|Perkins Veazie, Penelope|
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2003
Publication Date: N/A
Interpretive Summary: Decreasing water supplies for agriculture have increased the challenges for production. This experiment was done to determine how much deficit irrigation would affect watermelon productivity and melon quality (firmness, sweetness, and lycopene content). Yields were reduced when irrigation was half the recommended rate, but was less severe in triploid (seedless) varieties. Flesh firmness and sweetness was highest in seedless melons. Deficit irrigation at 75% of the recommended rate slightly increased lycopene content. The results of this study indicate that watermelon productivity and quality can be maintained if irrigation is applied at 75% of the recommended rate.
Technical Abstract: Many vegetable production regions in the southwestern US are strictly regulated on water use. In addition, demand for high quality and nutritious vegetables has increased. This study was performed to explore the effects of deficit irrigation on yield, fruit quality and lycopene content of red-fleshed diploid and triploid watermelon (Citrullus lanatus (Thunb) Matsum & Nakai) cultivars. Irrigation treatments were 1.0, 0.75 and 0.5 ET rates. Cultivars used were Summer Flavor 710, RWM 8036, Allsweet, Sugarlee, and SWD 7302 (diploids) and Summer Sweet 5244, SWT 8706, Sugar Time, and Tri-X-Sunrise (triploids). Total water applied through a subsurface drip system was 395, 298 and 173 mm, for the 1.0, 0.75 and 0.50 ET, respectively. Total yields were highest at 1.0 ET (53.9 t ha-1) compared to 0.5 ET (26.8 t ha-1). Triploids had a 34% higher total yield and fewer culls (2%) compared to diploid cultivars (25%). Highest yields were obtained for Sunrise, SWT 8706, and SWD 7302. Highest soluble solid content was measured for Sugar Time (13.4%) and was significantly higher than other cultivars (range 9.7-11.0 %). Triploid cultivars had a more firm flesh compared to diploids (12.0 vs. 9.9 N). Lycopene content increased slightly with maturity (55.8 to 60.2 ug g-1 fw), and was significantly higher at 0.75 ET than 1.0 ET in melons at ripe and overripe maturity stages. Lycopene content averaged over all treatments was 60-66 ug g-1 fw for triploids and 45 to 80 ug g-1 fw for diploid fruits.