The purpose of this lab is to measure genetic variation in black walnut and determine whether there is any correlation with variation in the environment of the seed source. You will determine the amount of genetic variability and whether there are ecotypes of black walnut.

Methods: Measure all the surviving trees from families (Michigan State University source number) 126, 218, 273, 230, 377, and 999 (Okla) on the assigned replicate for height (000 cm) and dbh (00.0 cm). Calculate the percent survival. Calculate the Survival Volume Index (SVI = volume of stem of surviving trees/number of planted trees) for each plot. Use the equation for the volume of a cone to calculate the volume of the stem. Calculate mean values per family per replicate for survival, height, diameter, SVI, number of multiple stems, and number of branches and use analysis of variance to test for family differences. Experimental layout is a randomized complete block design with 6 replicates.

Report: In the report show the data in a table which includes the family number, location of origin (county, state, latitude, longitude and altitude), and mean value for all traits. Show in a figure the relation of SVI to latitude of origin. Show in a figure of the eastern United States the location of each site of origin.

In the discussion be sure to include the reasons for the geographic pattern of variation.

1. You have measured phenotypic variation for several traits among 6 families. Is this variation due to genetic differences or environmental differences? Explain your answer.

2. Can the variation in each trait be explained by local adaptation to environment? What is the adaptation? Does black walnut have ecotypes?

3. Of what value is the information derived from a study such as this one?