Effect of temperature and moisture potential on germination and emergence in Lotus sp

Abstract

Two controlled cabinet experiments compared the germination of 6 Lotus genotypes over a range of temperature (0-40¦C) and moisture potentials (0 to -1.2 MPa). A field experiment compared the emergence of 5 Lotus genotypes over 18 sowing dates. Lotus cornzculatus cv. Grasslands Goldie. L. uliginosus, Grasslands Maku, G4703, G4704. and cv. Sharnae were included in both the controlled cabinet and field experiments. Lotus suaveolens CPI 35903 was included in the controlled cabinet experiments only and Trifolium repens cv. Haifa was included as a control in the field study. Of the commercially available Lotus cultivars, Grasslands Goldie provides the greatest flexibility in terms of sowing date in coastal New South Wales and could be successfully sown even in late autumn and winter as it had the lowest base temperature for germination and field emergence. G4703, Sharnae, and G4704 had a lower base moisture potential for germination than the other 3 Lotus genotypes but this was not translated to better field emergence. Lotus suaveolens had an extremely low base temperature for germination (l¦C) compared with L. uliginosus cv. Grasslands Maku (6.4¦C). Hybridisation of this species with both L. corniculatus and L. uliginosus could result in germplasm capable of germinating better at low temperature but still able to maintain the perenniality, rhizomatous habit, and presence of condensed tannin of L. uliginosus.