INHERITANCE OF POTATO-CHIP COLOR AT THE 24-CHROMOSOME LEVEL

Potato chip color is an important trait in determining quality and acceptability of cultivars for processing. Therefore, the genetics of potato chip color is important in varietal breeding. The use of 2x S. tuberosum Group Tuberosum haploid x 2x wild species hybrids provides disomic inheritance for genetic analysis of chip color. Two hundred forty haploid-species hybrids representing crosses between 15 haploids and 10 species were evaluated for potato chip color after 21 days reconditioning (18 to 20C) following 6 months at 4C. Phenotypic variation for chip color was found among the haploid-species hybrids. Crosses between good, medium, and poor performing clones were made in all combinations and 136 families were obtained. Progeny were evaluated for reversion resistance (chipping direct from 10C storage) and reconditioning (chipping from 4C after tuber warming) chip color. Variation for chip color was found among the progeny for each trait. Significant correlations between reversion resistance and reconditioning were found. Yet, the use of at least two chip tests (one for reversion resistance and one for reconditioning) is more informative than the use of one test and subsequent predictions made, regarding the other trait. A three locus hypothesis for both reversion resistance and reconditioning is proposed for the inheritance of each trait. One dominant allele at each of the three loci is necessary for good chipping. One or two loci may be common to both characteristics. Good chipping 2x hybrids that produce 2n pollen can be used to transfer this trait to the 4x level through use of 4x x 2x crosses.