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Background The understanding on how well GuttaFlow Bioseal (GFB) conforms to the root canal irregularities is unclear and requires further investigation. Purpose This study compared the obturated surface area, the extrusion of root filling material and the duration of obturation procedure between GFB and monocone. Methodology The root canal of twenty single-rooted mandibular premolars were prepared using Hyflex CM rotary files (Coltene/Whaledent). The samples were equally divided into two groups; GFB and monocone. The duration of obturation procedure was evaluated using a digital timer and a radiograph was taken to assess the presence of extrusion. The roots were sectioned perpendicularly to obtain 3 root segments; apical 1/3, middle 1/3 and coronal 1/3. All resected roots were mounted on brass stubs, sputter-coated with thin gold coating and observed under scanning electron microscope (Zeiss EVO50, Germany) at 20x magnification. The images were transferred to the SketchAndCalc Area Calculator software for evaluation of obturated surface area. The data was analysed with SPSS version 25.0. Results The median score of obturated surface area between GFB and monocone at the apical 1/3 was 86.51 and 83.00, at the middle 1/3 was 90.48 and 87.35 and at the coronal 1/3 was 93.00 and 83.39 respectively with statistically significant difference at the coronal 1/3. The extrusion of root filling material between GFB and monocone did not show statistically significant difference. The mean score of duration of obturation procedure between GFB and monocone was 149.50 and 137.60 respectively with statistically significant difference. Conclusion The obturated surface area at the apical 1/3 and middle 1/3 between GFB and monocone was comparable but at the coronal 1/3 the former showed 11.5% better. The extrusion of root filling material between GFB and monocone was equivalent. The obturation procedure with GuttaFlow Bioseal required 8.6% longer than the monocone obturation technique.

Plant virus infection significantly reduces the yield of many horticultural crops causing reduction in the production and productivity. Higher fertilizer application has often to overcome the yield reduction due to virus in many crops. A field experiment was conducted to find out the effect of increased doses of fertilizers on the banana bract mosaic virus (BBrMV) infected plants of French plantain cv. Nendran. The plant height, girth, number of leaves, number of fingers and the bunch weight had significantly increased with increased dose of fertilizer in the first and second crops with BBrMV infection. In the first crop, with the application of 125 and 150% of recommended dose of fertilizers (RDF), the BBrMV infected plants could produce bunches which were on par with that of healthy plants, receiving 100% RDF, but with prolonged days of flowering. In the second crop, though 125 and 150% RDF doses in the infected plants increased the bunch weight over 100% RDF by 14.60% and 18.33%, respectively, could not be able to compensate the yield loss due to virus infection. This may probably be due to the accumulation of virus over the period of two years. This is the first report on strategies for mitigating adverse effects of BBrMV in plantain.

Sigatoka leaf spot (Mycosphaerella musicola Leach) disease is a limiting factor in banana production in India and other places. Breeding for resistance is the most effective method to control Musa diseases. However, Musa improvement using conventional methods has been hampered due to lack of genetic variability, resulting to biotechnological approaches. In this regard, marker-assisted selection has become a reliable method to improve disease resistance in Musa. The objective of this study was to identify markers that may be linked to Sigatoka leaf spot disease in Musa, using RAPDs and converting such into sequence characterized amplified region (SCAR). Consequently, a total of 102 oligonucleotide OPERON primer pairs were used to screen genomic DNA from two resistant cultivars: Calcutta 4 (Musa acuminate, AA) and Manoranjitham (AAA), and two susceptible cultivars Anaikomban (AA) and Grande Naine (AAA) with only 11 (10.8%) of the primers being polymorphic. Eventually, OPK 01 and OPK 11 primers in Calcutta 4 were eluted, but only OPK 11 was sequenced and cloned using pGEM-2T vector, resulting to a band size of 4.3 KB, and the development of two SCAR markers. A FASTA search in the Musa genome database could not identify corresponding gene sequences that show homology with the sequenced PCR fragment. Finally, the SCAR marker was used to amplify genomic DNA from the segregating population which could not discriminate between resistant and susceptible samples. This may be due to amplification conditions, limited number of primers and most importantly, the absence of tight linkage with the gene of interest. In conclusion, it may be necessary to screen the segregating population with more reliable and reproducible amplified fragment length polymorphism.Key words: Marker-assisted selection, disease resistance, Musa, random amplification of polymorphic DNA (RAPD), genetic improvement, SCAR.