Growth, physiology and yield responses of cabbage to deficit irrigation

Field experiments were conducted in two seasons to investigate growth, physiology and yield responses of cabbage (Brassica oleracea L. cvs Pennant and Rio Grande) to deficit irrigation. In 2012 season, 50% of crop evapotranspiration (ETc) irrigation temporarily decreased plant size, reduced leaf area, fresh weight, relative water content, specific leaf area and gas exchange during late development, and decreased head fresh weight, size, marketable and total yield. Deficit irrigation at 75% ETc had little influence on plant growth and physiology, but it still reduced both marketable and total yield. In 2013 season, 75% ETc irrigation had little influence on plant growth, leaf characteristics, photosynthetic rate, head fresh weight and size, but it temporarily increased chlorophyll and carotenoid content, and decreased stomata conductance, transpiration, and marketable yield. Pennant, the green-head cultivar, had higher photosynthetic rate, head fresh weight, marketable and total yield than the red-head cultivar Rio Grande. In both seasons, deficit irrigations did not influence cabbage head dry weight, indicating that most yield reduction under deficit irrigations is related to water content.