Question

what is the only genotype for green seeds

Answer 1

Answer-

According to the given question-

Mendel has chosen seven characteristics for their study in pea plants and these characteristics are expressed as one of two form or traits. we know that the  genes are present on chromosomes and a  single gene responsible for controlling a single characteristic and are present on homologous chromosomes and termed as alleles. Two alleles of a gene in an organism are expressed and gives its phenotype which is a physical characteristics. While the genetic constitution is called  genotype. Mendel’s used a trait called seed color which was governed by a single gene and have two alleles. The allele of yellow-seed is dominant while the allele of green-seed is recessive. When we make a cross between two true-breeding plants such as a parent plant had yellow seeds while other plant parent had  green seeds, then after cross we get F1 generation which are all hybrid offspring and they all have yellow seeds. which are phenotypically identical to their true breeding yellow parent but their genetic content is not same. Organism which are homozygous for a gene with two identical alleles, are present on their each homologous chromosomes and their genotype is denoted as YY or yy where each letter denotes alleles for that particular genotype. Y is called dominant allele while y is called recessive allele. F1 generation yellow offspring   received each allele from their parents such as he get Y allele from yellow parent and y allele from green parent and have  genotype of  Yy.

Parents - ( Yellow ) YY yy (Green )

F1 Generation- Yy (Yellow)

when F1  offspring was self crossed i.e.

Yy Yy

then

	Y	y
Y	YY (Yellow)	Yy (Yellow)
y	Yy (Yellow)	yy (Green)

Which means that the green seed have only yy genotype or in other word we can say that the green seed have only pure homozygous recessive genotypoe.