Melhoramento genético de batata para processamento na forma de palitos pré-fritos

Abstract

Processed potatoes consumption has increased significantly in the last ten years. However, the low-quality material limits the development of this industry in Brazil, considering that only one third of the material used for this purpose is produced in the country. Thus, there is a need to aggregate production areas, which is directly related to the availability of new cultivars with yield stability under national growing conditions, adequate processing characteristics and high storage capacity. For a fast progress, the correct choice of parental genotypes is essential, as well as the characterization of elite clones regarding the behavior during storage and use of a practical and precise quantification method of reducing sugars, a capital parameter responsible for the color, aroma and flavor of the processed product. In this sense, three studies were developed. The first aimed to estimate genetic parameters of yield and processing traits, external physiological defects and external tuber appearance, and their implications on selection of a hybrid population consisting of 20 complementary character families of industrial quality and genetically distant. Percentage of commercial tuber weight, average tubers mass, external tuber appearance, and processing characters showed moderate to high broad sense heritability estimates, and glucose content, shape, texture and overall appearance of tubers can be subjected to higher selection pressure. The second study aimed to evaluate industrial quality characters of foreign and national cultivars, and clones developed by Embrapa, when subjected to storage at temperatures of 4.0ºC, 7.5ºC, 8.9ºC, and 20.0ºC. Long term storage was limited due to high fresh mass loss and sprouting, however, it did not change the dry mass content. As for glucose content, clone F50-08-01 was able to process up to 60 days after storage; cultivar Asterix up to 90 days; clone F31-08-01 for up to 120 days; and Markies, Ludmilla and F183-08-01 genotypes up to 180 days. Storage at 4ºC, 7.5ºC and 8.9ºC promoted glucose accumulation in potato tubers, and lower temperatures resulted in higher accumulation. The third study aimed to verify the reliability of use of amperometric biosensor (YSI®) to determine glucose content in potato tubers. Tubers of eight genotypes were produced in fall and spring seasons of 2015. Glucose content was determined by the spectrophotometric method, usually used to determine glucose in potato tubers, and by amperometric biosensor. The analysis was performed after curing the tubers, and at 30, 60 and 90 days after storage at low temperature. The correlation coefficient obtained between the two methods was positive and of high magnitude. The coefficient of variation observed for the data obtained by the biochemical analyzer was low. Amperometric biosensor has proved to be a reliable alternative for determining glucose content in potato tubers.