A new symbiotic pea mutant

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).

Figure 1. Plants:
a) Parental cultivar Rondo;
b) Mutant K9a.

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.