Influence of Plant Covering on Some Organic Compound Content and Pungency of Shallot Grown for Bunching Harvest

Quantity and quality of yield of shallot grown for bunching harvest with the use of covers was examined. There were two types of covers used: perforated polyethylene film (0.03 mm thick; with 100 holes per 1 m²) and polypropylene non-woven fabric. The control plants were shallots grown without cover. After harvest the content of dry matter, L-ascorbic acid, total and reducing sugars, saccharose and pyruvic acid was determined. The results of the study showed that there was no significant effect of covering plants with perforated polyethylene film or polypropylene non-woven fabric on the dry matter, sugars and L-ascorbic acid content in the shallots grown for bunching harvest. Also, covers used in the experiment did not have an influence on the level of pungency of shallots. However, the weather conditions of each year of the study had a significant effect on the content of the analysed compounds. Plants grown in 2004 had five times more L-ascorbic acid than plants grown in 2003. Inversely, total sugars content in 2003 was twice higher than in 2004.

Moreover it was proved that, the correlation between total sugars content and pungency of shallot grown for bunching harvest was significant (r= -0.9097).