THE SEED PRODUCTION OF RECOMBINANTS IN COMPARISON WITH THEIR PARENTS

30 RESEARCH REPORTS PNL Volume 12 1980

Hartmann, K. Institute of Genetics, University of Bonn, West Germany

The recombinant R 46C of our collection, homozygous for two mutated

genes (efr/efr, bif-l/bif-1), shows early flowering and ripening and reduced

penetrance of gene bif-1 for dichotomous stem bifurcation. This recombinant

was crossed with several mutants in order to study the influence of the

mutant genes on seed production.

The main traits of the mutants used are: mutant 122, narrow leaflets;

mutant 423, waxless stipules and pods; mutant 250, stem fasciation, late

ripening, small seeds; mutant 107D, stein fasciation, late ripening, small

seeds.

The resulting recombinants were compared with their parental genotypes

and in relation to our initial line 'Dippes gelbe Viktoria' = 100% (Fig. 1).

All recombinants are early flowering and ripening; thus gene efr

for earliness is not influenced by the mutant genes tested.

Recombinant R 833, homozygous for earliness, stem bifurcation (from

R 46C) and narrow leaflets (from 122) did not differ much from R 46C nor

from 122 with respect to the number of seeds per plant. Since the influence

of mutant 122 is to reduce the thousand seed weight, the seed weight per

plant of R 833 lies between that of R 46C and 122.

Recombinant R 837, homozygous for earliness, stem bifurcation, and

waxlessness (from mutant 423), showed a slight increase in the number of

seeds per plant as compared with the parental genotypes, almost reaching

the value of our initial line. But because of its reduced seed size the

seed weight per plant was not much higher than in recombinant R 833 but

not as reduced as in mutant 423.

PNL Volume 12 1980

RESEARCH REPORTS 31

The high yielding fasciated mutants 250 and 107D have a complex geno-

typic constitution, differing from our initial line in at least 15 mutant

genes. Recombinant R 46C was crossed with these mutants and several recom-

binants were obtained, one of which, R 863, is early (from R 46C) and very

tall (from mutant 250) but nonfasciated. A relatively high seed yield was

obtained in R 863 but the seed size was similar to mutant 250. The seed weight

per plant was good but the plants are so tall (70% higher than their parental

genotypes) that their cultivation in the field would be very difficult.

Recombinant R 870 is also early flowering and ripening and non-fasciated,

but only about 50% as tall as the parental genotypes. The number of seeds

per plant in R 870 was less than that of mutant 107D and about the same as

R 46C. The seed weight per plant was almost equal to that of R 46C. Since

the plants are considerably shorter than R 46C, R 870 can be considered an

improvement over R 46C.

Fig. 1. Some yielding characters of recombinants R 833, R 837, R 863,

and R 870 compared with those of their parental genotypes,

recombinant R 46C, and mutants 122, 423, 250, and 107D.

A - number of seeds per plant; B - thousand seed weight;

C - seed weight per plant. Each mean value is related to the

corresponding value of the initial line = 100%.