THE EFFICIENCY OF SOME MICRO-MUTANTS

16 RESEARCH REPORTS

PNL Volume 12

1980

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

Some of our radiation-induced mutants do not show any obvious morpho-

logical deviations from the initial line. They are somewhat later ripening

and their seed production is higher (mutant 37C, recombinant R 624), Two

other mutants differ from the mother variety so insignificantly that they

cannot be classified reliably in segregating families. This is the case

for mutant 68C having an increased number of ovules per carpel and for mutant

39 having a subtly deviating leaflet shape. Thus, these genotypes represent

typical "micro-mutants". Seed and protein production in these mutants was

compared with values obtained from genotypes with stronger anomalies.

The positive effect of the increased number of ovules per carpel in

68C is counteracted by the reduced number of pods per plant resulting from

the pleiotropic action of gene ion. Its seed and protein production per

plant was nearly equivalent to that of the mother variety (Fig. 1). Mutant

39 has good yielding properties combined with normal seed size and normal

protein content of the seed meal. In two years tested, its protein produc-

tion per plant was 20-30% higher than that of the initial line. This mutant

will be tested more intensively during the next generations.

Recombinant R 624 arose from the cross of mutant 489C (stem fasciation

and many other anomalies) x 142B (tiny plants with degenerating leaves).

Its seed production was determined from replicated rows grown in three

consecutive generations. The mean number of seeds per plant was regularly

higher than the control material, but because of reduced seed size the seed

weight per plant was not improved.

Mutant 37C is of particular interest because of its good yielding

capacity. It, too, was tested over three generations and showed a very high

seed production due to a strongly increased number of pods per plant.

Unfortunately, the seed size of this genotype is reduced. Thousand seed

weight for 1978 and 1979 was as follows: 1978: 222.80 g (mother variety:

283.40 g); 1979: 234.33 g (mother variety: 302.07 g). Protein content of

the seed meal was found to be approximately equal to that of the initial

line. Because of the high seed production, 15-20% higher values for the

protein production per plant were obtained in 1978 and 1979. The protein

quality, i.e. the relative amounts of the different amino acids, was normal.

Thus, the protein production of this micro-mutant exceeded the mother variety

in spite of having a strongly reduced seed size.



	PNL Volume 12 1980	RESEARCH REPORTS 17



	Fig. 1. Seed and protein production per plant of three Pisum mutants and a recombinant. All the values are related to the control values of the mother variety 'Uippes gelbe Viktoria'. Each dot represents the mean value for one year (39, 68C) or for one replication in 3 years (37C, R 024), respectively.