1. Morley, F. H. W., Bennett, D., and Axelsen, A., Austral. J. Agric. Res. (in the press).
2. Davies, H. L., and Bennett, D., Austral. J. Agric. Res., 13, 1030 (1962).
3. Bennett, D., Morley, F. H. W., and Axelsen, A. (in preparation).
4. Fox, C. W., McKenzie, F. F., and Oldfield, J. E., Oregon Agric. Exp. Sta. Tech. Paper, No. 1233 (1959).
5. Chang, T. S., J. Agric. Sci., 57, 123 (1961).