How can two tall pea plants produce a small pea plant

each of the two tall pea plants carry a recessive gene for a small plant in their genetic family tree

The height of pea plants is determined by their genetic traits, specifically the inheritance of tall or short height genes. Pea plants exhibit dominant and recessive traits for height, where tallness (T) is dominant over shortness (t).

When two tall pea plants are crossed, it is possible to produce a small or short pea plant if both plants are heterozygous for the height trait. This means that they possess one tall allele (T) and one short allele (t).

To determine the probability of producing a small pea plant, we need to use a Punnett square, which is a visual tool to predict the possible combinations of alleles in the offspring.

In this case, let's use the letters A and a to represent the alleles for plant height. A represents the tall allele (T) and a represents the short allele (t).

The Punnett square for crossing two heterozygous tall plants (Aa x Aa) would look like this:

A a
---------------
A | AA Aa
a | Aa aa

As you can see, there are three possible genotypes in the offspring: AA, Aa, and aa. The genotype AA represents a tall plant, Aa represents a tall plant (carrier of the short allele), and aa represents a short plant.

Therefore, in this particular cross, there is a 25% chance of producing a small pea plant (aa genotype) if both parent plants are heterozygous tall (Aa).