Pollen Germination and Morphologic Chracteristics of Some Male Date Palm Genotypes (Phoenix dactylifera L.) in Khuzestan Province

This study was conducted to investigate pollen germination and morphological chracteristics of 21 male date palms in Khuzestan province in a completely randomized block design with three replications. The percentage of viability of pollen grains was determined by acetocarmine staining test and the percentage of germination was determined using the modified Brewbaker and Kwack (MBK) culture medium. The morphological characteristics of pollen grains, including polar axis (P), equatorial axis (E), P/E ratio and the pattern of exine arrangement were also investigated using scanning electron microscope (SEM). The average viability percentage and pollen germination percentage of the genotypes were between 70.33 to 99% and 11.33 to 96.33 %, respectively. In addition, the results of mean comparison showed that the studied genotypes demonstrate more variation in the germination percentage compared to the viability percentage. The results showed that pollen grains of different genotypes were significantly different in terms of dimensions (polar and equatorial axis), percentage of viability and germination. The study of SEM micrographs showed that the pollen grains in all genotypes were monad, prolate, monosulcate and had reticulate and irregular exine ornamentation. Based on the dendrogram, the studied genotypes were classified into four main clusters, and genotypes with the same name from different regions were not included in the same cluster. This issue indicatess the correctness of the hypothesis of this study that the genotypes with the same name are different and their traditional naming by growers is incorrect. These findings showed that the morphological parameters and pollen germination traits could be used to identify the pollen of different date palm genotypes and to study their relationships.