Question

1. tall sunflowers are dominant to short, while yellow-colored flowers are dominant to orange. cross a plant that is heterozygous for both traits with a plant that is heterozygous for height, but homozygous dominant for flower color. what will be the possible genotypes and phenotypes of the offspring? show your work as a punnett square and write your answers as a phenotypic ratio.8. using the punnett square that you created for problem #7, answer the following questions:a. a sunflower farmer knows that most people prefer tall and yellow-colored flowers. if he grows 1000 sunflowers from these two parents, how many can he expect to have the desired traits?b. what should be the genotypes of the parent flowers (p generation) if he wants to ensure that all of the flowers in the f₁ generation are tall and yellow?

Explanation:

First, we confirm the parent genotypes:
Parent 1 (heterozygous for both traits): $TtYy$ (gametes: $TY, Ty, tY, ty$)
Parent 2 (heterozygous height, homozygous dominant color): $TtYY$ (gametes: $TY, tY$)

Step1: Correct Punnett Square Setup

	$TY$	$Ty$	$tY$	$ty$
$tY$	$TtYY$	$TtYy$	$ttYY$	$ttYy$

Step2: Classify Phenotypes

• Tall ($T\_$) and Yellow ($Y\_$): $TTYY, TTYy, TtYY, TtYy, TtYY, TtYy$ (6 out of 8)
• Short ($tt$) and Yellow ($Y\_$): $ttYY, ttYy$ (2 out of 8)

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For 8a:

Step1: Calculate desired trait ratio

Phenotypic ratio for tall + yellow = $\frac{6}{8} = \frac{3}{4}$

Step2: Calculate expected number

$1000 \times \frac{3}{4} = 750$

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For 8b:

Step1: Ensure dominant traits

To guarantee all $F_1$ are tall ($T\_$) and yellow ($Y\_$):

• For height: One parent must be homozygous dominant ($TT$) (so all offspring get a $T$ allele, ensuring tallness)
• For color: Both parents must be homozygous dominant ($YY$) (so all offspring get $Y$ alleles, ensuring yellow color)

Answer:

7. Phenotypic Ratio:

3 Tall, Yellow : 1 Short, Yellow

8a.

750 sunflowers

8b.

Both parent plants must be homozygous dominant for height and flower color: $TTYY \times TTYY$ (or one $TTYY$ and any $T\_YY$, but $TTYY \times TTYY$ ensures 100% tall yellow offspring)