Effects of organic cultivation with and without pest management of Adzuki bean (Vigna angularis) on yield characteristics, seed chemical composition, and antioxidant capacity

Adzuki bean (Vigna angularis) is an important crop in Taiwan, Japan and many countries. The bean varieties Kaohsiung No. 8 (KS8) and No. 9 (KS9) were grown in the spring of 2013 and 2014 at an organic certified farm and harvested at maturity from two organic cultivation management systems: organic with integrated pest management (OIPM) and organic without pest management (OWPM). The harvested seeds from OIPM and OWPM cultivations were compared for yield characteristics, seed chemical composition, and seed antioxidant capacity. The yield characteristics were significantly higher in OIPM than OWPM cultivation in 2013 and 2014 of both KS8 and KS9 varieties. The chemical composition of the two varieties for both years showed that OIPM cultivation had relative higher ash and crude protein contents, whereas OWPM produced significantly higher carbohydrate content. The OWPM cultivation expressed higher ABTS and DPPH antioxidant abilities, as well as contained higher total phenolic and flavonoid contents than OIPM. In conclusion, the OIPM increase the yield of Adzuki bean products, whereas OWPM cultivation expose the plants to pests and diseases occurring may increase the antioxidant activity and components. It may suggest that OWPM enhance the chance of the plants responding by inducing a protection system to prevent pathogen attack.