Potassium Level and Physiological Response and Fruit Quality in Hydroponically Grown Tomato

Tomato (Lycopersicon esculentum Mill.) is a popular vegetable in many parts of the world. The role of potassium in plant metabolism, growth, and development and its significance in production of marketable fruit and on fruit flavor and visual appearance are known. It is not clear how hybrids and nonhybrids, which differ greatly in growth and yield, respond to potassium. The tomato cvs. Pant T-3 (nonhybrid) and Avinash-2 (hybrid) were treated with three levels of potassium at 200, 300, and 400 mg·L−1 in Hoagland nutrient solution culture. ‘Avinash-2’ produced more fruit than the nonhybrid cv. Pant T-3. Fruit production increased as potassium concentration increased in both cvs., but magnitude of yield was greater for the nonhybrid cultivar. The highest leaf chlorophyll content, photosynthetic rate, and potassium contents were in plants treated with 300 mg·L−1 K in both cultivars. There was significant improvement in protein, ascorbic acid, lycopene, total soluble solids, reducing sugar levels, and titratable acidity in fruit as K concentration increased up to 300 mg·L−1. The cv. Pant T-3 responded better to K concentration than did ‘Avinash-2’. Application of adequate potassium is necessary to improve yield and quality of tomato and K availability had a role in improving fruit production and quality of a nonhybrid tomato more so than in a hybrid tomato cultivar.