Application Of Molecular Techniques For The Improvement Of Mango Production

Mango (Mangifera indica L.; Anacardiaceae), is one of the most economically important fruits grown especially in Asia, commonly known as the’King of fruits’. It is an important fruit tree crop grown commercially in tropical and subtropical region around the world. It is a highly cross-pollinated plant and most cultivars have arisen from selection of desirable types among naturally produced seedlings or seedlings selection from known mother trees presently, conventional breeding considered is one of the best approaches for new variety development. Mangos have some problems being handle in conventional breeding programs and these delay success in mango improvement. Prior to conventional breeding it is important to know the genetic relationships among the cultivars that may increase success rate in hybridization. In this study, we were examined23mango cultivars to know the genetic diversity and relationships collected from north-western part of Bangladesh and nine from Guangxi province, South China, against14inter simple sequence repeats (ISSRs) and18SrRNA primers. We also employed a simple and efficient RAA method for DNA amplification. Performing any kind of molecular research, high quality genomic DNA is the first step. Poor quality genomic DNA hinders the successful application of analytical DNA-based tools. Standard protocols for DNA extraction are not suitable for mature leaves of mango since jthe extracted genomic DNA often contains secondary metabolites that interfere with analytical applications. In this study, we employed an additional step to remove polysaccharides, polyphenols and secondary metabolites from genomic DNA extracted from young or mature leaf tissue then applied a modified traditional cetyl trimethyl ammonium bromide (CTAB) method. The use of0.4M glucose improved DNA quality, avoiding contamination and browning by polyphenolics, relative to the traditional CTAB method. This modified protocol was also used to extract high quality genomic DNA from other woody perennials such as walnut, guava, lychee, pear, grape and sugarcane. Out of14ISSR primers screened, six primers gave reproducible, polymorphic DNA amplification pattenrs, and were selected to construct a DNA fingerprinting table to distinguish the genotypes of mango. Using six ISSR primers51bands were generated, of which48(94.11%) were polymorphic. Among PCR-based techniques, ISSR has already been proven as novel technique for genetic diversity analysis.Molecular markers provide an attractive, efficient and more reliable alternative to morphological markers. In our present study, considering the banding patterns, all cultivars tested were distinguished from each other and showed ample diversity, indicating that ISSR-PCR was an effective method for identifying the mango varieties. ISSRs have been applied in many countries for identification, genetic diversity) analysis and relationships among mango varieties in Thailand, Australia, China and India. Based on UPGMA (unweighted pair group with arithmetic means) analysis23mango cultivars or varieties were clustered into four groups. We also used18SrRNA gene sequence to know the genetic relationship and diversity among these varieties. Nucleic acid amplification is essential to most nucleic acid testing strategies. The current techniques require sophisticated equipment or complex experimental procedures. Their uptake has been limited to the outside laboratories. A continuous electricity supply is expensive and comparatively difficult to some regions. In our study, we used a novel approach, recombinase-aid amplification (RAA) technology for target DNA amplification. It is a new developed method for the rapid amplification of DNA. Therefore, it is necessary to know the factors which influence its successful amplification. Many factors might be influence its amplification and primer length is one of them. We employed18pairs primer among which four primers constitute with difference base pairs and applied on different important crops e.g. Mango (Mangifera indica L.), Walnut (Juglans regia L.), Pear(Pyrus communis L), Grape (Vitis vinifera), Guava (Psidium guajava), Lychee (Litchi chinensis) and Sugarcane (Saccharum officinarum L.), and have found that its amplified successfully within the range18to28base pairs primer length. The18S rRNA gene sequences of each mango variety was identified on the basis of18S rRNA gene sequence of a Guti cultivar and has been deposited in GenBank database of NCBI under the accessions ranged from KC793984to KC794006. These results obtained from this study and database information might be helpful for further molecular research on mango.