Components of variance analyses for two classes of cultivars and average genetic advance estimated in corn yield trials

Abstract

This report checks the cultivar x location and cultivar x year interactions, utilizing information furnished by 81 Corn Yield Trials, Project EPE-1 (National Corn Trials), conducted between the crop years 1962/63 and 1967/68. The analysis shows that the effect of location on corn variability was greater than year effect. Hybrids and varieties were analysed in two different groups, according to the more or less wide genetic bases. A major variability in yield was found among varieties. The hybrid yields showed more stability in the different locations than variety yield, which had a wider genetic base. The varieties showed small variability in different years in the same location. The average genetic gain was estimated for production, and it was concluded that the number of locations where the trials were conducted were the most important factor in the insurance of the results of Project EPE-1. This paper also considers the National Corn Trials and their results.