Assessment of biodiversity among Palestinian landraces of Cucumis melo L. groups based on morphological descriptors and molecular markers (RAPD and ISSR)

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Omar B. Y. Mallah
Background: Economically; melons (snake cucumber and cantaloupes) are important crops cultivated in Palestine. Traditional melons are rain-fed crops. Although melons are differ in morphological traits such as shape, fruit color, taste, and flavor, low genetic variations between these crops is present.
Objectives: The aims of this study are to study the genetic variations between and within melon groups in Palestine using genetic markers (RAPD & ISSR), and to determine the relationships between molecular and morphological characterization, also to evaluate the efficiency of RAPD and ISSR genetic markers in discriminating between and within landraces of melon groups.
Methods: Biodiversity among 44 Palestinian landraces of melon was studied using RAPD and ISSR genetic primers, and morphological descriptors. Similarity matrixes and dendrograms were generated using SPSS (version 16) software. Resolving Power (Rp) was calculated for each primer.
Results: Morphological descriptors separated melons into two ‘groups’, Fakus (flexuosus) with two phenotypic subgroups (white and green), and cantalupensis.
From 14 RAPD primers used 132 bands were amplified, 75 bands were polymorphic (57%) and 57 were monomorphic (43%). Cluster analysis by RAPD results divided Palestinian melons into two clusters: Cluster I (contain all flexuosus accessions) and cluster II (contain all cantalupensis accessions). The highest similarity between flexuosus and cantalupensis accessions by RAPD primers was 0.86.
Nine ISSR primers produced 71 bands; all bands were monomorphic, so that there are no genetic variations revealed between melon accessions by ISSR primers. This indicated the highly genetic similarity between these groups.
Conclusions: RAPD primers proved efficient in discriminating between Palestinian melon groups, and gave an indications or marks about genetic variations within Flexuosus accessions. No genetic variations between Palestinian melon groups were observed when ISSR primers were used.
Results strongly indicated the importance of study the origin and diversity of Palestinian landraces of melons.

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