Agronomic, biochemical and genetic attributes of maize high grain quality accessions

Abstract

Nutritional quality of maize is low because maize protein is poor in several essential amino acids. The purpose of this research was to analyze agronomic traits and kernel biochemical and physical properties of 16 gene bank accessions which comprise a mini-core collection for grain quality and to identify populations for improving protein quality. Standard ZP341 hybrid was superior for half of agronomic traits tested, especially grain yield, which was higher from 24% to six times. Ten accessions had protein content over 14 % and were further analyzed for amino acid composition and kernel characteristics. Additionally, genetic relationships between the accessions were determined by Simple Sequence Repeats (SSRs) analysis with 30 primers. All accessions showed elevated contents of most essential amino acids. Population L492 with 1.87 and 0.68 g 100g-1 dry weight had the highest contents of leucine and phenylalanine, respectively, but also higher contents of most other analyzed amino acids (p<0.05). Cluster analysis based on SSRs also distinguished L492 by separating it from all other accessions. Compared to ZP341, accessions were significantly inferior in grain weight and dimensions (p<0.05), but superior in most hardness parameters (p<0.05). Pearson correlations revealed lack of negative correlations between biochemical traits, indicating a possibility for concurrent improvement of several amino acids. The best way of improving protein quality of elite materials is through backcrossing and as populations were chosen according to their good general combining ability (with IoDent, Lancaster and BSSS), they could serve for improvement of elite materials of these genetic origins.