6. Mutable golden stock.


In the breeding material resistant to grasshoppers a new golden stock appeared. The normal plant 41.689‑5 was selfed and in its progeny of 47 plants, there were 39 normal ones and eight golden ones. The new golden plant was crossed with the primitive g1, for allelomorphism. In one of the cases all of the eight F1 plants were normal, in other cases golden and normal plants appeared in variable proportions. In selfed lines of the new golden plant, some green plants also appeared. At first these results were attributed to foreign pollen or some other mistake. Later we saw that many plants of the new golden stock were mosaics with longitudinal green stripes. Some of these mosaic plants are even half green and others almost entirely green. In some others the main stalk is golden and the suckers are green.


Two of these mosaic‑golden plants were pollinated with a g1 tester stock, thus obtaining two small ears. Seeds were sown keeping in the ground the same order they had in the ear. Most of the plants obtained were green and a few were "mosaic". These latter plants came from grains more or less grouped in the ear forming rather irregular patches.


It seems that we have here a mutable allelomorph of golden‑1 or possibly a condition that provokes its mutability -- as in the case of Rhoades' Dt with respect to a. In case it were a modifier it would be a dominant, because in F1s from the cross g1 with "mutable golden", "mosaic golden" plants appear.


S. Horovitz

R. R. Ré