Combining Ability for Grain Moisture, Husk Moisture, and Maturity in Maize with Yellow and White Endosperms

White-endosperm (yyy) maize (Zea mays L.) is vital to the maize dry-milling industry. White maize generally has higher harvest grain moisture content than yellow maize of equal physiological maturity. This increases the grain drying cost of white maize. The objectives of the current field study were to evaluate comparative effects of 2 y, 1 y, and 0 y gene dosages on grain moisture, probe moisture measured via an electronic device, husk moisture, and growing degree days (GDD) to midsilk and to midpollen shed; and to compare the general (GCA) and specific combining ability (SCA) effects from yellow ✕ yellow and white ✕ white endosperm diallels. The yellow and white lines were derived from crosses and backcrosses among Oh7B and Mo14W inbred lines. In the yellow endosperm background, parental lines 4 and 5 contributed positive GCA effects to probe moisture whereas lines 1, 2, and 3 contributed negative effects. In the white endosperm background, parental line 3 contributed positive GCA effects for both probe moisture and grain moisture, and parental line 4 contributed negative GCA effects. Parental line 5 contributed positive GCA effects for husk moisture in the yellow endosperm background. Parental line 1 had a negative GCA effect for husk moisture. White parental line 4 would be conducive to decreasing grain moisture, and the use of this parent could result in earlier maturing white maize with relatively low harvest grain moisture. A few of the SCA and reciprocal effects were significant (p < 0.05). For probe moisture, the 2 y class was significantly higher than the 1 y and 0 y classes. For grain moisture, the 2 y class was significantly higher than the 0 y class. For midsilk GDD and midpollen GDD 2 y > 1 y > 0 y. The y allele might have had a pleiotropic dosage effect on all traits except husk moisture, and it is possible that a gene or a block of genes might be tightly linked to the y allele and be responsible for the later maturity and higher grain moisture content of white endosperm maize germplasm used in this study. Approved for publication by the director of the Louisiana Agric. Exp. Stn. as manuscript no. 88-09-259.