Introduction

Studies on the pollen morphology of 44 varieties of coconut (Cocos nucufera Linn.) have been made representing the coastal areas of the southern seas, ranging from South America in the west to Australia and the South Asian countries in the east. The polleniferous materials have been collected from the Central Plantation Crops Research Institute, Kasargode, Kerala and pollen preparations were made by acetolysis method. Data on pollen morphology have been generated through LM and SEM studies. Pollen characterizations have been presented for each variety according to the standard methods in the order of importance of pollen characters in comparative morphology, taxonomy and evolution.

A typical grain is monocolpate, with other unique features namely a polar cap for;hed by agglutination/aggregation of granules at the proximal end and striate ornamentation pattern radiating from the polar to the distal face of the grain. The variations in the apertural and exine ornamentation features provided the base, for cultivar differentiation, associated with which are the tertiary characters like pollen size and shape.

A mixture of monocolpate - elipsoidal grains and of spheroidal - megaporate grains were found in all varieties in varying percentages of each type. The pollen architecture has been found to be associated with the geographical distribution of the varieties, suggesting the impact of ecology on genetic variations as reflected in pollen morphology.