Biology 11th Edition by Cecie Starr ,Ralph Taggart

تمرين 16

As rose breeders know, several alleles influence specific traits, such as long, symmetrical, urn-shaped buds, double flowers, glossy leaves, and resistance to mildew . Alleles of a single gene govern whether a plant will be a climber (dominant) or shrubby (recessive). When a true-breeding climber is crossed with a shrubby plant, all F 1 offspring are climbers. If an F 1 plant is crossed with a shrubby plant, about 50 percent of the offspring will be shrubby and 50 percent will be climbers. Using symbols A and a to represent the dominant and recessive alleles, make a Punnett-square diagram of the expected genotypic and phenotypic outcomes in the F 1 offspring and the offspring of the cross between an plant and a shrubby plant.