Quantitative genetics of leaf morphology in Crepis tectorum ssp. pumila (Asteraceae)
1999
Andersson, S.
The present study of Crepis tectorum ssp. pumila employed the factorial mating design to examine the genetic (co)variance structure of leaf morphology in a population that appears to be homozygous for a major gene causing deeply lobed leaves. One set of factorials was based on widely dispersed plants (different patches, mean crossing distance 24 m), while the second was based on crosses between plants within 0.25 m(2) plots (within-patch crosses). Variance component analyses revealed significant levels of additive variation in leaf size and four measures of leaf shape, indicating a potential for further adaptive change--even after the fixation of a major mutation. Offspring from short-range crosses had a significantly shorter leaf perimeter and were more likely to produce weakly lobed leaves (a recessive character) than progeny representing the longer crossing distances, suggesting that this patchily distributed population is subdivided into patches of related individuals. However, the crossing distance between parents had no consistent effect on the additive and nonadditive genetic variances, and the patterns of association between characters, showing that spatially restricted samples of genotypes capture most of the (co)variation present in the population as a whole.
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