Research advances and prospects in Hevea brasiliensis breeding: From genetic foundations to strategic innovation

Hevea brasiliensis is the sole commercial source of natural rubber, yet its prolonged juvenile phase and lengthy breeding cycle have long constrained the pace of genetic improvement. This review traces the evolution of rubber tree breeding, from phenotypic selection and Mendelian hybridization to precision molecular breeding, highlighting the major achievements and inherent limitations of each stage. Despite gains in yield, key challenges remain unresolved, including a narrow genetic base, strong genotype-by-environment interactions, and low transformation efficiency. Crucially, none of the previously reported breeding methodologies could enable breeders to accurately select or predict major agronomic traits at the early juvenile stage, leaving a prolonged evaluation bottleneck unaddressed. To address these bottlenecks, this study proposes a forward-looking Breeding 4.0 framework. Distinct from conventional technology-focused reviews, this article highlights the integrative potential of genomic selection, CRISPR-mediated gene editing, and artificial intelligence-driven predictive models. We further emphasize the value of wide hybridization and regeneration-independent gene validation techniques in overcoming long-standing constraints in Hevea breeding and facilitating the transition from passive selection to proactive design. By combining precise allele-level manipulation with predictive modeling, Breeding 4.0 can not only accelerate genetic gain and compress the cultivar development timeline by more than half (from 25 to 30 years down to 10 years), but also enable the rational design of high-yielding, climate-resilient clones. This conceptual shift represents the innovative contribution of the present review and provides a strategic roadmap for addressing future environmental and industrial challenges while securing the sustainable global supply of natural rubber.