Crossed undersized (dwarf) tomato plants with ribbed fruits and plants of normal height with smooth fruits. In the offspring, two phenotypic groups of plants were obtained: undersized with smooth fruits and normal height with smooth fruits. When crossing low-growing tomato plants with ribbed fruits with plants with a normal stem height and ribbed fruits, all offspring had a normal stem height and ribbed fruits. Make crossbreeding patterns. Identify the genotypes of parents and offspring of tomato plants in two crosses. What is the law of heredity manifested in this case?
in the first cross, the digomozygous crosses with a homozygous plant in one way and heterozygous in another (to understand this, you need to write several options, this offspring is obtained only with such parents). in the second cross, everything is simpler – two digomozygotes cross (only in the second parent one trait will be dominant).
a – undersized individuals
A – normal height
b – ribbed fruits
B – smooth fruits
P: aabb x aabb
F1: aaBb – undersized individuals with smooth fruits
AaBb – normal height, smooth fruits
P: aabb x AAbb
F1: Aabb – normal height, smooth fruits.
In both cases, the law of independent inheritance appears, since these two traits are inherited independently.