Growth and yield response of selected crops to treatment with ComCat

[摘要] English: A recently commercialized natural bio-stimulant, ComCat®, that contains three activebrassinosteroids (BRs) of which two were identified previously, was scrutinized in thisstudy for its potential to be applied in the agricultural industry. Concerning objective(1), seven biotests were employed to quantify the bio-stimulatory activity of ComCat®under laboratory and glasshouse conditions. The product was tested at differentconcentration levels and the 0.5 mg �?1 application repeatedly emerged as theoptimum concentration in terms of contributing towards increases in all of theparameters measured. Treatment with ComCat® had little or no effect on seedgermination, but especially root growth of seedlings from different crops wassignificantly and consistently induced.Concerning objective (2), two cultivars for each of five test crops were treatedwith ComCat® over two growing seasons under field conditions in order to ascertaintheir yield response. Some of the test crops, but not all, showed cultivar sensitivity totreatment with ComCat®. However, overall the significant yield increases measured inone or both cultivars of the five different test crops and in one or both seasonsconfirmed the potential of ComCat® to be applied in agriculture and to contribute toeconomic prosperity for a farmer.Concerning objective (3), gas chromatographic analyses of a crude extract ofthe product as well as semi-purified fractions thereof by, using internal BR standards,were employed to identify an unknown BR contained in ComCat®. This wasconfirmed to be 24-epi-brassinolide. The latter as well as the previously identified 24-epi-castasterone and 24-epi-secasterone are known to be active BRs of thebrassinosteroid group.In conclusion, the bio-stimulatory characteristic of ComCat® was confirmedboth in vitro and in vivo under laboratory, glasshouse and field conditions in thisstudy. Significant yield increases in all of the test crops over two seasons in someinstances, confirmed the potential of ComCat® to be applied sustainably in theagricultural practice. Based on the results obtained in this study, three possibleapplication methods of ComCat® are suggested. These include 1) seed treatment, 2)foliar application or 3) soil application.

[发布机构] University of the Free State