Asociación entre calidad proteica de grano y poliembrionía en población braquítica de maíz enano

Abstract

High frequency polyembryony (PE) belonging to a dwarf maize population (BAP), could be associated to the essential aminoacids content in the grain. The objective of this assay was to establish the probable relation between polyembryony of a population of braquitic maize, and the grain content of lysine, tryptophan and raw protein. The following variables were evaluated: relation between PE and raw protein levels (PC), lysine (LI), and tryptophan (TR). The chemical determinations of these variables, in four generations of selection, were compared (1994; 1997; 2000, and 2003) of BAP, and two witnesses; one of a high protein quality (QPM), and another one representing the common maize. The PC was determined by the Kjeldhal method; LI and TR were quantified via gas chromatography. The data of the treatments, and witnesses, were analyzed under a completely randomized design, with two replications; average comparison via Tukey test (P<0.05) and a linear simple re gression analysis to detect possible relations between protein quality and cycles of selection for a high PE. The treatments showed differences (P<0.01) attributable to the genetic diversity, and the changes that the PE has undergone in this population due to the selection. For PC, the material QPM did not overcome the different cycles from BAP groups; whereas generation 2003 was equal to material QPM in the content of LI and approxi mated like the one of TR. Polyembryony showed a significant and positive relation in the content of LI and TR but not with PC; the gain per generation in aminoacids, LI, and TR was of 1.09 and 0.1 g respectively. The PE in this population turned out to be an alternative route to increase the protein quality of the maize grain.