tissue selected from the stem- and bud-end of reconditioned tubers having sugar-end disorder was compared by color after frying and chemical composition to tissue removed from the two ends of tubers without sugar-end disorder taken directly from cold storage at 45 F, and after reconditioning 3 weeks at 70 F. Chemical analyses of selected tissue suggested that the dark finish-fry color at the stem-end of sugar-end tubers following reconditioning at 70 F was due to the inability of the physiological systems within the tissue to convert reducing sugars to starch and/or to use these sugars in the respiratory process. Of the components analyzed, only a high reducing sugar content was associated with a dark finish-fry color. Neither sucrose nor free amino acid content was associated with the sugar-end disorder. Extending the reconditioning period at 70 F for sugar-end tubers did not lower the reducing sugar content or the darkening of the stem-end tissue on frying.     

Quantitative variation in diploid potatoes

Fifty clones selected from crosses between Phureja and Tuberosum haploids and 24 Tuberosum haploids were used to produce two Design I trials, and one Design II trial. Tests were conducted for 2 years at one location, and estimates were obtained for quantitative genetic variance for tuber number and weight. Estimates of genetic variance for tuber number were large, with approximately equal additive and dominance components. Additive genetic variance was the larger component for tuber weight for two of the three estimates. More results from other populations are needed to establish the relative importance of the quantitative genetic components in potatoes.