Resumo

GARCIA-PEREYRA, J et al. Amaranthus (Amaranthus spp.) grain yield and forage quality after cultivation at various densities in Northeastern Mexico. Phyton (B. Aires) [online]. 2009, vol.78, n.1, pp.53-60. ISSN 1851-5657.

We tested five Amaranthus genotypes (A. hypochondriacus 655, 653, 153-5-3, and Criollo Tlaxcala and A. cruentus genotype 33) at four population densities (31,250; 41,666; 62,500 and 125,000 plants/ha, during spring-summer (PV; July-December) 2000 and autumn-winter (OI) 2001 and 2002. Studies were conducted at the experimental station of the Agronomy Faculty of the Universidad Autónoma de Nuevo León, Mexico. A split plot experimental design on completely randomized blocks was used, with two replicates. The evaluated agronomic characteristics were grain yield (RG), dry matter yield (MS), plant height (AP), stem diameter (DT) and panicle length (LP). Crude protein (PC), ashes (C), acid detergent fiber (FDA) and neutral detergent fiber (FDN) were evaluated for stems and leaves in OI, 2001. The interactions (1) genotype x density x year, and (2) genotype x year were statistically significant (p<0.05) for all yield variables. The greatest RG during PV 2000 was determined on genotype 655 with 2,221 kg/ha, while in OI 2001 and 2002, the genotype with greatest RG was 33 with 1,274 and 1,926 kg/ha, respectively. The greatest RG was obtained with 125,000 plants/ha in all genotypes. Genotype 33, of A. cruentus, presented the greatest PC contents, with 95 and 248 g/kg in stems and leaves, respectively. The greatest FDA contents were 594 g/kg in genotype 655, and 252 g/kg in genotype 653. Genotype 655 showed the greatest FDN contents in stems (731 g/kg) and leaves (474 g/kg). Because of a greater PC concentration and RG, genotype 33 is recommended for extensive seeding during OI, and genotype 655 during PV.

Palavras-chave : Amaranthus cruentus; Amaranthus hypochondriacus; Genotypes; Population density.

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