Gottschalk, W. Institute of Genetics, University of Bonn
Federal Republic of Germany
Our high-yielding fasciated pea mutants do not flower under the
short-day conditions of Egypt. Brazil, and of climatically different
regions of India. The mutants therefore are of litle direct value in
those regions. Phytotron trials revealed that this behavior is due to
gene fis for long-day requirement. This gene hinders the initiation of
flowering in short day. It was found to be present in the genomes of
six independently arisen mutants of our collection, and in the commer-
cial fodder pea variety 'Ornamenta' developed by Scheibe using a
spontaneously arisen fasciated mutant.
In the F4 of the cross between our fasciated mutant 489C and
Blixt's cochleata (WL 5137). recombinant R 792B was selected; it showed
the following characters: very long internodes ("long III", a
hypostatic gene derived from mutant 489C); pronounced apical stem fas-
ciation, in the fasciated region often bifurcated (from 489C); earlier
than 489C (a hypostatic gene from 489C).
The recombinant was grown under short-day phytotron conditions (12
hrs darkness, 1 1 hrs light [preceded and followed by a half-an-hour of
"twilight"]; night temperature 15, day temperature 25C). In contrast to
the parental fasciated mutant 489C, the plants of R 792B flowered richly
under the short-day conditions. They reached an average height of 156
cm (mother variety 95 cm). Moreoever, the following mean values for some
other traits were obtained:
Thus, the plants exceeded the mother variety both in dry matter and
in seed production. Flowering began 52 days after sowing (mother
variety: 53 days).
Flowering of the recombinant was possible because the mutant gene
fis for long-day requirement was eliminated, enabling them to flower un-
der short days. Because of the long internodes, the recombinant would
not be suited for field cultivation. We shall therefore try to replace
gene "long III" by a gene for shorter internodes, while maintaining the
high seed production and the capability for flowering in short day.