Objective  In preparation of breeding new early-mature, cold tolerant, high yield winter-potato varieties the nutritional quality of the hybrid candidates was evaluated.

  Method  A randomized block experiment was conducted in the field to compare the contents of vitamin C, reducing sugar, dry matters, protein, mineral elements, and amino acids in 27 hybrid progenies of a cold tolerant, high yield, high quality Minshu 2 as the female parent and a very early-mature, high quality Zhonglongshu 1 as the male parent.

  Result  Significant variations on contents of the nutrients were found among the 27 cultivars. The coefficient of variations (CV) on vitamin C and reducing sugar were 22.4% and 18.3%, respectively, and smaller CV on dry matters and protein 10.8% and 14.9%, respectively. On minerals, the greatest differentiations were shown on Mg and Fe contents with CVs at 17.0% on Mg and 24.2% on Fe, but lower at 10.2% on K, and 12.1% on Zn. The contents of 17 amino acids varied in the CV range from 12.9% to 38.0% with Asp, Glu, Cys, Agr, and Pro higher than 25%, and the total amino acids at 14.6%. It appeared that these progenies were highly diverse genetically resulting in significant variations on their nutritional quality. Hence, careful selection of the hybrids would be necessary to maximize the nutritional quality of the new breed. Using the principal component and cluster analyses, 12 high-quality candidates including 1320040, 1320001, and 1320009 were preliminarily selected.

  Conclusion  The nutritional quality of the 27 hybrids with rich genetic diversity was compared. Accordingly, 12 were chosen as candidates for breeding experimentation.