Effect of main stem pruning and plant spacing on yam bean (pachyrhizus erosus L.)

Yam bean is a family of Leguminosae that developed as food crops of carbohydrate sources as well as protein from plant origin. Yam bean continuously grow up to 4-5 m and requires optimal plant spacing to keep the tubers enlarge optimally in the soil. The constraints that occur on the cultivation of yam bean are cultivation problems such as main stem pruning and arrangement the plant spacing in the optimal condition. This research was conducted from March 2017 to July 2017 at Bajulan Village, Papar Sub-District, Kediri Regency, East Java. The study used Factorial Randomized Block Design with two treatments and three replications. The first factor consisted of J20 = 20 x 30 cm plant spacing, J25 = 25 x 30 cm plant spacing, J30 = 30 x 30 cm plant spacing, and the second factor consisted of P25 = main stem pruning 25%, P50 = main stem pruning 50%, P75 = main stem pruning 75%. The result of this research showed that treatment plant spacing of 25 x 30 cm and treatment main stem pruning 75% could increase tuber weight and yield with total value of 991.02 g plant ^-1 and 166.49 t ha ^-1 .