Data from: Selection on early survival does not explain germination rate clines in Mimulus cardinalis

Premise Many traits covary with environmental gradients to form phenotypic
clines. While local adaptation to the environment can generate phenotypic
clines, other nonadaptive processes may also. If local adaptation causes
phenotypic clines, then the direction of genotypic selection on traits
should shift from one end of the cline to the other. Traditionally
genotypic selection on non-Gaussian traits like germination rate have been
hampered because it is challenging to measure their genetic variance.
Methods Here we used quantitative genetics and reciprocal transplants to
test whether a previously discovered cline in germination rate showed
additional signatures of adaptation in the scarlet monkeyflower (Mimulus
cardinalis). We measured genotypic and population level covariation
between germination rate and early survival, a component of fitness. We
developed a novel discrete log-normal model to estimate genetic variance
in germination rate. Results Contrary to our adaptive hypothesis, we found
no evidence that genetic variation in germination rate contributed to
variation in early survival. Across populations, southern populations in
both gardens germinated earlier and survived more.  Conclusions Southern
populations have higher early survival but this is not caused by faster
germination. This pattern is consistent with nonadaptive forces driving
the phenotypic cline in germination rate, but future work will need to
assess whether there is selection at other life stages. This statistical
framework should help expand quantitative genetic analyses for other
waiting-time traits.