Submitted to: Plant Breeding
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/10/2010
Publication Date: 8/10/2010
Citation: Brown, R.N., Barker, R.E., Warnke, S.E., Cooper, L.D., Brilman, L.A., Rouf Mian, M.A., Jung, G., Sim, S.C. 2010. Identification of quantitative trait loci for seed traits and floral morphology in a field-grown Lolium perenne x Lolium multiflorum mapping population. Plant Breeding. 129:29-34. Interpretive Summary: Annual ryegrass and perennial ryegrass differ in the requirements for initiation of flowering and in other morphological traits. Generally, annual ryegrass spikes are larger than perennial ryegrass and have more spikelets, more florets per spikelet, larger seeds, and have awns. The seed head characteristics of annual ryegrass generally result in higher seed yields for this species. The location of genes that control these characteristics was studied using a ryegrass populations developed by crossing annual with perennial ryegrass. Markers that identify these gene locations will be used in test to screen for annual ryegrass contamination of perennial ryegrass seed lots.
Technical Abstract: Lolium multiflorum Lam. and L. perenne L. differ in the requirements for initiation of flowering, and in other morphological traits. Generally, L. multiflorum spikes are larger than L. perenne spikes, and have more spikelets, more florets per spikelet, larger seeds, and awns. The greater number of spikelets and florets and larger seeds are associated with higher seed yield in L. multiflorum. Ryegrass (Lolium sp.) cultivars are produced through seed and understanding the genetics of seed production traits would aid in plant improvement. A total of 29 QTL for seed production related traits were identified in this study. Clusters of QTL for spike length, spikelet number, floret number and seed size are located on linkage groups 2 and 4 with additional QTL on the other linkage groups. Linkage groups 2 and 4 appear to be the most important for distinguishing L. multiflorum and L. perenne. In addition to the clustered floral structure QTL, QTL for the presence or absence of awns are located on linkage group 4 that contains a QTL for vernalization response. These QTL will be used to develop molecular markers for marker-assisted screening of L. perenne seed lots to detect contamination with L. multiflorum.