ARS | Publication request: Enhancement of tomato fruit lycopene by potassium is cultivar-dependent

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: March 30, 2007
Publication Date: April 30, 2007
Citation: Taber, H.G., Perkins Veazie, P.M., White, W.S., Rodermel, S.R. 2007. Enhancement of tomato fruit lycopene by potassium is cultivar-dependent [abstract]. HortScience. 42(4):934.

Technical Abstract: Functional foods, those containing bioactive ingredients known as phytochemcials or nutraceuticals, are known to increase health and fitness. An example is the red color compound lycopene found in tomato fruit that inhibits development of some cancers, specifically prostate cancer. Some researchers have found that increased potassium fertility increases lycopene content in tomato. The purpose of our experiments was to determine the response of high and average lycopene tomatoes to increased potassium in greenhouse and field experiments. The 2004 experimental design was a factorial, split-plot, randomized complete block with 4 replications. The whole unit was K rates (0 to 372 kg K'ha**-1 as KCl). The subunit was cultivar, either Mountain Spring or the high lycopene Florida hybrid, FL8153. The soil type was a well drained, central Iowa loam with a soil test level of 89 kg K'ha**-1, considered low. The soil K application effect on total marketable fruit yield was linear (P<.001, Y = 53 Mg'ha**-1 + .7x, r**2 =.5) with both cultivars responding similarly. Fruit K analysis indicated a linear response to fertilization across four harvest dates, from 1230 to 2000 ppm, fresh weight basis. Harrvest date had no effect on fruit lycopene concentration, but there was a significant (P=.006) interaction of K fertilization rate and cultivar. Mountain Spring lycopene concentration was not enhanced by higher K fertilization; however, FL8153 contained 11.2 mg'kg**-1 more lycopene at the highest K rate compared to lower rates, a 21.7% increase. Overall, the FL8153 variety contained 9.5 mg lycopene'kg**-1 fruit tissue more than Mountain Spring.