THE RELATIONSHIP BETWEEN ENDOSPERM DEVELOPMENT AND MORPHOLOGIC CHARACTERS IN THE F2 GENERATION OF A T. DICOCCUM × T. VULGARE CROSS

Abstract

The relationship between the degree of plumpness of F2 seeds and the type of the resulting F2 plants was studied in the cross Vernal (T. dicoccum) × Marquis (T. vulgare). A random sample of F2 seeds was divided into three classes based upon kernel plumpness, viz. plump (Class A), slightly shrunken (Class B), and shrunken (Class C). In these there were by number 55.5, 41.0 and 3.5% of seeds respectively. Emergence of F2 plants in the field was 64, 58 and 36% for Classes A, B and C. The F2 plants were studied for 13 morphological characters. Comparing the populations for all characters combined, Class A was more dicoccum-like than Class B, and Class B much more dicoccum-like than Class C. The proportion of vulgare-like character was 16, 20 and 32% for Classes A, B and C, respectively. Considering the character of the individual plants, the ratios of dicoccum-like to vulgare-like were 12.1:1, 5.3:1, and 2.2:1 for classes A, B and C, respectively. Furthermore, the vulgare-like plants of classes A and B were less vulgare-like than those of Class C. There were present, however, in Classes A and B some plants that were fully as vulgare-like as any in Class C. These results indicate that, in an interspecific wheat cross, the breeder should give special attention to the shrunken F2 seeds if he has very limited nursery space and a large amount of seed; whereas if he has plenty of space for a large population, special care of shrunken F2 seeds does not seem warranted.