Pollen morphology and variability among the wild Cannabis sativa L. from the western Himalaya, India

Abstract

The present study aimed to examine the intraspecific variation in pollen traits of genus Cannabis from Western Himalaya, India. A total of 1650 pollen grains from 55 accessions collected from an altitudinal range between 259 and 2751 m a.s.l from the western Himalayas, India were analyzed by (LM) light microscopy and (SEM) Scanning Electron Microscopy. Six quantitative characters, i.e., length of the polar axis (P), length of equatorial axis (E), exine thickness (Ex), number of granules (Ng), pore diameter (Pd), and P/E ratio were studied. Pollen grains of maximum accessions were tricolpate while pollen grains of three accessions i.e., CAN17, CAN25 and CAN31 were tetraporate. Majority of the pollen grains were prolate spheroidal (83.64%) whereas 1.82% was spheroidal. PCA indicated that the first four components account for 69.9% of the total variability. PC1 attribute 34.41% of the variability with equatorial diameter being the significant variable, whereas PC2 contributed 19.57% variability having length of polar axis (P) and shape class (P/E) as the significant variables. PC3 contributed 20.1% of the total variability with PE and number of granules being the significant variables. Pollen size, aperture number, and surface ornamentation may prove useful in species discrimination. This current study gives a first-hand report on the palynological variation of wild Cannabis populations of the Western Himalaya, India.