Question: Question 3 (5 pts). A sunflower breeder wants to increase the number o

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Question: Question 3 (5 pts). A sunflower breeder wants to increase the number of seeds per capitulum (flow... Question 3 (5 pts). A sunflower breeder wants to increase the number of seeds per capitulum (flower head) of each plant. The breeder selected plants with relatively high number of seeds per capitulum from an open pollinated population 1 and mated them to produce population 2. Several statistics have been estimated for population 1. A subset of those statistics has been estimated for population 2.

Show your work for all answers Average number of seeds per capitulum for population 1: 854

Average number of seeds per capitulum for population 2: 1044

Average number of seeds per capitulum of plants selected from population 1 to create population 2: 1253

Phenotypic variance for number of seeds per capitulum for population 1: 2673

Genotypic variance for number of seeds per capitulum for population 1: 1879

Additive variance for number of seeds per capitulum for population 1: 562

Environmental variance for number of seeds per capitulum for population 1: 154

a. What is the estimated selection differential for seeds per capitulum?

b. What is the estimated selection response for seeds per capitulum?

c. Based on the average seeds per capitulum for population 1 and 2, what is the estimated narrow-sense heritability?

d. What is the broad sense heritability for seeds per capitulum in population 1?

e. What is the variance due to genotype by environment interaction for population 1?

Explanation / Answer

Ans a: 399

Selection differential = (Average number of seeds per capitulum of plants selected from population 1 to create population 2) - (Average number of seeds per capitulum for population) = 1253 - 854 = 399.

Ans b: 1044

Realised heritability = [(Average number of seeds per capitulum for population) - (Average number of seeds per capitulum for population)] / [(Average number of seeds per capitulum for population) - (Average number of seeds per capitulum of plants selected from population 1 to create population 2)]

= (854 - 1044) / (854 - 1253) = 0.47619 (i.e. 47.61%)

So, response to selection = Average number of seeds per capitulum for population + [Realised heritability x [(Average number of seeds per capitulum of plants selected from population 1 to create population 2) - (Average number of seeds per capitulum for population)]] = 854 + [0.4761 x (1253 - 854)] = 854 + [399 x 0.4761] = 854 + 190 = 1044.

Ans c: 0.21

Narrow-sense heritability = Additive variance / Phenotypic variance = 562 / 2673 = 0.21

Ans d: 0.91

Broad-sense heritability = (Additive variance + Genotypic variance ) / Phenotypic variance = (562 +1879) / 2673 = 0.91

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