Alec Wills

B.Ag.Sci. Honours (2022)

Growth and development of three subterranean clover cultivars and their tolerance of herbicide application (PDF unavailable)

Research Overview

Alec quantified the growth and development of subterranean clover cultivars ‘Denmark’, ‘Wooggenullup’ and ‘Whatawhata’ for dryland pasture production at Ashley Dene, Canterbury. The development of new cultivars for dryland systems is critical to sustain viable returns from sheep and beef systems with ‘Whatawhata’ evaluated for New Zealand systems. Results showed ‘Whatawhata’ required 260±21.2 °Cd to produce its first trifoliate with phyllochron thereafter 64.4±7.0 °Cd/leaf. ‘Woogenellup’ thermal time requirement in the field (230±21.2 °Cd) and controlled experiment (188±9.29 °Cd) was consistent with published values. Thermal time requirement up to the fourth trifoliate leaf stage was between 417-489 °Cd. Runner initiation occurred with a change in photoperiod. ‘Whatawhata’ (952±10.9 °Cd) and ‘Denmark’ (962±10.9 °Cd) required the same amount of thermal time after the 21st of June to produce their first flower. This was longer than for ‘Woogenellup’ (883±10.9 °Cd). Herbicide tolerance of ‘Whatawhata’ was comparable to ‘Denmark’ and ‘Woogenellup’ with a similar response reported for pastures sprayed with flumetsulam and imazethapyr. However, the application of recommended herbicides for weed suppression did not increase total DM yield compared with unsprayed pasture. Phytotoxicity scores supported the lack of difference, with none of the pasture components reaching the commercial threshold (7) for high yield suppression. Cooler temperatures (<10 °C at application) may have lowered the efficacy of herbicides utilised. Based on data from this experiment, ‘Whatawhata’ can be managed as a ‘Late’ cultivar in New Zealand with establishment and grazing management consistent with that outlined for other small leafed cultivars like ‘Denmark’.

Alec’s project formed part of the Hill Country Futures programme (BLNZT1701) funded by Beef + Lamb New Zealand, MBIE, Seed Force New Zealand and PGG Wrightson Seeds. Prof. Derrick Moot supervised the project.