Differences in Tillering of Long‐ and Short‐Leaved Perennial Ryegrass Genetic Lines under Full Light and Shade Treatments

• Published in: Crop science 2000-07, Vol.40 (4), p.1095-1102
• Main Authors: Bahmani, I., Hazard, L., Varlet‐Grancher, C., Betin, M., Lemaire, G., Matthew, C., Thom, E. R.
• Format: Article
• Language: English
• Subjects: Adaptation to environment and cultivation conditions; Agricultural industry; Agriculture; Agronomy. Soil science and plant productions; Biological and medical sciences; Environmental Sciences; Fundamental and applied biological sciences. Psychology; Genetics; Genetics and breeding of economic plants; Grass breeding; Grasses; Life Sciences; Physiological aspects; Plant breeding; Plant genetics; Plant growth; Rye; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2000.4041095x

There is uncertainty among plant breeders as to which characteristics to select for to optimize grass growth dynamics. The objective was to study the relationship between leaf length and tillering in perennial ryegrass (Lolium perenne L.). Two long‐leaved and two short‐leaved genetic lines were grown in simulated shade and near‐full sunlight (control) environments. The genetic lines were New Zealand cultivars Ellett (long‐leaved) and Grasslands Ruanui (short‐leaved), both early flowering. The other two were late‐flowering divergent selections ‘LL’ (long‐leaved) and ‘SL’ (short‐leaved). Differences between genetic lines in leaf length were attributable mainly to higher leaf elongation rate (LER) in the two long‐leaved genetic lines, and leaf elongation duration (LED) did not differ significantly between genetic lines. Grasslands Ruanui had a higher tiller number per plant than Ellett in both light environments, explained by higher site filling but similar leaf appearance rate (AL). In contrast, LL had a higher tiller number per plant than SL, arising from a higher AL in LL. This difference decreased during the experiment under the control treatment because SL tended to have a higher site filling ratio than LL. However, in the shade treatment, differences in tiller number between LL and SL were more mediated by AL than site filling. Therefore, selection for high LER and long lamina length, even though associated with reduced site filling in all treatments, did not necessarily result in reduced tiller number per plant.