ACTION OF GENE gf AS INFLUENCED BY ENVIRONMENT AND BACKGROUND GENOTYPE

PNL Volume 12 1980 RESEARCH REPORTS 23

Gottschalk, W. Institute of Genetics, University of Bonn, West Germany

Gene g_f of Pisum causes reduced flowers which are greenish in color

due to the presence of some chlorophyll in the petals. Plants of the X-ray

induced mutant 189 of our collection are homozygous for gf but are otherwise

normal. They flower belatedly and show unusual sensitivity to changes in

environmental conditions. Plants of this genotype produced a seed yield

about 50% higher than that of the mother variety in 1978, but no seeds at

all in 1977. In the other 13 generations tested so far, the mean values for

seed yield per plant ranged between 1 and 79% of the control values of the

initial line.

In 1979, 22 different recombinant lines were available at our institute,

all homozygous for gf and one or several other mutant genes of our collection.

They were grown in several replications and their seed production was compared

with that of the parental mutant 189 (Fig. 1). The seed yield of mutant 189

Fig. 1. Seed production of mutant 189, homozygous for gene gf,

and of 22 recombinant lines homozygous for gf and for

other specific genes. Each dot represents the mean

value for the number of seeds per plant obtained in

1979. All the values are related to the control values

of the initial line.

24 RESEARCH REPORTS

PNL Volume 12

1980

was very low, ranging between 3.6 and 7.6% of the control over 5 replications

(lefthand part of the figure). Some of the green flowering recombinants had

an equally low seed production so yield was not improved by combining gene

gf with the other genes involved. Some other recombinant types, however,

showed a strikingly better yield than mutant 189; details can be seen from

the figure. Of particular interest is a small group of long-stemmed recombinants

exceeding mutant 189 by 400 to 800%. This holds true for certain fasciated

as well as for certain non-fasciated genotypes, the genes for stem fasciation

and long internodes deriving from mutant 489C of our collection.

These findings show that the reduced seed production of mutant 189 is

not necessarily correlated with the presence of gene gf. On the contrary,

combinations between gf and other mutant genes gave excellent yields. Thus,

gene gf shows a high degree of dependence not only on certain environmental

factors but also on the genotypic background.

Mutant 189 is without any interest for pea breeding. It is quite possible,

however, that other genes of known agronomic value might show a similar behavior.