Changes over time in the allelochemical content of ten cultivars of rye (Secale cereale L.)

• Published in: Journal of chemical ecology 2005, Vol.31 (1), p.179-193
• Main Authors: Reberg-Horton, S.C, Burton, J.D, Danehower, D.A, Ma, G, Monks, D.W, Murphy, J.P, Ranells, N.N, Williamson, J.D, Creamer, N.G
• Format: Article
• Language: English
• Subjects: Agricultural practices; Allelopathy; Amaranthus - drug effects; Amaranthus - growth & development; Animal and plant ecology; Animal, plant and microbial ecology; Autoecology; Benzoxazines; Biological and medical sciences; Cereal crops; Cover crops; Cultivars; Eleusine - drug effects; Eleusine - growth & development; Fundamental and applied biological sciences. Psychology; Growing season; Herbicides - isolation & purification; Herbicides - toxicity; Liquid chromatography; maturity stage; Oxazines - isolation & purification; Oxazines - toxicity; phenology; Pheromones - isolation & purification; Pheromones - toxicity; Phytotoxicity; Plant Roots - drug effects; Plant Roots - growth & development; Plants and fungi; Seasons; Secale - chemistry; Secale cereale; Soil fertility; Species Specificity; Tissues; weed control; Weeds
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1007/s10886-005-0983-3

Published studies focused on characterizing the allelopathy-based weed suppression by rye cover crop mulch have provided varying and inconsistent estimates of weed suppression. Studies were initiated to examine several factors that could influence the weed suppressiveness of rye: kill date, cultivar, and soil fertility. Ten cultivars of rye were planted with four rates of nitrogen fertilization, and tissue from each of these treatment combinations was harvested three times during the growing season. Concentrations of a known rye allelochemical DIBOA (2,4-dihydroxy-1,4-(2H)benzoxazine-3-one) were quantified from the harvested rye tissue using high performance liquid chromatography (HPLC). Phytotoxicity observed from aqueous extracts of the harvested rye tissue correlated with the levels of DIBOA recovered in harvested tissue. The amount of DIBOA in rye tissue varied depending on harvest date and rye cultivar, but was generally lower with all cultivars when rye was harvested later in the season. However, the late maturing variety 'Wheeler' retained greater concentrations of DIBOA in comparison to other rye cultivars when harvested later in the season. The decline in DIBOA concentrations as rye matures, and the fact that many rye cultivars mature at different rates may help explain why estimates of weed suppression from allelopathic agents in rye have varied so widely in the literature.