Analysis of genotypic differences in developmental stability in Annona cherimola

The genetic basis of developmental stability, measured as asymmetry (fluctu ating asymmetry in leaves), was analyzed in leaves and flowers of cherimoya (Annona cherimola Mill) and atemoya (A. cherimola x A. squamosa). The indi viduals analyzed belonged to a controlled collection of cultivars (clones) that had previously been characterized by means of isozymes. We used a nest ed design to analyze the differences in asymmetry at several sampling level s: individual leaves and flowers, individual trees, and genotypes. The clon al repeatability of developmental stability was nor significantly different from zero, thus suggesting the absence of heritability of the asymmetry fo r leaves and flowers under these environmental conditions. No relationship between asymmetry and individual heterozygosity was found, but leaf fluctua ting asymmetry was significantly related to particular isozymic genes. Peta l and leaf size showed a phenotypically plastic response to the exposure zo ne of the tree (mainly due to light). Leaf fluctuating asymmetry also showe d such a plastic response. No significant correlation was found between asy mmetry and any pomological characters (some of these being fitness related) . Finally, the hybrid species (atemoya) did not show larger developmental i nstability than did the parental species (cherimoya). All these data show t hat cherimoya asymmetry reveals the random nature of developmental noise, w ith developmental stability for leaves being possibly related to specific c hromosome regions, but with weak evidence for genotypic differences in deve lopmental stability.