Evaluation of eggplant genotypes for resistance to phomopsis blight: Plant materials and experimentation: Seeds of 10 eggplant cultivars, ISD-006, Laffa S, Dohazari G, Jessore L, Singhnath, Marich begun S, Marich begun L, BAU Begun-1, Ishurdi L, and Chega, were obtained from the IPM Lab, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, Bangladesh. The experiment was conducted in the field laboratory of the Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh. The experiment was laid out in a randomized complete block design with 3 replications. The unit plot size was 4.0 x 2.5 m, maintaining a row to row distance 60 cm and plant-to-pant distance of 50 cm. Fertilizers were applied at recommended doses. Irrigation and intercultural operations were conducted when necessary. Inoculation of eggplant with Phomopsis vexans: A virulent isolate of Phomopsis vexans was used for inoculation. The cultures were collected from the IPM lab and multiplied in potato dextrose agar medium. In each plot, inoculation of 5 plants was conducted during the pre-flowering stage and 5 plants during the fruiting stage. A 70 mL spore suspension (5 x 106 spores/mL) was sprayed onto each plant. Spraying was done at afternoon, and inoculated plants were covered with a moist transparent polythene bag for 48 h to ensure better infection. Assessment of Phomopsis blight and fruit rot:After inoculation, symptoms on leaves, flowers, and fruits were observed at 7-day intervals for up to 21 days. Data regarding leaf infection (%), percent leaf area diseased (LAD), flower infection (%), fruit infection (%), and percent fruit area diseased (FAD) were recorded. Disease severity was recorded according to the standard rating scale (1-5). The percent disease index (PDI) was calculated according to the formula described. Harvesting and data recording: Characteristics affecting eggplant yield were examined and data were recorded for all plants. Plant height, number of primary branches per plant, number of secondary branches per plant, number of fruits per plant, fruit length, fruit breadth, and individual fruit weight were recorded in the field. Mature fruits were harvested at the edible stage at an interval of 7 days. Five fruits per variety were allowed to ripen and the seeds were collected to grow plants in the following year. Data analysis: Data were analyzed to determine statistical significance. Analysis of variance followed by Duncan’s multiple range test (DMRT) to test the differences between the genotypes using the computer based software MSTATC. Molecular characterization of eggplant cultivars using RAPD markers:Genomic DNA extraction and quantification; The seeds of 10 selected eggplant cultivars were used for the RAPD analysis. To obtain genomic DNA, the youngest healthy leaf samples collected from 15-day-old seedlings were used. A modified cetrimonium bromide mini-prep method was followed to extract DNA from leaf samples. The concentrations of DNA in the samples were determined using a UV spectrophotometer at 260 nm. DNA quality was verified by electrophoreses on a 0.8% agarose gel in Tris-boric acid-EDTA buffer.PCR amplification and electrophoresis: RAPD amplification reactions were conducted following the procedure described with some modifications. Screening was conducted with 14 arbitrary decamer primers (Bangalore Genei, India). Three primers (OPA17, OPB07, OPE8) showing scorable and good reproducible bands were selected for subsequent RAPD analysis of eggplant germplasms. PCR reactions were performed on each DNA sample in a 10-μL reaction mixture containing 1X PCR buffer (10 mM Tris HCl pH 8.5, 50 mM KCl, and 15 mM MgCl2), 10 mM of each dNTP, 5 pmol primer, 2 U Taq DNA polymerase (Bengalore Genei, India), 100 ng genomic DNA, and the remaining volume in sterile deionized water. DNA amplification was carried out in a DNA thermocycler (Biometra, Röttingen, Germany) with the following thermal profile: initial denaturation for 3 min at 94°C followed by 41 cycles of 1 min denaturation at 94°C, 1 min annealing at 35°C, and extension at 72°C for 2 min. A final extension step at 72°C for 7 min was conducted for complete extension of all amplified fragments. The PCR products were stored at 4°C until electrophoresis. Reaction mixtures were mixed with 2.0 μL 6X loading dye. Amplified fragments were separated on a 1.5% agarose gel (Bangalore Genei, India) in 0.5X Tris-boric acid-EDTA buffer along with 20 bp DNA weight marker (Bengalore Genei, Bangalore, India) for 2 h at 100 V. The gel was stained with 0.1 μg/mL ethidium bromide solution for 15 min. Fragments were visualized under a UV transilluminator and photographed using the Gel Documentation System. Scoring and data analysis: Each band was considered to represent a phenotype at a single locus because all RAPD markers were dominant. The amplified bands were visually scored as present (1) and absent (0) for each individual and each primer. The scores obtained were pooled to create a single data matrix. This was used to estimate polymorphic loci, Nei’s genetic distance, genetic diversity, genetic distance (D), and the unweighted pair group method with arithmetic mean dendrogram using the computer program, POPGENE . The same program was used to test for homogeneity in different loci between population pairs.