A new symbiotic pea mutant

Sidorova, K.K., Vlasova, E.Y., Mischenko, T.M. and Shumny, V.K.
Institute of Cytology and Genetics, Novosibirsk 630090, Russia

A new symbiotic pea mutant K9a has been induced from the cultivar Rondo after treatment of seeds with EMS. The mutant is semidwarf (Fig.1). Leaflets, stipules and pods are reduced, roots are short and thin. The vegetative period is long. Plants were grown using a standard mineral solution [1]. Plants were inoculated by Rhizobium leguminosarum strain 250a. The mutant shows abundant nodulation, especially in the absence of nitrate (Fig. 2) (Table 1).

SIDOROVA.JPG (22016 bytes) Figure 1. Plants:
a) Parental cultivar Rondo;
b) Mutant K9a.		 SIDOROV1.JPG (38528 bytes) Figure 2. Roots:
a) Parental cultivar Rondo;
b) Mutant K9a.

Table 1. Plant height and the number of nodules in the mutant K9a
and the cultivar Rondo growing without and with nitrate

Without nitrate

With nitrate

Variant

Height, cm

Nodules,
number
per plant

Nodule
description

Height, cm

Nodule,
number

Nodule
description

Mutant k9a

19.2+4

219.0+8.7

medium and
large, pink

23.7+1.7

 38.7+4.3 small and
medium,
pale pink

Rondo

40.1+5

79.4+6.0

 medium and
large, more
branching
nodules than on
the mutant, pink		 58.0+1.4 47.2+5.4 small and
pale pink

 

Table 2. Segregation in F2 after crossing mutant K9a to the parental cultivar Rondo

Cross

Phenotype of F1

Segregation in F2
(wildtype: mutant)

Chi-sq.
3:1

P

K9a x Rondo

Stem, leafs, roots
and nodulation as in Rondo

94:28

0.273

0.6-0.7

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1. Feenstra, W.J. and Jacobsen, E. 1980. Theor. Appl. Genet. 58:39-42.