IMPROVEMENT OF AN EARLY FLOWERING GENOTYPE THROUGH RECOMBINATION

24 RESEARCH REPORTS

PNL Volume 12

1980

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

The recombinant R 46C of our collection is homozygous for genes efr

(flowering 7-10 days earlier than the mother variety) and bif-1 (dichotomous

stem bifurcation). It has little agronomic value as such because seed pro-

duction was low in most of the 21 generations tested so far (Fig. 1; lefthand

part).

Recombinant R 46C was crossed with many mutants in order to combine

gene efr with other genes or gene groups of the genome. The respective

recombination types were then selected and developed into pure lines. The

seed production of 59 different early flowering recombinant strains was

evaluated and compared with that of the parental recombinant R 46C in 1979

(Fig. 1). Most genotypes were grown in 3-5 replications with 20 plants per

replication.

PNL Volume 12 1980

RESEARCH REPORTS 25

Fig. 1. Left: Seed production of the early flowering recombinant R 46C

in 21 generations. Each dot represents the mean value for

the number of seeds per plant for one generation as related

to the control values of the mother variety 'Dippes gelbe

Viktoria'.

Right: The seed production (number of seeds per plant) of 59 early

flowering recombinant lines as related to the control value

of R 46C. Each dot represents the mean value for one line

grown in 1979.

The genetically heterogeneous material can be subdivided into five

morphologically different groups according to internode length, stem fas-

ciation or bifurcation, leaf morphology, or other mutant characters. In each

group, some of the genotypes produced considerably more seed than R 46C.

This was true not only for longstemmed genotypes, but also for some recom-

binants with reduced internode length or even for some dwarfy genotypes.

The findings show that it was possible to improve the selection value

of the early flowering recombinant R 46C by combining its two mutant genes

with other mutant genes of the genome. The recombinants available represent

an interesting series for studying problems of interactions between mutant

genes.