Abstract:
An inbred cabbage line (Brassica oleracea L. (Capitata group))
and an inbred broccoli line (B. oleracea L. (Italica group)) were
crossed. F₁ progeny were vigorous annuals. Of 3,260 F₂ plants, 250
were biennials and 70 developed cabbage heads. Of these 70, 32 were
annuals. Days to first visible buds of the annuals and internode
length varied continuously and appeared to be controlled by a few genes
with modifiers. Both are primarily controlled by additive gene action
as shown graphically and by the heritability estimates calculated by
Warner's method.
Cabbage head forming ability, clasping of leaves and annual-biennial
habit also appear to be controlled by a number of genes. Open
leaves were dominant over clasped; annual habit was dominant over biennial;
and cabbage head forming plants were a minority. Chi square
tests showed a highly significant association between cabbage head
forming ability and biennial habit. Clasping of leaves, a factor in
cabbage heading, was also shown to be associated with biennial habit.
