B.Ag.Sci. Honours (2015)
Changes in harvest index and remobilisation of pre-anthesis carbohydrate reserves in wheat can lead to high seed yields. In comparison, perennial ryegrass has a low harvest index and, at maturity, the crop can have high quantities of carbohydrates left in the stubble which has not contributed to seed yield. Thomas reported Moddus® increased perennial and Italian ryegrass seed yield by approximately 29%, from 1,650 kg seed/ha at 1.6 L/ha to 2,135 kg seed/ha when 3.2 L/ha was applied. Application rates <1.6 L/ha produced sed yields similar to the Control (0 L/ha). The seed yield increase in perennial and Italian ryegrass was achieved through increased number of seeds produced per spikelet. Vegetative stem length in perennial and Italian ryegrass was reduced from 62 cm to 41 cm by application of 1.6 L/ha of Moddus® and further reduced to 36 cm with an application rate of 3.2 L/ha. Thomas was supervised by Dr Jeff McCormick, Dr Alan Gash and Richard Chynoweth (Foundation for Arable Research).