|Author: ||C.C. Gunter|
|Keywords: ||vegetable, cropping systems, fertility, nutrition|
Yellow shoulder disorder of tomato is distinguished by discolored regions under the skin of ripe fruit.
This disorder involves abnormal fruit development and is not a delay in fruit ripening.
Multiple factors contribute to the potential development of this disorder including variety, weather, and location effects.
This disorder has been linked to low potassium levels during fruit development.
The study was designed to gain an understanding of the proper potassium rate and the timing of those rates on the development of the yellow shoulder disorder.
Potassium chloride was delivered at three rates and at three critical physiological timings during the flowering cycle.
Four processing tomato varieties were used for this study.
Fruit color quality was measured following harvest.
Soil potassium was also measured and compared across timing and rate treatment combination.
In variety 331, an early application at the low rate of potassium resulted in better hue values than other treatments for this variety.
Also, higher rates of potassium applied late in the flower development cycle produce fruit with less color uniformity than early application.
In variety 611, treating plants with the low rate of potassium in the middle of flower development resulted in fruit with less internal white tissue compared to those receiving high rates of potassium.
This held true for varieties 9423 and 9704 also.
In the case of 9704, the highest rate of potassium applied late in the flowering cycle produced fruit with more internal white tissue than plants treated with the lowest rate of potassium applied early in flower development.
This study suggests that growers may currently be over-fertilizing with potassium and suggests a method to maximize potassium fertilizer application for fruit color quality.
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