Molecular Assessment of Established Clonal Propagated Mulberry (Morus nigra L.)
Authors: A. Ismail Ismail , S. Dessoky El Dessoky , O. Attia Attia , M. Saleh Osama 
Published: June 2022

Mulberry (Morus Sp.) is one of the economically important trees cultivated for the tasteful fruits, its several pharmaceutically important chemicals potential, timber, cosmetic and in silk industry for its foliage, also in various molecular breeding applications. The origins of most cultivated mulberry varieties are believed to be in the area of China-Japan and in the Himalaya foothills. and it now has a very wide distribution range in Asia-Europe (from Korea to Spain, including China, India, Central Asia, and Near East); in Africa (North and East Africa) and in America (from the U.S.A. to Argentina, including Mexico, Central America, Colombia and Brazil). In Saudi Arabia, Mulberry grown well and spread in different places such as Taif Province (El Shafa region), Eastern region; Al-Ehsaa Province and some southern areas. Nodal explants of Morus nigra were clonally propagated in vitro for plant regeneration. Auxiliary shoot buds have been promoted in Murashige and Scoog (MS) media in a variety of cultural contexts. The largest number of shoots (13.00 ± 0.47) with an average length of 2.00 ± 0.47 cm was initially obtained from a medium containing 2.0 mg / L N6-benzyladin (BA) and 3% sucrose. Recurrent subcultures provided the highest number of seedlings (approximately 29.30) for excavation after the fourth passage. Seedlings were rooted in 1/2 MS medium supplemented with 1.0 mg / 1 indole-3-butyric acid (IBA). Successfully, about 90% of the plantlets acclimatized. Along with the determination of the genetic variations between three mulberry genotypes including two cultivated accessions (Morus alba) and one wild genotype (M. nigra) utilizing inter-simple sequence repeat (ISSR) markers. Genetic variation and phylogenetic relationship of mulberry germplasm collection have been studied. All ISSR markers used in this study revealed higher genetic diversity in the wild species comparing with cultivated species. ISSR matrices reported that the mean genetic similarity coefficient was 0.7677 for all mulberry genotypes. Although some differences have been observed, much similarity has been obtained in dendrogram topology. Cluster analysis of the ISSR using UPGMA software revealed that wild species were genetically distinct. The correlation coefficients of similarity for the ISSR used are statistically important. The Principal Coordinate Analysis (PCA) for ISSR data also supports its UPGMA clustering. The average number of genetic variations recorded in mulberry genotypes was 0.287±0.096. Dendrogram (Unweighted peer group method analysis) classifies mulberry accessions into two main groups; Admissions collected from the western area of Taif, and the other comprised two sub-clusters including one isolate, i.e., M nigra, a collection from Al shafa. Contains access to another sub-cluster southwest regions of Taif, which belong to Morus nigra wild growing. These accessions of mulberry were found to be genetically similar to north and southwest Taif Province. These results have significant implications for improving the mulberry germ plasma characterization, conservation and investigates of the genetic diversity among the mulberry species grown in Taif governorate and to establish a micro-propagation system as germplasm conservation to preserve the assets of local mulberry and thus develops an easy and effective method to identify native genotypes in a limited space and time frame.