THE INHERITANCE OF ASCORBIC ACID CONTENT IN CABBAGE

Abstract

IN A RECENT paper, Smith and Walker (1946) emphasized the influence of heredity on the ascorbic acid (vitamin C) content of cabbage. Their studies revealed that while environmental factors such as season of growth, time of harvest, and possibly rainfall and amount of sunlight may affect the total amount of this vitamin in cabbage heads, significant differences occur between cabbage varieties and between certain strains or lines within a variety. They found that among the varieties tested, All Head Select usually contained the least amount of the vitamin while Jersey Queen contained the most. A line of Wisconsin All Seasons, derived by a number of generations of close breeding, was discovered to have an unusually high ascorbic acid content. During four consecutive years, repeated analyses of heads from progenies from selfed or sib-crossed individuals showed that the high-vitamin content was relatively stable within this line. F1 hybrids between individual plants from this strain and from low-vitamin strains were reported to have an ascorbic acid content intermediate between the two parents. The purposes of the present work were: (1) to nmake use of the high-vitamin line of cabbage as parental material from which, by hybridization and selection, the factors for high ascorbic acid content could be incorporated into standard commercial varieties; (2) to study the mode of inheritance of factors influencing high production of this vitamin in cabbage. In this paper are included the F1 data from twenty-three crosses and the F2 data from eight of those crosses. Inasmuch as it was not possible to secure complete data from the F3 generation, which admittedly would add much to the genetic interpretation of the inheritance of ascorbic acid content, only the F1 and F2 data are presented in this report. METHODS AND MATERIALS.-The three-slice method of analysis of cabbage heads described by Smith and Walker (1946) was used without modification to determine the ascorbic acid content of all cabbage studied. In 1944, the recommended six-head sample was used to obtain the content of the parent and F1 lines. Since segregating F2 populations were studied in 1945, all available heads were analyzed to determine frequency distributions in the parent lines as well as in the F1 and F2 progenies. With the hope of facilitating future seed production by preserving cabbage heads on the plants, a limited attempt was