Average Gene Frequency Estimates in Two Open‐Pollinated Cultivars of Corn1

Abstract

The purpose of this study was to obtain information on average gene frequency in two corn (Zea mays L.) populations. A design I mating system consisting of 100 males crossed to three females was developed in each of two open pollinated cultivars, ‘Golden Jewel’ and ‘Osterland's Yellow Dent.’ In addition, the male plants of the design I in each cultivar were selfed and crossed to females of the other cultivar. The intra‐population progenies, the inter‐population progenies, and S1 progenies from each cultivar were evaluated at two locations for yield, ear moisture, stalk lodging, and ear height. Days to flower was evaluated at one location only.Ratios of estimated genetic components of variance and covariance were compared with corresponding theoretical ratios computed for various gene frequencies and levels of dominance. From these comparisons, approximate ranges of the gene frequencies in the two cultivars and relative magnitudes of gene frequencies were obtained.The average frequency of favorable genes for yield appeared to be greater than 0.5 in both cultivars. There was some indication that the frequencies of favorable genes were lower for the other traits than those for yield. The ratios of variances among S1 progenies and covariance of S1 progenies with intra and inter‐cultivar crosses did not appear to add new information on gene frequencies, but supported the information gained from the comparison of the ratio of additive to dominance variance, the ratio of intra to inter‐cultivar variance, and the ratio of covariance of intra‐cultivar crosses with inter‐cultivar crosses. The average gene frequency for yield appeared to be higher in Osterland's Yellow Dent than in Golden Jewel.