Breeding Strategies in Silkworm (Bombyx mori) for Environmental Adaptation: A Structured Narrative Review

Résumé

Climate variability increases the exposure of Bombyx mori to heat, humidity extremes, variable mulberry quality and pathogen pressure. The insect's long domestication history improved silk output but also narrowed genetic diversity and increased dependence on managed rearing. This structured narrative review evaluates conventional selection, hybrid breeding, marker-assisted selection, population genomics, transcriptomics and genome editing as strategies for environmental adaptation. English-language literature published from 2000 to 26 June 2026 was identified using combinations of major bibliographic databases and reference-list searches. Studies were assessed according to clarity of genetic material, stress definition, controls, replication, outcome measurement, statistical analysis and source traceability. Owing to substantial heterogeneity in strains, stress treatments and endpoints, the evidence was synthesised thematically rather than meta-analysed. Phenotypic selection and multi-environment hybrid testing remain the most deployment-ready approaches because they measure survival, productivity and silk quality simultaneously. Marker-assisted selection can accelerate introgression when loci are independently validated, whereas pan-genomic and genome-wide association resources expand the search for adaptive alleles and improve parent selection. Transcriptomics and functional studies identify heat-shock, antioxidant, immune and silk-gland pathways, but expression changes require causal validation. CRISPR-based studies have established efficient editing and produced promising antiviral and heat-resistant lines, although regulatory, pleiotropic and seed-system constraints limit immediate field deployment. The review concludes that climate-adaptive breeding should use a staged pipeline combining germplasm conservation, controlled stress screens, measured environmental covariates, cost-effective molecular support and multi-season, multi-location validation. In emerging African sericulture systems, investment in field phenotyping, parental-stock management and delivery of locally tested hybrids is as important as investment in advanced genomics.