Optimal sowing dates of three species of grain-bearing amaranth in the semi-arid Argentine Pampa

Abstract

Determining the optimal sowing date is important when evaluating the production potential of any new crop. Field trials were performed with Amaranthus cruentus L., A. hypochondriacus L. and A. mantegazzianus Pass. from 1999 to 2002 in the semi-arid Argentine Pampa in order to establish the best sowing dates for grain production. Crops were sown at 15 day intervals during November, December and January. The following variables were then measured: plant height, days to anthesis, production of biomass, grain production, harvest index, final number of plants and plant losses. Rainfall strongly influenced these variables, depending on sowing date. In all years, A. mantegazzianus produced the lowest grain yields. The latest sowing date is not recommended since the light and temperature conditions during the final part of the phenological cycle have a negative effect on grain yield. The best results were obtained when sowing was performed from the second half of November through to the end of December.