Estimation of genetic variability, GCA and SCA effects for development of early and high yielding bell pepper hybrids suitable for protected cultivation

The present investigation involves 29 diverse bell pepper genotypes for variability studies and 14 promising lines (11 lines and 3 testers), 33 F1 and 1 standard check for combining ability studies. The objective of the study was to assess the nature and magnitude of genetic variability among the bell pepper genotypes for yield and other horticultural traits and to identify the potential parental lines and cross combinations suitable for the protected environment based on the estimation of general combining ability and specific combining ability. A wide range of variability was observed for most of the characters studied. The genotypes viz., Kashmir Sel-1 (L2), DARL-10 (L9) and UHFSP(Y)-11 (L11) for marketable fruit yield per plant and Kashmir Sel-1 (L2), UHFSP(Y)-11 (L11) and DARL-01 (L5) for earliness were good general combiners and these may be included for exploiting hybrid vigour or development of purelines. On the basis of specific combining ability effects and per se performance, the crosses viz., ARCH-19 (L1) × Solan Bharpur (T1), DARL-10 (L9) × California Wonder (T2) and UHFSP(Y)-11 (L11) × Yolo Wonder (T3) were the best cross combinations for marketable fruit yield per plant and number of marketable fruits per plant under protected environment. The cross combinations viz., DARL-10 (L9) × California Wonder (T2), DARL-01 (L5) × California Wonder (T2), LC (L10) × Solan Bharpur (T1) and Kandaghat Sel-9 (L7) × Solan Bharpur (T1) shows significant negative SCA for earliness and could be used for development of early hybrids

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Not AvailableInappropriate and disproportionate use of antibiotics is contributing immensely to the development of antibiotic resistance in bacterial species associated with food contamination. The use of natural products in combination can be a potent alternative hurdle strategy to inactivate foodborne pathogens. Here, we explored the pro-oxidant properties of essential oil linalool and vitamin C in combination with copper (LVC) in combating the foodborne pathogens Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi using a three-dimensional (3D) checkerboard microdilution assay. Antibacterial activity in terms of the MIC revealed that the triple combination exerted a synergistic effect compared to the effects of the individual constituents. The bactericidal effect of the triple combination was confirmed by a live/dead staining assay. Reactive oxygen species (ROS) measurements with the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling assay and scanning electron microscopy imaging strongly suggested that the increase in ROS production is the underlying mechanism of the enhanced antibacterial potency of the LVC combination (linalool [1.298 mM], vitamin C [8 mM], copper [16.3 μM]). In addition, the hypersensitivity of oxidative stress regulator mutants (oxyR, katG, ahpC, and sodA mutants) toward LVC corroborated the involvement of ROS in cell death. Live/dead staining and changes in cellular morphology revealed that oxidative stress did not transform the cells into the viable but nonculturable (VBNC) state; rather, killing was associated with intracellular and extracellular oxidative burst. Furthermore, the LVC combination did not display toxicity to human cells, while it effectively reduced the pathogen levels in acidic fruit juices by 3 to 4 log CFU/ml without adversely altering the organoleptic properties. This study opens a new outlook for combinatorial antimicrobial therapy.IMPORTANCE There is a need to develop effective antibacterial therapies for mitigating bacterial pathogens in food systems. We used a 3D checkerboard assay to ascertain a safe synergistic combination of food-grade components: vitamin C, copper, and the essential oil linalool. Individually, these constituents have to be added in large amounts to exert their antibacterial effect, which leads to unwanted organoleptic properties. The triple combination could exceptionally inhibit foodborne Gram-negative pathogens like Vibrio fluvialis and Salmonella enterica subsp. enterica serovar Typhi at low concentrations (linalool, 1.298 mM; vitamin C, 8 mM; copper, 16.3 μM) and displayed potent microbial inhibition in acidic beverages. We found increased susceptibility in deletion mutants of oxidative stress regulators (oxyR, katG, ahpC, and sodA mutants) due to ROS generation by Fenton's chemistry. The results of this study show that it may be possible to use plant-based antimicrobials in synergistic combinations to control microbial contaminants.Not Availabl