An Apetalous Mutation in Turnip (Brassica campestris L.)

Abstract

DURING the year 1938–39 a stray plant of Brassica was discovered, in a lucerne field, which looked strikingly different from any of the plants in the very extensive collection of oleiferous Brassicas which were being grown for cytogenetic study. An examination of this erect, compact plant showed that the flowers were devoid of the bright yellow petals characteristic of the genus and that this was the reason for its peculiar appearance. A number of unopened buds were dissected and examined and in every case it was found that the stamens were inserted immediately after the sepals, the whorl of petals being absent. Seed-setting was excellent under conditions of both self- and open-pollination. The chromosome number of the plant was determined at pollen meiosis as n = 10, that is, the same as in ordinary turnip, which it closely resembled in morphological characters.