The importance of the period immediately preceding anthesis for grain weight determination in wheat

Abstract

Although individual grain weight is an important source of variation for grain yield, there is still poor understanding of the causes determining final grain weight. Almost all studies conducted for understanding the determinants of grain weight have been focused on the post-anthesis period. However, there is important evidence that pre-anthesis conditions could also modify final grain weight. Three experiments including different sowing dates, genotypes and temperature regimes between booting and anthesis, were carried out in Argentina and Mexico to analyse the effect of temperature and associated traits during the pre- and post-anthesis periods on grain weight under field conditions. In these experiments final grain weight could not be explained by average or maximum temperature during the post-anthesis period. However, average temperature between booting and anthesis was closely related to the observed grain weight differences, probably as a consequence of the effects of this factor on carpel growth. Differences in grain weight between genotypes and grain position were successfully explained by differences in carpel weight at anthesis. These results suggest that our knowledge to determine grain weight could improve if the immediately pre-anthesis period conditions were taken into account.