Screening pasture species for shade tolerance

The effects of shade on tillering ability as well as biomass production of hill pasture species which differed in morphology and for shade tolerance was evaluated. A split-plot design with four replicate blocks was employed for the experiment, in which five levels of shade were applied within 1.25 x 0.84 x 0.45 m metal frames covered by Sarlon cloth to shade light from all directions. The main plot treatments were 14, 18, 27, 43, and 73% of the ambient photosynthetically active radiation (PAR). Ten different pasture species: Dactylis glomerata L. cv. Grasslands Wana; Lolium perenne L. cv. Grasslands Nui, high endophyte; Holcus lanatus L. cv. Massey Basyn; Plantago lanceolata L. cv. Grasslands Lancelot; Festuca arundinacea Schreb. cv. Grasslands Advance; Agrostis capillaris L. cv. Grasslands Muster; Poa trivialis L. cv. Sabre; Trifolium repens L. cv. Grasslands Tahora, Trifolium subterraneum, L. cv. Karridale; and Lotus uliginosus Schkuhr cv. Grasslands Maku were grown in pots as subplots. Twelve to fourteen plants were maintained per pot, and plants were watered daily. Water and fertiliser were non- limiting. The experiment ran from 5 June to 6 September, 1996. Shoot dry weight, tillers/runners/stolons/number of branches per plant, and specific leaf area were determined at 15-day intervals for five harvests. At each harvest, plants were clipped to 5 cm height. Shade had a marked effect on tillering ability of all grass plants. However, mean tiller numbers per plant at the final harvest in the lowest PAR (14% ambient) were significantly higher (P<0.0001) for Holcus lanatus (4) and Dactylis glomerata (4) than for the other grass species. Similarly, Lotus uliginosus produced a higher (Ptiller numbers per plant (to that of 73% ambient PAR), where Dactylis glomerata had about 20% of its tiller production in the highest level of shade (14% ambient PAR) compared with Lolium perenne which had 5 %. The results are discussed in terms of the desired attributes of shade tolerant pasture species.