title: Initial characterisation of low and high seed dormancy populations of Lolium rigidum produced by repeated selection.
abstract: The physiological and biochemical bases of seed dormancy in Lolium rigidum (annual ryegrass) are largely unknown, and study of this process is complicated by the outcrossing nature of the species and the strong influence of environment on seed dormancy. In order to identify heritable biochemical factors contributing to seed dormancy in L. rigidum, seeds from a field-collected population were used to select sub-populations with consistently low or high seed dormancy over four generations. Low-dormancy seeds showed constitutive alpha-amylase activity prior to imbibition, higher concentrations of polyphenols and cis-zeatin, and lower abscisic acid and cis-zeatin riboside concentrations than high-dormancy seeds. Selection for high dormancy was associated with a reduction in response to dark-stratification for 21d at 20 degrees C (an effective means of releasing dormancy in the original, unselected population) over successive generations, but fluridone remained effective in breaking dormancy. Crossing of low- and high-dormancy populations indicated that dormancy level was not dependent upon the maternal genotype of the seed, and that the constitutive alpha-amylase activity and high seed anthocyanin concentrations characteristic of the low-dormancy populations were not correlated to high basal germination ability.
authors.affiliation: Western Australian Herbicide Resistance Initiative, School of Plant Biology, University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia. danica@plants.uwa.edu.au
authors.forename: Danica E
authors.initials: DE
authors.lastname: Goggin
authors.forename: R J Neil
authors.initials: RJ
authors.lastname: Emery
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Powles
authors.forename: Kathryn J
authors.initials: KJ
authors.lastname: Steadman
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000872:Anthocyanins / Q000378:metabolism; D050260:Carbohydrate Metabolism; D003433:Crosses, Genetic; D005419:Flavonoids / Q000378:metabolism; D018525:Germination / Q000502:physiology; D008129:Lolium / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D010636:Phenols / Q000378:metabolism; D057445:Plant Dormancy / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism; D059808:Polyphenols; D012639:Seeds / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development*; D012641:Selection, Genetic; D015026:Zeatin / Q000378:metabolism; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010636:Phenols; D010937:Plant Growth Regulators; D059808:Polyphenols; D000040:Abscisic Acid; D015026:Zeatin; D000516:alpha-Amylases