The Journal of Agricultural Science


Effect of temperature and carpel size during pre-anthesis on potential grain weight in wheat

D. F. CALDERINI a1c1, L. G. ABELEDO a1, R. SAVIN a1 and G. A. SLAFER a1
a1 Departamento de Producción Vegetal, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, 1417 Buenos Aires, Argentina


The effect of environmental conditions immediately before anthesis on potential grain weight was investigated in wheat at the experimental field of the Faculty of Agronomy (University of Buenos Aires, Argentina) during 1995 and 1996. Plants of two cultivars of wheat were grown in two environments (two contrasting sowing dates) to provide different background temperature conditions. In these environments, transparent boxes were installed covering the spikes in order to increase spike temperature for a short period (c. 6 days) immediately before anthesis, i.e. between ear emergence and anthesis. In both environments, transparent boxes increased mean temperatures by at least 3·8 °C. These increases were almost entirely due to the changes in maximum temperatures because minimum temperatures were little affected. Final grain weight was significantly reduced by higher temperature during the ear emergence–anthesis period. It is possible that this reduction could be mediated by the effect of the heat treatment on carpel weight at anthesis because a curvilinear association between final grain weight and carpel weight at anthesis was found. This curvilinear association may also indicate a threshold carpel weight for maximizing grain weight.

(Received October 21 1998)

c1 To whom all correspondence should be addressed at: Facultad de Agronomía, Cátedra de Cereales, Av. San Martin 4453 (1417) Buenos Aires, Argentina. E-mail: