The effects of different water stress conditions on yield and quality of some curly (Lactuca sativa var. crispa) and cos (Lactuca sativa var. longifolia) lettuce varieties

This research was carried out in a plastic greenhouse in the Faculty of Agriculture in Akdeniz University to examine the effects of different water stress conditions on yield and quality of some curly (Lactuca sativa var. crispa) and cos (Lactuca sativa var. longifolia) lettuce varieties. Campania curly and Bitez cos lettuce varieties were used as plant material and seedlings were planted at 50 x 40 cm spacing. In the study, the size of the parcel was 1.6 m2 and there were 10 plants in each repetition. In the research the following applications were used: GS (conventional irrigation), %125 S (125% irrigation according to Class-A Pan evaporation), %100 S (100% irrigation according to Class-A Pan evaporation), %75 S (75% irrigation according to Class-A Pan evaporation), %50 S (50% irrigation according to Class-A Pan evaporation), YIS %125 (125% irrigation according to class-A Pan evaporation applied on the two halves of the plant roots alternatively in each successive irrigations), YIS %100 (100% irrigation according to class-A Pan evaporation applied on the two halves of the plant roots alternatively in each successive irrigations), YIS %75 (75% irrigation according to class-A Pan evaporation applied on the two halves of the plant roots alternatively in each successive irrigations) and YIS %50 (50% irrigation according to class-A Pan evaporation applied on the two halves of the plant roots alternatively in each successive irrigations). In the study, the content of chlorophyll, L, Hue and Chroma colour values, head length (cm), root collar diameter (mm), number of leaves (leaf/plant), total soluble solids (%), pH value, average head weight (g/plant), total yield (kg/da), marketable yield (kg/da), leaf area and irrigation water use efficiency parameters were determined in curly and cos lettuce plants. As a result of the study, it was found that GS and 125% S applications yielded the best results in terms of head length, root collar diameter, leaf area, total and marketable yield, total head weight, marketable head weight and irrigation water use efficiency of curly lettuce. When YIS 100% and YIS 50% applications of Bitez lettuce variety are excluded and conventional and partial root irrigation applications given the same amount of water are compared, it was observed that the conventional irrigations were prominent in head length, root collar diameter, number of leaves, total yield, marketable yield, total yield head weight and marketable yield head weight.