F.L. Gorel , V.A. Berdnikov, S.M.Rozov, O.K.Kosterin

Institute of Cytology and Genetics, 630090, Novosibirsk, RUSSIA

The genome region containing locus d (anthocyanin ring in the leaf axil) attracts attention by the presence of several other genes (Pur, And, Ans, rup, sru) responsible for distribution of anthocyanin in vegetative parts of the plant (see the map of Pisum linkage groups [1].) Recently it was shown in our laboratory that the gene Astr, which determines the anthocyanin stripes on the pod wall in many strains of P.fulvum, is also linked to the gene d [2]. At the same time in the vicinity of the gene d there is another locus Pur affecting the anthocyanin distribution in epidermis of the pod wall and funiculi. So, Astr might be an allele of gene Pur specific for P. fulvum. To clarify this question we used the line Asteroid carrying dominant alleles of genes d, Pur and Astr. Synthesis of this line was as follows: among F2 from the cross cultivar Alpha (a, D, astr, pur) X P.fulvum VIR-6070 one vigorous and fertile plant with phenotype Astr was chosen and its descendant after selfing was crossed with the line WL-1255 (A,D,astr,Pur). The plant with phenotype D,Astr,Pur was chosen from F2 and crossed again with the line WL-1255. The presence of Pur was detected by examining the color of funiculi. The gene Astr is reliably determined both in field and in greenhouse and can be used in genetic analysis as reliable and harmless marker. After three generations of selfing , the line Asteroid with unified phenotype of plants was established.

Line Asteroid was crossed with WL-1514 (astr,d,pur).

Analysis of F2 (Table 1) leads to the following recombination relationships:

It is obvious that Astr and Pur are separated by a substantial map distance.

Attribution of gene d to any linkage group still remains not quite certain. Recently it has been demonstrated that the breakpoint of the Twt-translocation is linked both to the gene d and to the markers of linkage group I [3,4]. The cytological analysis of crosses with the set of standard translocations indicates that the other component of Twt-translocation must be a chromosome residing linkage group VI.

We crossed the Asteroid with the Twt-translocation (Twt, D, pur, astr), the phenotypes of F2 progeny are represented in Table 2.

A heterozygous state of Twt was detected by 50% -sterility of pollen. The recombination relationships obtained permit us to construct the map, where the breakpoint of Twt-translocation is situated closer to locus Astr.

The question arises which gene of P.sativum is allelic to Astr of P.fulvum. If locus Astr is placed on linkage map in 6 cM from d in opposite direction of Pur, it gets in vicinity of gene rup which manifests in numerous anthocyanin dots and short stripes on the pod wall. We have met a similar phenotype in some strains of wild pea ( L-100, L-101 from N. Weeden's collection ) formally beloning to P.sativum humile but sharing some traits typical for P. fulvum. One can suppose that rup is recessive allele of Astr, we are to check this hypothesis.

This work was partially supported by the Russian State Program for Fundamental Research.

References:

1. Weeden, N.F., Swiecicki, W.K., Ambrose, M., Timmerman, G.M. 1993. Pisum Genet. 25: 4.

2. Bogdanova, V.S., Trusov, Y.A., Kosterin, O.E. 1995. Pisum Genet. 27: 1-4.

3. Gorel, F.L., Temnykh, S.V., Lebedeva, I.P., Berdnikov, V.A. 1992. Pisum Genet. 24: 48-51.

4. Temnykh, S.V., Gorel', F.L., Berdnikov V.A., Weeden, N.F. 1995. Pisum Genet. 27: 23-25.