Onion and sunflower show:
Onion Allium cepa and sunflower Helianthus annuus exhibit relatively low inbreeding depression compared to highly sensitive cross-pollinated crops. Genetic basis involves fewer lethal equivalents and prevalence of additive gene action for bulb weight and head diameter. Upon selfing, reduction in size about 10 to 20 percent observed, plants retain viability, flowering and seed set adequate for line maintenance. Low depression suggests partial self-compatibility evolved, some purging during domestication and reliance on additive QTL not strongly influenced by dominance. Breeding exploits this to
Ref: FSS e-courses Onion breeding depression; Janick Encyclopedia Sunflower; Singh BD Table depression categories.