Distinguishing Annual From Perennial Ryegrass1
- L. W. Nittler and
- T. J. Kenny2
Since the fluorescence test for distinguishing seeds of Italian ryegrass (Lolium multiflorum Lam.) from those of perennial ryegrass, (Lolium perenne L.) is not always reliable, there is a need for a new method of distinguishing these species. This study was undertaken to determine temperature and nutritional requirements for rapid development of species differences.
Seeds were planted in sand and plants were grown with continuous light and with a temperature of 24 C or with alternating temperature of 27 C for 20 hours and 16 C for 4 hours. Nutrient solutions were made by adding 3.8, 7.5, or 15.0 ml of molar ammonium nitrate per liter of a solution lacking N. One treatment used the lowest N solution the entire experiment. Others used this solution the first 6, 8, 10, or 15 days and then medium or high N solution until 3 weeks after the seeds were planted.
No plants grown from perennial ryegrass seed produced stems or heads. In contrast, up to 70% of Italian ryegrass seedlings had stems and up to 10% were headed out. Stem development and heading were not affected significantly by nutrient treatment. Alternating temperature resulted in significantly (1% level) more plants with stems or heads than constant 24 C. Italian ryegrass plants that had not developed stems could be identified by the fact that they had rolled leaf buds. In contrast, perennial ryegrass seedlings had folded leaf buds.
Growing seedlings with alternating temperature and any of the nutrient treatments used in our experiments appears to be a practical method of distinguishing these species.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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