Growth, accumulation and distribution of dry matter in two varieties of amaranth (Amaranthus hypochondriacus L. y A. cruentus L.) under fertigation

Amaranth is a crop adapted to arid and semi-arid agroclimatic conditions. Its grain yield can be increased with fertigation, but there is limited information on growth parameters and crop yield under this system. The objective of this work was to characterize growth, accumulation and distribution of biomass of two varieties of amaranth (Frondosa and Dorada) with fertigation. The experimental phase was carried out is Salinas, San Luis Potosi, at a density of 25 plants per m2. Organomineral fertilization was applied to soil, and chemical fertilization through irrigation, whose total water sheet was 321 mm. Frondosa compared to Dorada, reached faster maturity and presented higher values of: leaves number, panicle length and dry biomass, as well as harvest index (gain/total dry biomaas). Thermal requirement was 910.7 degrees C and 968.6 degrees C for Frondosa and Dorada, respectively. Frondosa had higher water use efficiency (WUE) (7.1 kg mm(-1)) in grain production (2.3 t ha(-1)), but WUE for fresh biomass (69.6 t ha(-1)) was higher in Dorada (216.6 kg mm(-1)). Environmental conditions in Altiplano Potosino are favorable to produce amaranth with high yield (grain or forage) under fertigation.