EFFECT OF INTERACTION OF CROP MANAGEMENT FACTORS ON THE GLYCOALKALOIDCONCENTRATION OF POTATO-TUBERS

Potato tuber glycoalkaloid content was measured in response to nitroge n fertilizer rate, storage temperature, length of storage period and c ultivar. Cvs Gemchip, Norchip and Russet Burbank were grown with appli ed nitrogen fertilizer rates of 0, 168 or 336 kg/ha and then stored at either 4.4 or 10-degrees-C. Total glycoalkaloid content was determine d one month before harvest, at harvest, after three months of storage and after nine months of storage. Higher rates of nitrogen, higher sto rage temperature and a period of storage all resulted in significantly (P < 0.05) higher concentration of glycoalkaloids. The cv Norchip had higher glycoalkaloids than cvs Gemchip or Russet Burbank. Only the st orage period had more influence than the environment (difference betwe en years). Significant (P<0.05) two-way interactions were detected for year x cultivar, year x nitrogen, storage period x cultivar and nitro gen x cultivar. Most interactions were due to the unique responses of cultivars.