الفهرس 
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Abstract
Almond is a commercially important plant, little is known about the variation among its genotypes and consequently the traditional methods for genotypes identification is lacking. This investigation was mainly performed to study the physicochemical characteristics, biochemical composition and molecular structure of top quality eighteen commercial almond genotypes in Libya. These genotypes are Bezotta (1), Amazitto (2), Grabillo (3), Avola (4), Castilla (5), Santuoro (6), Mondorilla Bianca (7), Mondorilla ladolcsi (8), Rachil (9), Fragillia (10), Montiron (11), Fragillia de bagilia (12), Isabella (13), Branchibatta (14), Ansperabilla (15), Faccinado (16), City Bianca (17) and Romana (18). The eighteen genotypes were compared firstly according to the morphological characters of the fruits. Secondly, the content of total oil, Linoleic acid and proteins were measured to discriminate between these almonds genotypes under investigation on the biochemical level. Thirdly, two PCR based marker systems (SRAP and ISSR) were applied to determine the biodiversity among these almond genotypes at the molecular level.
The results indicated that the eighteen genotypes showed variations in there fruit morphology and biochemical composition. The fruit length, the fruit diameter, the fruit fresh and weights, number of fruits/tree and total yield / year were varied among these genotypes. On the biochemical level, the eighteen almond genotypes exhibited significant differences in their total oil, linoleic acid and protein contents.
On the molecular level, DNA variations were detected using twenty combinations of SRAP markers and nine ISSR molecular protocols. All markers used generated polymorphic bands among the different genotypes which can be used as molecular markers for their variation. The genetic distance between genotypes was also estimated from banding patterns. SRAP generated 98 bands using twenty SRAP primer pairs. Out of the generated bands there were 22 common bands while 14 bands were unique and can be used as molecular markers for the cultivars used in this study. Eight bands out of these markers considered as positive markers and six bands out of the aforementioned markers considered as negative markers.
One hundred and eleven bands were generated using 9 ISSR primers with the eighteen almond genotypes. Out of the generated bands, there were 3 common bands and 19 unique bands that could be used as marker to distinguish between almond genotypes under investigation. fourteen bands out of these markers considered as positive markers and five bands out of the aforementioned markers considered as negative markers.
Similarity indexes were calculated for the eighteen almond genotypes at the molecular level. The results showed varied similarity values between each genotype pairs indicating a different distances in their genetic relationships.
The results represented a kindly little shuffling in the arrangement in the cultivar relations according to the two used molecular techniques (SRAP and ISSR), as in SRAP, the two most closely related cultivars were Ansperabilla and Faccinado with similarity value of 0.819, while it was 0.683 between genotypes Ansperabilla and Faccinado as revealed from ISSR data. On the other hand, the two most distantly related cultivars, according to SRAP data, were Avola and Castilla, with similarity value of 0.423, while it was 0.184 between genotypes City Bianca and Castilla, according to ISSR data. Dendrogram was conducted for the eighteen genotypes under investigation using the two used molecular techniques. The results also revealed a different distances in their genetic relationships