Seasonal changes in carbohydrate/nitrogen levels during field rooting of Rosa multiflora ‘Brooks 56’ hardwood cuttings

Abstract

Texas field rose plant producers sometimes experience poor field rooting of Rosa multiflora cultivar ‘Brooks 56’ hardwood cuttings, which are used as rootstock. To establish the best time of year for rose propagation, leafless hardwood cuttings were harvested from field-grown stock plants and propagated in raised field soil beds at intervals of 2–4 weeks from November to February. At the initiation of each propagation date, basal, medial and apical cuttings were analyzed for seasonal fluctuation of nitrogen, starch and soluble carbohydrate content to determine if rooting of R. multiflora cuttings was correlated with these parameters. Cutting position had no effect on percent rooting, however basal cuttings had the lowest root number. Starch content was positively correlated and nitrogen negatively correlated to rooting. In the carbohydrate-nitrogen component, the starch N and total carbohydrate (soluble and insoluble carbohydrates) N ratios of cuttings were more highly correlated to rooting than soluble carbohydrate N . Maximum rooting of cuttings for field propagation was from 15 November to 15 December, which also corresponded to a low N and higher starch content in propagules harvested from stock plants. Arginine was one of the most prevalent amino acids in cuttings under both high and low rooting periods.