Morphogenetic and Structural Variables in Five Cultivars of Lolium sp.

Abstract

Morphogenetic variables: leaf elongation rate (TEF), leaf senescence rate (TSF), leaf appearance rate (TAF) and leaf lifespan (VMF), and structural variables (number and leaves length per tiller and tiller density) were estimated on cultivars of Lolium sp.: INIA Titán (Titán), INIA Cetus (Cetus), Conker (Conker), Maverick Gold (Maverick) and Dominó (Dominó). The objective was to evaluate if the cultivars were different in these variables, response to temperature, and the usefulness of characterizing each cultivar, in order to define the appropriate management for each sward. Lineal regression models were adjusted between leaf tissues fluxes and daily mean temperature. Quadratics´ models were evaluated, if showed no significant lineal regression. Analysis of variance was made for the different variables for the experimental period (July to September) and means were compared to Tuckey´s test (p≤0.05). According the phyllochron, Conker and Maverick were cultivars with rapid leaf turnover, with high TEF, that would reach quickly the optimal leaf area index (LAI), with a lower VMF and a higher TSF. This was associated with a higher tiller density (not statistically significant) and therefore these cultivars would be more adapted to frequent defoliation. Tetraploid cultivars Dominó and Titán stood at the other end, with a lower density of tillers, TAF, TEF y TSF, and a higher VMF, so they would be adapted to less frequent grazing. Cetus presented an intermediate behaviour for morphogenetic variables.