34 PNL Volume 17 1985 RESEARCH REPORTS

GENETICAL STUDIES OF THE PISUM SATIVUM ROOT SYSTEM

Jensen, F. H. Pajbjergfonden Plant Breeders

Dyngby, DK-8300 Odder, Denmark

Very little is known about the genetics of the pea root in general

or of the variability of roots of different pheno-/genotypes and the

relations to seed yield components.

Jean (2), in his early work on the heritability of root morphology

in peas, concluded: "The evidence, then, suggests strongly that heredi-

tary genes accompanying those that determine height are the causative

factors that determine root penetration in the case of peas, and not the

physiological demands alone of the aboveground parts". It has been im-

possible to find other references of similar studies since then, but

Veitenheimer and Gritton (4) have initiated a crossing program to study

root genetics.

Zobel (5) used mutagenesis to study root systems of peas and indi-

cated that selection for desired root variability should be successful

either by utilizing genepools or through mutation breeding. Ali-Khan

and Snoad (1) analyzed seven root and shoot characters of 30 pea geno-

types and found considerable genetic variation in all characters

studied.

At Pajbjergfonden a three-year project has been funded to investi-

gate the root system of peas^1/. Two experiments have yielded the

following results:

A. The initial root growth of ten pea varieties was studied in the

greenhouse in Jan/Feb 1984. Table 1 shows the varieties used, among

which were white and colored flowered dry edible and garden peas.

'Filby' is a leafless pea and M131-81 and 'Wensum' are semi-leafless.

M131-81 is a progeny from a cross 'Finale' x 'Filby'. The plants were

grown in a sandy loam in PVC tubes (85 cm long, 10.5 cm diam), two

plants per tube. Five replicates of each variety were harvested at

four-day intervals, beginning six days after sowing. Total root length

was measured using procedures described by Newman (3).

The results in Table 1 show highly significant differences in most

characters. Of genetical interest are the varieties Finale, Filby, and

M131-81, and I believe the significant similarities and differences

between these three varieties give some indications of heritability.

Both from this experiment (Table 2) and from a screening of 400

varieties, we found good correlations between total root length and

shoot length. If this correlation is caused primarily by physiological

interactions between root and shoot there may be difficulty in breeding

for larger roots.

B. Results from a screening of 39 pea genotypes (most old land-

races) from Stig Blixt are shown in Table 3. Here, too, the root/shoot

ratio shows a large variation among varieties.

To study in more detail the interaction between root/shoot, crosses

have been made between very tall varieties with a large root system and

commercial varieties with smaller roots. F2 will be grown this spring

for a root test. In addition a crossing program has been set up using

genotypes with well described genes for the shoot received from I. C.

Murfet.

1. Ali-Khan, S. T. and B. Snoad. 1977. Ann. Appl. Biol. 85:131-136.

2. Jean, F. C. 1928. Botanical Gazette 86:318-329.

3. Newman, E. I. 1966. J. Appl. Ecol. 3:139-145.

4. Veitenheimer, E. E. and E. T. Gritton. 1984. PNL 16:73-74.

5. Zobel, R. 1974. PNL 6:58-59.

^1/ Financial support for the project was provided by the Danish

Agricultural and Veterinary Research Council.



	PNL Volume 17 1985	RESEARCH REPORTS 35



	Table 2. Correlation coefficients among five root and shoot characters _in seven successive harvests of ten pea varieties.



	Table 3. Ranges of root measurements of 39 pea geno- types from S. Blixt, compared to Bodil , the most grown dried pea in DK. Grown to _beginning podfilling in soil in PVC-tubes.