Berdnikov, V.A., Gorel', F.L., Kosterin, O.E., Rozov, S.M and Skripkina, T.A.

Institute of Cytology and Genetics, Novosibirsk, 630090, Russia

After treatment the seeds of the line SG with 0.15% EMS a new recessive mutation drastically affected the leaflets (Fig. 1) and petals was detected among M2 plants. We called it narrow sail and symbolized nas. This mutation reduces the width of leaflets to 1/3 - 1/4 of normal and, to a less extent, stipulae (Fig 1) and makes the tendrils more flat.

Fig.1 The leafs and stipulae of the homozygotes for the mutation nas

Its effect of tendrils reminds that of tlw in a heterozygous state (Fig 2).

Fig.2 Cross-sections through the central tendril at its base (below) and terminal part (above) of a homozygote for the nutation nas.

But the most remarkable effect it exerts on the sail reducing it to a narrow stripe (Figs 3).

Fig.3 A flower of the homozygote for the mutation nas (left and middle) and a normal flower (right).

Other structures of the flower appear to be unaffected, but after fertilization the pistil develops into an abnormal reduced pod without seeds and with the dorsal suture opened (Fig. 4).

Fig.4. An abortive pod of a homozygotes for the mutation nas.

In spite of female sterility, the mutant plants are vigorous, their proportion among the F2 populations being very close to 1/4. The pollen is well-viable and can be readily used for pollination.

We could not find the linkage relationship of the new mutation with the markers a, i, r, tl, gp, cri, le, n, involved in three crosses, the cross-over values did not deviate significantly from 50%.

The mutation nas can be used, in combination with male sterility factors, for constructing cross-pollinating populations of the pea.

This work was partly supported by Russian National Program "Russian Fund for Fundamental Research".