Input - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 55

the fi rst founder will produce two offspring in the fi rst generation of the
trial population, while the second must continue through fi ve generations
as a non-reproductive individual, then produce two offspring in its sixth
generation. Thus, these two founders will reproduce at different ages of the
population, even though they both enter the population in the founding
generation. Note that when a founding generation is specifi ed, if some of
those founders are not reproductive for several years, the grid points of
these non-reproducers are considered to be occupied and cannot become
occupied by new offspring until mortality occurs. For example, some of
the non-reproducers may die as a population develops through generations
because of the age-specifi c mortality statement specifi cations (see above),
opening up their grid point for establishment by a new offspring. Using the
age option, one can thus explore the effects of populations being established
by founders of different ages that become reproductive over two or more
generations.
In the same founder statements given just above, the fi rst founder is
placed at the grid point with (x,y) coordinates of (0,0), while the second
is 6 grid units to the right (6,0), with 5 grid units between these founders.
Only one founder can be assigned to any one grid point.
Those same two statements also designate the founders as being
one male (the first) and one female. When offspring are generated,
NEWGARDEN assigns each to be a male or female in a 1:1 ratio. These
designations are retained by NEWGARDEN for each individual, but they
do not apply if the user has earlier specifi ed
Dioecious value = “false”.
By designating dioecious to be true, one can use the founder statements to
examine the effect of changing the sex ratio of the founders on the retention
of diversity as the population develops. In the appendices, examples of
complete founder data input arrays can be found to demonstrate how
founder arrays can be changed; these can easily be clipped by a user into
a user data input fi le.
Initial Founder Statements: Some Considerations
Some potential variations concerning the initial founder population
statements have been outlined in previous sections, and others will be
explored in following chapters. In most cases, the nature of the realism
of these statements is, for the most part, rather self-explanatory. For
example, one variant of the founder input statements discussed earlier
demonstrated how different founders could be designated to become
reproductive at different population generational times. This allows one
to compare admixing, on different schedules, of new individuals into