This research was focused on determination of the correlation between soluble sugar content in green asparagus (Asparagus officinalis L.) spears and yield. In 2000-2002, green spears of the cultivar 'Thielim' were cut every day from the end of April to the middle of June. Sucrose, glucose, and fructose content was determined every 10-14 days by means of an HPLC method. The content of fructose was not correlated but the ratio of fructose to glucose content was positively correlated with the yield (r=0.92). When the ratio of fructose to glucose content in spears increased by 0.13, the yield increased by about 1 t·ha-1. Content of glucose, sucrose and soluble sugar were negatively correlated with yield (r = -0.76 r = -0.77 and -0.79, respectively). When glucose, sucrose and soluble sugar content in spears decreased by 0.29 mg·g-1, 0.20 mg·g-1 and 0.85 mg·g-1, respectively, the yield increased by about 1 t·ha-1. During the first twenty days of harvest the calculated amount of soluble sugar accumulated in harvested spears was correlated with the yield in the remaining harvest period as well as in the whole harvest season. The effect of temperature and solar radiation on the yield and sugar content in spears is discussed in the paper.
