Question

Test cross of dihybrid ratio is \[1:1:1:1\] .It proves that
A. ${F_1}$ hybrid produces four different progeny
B. ${F_1}$ hybrid is homozygous
C. Two different progeny are produced by parents.
D. None of the above

Answer 1

Hint: Test cross is done to identify the genotypic ratio of the organism in this cross the dominant genotype is crossed with homozygous recessive gene .The mendelian ratio for test cross is \[1:1:1:1\] in which alleles are crossed with independent gametes. In test cross the dominant ${F_1}$ hybrid is crossed with the recessive gene which is completely different in the cross hereditary hence, it is specific for producing different phenotypic daughter hybrids This cross is mostly preferred than back cross.

Complete answer:
The ratio of the cross in the hereditary indicates number of individuals and number of offspring or number of characters now in this ratio \[1:1:1:1\] we can observe four different phenotypes which have different characters which mean four different progeny are produced.
${F_1}$ hybrid produces four different progeny.
-Option A is correct because we can observe four different progeny from the test cross which is mostly done between ${F_1}$ hybrids.
-${F_1}$ hybrid is homozygous.
-Option B is not correct even it is homozygous or heterozygous it will not explain the test cross ratio \[1:1:1:1\] with different progeny.
-Two different progeny are produced by parents option c is not correct according to the ratio it explains that four different progeny with different phenotypes are produced by the parents.
-None of the above options D is not correct because the phenotypic ratio is explained by the option A which is ${F_1}$ hybrid produces four different progeny.

Hence, the correct answer is option (A).

Note: Test cross is preferred for understanding the hereditary but there is a disadvantage but in the test cross the large number of offspring are produced which is hard to segregate and provide a complete conclusion report for the species. Because it is simply a cross between unknown genes.