Y. Hirata et al., GENETIC CONSTITUTION OF GERM-CELLS IN INTERVARIETAL AND INTERSPECIFICCHIMERAS OF BRASSICA INDUCED BY IN-VITRO GRAFTING, Theoretical and Applied Genetics, 89(2-3), 1994, pp. 249-254
The characteristics of intervarietal and interspecific chimeras synthe
sized by the graft-culture method were determined by morphology, antho
cyanin pigmentation pattern, and crossing. In an intervarietal chimera
between 'YR-ranpou' (green cabbage) and 'Ruby ball' (red cabbage) in
Brassica oleracea, a segregation phenomenon was noted in which seeds g
iving rise to purple and green plants were both produced in a single c
apsule in F-1 progeny from crosses of chimeras with YR ranpou, the ant
hocyanin-free graft partner type. The degrees of segregation varied, r
eflecting the structure of the chimeras. YR ranpou-dominant chimeras p
roduced capsules in which seeds gave rise to green plants at a high fr
equency, while Ruby ball-dominant chimeras produced capsules in which
seeds in one capsule gave rise to purple plants at a high frequency. M
ixed chimeras produced capsules with green plants or purple plants mor
e regularly than did other chimeral types. Furthermore, a chimeral typ
e in which seeds gave rise to green and purple plants was found in 3.2
% of the total crosses. Segregation patterns in the progenies correspo
nded with the chimeral types. Chlorophyll-deficient variation (resulti
ng in variegation or the production of albino plants) was found at a f
requency of 2.6%. These results show that chimeric tissues are actuall
y in a mixed state and that either the ovary develops from more than t
wo cells or else that variation occurs in the germ-cell layer. In inte
rspecific chimeras between Ruby ball and Komatsuna (B. campestris) var
ious types of chimeras generally showed low pollen fertility, few caps
ules, and low seed-setting. Progenies from selves (geitonogamy), open
crosses and crosses with the two parental species produce a predominan
tly homogeneous genotype showing either the Ruby ball or the Komatsuna
type. Only two crosses produced four interspecific hybrids which expr
essed variations in their morphological and isozymic characters.