Mutation air dots (adt) with slight uni^tac-like effect on the leaf

Gorel, F.L., Berdnikov, V.A. and                            Inst. of Cytology and Gen., Russian Acad. of Sci.

Kosterin, O.E.                                                                                                    Novosibirsk, Russia

      A recessive mutation adt was found in M₂ plants after EMS treatment of seeds of the stock SG. Formally, this mutation can be classified as an aeromaculata type (1). The most distinct feature of adt mutants is the numerous tiny grey spots along veins of leaflets and stipules (Fig. 1). In addition to this trait there are many devia-tions from the normal phenotype. The coloration of wings is very similar to that of the standard (Fig. 2), the pods are shorter and wider, and the leaves often (but not always) look like the leaves of the uni^tac mutant (3) in that the terminal tendril are replaced by a leaflet (Fig 1). The mutant was used to produce an isogenic line AIR. Despite resemblance of our mutant to uni^tac plants, F₁ plants from the cross with the line homozygous for uni^tac had wild-type phenotype, and the phenotype segregation pattern in F₂ suggested the absence of tight linkage between uni and adt. The cross of the line AIR (i, R, Gp, u, Wb, K, S, D^w, Pl, m, St) with the tester line WL1518 (I, r, gp, U^st, wb, k, s, d, pl, M, st) gave evidence for a linkage with the locus M (Table 1). The relatively weak linkage to M and lack of linkage to St suggests that adt is located near the upper tip of LG III, although this conclusion should be considered as preliminary.

Table 1. Joint segregation data for the loci Adt, M and St at the linkage group III obtained in F₂ of the cross AIR x WL1518.

¹ p<0.0001

      Like uni^tac, adt manifests some antagonism with afila. The leaves of triple homozygotes adt/adt af/af tl/tl found among F₂ pants, after crossing AIR with the line homozygous for a, af, and tl, are not as strongly ramified as those of af tl^w.  Rather the phenotype is more similar to that of uni^tac af tl^w (Fig 1). We cannot exclude that Adt may be one of the X-factors with Uni-like function postulated by Hofer and Ellis (2).

Acknowledgement: This work was partly supported by the 'Russian Fund for Fundamental Research', grant No 02-04-494260.

1.   Blixt, S. 1972. Agri Hortique Genet. 30: 1-293

2.   Hofer, J, Ellis, T. J. M. 1998. Trends Plant Sci. 3: 439-444.

3.   Sharma, B. 1972. Pisum Newslett. 4: 50.