Question

: In a mating of pea plants the F1 generation yielded offsprings in the following quantities: 595 yellow smooth : 198 green smooth: 198 yellow wrinkled: 66 green wrinkled. What were the likely genotypes of the P generation that produced these results?
A. YYRR x yyrr
B. YyRr x YyRr
C. Yyrr x YyRr
D. YYRR x yyRr

Answer 1

Hint:-In the name dihybrid cross the “ di “ indicates that there are two traits involved example R and Y and the “ hybrid “ indicates that each trait has two different alleles example R and r , or Y or y , and “ cross “ means that there are two individuals ( usually father and mother ) who are combing or crossing their genetic information.

Complete Answer:-a dihybrid cross allows us to look at the pattern of inheritance of two different traits at the same time. For example, say we are crossing two pea plants. The two traits we are looking at are the seed colour and shape. The first seed is green and wrinkly and the second is yellow and smooth.
 The given example is of dihybrid cross involving seed colour and seed shape. The number of plants obtained in the $$F_1$$ generation yielded offsprings were 595 yellow smooth : 198 green smooth : 198 yellow wrinkled : 66 green wrinkled. This count can be approximated to the phenotypic ratio 9 : 3 : 3 : 1. this ratio can be obtained by crossing the plants of the P generation with genotype YyRr x YyRr
The dihybrid cross is easy to visualize using a punnett square of dimension 16. as shown below:

Note:- Dihybrid cross is a cross between two different lines / genes that differ in two observed traits. in the dihybrid cross the genotypes can be grouped into four phenotypes, for example 1 YYRR + 2 YYRr + 2 YyRR + 4 YyRr = 9 Y-R- smooth yellow peas. The ratio of these phenotypes is of course 9 : 3 : 3 : 1.