The figure describes the percent oil content in corn from di

The figure describes the percent oil content in corn from different generations. In 1899, the mean oil content was 5.65% dry mass, the mean of the selected plants was 6.30% dry mass, and the mean of all plants in 1900 was 6.10% dry mass. What is the expected slope of a parent-offspring regression (narrow-sense heritability) for corn oil content?

0.69

1.60

2.19

2.56

	a.	0.69
	b.	1.60
	c.	2.19
	d.	2.56

Year 1900 plants Selected year 1899 plants Discarded year 1899 plants 16 14 12 10 4.0 4.5 5.0 5.5 6.0 6.5 7.0 I I Percent oil content I I I I I I H I I I 1900 I mean I HI 1899 Selected mean mean

Solution

Answer:

The expected slope of a parent offspring regression (narrow sense heritability) can be estimated using the regression/correlation method by slope of the regression of the offspring phenotype value on the mean of the two parental values.

slope ~ h² = R/S, where R is the response to selection (difference in offspring mean trait and parental mean trait) and S is called the selection differential (difference in mean trait between the population and selected parents of next generation)

In this case:

S = 6.30 - 5.65 = 0.65 and

R = 6.10 - 5.65 = 0.45

Therefore h2 = R/S = 0.45/0.65 = 0.69