Author(s): Funda Eryilmaz Acikgoz
The aim of this study is to determine the changes in quality of pak choi in successive growing seasons. Experiments were carried out in a PE covered cold greenhouse in late autumn-early winter and late winter-early spring growing period in Turkey (41°11’ N, 27°49’ E). Results showed that morphological features, the leaf area (73.82 mm2), leaf length (31.21 mm), average leaf width (2.70 mm), maximum leaf width (3.92 mm), mass (95.27 g) and moisture content values of leaves (0.90% w.b.) were higher in late autumn-early winter period but leaf thickness (0.33 mm) contents were higher in late winter-early spring period. Yield characteristics investigated were affected by season and were found relatively higher in late autumn-early winter than late winter-early spring growing period. And it was 5713 kg ha-1 in late autumn-early winter growing period and 5034 kg ha-1 in late winter-early spring growing period. In point of the dry matter content investigated were affected by season, and were higher in late autumn-early winter than late winter-early spring growing period. It was 12.4% in late autumn-early winter growing period and 10.25% in late winter-early spring growing period. Account of total protein of plants grown in late autumn-early winter (25.16%) was higher than in late winter-early spring (22.45%) growing period. Sowing time did affect ascorbic acid content significantly. It was 44.21 mg.100-1 g in late autumn-early winter growing period and was recorded as 38.02 mg.100-1 g in late winter-early spring growing period. Color parametres L, a, b values were measured as 27.92; -6.98 and 8.53 in late autumn-early winter and as 21.64; -5.48; 7.49 late winter-early spring. Sowing time did affect color parameters content significantly. Late autumn-early winter growing time result was higher than in late winter-early spring growing time. With regard to mineral content N (4.67%), P (0.65%), Cu (9.32 ppm), Fe (879.6 ppm) and Zn (49.13 ppm) values were higher in plants grown in late autumn-early winter in comparison with plants grown in late winter-early spring as K (4.45%), Ca (2.36%), Mg (0.41%) and Mn (62.25 ppm) values of plants were higher in late winter-early spring growing period. Results of the study indicated that different weather conditions influenced the pak choi yield and the chemical composition of the leaf as well. Pak choi with its relatively short cultivating period, easy growing, and dietary value can be a good alternative crop for late autumn-early winter growing period in cold greenhouses.
