title: Isolation of prostrate turfgrass mutants via screening of dwarf phenotype and characterization of a perennial ryegrass prostrate mutant.
abstract: Prostrate turf varieties are desirable because of their increased low mowing tolerance, heat resistance, traffic resistance and ground coverage compared with upright varieties. Mutation breeding may provide a powerful tool to create prostrate varieties, but there are no simple, straightforward methods to screen for such mutants. Elucidation of the molecular basis of the major 'green revolution' traits, dwarfism and semi-dwarfism, guided us to design a simple strategy for isolating dwarf mutants of perennial ryegrass (Lolium perenne L.). We have shown that gamma-ray-mediated dominant dwarf mutants can be easily screened for at the three-leaf stage. About 10% of dwarf mutant lines also displayed a prostrate phenotype at mature stages (>10 tillers). One prostrate line, Lowboy I, has been characterized in detail. Lowboy I had significantly shorter canopy, leaf blade and internode lengths compared with wild type. Lowboy I also exhibited greater tolerance to low mowing stress than wild type. Exogenous gibberellic acid (GA) restored Lowboy I to a wild-type phenotype, indicating that the dwarf and prostrate phenotypes were both due to GA deficiency. We further showed that phenotypes of Lowboy I were dominant and stably inherited through sexual reproduction. Prostrate turfgrass mutants are difficult to screen for because the phenotype is not observed at young seedling stages, therefore our method represents a simple strategy for easily isolating prostrate mutants. Furthermore, Lowboy I may provide an outstanding germplasm for breeding novel prostrate perennial ryegrass cultivars.
authors.affiliation: College of Landscape Architecture and Arts, Northwest A&F University, Yangling 712100, China; Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269, USA.
authors.forename: Junmei
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Chandra
authors.initials: C
authors.lastname: Thammina
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Huseyin
authors.initials: H
authors.lastname: Yer
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Rania
authors.initials: R
authors.lastname: El-Tanbouly
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Manon
authors.initials: M
authors.lastname: Marron
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Katin-Grazzini
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut, Storrs, CT 06269, USA; College of Life Sciences, Hubei University, Wuhan 430062, China.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: John
authors.initials: J
authors.lastname: Inguagiato
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: McAvoy
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Guillard
authors.affiliation: College of Horticulture, Northwest A&F university , Yangling 712100, China.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Plant Science and Landscape Architecture, University of Connecticut , Storrs, CT 06269, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li