| Abstract: | Three hundred sixty-five S1 and 234 S2 seedling populations of timothy (Phleum pratense L.) were examined for their segregations for chlorophyll deficiencies. Arrays of both self-and open-pollination families indicated a lack of concentration at definite levels, with ratios expressed forming a continuous series from 4.6:1 to 572:1 for green: chlorophyll-deficient types in the S1 generation. The S2 populations examined ranged from 1.8:1 to 244:1. Arrays were very similar in their distributions.Sixty-three plants yielded chlorophyll-deficient types in both S1 and S0 populations. From these, it was calculated that 7 to 8 percent of natural self-pollination may occur in timothy.Except at two levels (28:1 and 143:1 tetradisomic) assumption of tetradisomic or simpler inheritance patterns resulted in lower calculated percentages of natural self-pollination than resulted from assumed hexasomic inheritance. No apparent explanation is available to account for these divergences from the regular pattern encountered.Results of cooperative work of the Crops Research Division, Agriculture Research Service, U.S. Department of Agriculture and the Wisconsin Agricultural Experiment Station, Madison.Research Agronomist, Crops Research Division, Agriculture Research Service, U.S. Department of Agriculture and Associate Professor, and Professor of Agronomy, Wisconsin Agricultural Experiment Station, respectively. |
