EFFECTS OF SOWING DATE AND FOLIAR SPRAYS OF POTASSIUM ON BLOTCHY RIPENING OF WINTER CROP TOMATO

Under greenhouse conditions blotchy ripening severely affects tomato fruits which ripen during March and April and cause large economic losses.
This fruit disorder was studied to determine how the yields and the extent of blotch were influenced by sowing dates in long term tomato cultivation.
When plants reached the fifth flower stage, K sprays were started and repeated at 20 day intervals.
The tomato cultivar Fantastic, which is often used as a single crop and is sensitive to blotch, was used in the experiment.
In the tomato plants treated with K sprays 8–10 times at a rate of 0.5% K₂O in the form of KNO₃ blotch was not eliminated.
Leaf K content and yield were not affected, as well.
The K content of early sown tomato plants was higher and at an optimum level during the fifth flower cluster stage, compared with the later sowing dates.
When sowing dates were earlier that mid September, the percentage and severity of blotch were reduced.
The early sowing date (Aug. 5) extended the harvest by three months and yield was up to 50% higher in comparison with the traditional sowing date (Sep. 18).

International Symposium Greenhouse Management for Better Yield & Quality in Mild Winter Climates

M.E. Durceylan, T. Polat, H. Cevri

Tomato, fruit disorders, blotchy ripening, potassium, foliar sprays, sowing dates

https://doi.org/10.17660/ActaHortic.1999.491.33