|Authors: ||A. Darrigues, A. Clivati McIntyre, D.M. Francis, S.J. Schwartz|
|Keywords: ||yellow shoulder disorder (YSD), lycopene, ß-carotene, phosphorous, potassium|
The predominant carotenoids in tomato, ß-carotene and lycopene, provide health benefits. ß-carotene is recognized as a nutrient due to pro-vitamin A activity and lycopene consumption has been correlated with a reduction in certain cancers.
Despite the potential benefits, the processing industry does not place value on carotenoid content in contract fee structures or processor grades.
Color, an indirect measurement of carotenoid content, and color uniformity are valued in the grading system.
The quality of tomato, as defined by its grade, can be reduced by ripening disorders such as yellow shoulder disorder (YSD) that affect the uniformity of fruit color.
We show that lycopene and ß-carotene are reduced by 18.6% and 21.8%, respectively, in fruits affected by YSD. A survey of YSD incidence in the Midwest, USA, between 2001 and 2003 indicated that soils with lower phosphorous (P) and lower available potassium (K) are more prone to YSD. Currently 23% of the tomato processing fields in this region are at a higher risk of YSD due to soil fertility.
Targeted application of K by drip irrigation and adequate soil nutrition have a positive impact on both yield, fruit color, and color uniformity.
YSD also has a genetic cause.
Best management practices to reduce the risk of YSD combine fertility management with varieties that are more resistant to the disorder.
These approaches can be used to optimize the potential for health benefits due to higher carotenoid content and may be encouraged under current contract structures.
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