IMPACT OF GEOGRAPHICAL DISTRIBUTION ON GENETIC VARIATION OF TWO DATE PALM CULTIVARS IN ARID REGIONS

This study was conducted to assess the genetic variation responses of two date palm (P h oen ix d a ctylifera. L.) cultivars (Barhee and Khalas) in relation to their geographical distribution in three regions of Saudi Arabia, namely (Alahsa, Qassim, and Al-Kharj). A set of this method as the conserved DNA-derived polymorphism (CDDP and SCoT) start codon targeted primers have been used to distinguish the variation between the two previous cultivars. The average diversity (h) was 0.22 for CDDP marker with an average of polymorphism 46%, and 0.26 for SCoT marker with an average of polymorphism 55%. The similarity matrices based on Jaccard Coefficient among populations have scored positive values that ranged from 0.08 to 0.61 for SCoT marker, from 0.04 to 0.52 for CDDP marker, and from 0.07 to 0.53 for both markers. The major value of CDDP similarity has been scored 0.52 between (Khalas Al-Kharj; KK) and (Khalas Qassim; KQ), and between (Barhee Al-Kharj; BK) and KQ; followed by 0.49 between KK and (Khalas Alahsa; KH). While the major values for SCoT have been recorded as 0.61 similarities between (Barhee Alahsa; BH) and (Barhee Qassim; BQ); followed by 0.55 similarity between KQ and BH, and between KK and KH. The investigation derived by UPGMA cluster analysis revealed that BQ and BH are very close cultivars. The results revealed that the polymorphisms of both markers (CDDP and SCoT) are reliable tools to identify the dis-/similarities and phylogenetic relationships of the germplasm populations.