A COMPARISON OF THE GROWTHS OF WILD AND OF CULTIVATED OATS IN MANGANESE-DEFICIENT SOILS

Two species of wild oats, Avena fatua and A. ludoviciana , and two varieties of cultivated oats for comparison, were grown to maturity in pots of manganese-deficient soil with and without added manganese.
A. ludoviciana showed different leaf symptoms of manganese deficiency from A. fatua and the cultivated varieties. In other respects wild and cultivated oats were similar in their responses to the level of manganese supply, though differences were observed in the severity of the effects. These are summarized in Table 6. The relative susceptibility to manganese deficiency of the wild and cultivated oats differed according to the effect considered. The total dry weight at harvest is an integration of all the preceding effects on growth and is therefore presumably the best single criterion for determining susceptibility to manganese deficiency. On the basis of per cent loss of total dry weight at harvest due to lack of manganese, A. fatua is judged less susceptible and A. ludoviciana more susceptible than the two cultivated varieties and no distinction can be made between the latter.
The most interesting differences between wild and cultivated oats in response to the level of manganese supply occurred in seed production. Manganese-deficient wild oats showed a smaller reduction in the number of seeds formed but a greater reduction in the size and manganese content of individual seeds than the cultivated varieties.
Manganese deficiency lowered the percentage of viable seeds and the percentage of dormant seeds produced by both A. fatua and A. ludoviciana.