6. Sorghum is an important cereal crop whose quality and appearance could be affected by the presence of pigments in the pericarp (the walls of the plant ovary). The article A Genetic and Biochemical Study on Pericarp Pigments in a Cross Between Two Cultivars of Grain Sorghum, Sorghum Bicolor

(Heredity, 1976: 413—416) reports on an experiment that involved an initial cross between CK60 sorghum (an American variety with white seeds) and Abu Taima (an Ethiopian variety with yellow seeds) to produce plants with red seeds and then a self-cross of the red-seeded plants. According to genetic theory, this F2 cross should produce plants with red, yellow, or white seeds in the ratio 9:3:4. The data from the experiment follows; does the data con rm or contradict the genetic theory?

Test at level .05 using the P-value approach.

pi  15.5  0 i  5.5 0 2/30.

Seed Color Red Yellow White Observed Frequency 195 73 100