Abstract:

Pollen morphology of 47 kinds of pomelo and 5 other citrus were examined using scanning electron microscope（SEM）. The results of phenotypic character indicated that the pollen morphology had abundant diversity. There were large differences on pollen size and shape. The volume（Polar axis × Equator axis）of the largest pollen is around two times as large as the smallest one. The shape of most pollen is oval. To all other pollen，exine ornamentation were reticulate and mesh were roughly round，expect for the pollen of Daoxian Yeju which has no obvious mesh and mesh ridge. All other pollen had 4  bourgeon channels，only a few had 5 bourgeon channels. They annularly distributed in equal space，and extended nearly to two poles，expect for the pollen of Yamasaki Wase which were almost squashed. The pollen of material with high acidity was always long oval, such as sour pomelos，lime，and lemon. They had large mesh size，widen mesh ridge and the holes of germination embedded in bourgeon channels，and vice versa. Clustering analysis on the basis of pollen phenotypic character，52 materials could be divided into 5 groups when the genetic distance was 1.2. The significance of the study on pomelo classification and genetic diversity was discussed through pollen morphological characters.

Key words: pomelo, germplasm, pollen morphology, SEM, genetic diversity