Effect of growing period and cultivar on the yield and biological value of Brassica rapa var. narinosa

English. The aim of the present study was to evaluate the usefulness of Brassica rapa var. narinosa for field production in Central European climatic zone in order to introduction of this species to large-scale farming. Chinese flat cabbage cultivars, ‘Tatsoi’ and ‘Misome’, were the object of the 2-year-long field experiment in south Poland, conducted in 2 terms: plantings in the middle and at the end of August, harvests in the middle of September and on the beginning of October (1st and 2nd growing period, respectively). Plants were evaluated for morphological and chemical variability at the transplant stage. The yield and bioactive compounds content in the leaf petioles of mature plants were also studied. Analyses of juvenile plants, conducted before transplanting, showed that ‘Misome’ transplants were greater, but they had less leaves then ‘Tatsoi’. Transplants of both cultivars from the 2nd growing period had greater fresh weight, but the content of dry matter, soluble sugars and carotenoids was lower. Total and marketable yield, rosette mass, L-ascorbic acid and crude fibre content were greater for both cultivars planted in the middle of August and harvested in the middle of September. Leaf petioles of Chinese flat cabbage from the 2nd growing period were significantly richer in dry matter and soluble sugars. Only the level of carotenoids and chlorophylls was not influenced by the growing period. ‘Misome’ gave the greater marketable yield of better structure, and had a higher content of biologically active compounds than ‘Tatsoi’, with the exception of crude fibre. In Central Europe conditions, this cultivar should be recommended for plantings in the middle of August to achieve the best yields of high nutrient content.

English. biological value, Chinese flat cabbage, timing, transplants, yield

15

546-552

2