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Restricted tillering in triticale cv. currency - an impediment to grain yield?

J.B. Golding

Sunraysia Horticultural Centre Victorian Department of Agriculture and Rural Affairs P.O. Box 905 Mildura Victoria 3500

Limited evidence suggests that triticale cultivars may tiller less profusely than wheat cultivars of similar maturity (1). Significant differences in tillering abilities between triticale and wheat may influence management practices, such as seed rate or amount of fertiliser applied. However, there is little work that has critically examined tillering in triticale and its significance to grain yield.

Methods

Tillering was manipulated by applying various levels of nitrogen (N) and phosphorus (P) to plants growing in a virgin sandy loam soil from Palmer, South Australia which contained the equivalent of 3kg mineral N/ha and 0.14kgP/ha. Three plants of wheat (cv. Spear), rye (cv. S.A. commercial) and triticale (cv. Currency) were grown in 15cm pots. Nitrogen was applied at rates of 0, 50 and 100kg/ha, and P, as CaH2(PO4)2 H20, was applied at the rates of 0 and 40kg/ha. Because of severe P deficiency, the OkgP/ha treatments were increased to 10kgP/ha 4 weeks after emergence. The pots were weighed regularly and rewatered to 90% field capacity. Tillers numbers were counted each week. At maturity grain yield and yield components of the main stem and tillers were measured. Water use (WU) and water use efficiencies (WUE) were calculated.

Results and discussion

Only the variety x N interactions are discussed, because final tiller number and yield were not significantly affected by P. Adding N increased tiller and ear numbers in all three cereals, but Currency produced fewer tillers and the response to N was significantly greater than Spear and rye. Currency compensated for having fewer tillers by producing more spikelets per ear and setting more grains/spikelet, thereby producing more grains/pot than the other two cereal; average kernel weights of Currency were also greater than those of wheat and rye. Total WU of Currency was less than that of the other cereals, particularly at the higher rates of N. WUE of Currency was also higher at all levels of N and increased with increasing N application, whereas the WUE in wheat and rye didn't increase after 50kgN/ha.

This experiment showed that the yield of Currency was not restricted by less profuse tillering and it was able to compensate by producing more grains per ear and heavier kernels. Indeed, Currency's restricted tiller production was associated with lower WU and higher WUE.

1. l. McDonald, G.K., Sutton, B.G. and Ellison, F.W. (1984). Aust. J. Exp. Agric. Anim. Husb. 24, 236-243.

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