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This study compared the sequence variations and expressions of 12 chloroplastic and 8 mitochondrial genes in three pepper ( Capsicum annuum L.) cytoplasmic male sterile (CMS) lines, their maintainers and two control cultivars. The results showed that the three CMS lines were highly similar in chloroplastic and mitochondrial fragment sequences, with average similarities of 96.81 and 98.73 %, respectively, and their chloroplastic trnH- psbA intergenic spacer, photosystem II 47 kDa protein ( psbB) genes, mitochondrial apocytochrome b ( cob) and RNAD fragments have 1, 9, 8 and 7 distinct sites from the maintainer lines, respectively, and could be used as informative sites to distinguish CMS lines from the maintainer lines. Meanwhile, the expressions of mitochondrial cob, RNAD and pvs in the reproductive organs (flowers) of CMS lines are different from those of the maintainer lines, but their expressions in the vegetative organs (roots and leaves) are similar. The results indicate that cytoplasmic DNA polymorphisms are rare in CMS lines, and mitochondrial cob, RNAD and pvs genes are closely related to pollen abortion. [ABSTRACT FROM AUTHOR]

To illustrate the effects of domestication on wild pepper, we compared the seed micromorphology and germination characteristics of two wild pepper strains and their corresponding cultivars. The results showed that compared to their corresponding cultivars, wild pepper seeds are significantly smaller, have more groove and ridges on the surface, higher water imbibition rate, higher germination rate and higher α-amylase activity, and digest starch granules faster. The results indicate that the smaller wild seeds are easier to spread; more grooves and ridges on the surface and higher hilum ratio benefit their water imbibition, and rapid decomposition of starch granules and higher α-amylase activity are in favor to germination. By contrast, increased seed size will lead to a reduced germination rate and decreased adaptive ability to water environmental change. Thus, seed size is the result of natural and artificial selection, and whether larger seeds of various pepper cultivars are meaningful in evolution is debatable. [ABSTRACT FROM AUTHOR]