Chronological review of micropropagation of cucumber (Cucumis sativus L.) and cucurbits (Cucurbita spp.)

Micropropagation is a key biotechnological method for rapid and large-scale propagation of horticultural
crops. Nowadays, micropropagation plays a key role in production of disease-free plants, conservation of genetic
resources and it is an essential tool in crop breeding programs. Cucumber (Cucumis sativus L.) and cucurbits
(Cucurbita spp.) are economically important species that have been widely studied for in vitro regeneration.
This review synthesizes research protocols reported over the past decades, focusing on explant type, culture
media, and plant growth regulator combinations. A total of 29 studies on cucumber and 11 studies on
cucurbits were analyzed to identify research trends over time and critical factors affecting micropropagation.
Cytokinins, mainly BAP, have been consistently effective for adventitious shoot induction, while auxins such
as 2,4-D promoted callusogenesis in cucumber. Optimal regeneration of cucumber often relied on cytokinin–
auxin combinations, with cotyledons and hypocotyls showing high morphogenetic potential. For cucurbits,
shoot tips, nodal segments, and cotyledons have been the most responsive explants where BA-based
treatments have achieved superior shoot proliferation, and IBA has supported efficient rooting. Genotype-
specific responses and hormonal balance are critical factors for successful micropropagation for both crops.
Well-designed micropropagation protocols are essential for efficient regeneration and genetic improvement
of both crops. Understanding explant-specific and genotype-dependent responses to plant growth regulators
can enhance the reproducibility and scalability of in vitro systems, opening the way for advanced breeding and
biotechnological applications.