†in the Department of Farm crops, Oregon State College, Corvallis, Oregon, U.S.A.
Regional Research Centre (Pirrcom), Patiala
*Part of a thesis submitted to the Graduate faculty, Oregon State College, Corvallis, Oregon (U.S.A.), in partial fulfilment of the requirements of the Ph.D. degree.
Studies on the inheritance of date of heading in three wheat crosses of Alba x Norin 10, White Winter x Norin 10 and White Holland x Norin 10 were conducted at the Hyslop Agronomy Farm Corvallis, Oregon, U.S.A., in 1955 and 1956. The parents and F2 generation of each cross were grown in 1955. In addition to the above generations, 1956 planting consisted also of F1 and F3 generations.
Inheritance of date of heading was governed by at least two pairs of genes, one gene being more effective than the other in the induction of early heading. Partial dominance of earliness over lateness was demonstrated. It was concluded that Norin 10 was of the genotype, AA BB, and Alba, White Winter and White Holland, of the genotype, aa bb.
On an average of three crosses in two years, the heritability value for date of heading was 93.2 per cent, which indicated that a great part of the total F2 variation was genetic.
