Genetic Analysis of Quality Protein Maize (QPM) Genotypes

摘要

The concept of 'Quality Protein Maize' (QPM) has opened the opportunities for nutritional improvement in maize through QPM breeding. A study was conducted with six maize inbreds, comprising both non-QPM and QPM types and their 30 hybrids derived in a diallel fashion, to understand the potential of parents and hybrids for QPM breeding at Tamil Nadu Agricultural University (TNAU), Coimbatore, India. The genotypes were evaluated for eleven yield traits and two quality traits, namely grain protein and tryptophan. Predominance of dominant gene action revealed by the grain yield and its component traits indicated the possibility of exploiting promising hybrids. Grain protein and tryptophan content were also controlled by dominant gene action. The parent UMI 124 was identified as promising as it had desirable mean value and general combining ability (gca) effect for cob length, grain breath, number of grains per cob, grain yield and grain protein. The inbred UMI 217 registered desirable combining ability for both grain yield and tryptophan and showed promise for QPM breeding. Three hybrids viz., UMI217×CML176, UMI369 ×UMI124 and UMI124×CML176 possessed high mean, heterosis and significant specific combining ability (sca) effect for grain yield, and were identified as promising. The hybrids CML176×UMI124 and CML176×DMR QPM 17 had qualified for designation as QPM hybrids. The study revealed that the best hybrids can be obtained from dent × flint or flint x dent or yellow × white cross combinations. Correlation analysis revealed the positive association of grain yield with six characters viz., number of grains per cob, grain length, grain breadth, cob length, cob girth and ear height. Both grain protein and tryptophan had negative but non-significant association with grain yield.