|
This research was carried out at As-Sweida Agricultural Scientific Research Center and farmer's fields during the years 2019-2020 on thirteen genotypes of hazelnut grown in the As- Sweida Governorate ( GT1, GT2, GT3, GT4, GT5, GT6, GT7, GT8, GT9, GT10, GT11, GT12, GT13), and twelve wild genotypes of hazelnut which are naturally distributed in the sites of Hadiya and Bteisa al-Jurd in Homs Governorate (WG1, WG2, WG3, WG4, WG5, WG6, WG7, WG8, WG9، WG10, WG11, WG12), to study their morphological characterization and to evaluate their behavior, and to determine the degree of genetic relationship among them using Inter- Simple Sequence Repeat (ISSR) technique. The results of morphological characterization showed that there were morphological differences between the cultivated hazelnut genotypes, where Cluster analysis divided the studied population into 5 major clusters. The first cluster included the genotype GT6, and the second cluster included the genotypes (GT5, GT12, GT13), while the genotype GT7 signed in the fifth cluster, and the fourth cluster included the genotypes GT8 and GT9, whereas the third cluster included the rest of genotypes. As for the Principal Component (PC) analysis gave 4 major components with a variation of 84.44%, and as a result, both cluster analysis and Principal Component analysis had a positive role in distinguishing between studied genotypes. The optimal requirements of chilling hours were determined. the studied genotypes were varied in their response to various applied chilling levels, where the GT3, GT9, GT10, GT11 genotypes responded positively towards high chilling levels, Whereas the response of the rest of the genotypes was greater to the various levels of applied chilling hours. it was found that the genotypes GT5, GT6, GT7, GT12 were environmental flexibility where the need of these genotypes ranged between 300- 1200 chilling hours, while the need for the genotype GT11 was 1200 chilling hours which contributes to the expansion of the cultivation of this tree in the appropriate environmental areas. The study of pollen grains viability and fertility in the studied genotypes showed that the shape of pollen grains was relatively dissimilar which had obvious effect on viability and fruit set rate, where the obscure shape (polygonal) was distinguished by its high viability compared to the spherical and circular shapes. The majority of the studied genotypes showed low rates of self- compatibility except for GT10 genotype that revealed the highest value (22%). The results also showed a high percentage of fruit set resulting from cross- pollination compared to self- pollination, and the highest value reached to 46,37% in GT10 genotype. On the other hand, our results proved the efficiency of ISSR markers for distinguishing the genetic variation among the studied genotypes, and revealed the high efficiency of some primer pairs as (P4W, P6A, P10A) to produce the largest number of Polymorphic bands (9 bands each) with 100% polymorphism, and the highest degree of genetic similarity was between the WG11 genotype and WG9 , WG12 genotypes (0.969- 0.962) respectively.
|
