EFFECT OF POTASSIUM ON THE GROWTH, YIELD AND FRUIT QUALITY OF SWEET PEPPER (Capsicum annuum L.) VARIETIES IN SUDAN SAVANNA, NIGERIA

Field experiment was conducted during the 2017 and 2018 wet seasons in Tudun Wada, Kano State, Nigeria (Lat. 11.28°N; Long. 8.59°E) to evaluate the effects of potassium fertilization on the growth, yield, and fruit quality of sweet pepper varieties. The study comprised of a 3 × 4 factorial arrangement of three cultivars (Dan Kawari, Dan Mashaya, and Yolo Wonder) and four rates of potassium (0, 50, 100, and 150 kg K ha⁻¹). These were laid.in a randomized complete block design with three replications. Results revealed that variety significantly (p < 0.05) affected plant height, number of fruits, fruit yield, and ascorbic acid content. Dan Kawari produced the tallest plants (51.2 cm), more number fruits per plant (93.0 and 85.7), and highest ascorbic acid (55.1 mg/100 ml), outperforming all other varieties. Potassium fertilization significantly (p < 0.001) improved fruit quality traits including ascorbic acid (from 21.9 to 76.3 mg/100 ml), total soluble solids (from 1.22 to 3.76 °Brix), phenolics (from 19.8 to 35.9 mg/g), and flavonoids (from 2.3 to 7.3 mg g-1), with peak values at 150 kg K ha⁻¹. The study suggests that Dan Kawari treated with 150 kg K ha⁻¹ offers the best performance in terms of agronomic and fruit quality traits. Integrated nutrient management is recommended to address soil fertility constraints and maximize pepper productivity in the study area