Effect of different doses of triacontanol on growth and yield of kohlrabi (Brassica oleracea L. var. gongylodes)

Triacontanol (TRIA), an endogenous plant growth regulator, promotes various metabolic activities in plants, resulting in improved growth and development in kohlrabi. The objective of this study was to assess the effect of different doses of triacontanol on the growth and yield of kohlrabi. This study was carried out in a randomized complete block design (RCBD) with five replications at Purkot Daha, Gulmi, Nepal, from October 2020 to January 2021. The treatments consisted of four doses of triacontanol (Niraculan 0.05% EC) diluted in water viz 0 mL L(−1) (control), 1 mL L(−1), 1.5 mL L(−1) and 2 mL L(−1). The results showed that triacontanol application significantly increased plant height, number of leaves, leaf length, and width of the large leaf at 40 days after transplanting (DAT). Plants treated with triacontanol at the dose of 1 mL L(−1) produced the highest plant height (14.61 cm), which was statistically at par with 0 mL L(−1) (12.76 cm) and 2 mL L(−1) (14.26 cm). Similarly, at 40 DAT, plants treated with triacontanol at the dose of 2 mL L(−1) produced the highest number of leaves (5.56), which was statistically at par with 1 mL L(−1) (5.4) and 1.5 mL L(−1) (4.96). Likewise, at 40 DAT, the highest length of large leaf (13.95 cm) and width of the large leaf (5.09 cm) were found in plants treated with triacontanol at the dose of 1 mL L(−1), which was statistically similar with 2 mL L(−1). The yield was found to be higher (6.75% to 40.4%) in plants treated with triacontanol as compared to plants treated with triacontanol at the dose of 0 mL L(−1). A significant difference was found in the harvest index. The highest harvest index (0.39) was found in plants treated with triacontanol at the dose of 2 mL L(−1), which was statistically similar with 1 mL L(−1) (0.35) and 1.5 mL L(−1) (0.39). The lowest harvest index (0.31) was found in plants treated with 0 mL(−1). This study suggests that farmers can apply triacontanol at the dose of 1 mL L(−1) to enhance the growth and yield of kohlrabi.