Abstract
An investigation was carried out to study the morphological and molecular characterization of mango germplasm at the Fruit Tree Improvement Programme, Germplasm Centre, Bangladesh Agricultural University, Mymensingh. The experiments were conducted during the period of 2011-2014. Twenty nine mango germplasm were considered in this study. A wide range of variations among the germplasm in respect of different characters were observed. The highest tree volume and leaf area were recorded in BAU Aam-8 and the lowest tree volume and leaf area were observed in Accession-0031 and BAU Aam-9, respectively. The earliest flowering occurred in BAU Aam-4 and the latest flowering occurred in BAU Aam-17. The number and percent bisexual flowers per panicle were the highest in BAU Aam-14 and the lowest in Accession-0022. The highest yield per plant (21.70 kg) was recorded in BAU Aam-21 and the lowest was found in Accession-0030. The heaviest fruit was recorded in Accession-0030 (587.50 g) and the lightest fruit was obtained from BAU Aam-2 (160.00 g). Percent edible portion was the highest in Accession-0029 and the lowest in BAU Aam-9. On the basis of organoleptic evaluation, BAU Aam-14 seemed to be the best germplasm followed by BAU Aam-7, BAU Aam-16 and BAU Aam-18. B-Carotene was the highest in BAU Aam-8 and the lowest in Accession-0029. The highest TSS was recorded in Accession-0029 followed by BAU Aam-11, BAU Aam-14 and the lowest in BAU Aam-3. The morphological study revealed that the germplasm BAU Aam-14 was the best in respect to fruit quality, yield and regular bearing habit. Genetic diversity was assessed by 11 morphological characters. In all the traits, genotypic coefficient of variation (GCV) was always smaller than phenotypic coefficient of variation (PCV). Based on D2 analysis, the 29 mango germplasm were grouped into five clusters. The highest inter cluster distance was between cluster III and IV and the lowest was between cluster II and V. Considering univariate and multivariate study, six germplasm viz., BAU Aam-1, BAU Aam-7, BAU Aam-8, BAU Aam- 14, BAU Aam-18 and BAU Aam-21 will be selected for breeding programme. RAPD) analysis of 29 mango germplasm was done to estimate genetic diversity at DNA level. Eighty six clear and repeatable bands were scored from nine selected RAPD primers. Out of the 86 bands, 62 (72.09%) bands were polymorphic and 24 (27.90%) bands were monomorphic. The highest genetic distance (0.604) was found between BAU Aam-9 and Accession-0029 and the lowest genetic distance (0.036) was observed between Accession-0025 and Accession-0027. Average gene diversity (h) and Shamon's Information Index (I) for nine primers across different germplasm were 0.261 and 0.389, respectively. The UPGMA dendrogram based on Nei's (1972) genetic distances, 29 mango germplasm were grouped into 16 clusters. Twenty nine mango germplasm were used for this study to estimate genetic diversity using three microsatellites (SSR) markers. Three primers viz., MNSSR14, SSR16 and SSR19 showed polymorphism. A total of 21 alleles were detected among the 29 mango germplasm with an average of 7.0 alleles per locus. Polymorphism Information Content (PIC) ranged from 0.688 to 0.787 with an average of 0.727. According to Nei's (1973) the average gene diversity for all microsatellite loci in 29 mango germplasm is 0.763. A dendogram based on total microsatellite polymorphism, 29 germplasm were grouped into five major clusters were formed at genetic similarity level of 0.00-0.44. The information about the genetic diversity will be very useful for proper identification and selection of appropriate parents for future breeding programme.