Micro-Mel and Mini-Mel short life cycle dwarf lines with Solanum anguivi introgressions as the first model varieties for eggplant research and breeding, with potential ornamental applications

Eggplant (Solanum melongena) research has been hindered by the lack of suitable model plants. The development of Micro-Mel and Mini-Mel, two short-cycle dwarf model lines with introgressions from the wild relative Solanum anguivi, represents a breakthrough in eggplant research. Both lines were characterized using 30 phenotypic descriptors and compared to their parental lines and Micro-Tom. Micro-Mel has determinate growth, early flowering (41.0 days post-transplantation), and physiological fruit maturity at 103.7 days. Mini-Mel is around 3 cm taller, with indeterminate growth, later flowering (57.2 days) and fruit maturity (114.7 days), with a more conventional architecture. Both are significantly shorter than other dwarf eggplants (30 cm at 50 days), reaching only 6.83 cm and 7.93 cm at 60 days. Micro-Mel and Mini-Mel complete three and two and a half full seed-to-seed cycles per year, respectively. Their compact size makes them ideal for space-limited environments, controlled growth chambers, speed breeding, and urban or ornamental horticulture. Whole-genome sequencing (23X coverage) identified 179,653 SNPs between the parental lines, revealing heterozygosity rates of 0.00098% (Micro-Mel) and 0.00123% (Mini-Mel). Micro-Mel and Mini-Mel have 8.50% and 10.79% of their genomes introgressed from S. anguivi, respectively, including 18 shared introgressions. Notably, three orthologues of dwarfism-related genes in tomato (SlDREB1, SlER, and SlSERK1) were identified within these introgressions. The compact, short-cycle nature of Micro-Mel and Mini-Mel accelerates breeding and supports research in genetics, physiology, and cultivar development, while their miniature stature and abundant flowering and fruiting confer them clear ornamental potential.