GENOTYPIC VARIATIONS IN QUALITY AND SHELF-LIFE OF FRESH ROOTS OF PHILIPPINE SWEET-POTATO GROWN IN 2 PLANTING SEASONS

Sweet potato breeding in the Philippines has recently integrated root quality and shelf-life attributes in varietal development. In this stu dy, the harvest and post-harvest quality of the fleshy roots of differ ent sweet potato genotypes were determined. These genotypes included t he existing recommended varieties and the elite selections from the po lycross breeding nursery and were grown during the dry and wet plantin g seasons. Dry matter, starch, sugar and protein contents of freshly h arvested roots were found to differ widely with genotype. During stora ge at ambient temperatures, starch content decreased, sugar content in creased and in some genotypes dry matter increased. Protein content of the stored roots varied only slightly from that of fresh roots. The d ifferent genotypes also differed in the degree of weight loss, shrivel ling, decay and consequently, shelf-life. Some genotypes had short-liv ed roots (less than 1 month) while others had roots which were still m arketable at the end of the 3-month storage period. Root quality and s helf-life similarly varied with planting season. Some genotypes had in creased dry matter, starch and sugar contents and long shelf-life when planted in the dry season while others had these characteristics when produced in the wet months. Protein content generally decreased in we t-season-produced roots. However, a number of genotypes had comparable root quality and shelf-life regardless of planting season.