Genetic Variability of Agronomic Traits of Low Nitrogen Tolerant Open-Pollinated Maize Accessions as Parents for Top-Cross Hybrids

Discrimination among parental accessions maintains the agronomic performance and purity of hybrids. Low nitrogen tolerant open-pollinated maize were screened for variation in agronomic characters, parents' identification and grouping using principal component and single linkage analyses, Pearson's correlation and bi-plot methods. The accessions were genetically distinct and diverse. BR9928-DMRSRLN proved intercrop-able and drought tolerant. LNTP-WC3, Sint-Marzoca-Larga and ART/98/SW5-OB were best pollen materials. Pairs of days to anthesis and silking, total number of leaves and ear height, leaf length or width and number of leaves below uppermost ear, veination index and leaf width, and shell and field weights can be improved simultaneously. First four PCs accounted for 80% variability. PC I had the strongest discriminating ability but insufficiently distinguished the accessions. First three PCs identified anthesis-silking-interval, plant height, number of veins, ear height, total number of leaves, leaf width, veination index, field and shell weights, days to anthesis and silking as discriminators. The accessions clustered into three. LNTP-YC6 and ILE-1OB flowered earlier; BR99TZL-Comp4DMSRSR and Sint-Marzoca-Larga yielded highest