Chilling stress applied to broccoli transplants of different age affects yield of the plants cultivated in summer

Abstract

Broccoli is native to moderate climatic zone, and summer cultivation of this species in Central Europe conditions leads to a decrease of heads quality. The aim of present investigations was application of dark-chilling at 2°C for 1 and 2 weeks to transplants of various ages to enhance its tolerance against adverse conditions in the field and to modify the yield potential. Broccoli cv. Monaco F1 can be recommended for summer production in Central Europe, because of high yield potential and lack of buttoning in high temperature conditions. Dark-chilling of 4-week-old transplants for two weeks significantly increased the yield, but also the percentage of stems with hollows as compared to control. Significant advancing of harvest together with prolongation of the harvest's period can be achieved by the use of 6 and 8-week-old transplants chilled for 2 weeks. Dark-chilling of 10-week-old transplants resulted in forming of smallest heads with the highest percentage of hollow stems.