Growth responses of potato ( Solanum tuberosum ) grown in a hot tropical lowland to applied paclobutrazol: 2. Tuber attributes

Abstract The growth responses of potato ( Solanum tuberosum ) to leaf and soil applied paclobutrazol (PBZ) under the hot tropical climate of eastern Ethiopia was investigated in two field experiments. A month after planting, PBZ was applied as a foliar spray or soil drench at rates of 0, 2, 3, and 4 kg active ingredient (a.i.) PBZ/ha. A randomised complete block design with three replications was used. Averaged over the methods of application, PBZ increased tuber fresh mass, dry matter content, and specific gravity while promoting earlier tuber initiation and reduced tuber number. Root application of PBZ significantly increased crude protein content whereas both foliar and root PBZ applications extended the dormancy period. PBZ reduced the potassium and magnesium contents of the tubers. Tuber sulfur and copper contents were unaffected by either of the treatments. Foliar‐applied PBZ increased the calcium content of tubers. Applying PBZ as a soil drench increased total tuber nitrogen. Both foliar and root applications increased tuber iron content while reducing phosphorus levels. PBZ increased tuber yield, improved quality attributes such as dry matter content, crude protein, and calcium (Ca) content and extended the dormancy period of potato tubers grown in the hot tropical lowlands of eastern Ethiopia.