Question

In the Cucurbita, w is epistatic over Y and y, normally responsible for yellow and green colour fruits respectively. It produces white fruits. What is the ratio of in the progeny of cross WwYy x wwYy?

a)	9 white	:	7 yellow	:	0 green
b)	3 white	:	4 yellow	:	1 green
c)	4 white	:	3 yellow	:	1 green
d)	2 white	:	1 yellow	:	1 green

Answer 1

Hint: The pairing or crossing of two dissimilar genotype plants or lines is known as hybridization. The crossing is carried out in plants by placing pollen grains from one genotype, i.e., male parent, on the stigma of flowers from another genotype, i.e., female parent.

Complete answer:
Three kinds of fruit colours are present in Cucurbita: yellow, green and white. White is dominant over other colours, while green is dominant over black. The influence of the yellow colour gene(Y) is masked by the gene for white colour(W). Only when the dominant epistatic gene is expressed by its recessive allele(w) is the yellow colour produced. The colour of the fruit is green when the hypostatic gene is also recessive(y). White fruit genotype WWYy, Yellow fruit genotype-wwYy, wwyy green fruit. When a cross is made between WwYy, wwYy, 8 progeny are white, 6 are yellow and 2 are green in the next generation. The proportion is 4:3:1.

Additional information:
Genotype and phenotype are common concepts in genetics used to describe an organism's appearance, function, and behaviour. The genotype is characterised as the set of genes that decide the characteristic or trait of the organism when expressed. The genotype is in simpler words, the genetic contribution to the phenotype.
All the measurable traits of an organism are phenotypes. For instance, all traits of a specific phenotype are height, hair colour, mating behaviour and movement pattern. As a consequence of environmental conditions, phenotypes can shift, or their characteristics can change as an organism develops or adapts.
It's difficult to provide precise genotype examples. The word only means "the genes a particular organism has. Any example of a genotype will just be a map of the chromosomes of a single living thing, or DNA molecules responsible for different genetic traits. Getting those genes, however, does have detectable effects.

So, the correct answer is ‘4 white : 3 yellow: 1 green’.

Note:
A dihybrid cross is a breeding experiment between two species for two characteristics that are similar hybrids. In other words, a dihybrid cross is a cross between two species, with two distinct characteristics being heterozygous for both. In this type of phenotype, the individuals are homozygous for a particular feature. DNA segments called genes decide these traits. The parents bear separate pairs of alleles for each trait in a dihybrid cross.