Resumen

PEREZ MENDOZA, Claudia et al. Seed size and its relationship with physiological quality in forage maize cultivars. Agric. Téc. Méx [online]. 2006, vol.32, n.3, pp.341-352. ISSN 0568-2517.

The objective of this study was to evaluate the relationship between seed size and its physiological quality in forage maize cultivars. The study was carried out during 2002 at the Colegio de Postgraduados and Valle de México Experimental Stations. The research consisted of two phases: in the first, the physical quality of the seed was characterized throughout its shape and size: fl at large and fl at medium. In the second, its physiological quality was determinated through standard germination test in laboratory and vigor tests conducted in microtunnel and field conditions. Nine cultivars of forage maize were evaluated using a randomized block design with four replications in a factorial array of treatments. The relationship between physical and physiological characteristics with field performance was determined. Cultivar differences (p<0.05) were found for most of the evaluated traits related to physical and physiological quality, except for the percentage of viability. Seed size showed a signifi cant effect (p<0.05) on a large number of traits related to of physical quality, with exception of seed density. In regard to the physiological quality traits, signifi cant differences (p<0.05) were only found in root dry weight evaluated in laboratory conditions. As for physical quality, a multivariate analysis granted the larger weight to the traits seed length and weight of 1000 seeds. For the physiological quality in laboratory, plantlet and root dry weight were the most relevant variables, whereas in microtunnel, plant dry weight and rate of emergence were the most important. The traits that contributed to explain the field response were: weight of 1000 seeds, seed lenght, rate of emergence and plant dry weight. The quality of forage maize seed is more dependent on the genotype of the cultivar than on the seed size. The seed of cultivars Campeón, HS-2, Promesa and VS-22 showed the higher physical and physiological quality.

Palabras llave : Zea mays L; seed quality; field establishment; seed size.