Water deficit is a major constraint on pepper (Capsicum annuum) yield, yet the genetic architecture of reproductive-stage drought tolerance remains poorly resolved. We phenotyped a Balkan C. annuum diversity panel (n = 133) and an interspecific backcross inbred line (BIL) population (n = 76) under well-watered (WW) and water-stress (WS) conditions. WS was applied from anthesis of the second truss as a stepwise reduction in irrigation volume relative to WW (30% for 7 days, then 60% thereafter), maintained for 90 days across the reproductive period. We assessed yield components, soluble solids, and stress-tolerance (STI) and stress-susceptibility (SSI) indices. Genome-wide association study (GWAS) identified 104 SNP-trait associations (P < 1×10-5), and QTL mapping detected 38 significant QTLs (1,000 permutations, α = 0.01), with the QTL intervals defined at LOD ≥ 8. Integrating GWAS and QTL mapping under WS revealed overlapping loci on chromosomes 5 and 6, harboring two consensus intergenic SNPs associated with yield components and soluble solids. Haplotype analysis linked chromosome 5 alleles to higher fruit number and soluble solids. At chromosome 6, the G allele at SNP 6_28348737 was enriched in tolerant lines for fruit number. These regions harbor candidate genes for reproductive development and stress response, including GREEN RIPE-LIKE1 (GRL1), CYP77A19, Endoglucanase-like, and FLOWERING PROMOTING FACTOR 1 (FPF1), possibly through cis-regulatory variation. Together, these results advance understanding of the genetic basis of pepper yield under drought and identify candidate breeding markers.
This study evaluates the effects of the biological products “Trichodermin” (Trichoderma viride, strain Trv1, titer 1×10⁸ c/mL), “Extrasol” (Bacillus subtilis, titer 1×10¹⁰ CFU/mL), and a bacterial formulation based on Enterobacter cloaceae (titer 1×10¹⁰ CFU/mL) on biometric parameters, productivity, early yield, and the immune response of greenhouse-grown pepper (Capsicum annuum, cv. “Piruet F1”) to white mold infection. The experiments were conducted from 2021 to 2023 at the Maritsa Vegetable Crops Research Institute, Plovdiv, in an unheated steel-glass greenhouse. Pepper plants were cultivated under a 90/60/40 cm spacing scheme. The biological products were applied via pre-sowing seed soaking for 4 hours in undiluted mother solutions, followed by two soil treatments (10 mL/10 L water per 20 m²) — after transplanting and during mass flowering. The results demonstrated the positive effects of Bacillus subtilis, Enterobacter cloaceae, and Trichoderma viride on plant biometric parameters, disease resistance, and yield. Treated plants showed an increase in plant mass by 14%–23%, root mass by 21%–32%, and leaf mass by 24%–36%. Total yield increased by 23%–28%, while early yield improved by 12.5% with “Extrasol”, 19% with Enterobacter cloaceae, and 24% with “Trichodermin”. Artificial infection with Sclerotinia sclerotiorum using the decapitation method confirmed that the biological products enhanced the immune response in pepper plants. The reduction in necrosis caused by white mold was 56% with “Trichodermin”, 44.8% with “Extrasol”, and 35.5% with Enterobacter cloaceae. Keywords: antagonists, Capsicum annuum, growth stimulation, non-specific induced resistance, productivity, Sclerotinia sclerotiorum
The review summarizes practical experiences in using mutation breeding for crop improvement in South-Eastern Europe (SEE) and Central Asia (CA), demonstrating that mutation breeding can be a field-validated, effective approach for developing climate-resilient crops. Drawing on coordinated research conducted within national breeding programs and international initiatives supported by FAO/IAEA, applied methodologies, trait-evaluation strategies, and concrete breeding outputs in cereals, legumes, and industrial crops are presented. The use of gamma irradiation, fast neutrons, and chemical mutagens has successfully generated stable mutant lines stable mutant lines with enhanced traits, such as increased thousand-grain weight in wheat, altered oil quality in sunflower, and improved drought tolerance in common bean and sesame. The integration of classical pedigree selection with modern breeding tools such as high-throughput phenotyping, molecular and biochemical markers, and doubled-haploid technology has enabled earlier and more efficient identification of superior genotypes in mutation breeding programs. The review underscores the practical relevance of mutation breeding in contemporary pipelines to maintain yield stability and quality under adverse environmental conditions.
Abstract Laser-based irradiation has emerged as a promising approach for modulating seed germination and early plant development through controlled photobiological stimulation. The results indicate a non-linear dose-dependent response of radish seeds to UV irradiation, with a clear transition from inhibition at low and high doses to stimulation at intermediate exposure levels. These findings suggest that carefully controlled UV LED Treatment may serve as a potential tool for modulating seed germination and early plant development. However, the observed effects are cultivar-dependent, and further studies are required to clarify the underlying physiological and molecular mechanisms, as well as to evaluate subsequent stages of plant growth and development.
Tomato landraces represent an important source of genetic diversity for restoring fruit quality traits that may have been reduced during modern breeding. This study evaluated the potential of landrace-derived breeding lines as parental material for developing tomato hybrids with improved and balanced fruit quality. Thirteen breeding lines selected from local tomato populations and one male-sterile line were used to produce 19 F₁ hybrids, which were all evaluated together under open-field conditions over two consecutive growing seasons (2023 and 2024). Fruit quality was characterized through biochemical, physicochemical, colour, and textural traits, including dry matter, soluble solids, titratable acidity, vitamin C, total polyphenols, antioxidant capacity, firmness, and CIELab colour parameters. Integrated indices and multivariate analyses were used to assess complementary quality components and identify superior hybrid combinations. Significant genotype and genotype × year effects were detected for all evaluated traits, demonstrating substantial genetic variation together with season-dependent responses. Hybrids generally showed higher mean values than parental lines for several quality-related traits, although performance varied considerably among individual combinations. Hybrid 171 × 174 exhibited the most distinctive integrated profile, combining high dry matter (7.0%), soluble solids (5.7 °Brix), vitamin C (43.0 mg 100 g⁻¹ FW), total polyphenols (749 mg GAE 100 g⁻¹ DW), and fruit firmness (24.8 Shore degrees), and also showed the highest Antioxidant Capacity Index and Texture Score. Hybrids 347 × 352 and 343 × 6 also combined favourable compositional, antioxidant-related, and textural characteristics. Parental contribution analysis identified lines 171, 174, 6, 343, and 352 as frequent contributors to top-performing hybrid combinations across multiple quality traits. The current results demonstrate that complementary fruit-quality characteristics present in landrace-derived germplasm can be effectively combined through hybridization and highlight the value of integrated multi-trait evaluation for identifying promising parental lines and F₁ hybrids for quality-oriented tomato breeding.
