For each problem define the interactions and write out the F₁ and F₂ cross genotypes.  In short hand notation (e.g. A_B_) indicate the genotypes that make up each phenotype. 

Punnett Square for the F₂ of a dihybrid cross:

1.    One strain of homozygous Dewgongs can emit a cold blast of air (ice beam). A second homozygous strain can do the same thing, The F₁ progeny between these two genetically different homozygous strains emits a freezing cold and colored blast of air (aurora beam). The F₂ progeny produce ice beam: aurora beam in a 7:9 ratio (seen in thousands of progeny).

(Hint: Description 3)
  

2.    In the Vileplumes,  poison spores (A) are dominant to stun spores (a).  Antidote (B) is an autosomal dominant gene which has no obvious phenotypic effect of its own.  Antidote has the epistatic effect of weakening any plant that is homozygous for Poison spores. That is, it changes the phenotype of poison spores into stun spores.  A completely homozygous Poison-spore, non-antidote Vileplume is crossed to a completely homozygous Stun-spore, antidote Vileplume. What will be the phenotypic ratio of poison spore to stun spore in the F₂?

(Hint: Description 6)

3.   Professor Oak has two pure breeding strains of Nidorans who are homozygous for tackle. When he crosses these two strains, all of the F₁ progeny also have a new phenotype Double Kick. In the F₂, he gets another new phenotypes, growl. The three phenotypes Double kick: tackle: growl occur in a 9:6:1 ratio.

(Hint: Description 7)

4.   In Dustbunnies (a close relative of rumbunnies) Black (B) is codominant to white (b). The heterozygote is called Streaky-Gray.  At a second locus Color (A) is dominant to Colorless (a).  Homozygous colorless masks the effects of alleles at the Black/White locus. What is the phenotypic ratio of the dihybrid cross in the order (Black, Streaky-Gray; White)?

(Hint: Description 8)

5.  Coracle bugs spin around on the surface of small streams. One strain of bugs spins only to the right and a second strain spins only to the left. The F₁ progeny between a right spin and a left-spin beetle go straight ahead. The F₂ progeny are straight, left and right in a 9:4:3 ratio.

(Hint: Description 2)

6.  Irish crossed two pure-breeding stocks of dark brown hops. The F₁ were all dark brown. The F₁ were crossed to provide an F₂ which had 1500 dark brown and 100 golden brown hops. Explain and diagram the genetic system that would give these results.

(Hint: Description 5)

7.  One homozygous strain of the silkworm (Bombyx mori) lays white eggs, and another lays black eggs. You cross the black and white pure breeding strain.  The F₁ progeny are white.  In the F₂  you obtain white,  black and pink eggs in a 12:3:1 ratio. 
(Hint: Description 4)

8.   Professor Asher Swampdoor mainly works on mice but he has developed a new strain of Night Blooming daylilies (Hemerocallis nocturne) which he calls night lilies. He has two pure breeding strains of night lilies which glow fluorescent orange. When he crosses these two strains, all of the F₁ progeny also glow fluorescent orange. In the F₂, he gets two new phenotypes, fluorescent red and fluorescent yellow. The three phenotypes (red, orange, yellow) occur in a 1:14:1 ratio. Subsequent work showed that red and yellow night lilies breed true when selfed.  

(Hint: No Description like this given in examples - answer)