Pungency of red radish storage roots is unaffected by spent mushroom substrate or yard waste compost treatments used for field production.

摘要

Field experiments were conducted at Bixby, OK, USA, in 2007. 4 compost treatments and an unamended control were compared for field production of 8 (spring) or 4 (autumn) red radish cultivars. Treatments were either spent mushroom substrate or yard waste compost spread over plots to an average depth of 2.5 or 5 cm and preplant-incorporated approx. 5-7 cm deep. Radishes were direct-seeded into prepared plots and subsequently grown using standard cultural practices. Samples of median-sized marketable storage roots were shredded and juice was analysed in the laboratory for pungency as measured by isothiocyanate (ITC) concn. (primarily 4-methylthio-3-butenyl isothiocyanate). In the spring, mean ITC concn. ranged from 28.2 to 36.8 mumol per 100 g juice in storage roots from the 4 compost treatments, and differences were not significant ( alpha = 0.05). There were not enough storage roots to analyse from the unamended control plots as a result of herbicide toxicity. Cultivars differed in mean concn. of ITC, ranging from a high of 52.9 mumol per 100 g juice for Cherry Belle to a low of 19.2 mumol per 100 g juice for Crunchy Royale. In the autumn, mean ITC concn. ranged from 10.5 to 24.6 mumol per 100 g juice in storage roots from the 4 compost treatments. Differences were not significant ( alpha = 0.05), and there were no differences from the control value of 17.5 mumol per 100 g juice. Mean ITC concn. was 19.9 mumol per 100 g juice for the 4 cultivars tested in the autumn, and the cultivars did not differ. Results indicated that the tested compost treatments did not affect pungency of red radish storage roots as measured by concn. of ITC.