QTL Analysis of Morphological, Developmental, and Winter Hardiness-Associated Traits in Perennial Ryegrass

Abstract

key variables: leaf appearance rate, leaf elongation rate, and leaf lifespan. The expression of each of these traits is Quantitative trait loci (QTLs) for a number of agronomically imunder both genetic and environmental control (Lemaire portant traits of perennial ryegrass (Lolium perenne L.) were identiand Chapman, 1996), and leaf development in Lolium fied by means of a reference molecular marker-based genetic map. Replicated phenotypic data was obtained for a number of field-assessed has been demonstrated to be under genetic control in a morphological and developmental traits as well as the winter hardinumber of studies (Edwards and Cooper, 1963; Rhodes, ness-associated characters of winter survival and electrical conductiv-1973; Hazard et al., 1996). Structural characteristics of ity. Marker-trait association analysis was performed by a number of plants such as tiller number, leaf number, and leaf size methods, and a high degree of congruence was observed between the are the result of these morphogenetic traits, and their respective results. QTLs were detected for morphological traits such measurement in breeding programs allows a dissection as plant height, tiller size, leaf length, leaf width, fresh weight at of the complex herbage yield trait as well as predictions harvest, plant type, spikelet number per spike and spike length, as well of the response to grazing. as the developmental traits of heading date and degree of aftermath Different ecoclimatic regions, or pastures under difheading. A number of traits were significantly correlated, and coinciferent grazing regimes, may provide alternative selecdent QTL locations were identified. No significant QTLs for winter survival in the field were identified. However, a QTL for electrical

GISH/FISH mapping of genes for freezing tolerance transferred from Festuca pratensis to Lolium multiflorum

“…Recently, the vernalisation locus Vrn1 mapped onto wheat chromosome 5A (Galiba et al, 1995) was located on chromosome 4 in L. perenne (Jensen et al, 2005). Moreover, on the same chromosome in perennial ryegrass, close to a heading date locus, was identified a QTL for electrical conductivity corresponding to frost tolerance (Yamada et al, 2004). Principal genes for photoperiod response, which could also be involved in the regulation of freezing tolerance, have been mapped on wheat chromosome 2 (Law et al, 1978;Law, 1983, 1984;Sourdille et al, 2000).…”

QTL analysis and comparative genomics of herbage quality traits in perennial ryegrass (Lolium perenne L.)

“…The development of near infra-red reflectance spectroscopy (NIRS) analysis for prediction of forage quality has facilitated rapid and non-destructive evaluation of samples from plant breeding programs. NIRS has been used to develop calibrations to predict a wide range of forage quality traits (Marten et al 1984; Smith and Flinn QTLs for a number of traits related to vegetative and reproductive morphogenesis, reproductive development and winter hardiness have already been identified (Yamada et al 2004). The framework marker set, that is dominated by anonymous and non-genic genetic markers, may be selectively enhanced with functionally-associated genetic markers based on expressed sequences (Kurata et al 1994;Chao et al 1994;Schneider et al 1999;Tanksley et al 1992).…”

Molecular Regulation of Flowering Time in Grasses

“…In addition, the major QTL in the F 2 /WSC and ILGI perennial ryegrass populations was identified on LG7, which is associated with the position of the genes Hd3a and Hd1, two heading date genes of rice on chromosome 6. However, analysis of the ILGI population grown in Japan identified a QTL on LG4, but not the QTL reported on LG7 [50,51]. This result emphasizes the importance of adaptation in plants to the broad range of agro-environmental conditions in which they grow.…”