Sweet corn quality is determined by such characteristics as ear length and diameter, number of kernel rows per ear, ear fill and productivity, as well as nutrient content in kernels. These traits may be influenced by environmental conditions and cultivation methods. A field experiment was conducted in 2006-2008 to examine the effect of different sowing dates (26th April, 10th and 24th May) and covering with nonwoven PP on quality traits of sweet corn ear. The experiment was carried out in eastern Poland (52º03’ N; 22º33’ E). Sweet corn formed ears characterised by better biometrical parameters in the cooler and wetter years 2007 and 2008 compared with the warm and dry 2006 in which, however, corn kernels contained more ascorbic acid, total sugars and sucrose than in other study years. As corn sowing was delayed, ear diameter, kernel weight, number of kernel rows per ear and dry matter content of kernels increased gradually. Most total sugars and sucrose were determined in the kernels of corn sown on the second date. In 2006, ears with most kernels were harvested from plots sown with corn on the first date, while in the cooler and wet weather during the 2008 growing season the best ear fill was found for the second and third sowing date. Covering corn in the initial stages of crop development increased biological productivity of ears as well as the dry matter content, total sugars and sucrose in kernels. ‘Sweet Nugget F1’ and ‘Sheba F1’ produced longer ears with heavier kernels which also contained more dry matter, total sugars and sucrose than ‘Rana F1’ which, however, had most kernel rows and kernels per ear.

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