Progress in genetic improvement of citron watermelon (Citrullus lanatus var. citroides): a review

Citron watermelon (Citrullus lanatus var. citroides) is an important tropical crop belonging to the Cucurbitaceae family. It possesses novel genes for biotic and abiotic stress tolerance and horticultural traits useful for breeding including sweet dessert watermelon. There is a lack of research priority limiting the genetic improvement and cultivar deployment of citron watermelon. Genetically diverse citron watermelon genetic resources are important to identify and select suitable genotypes for cultivar development incorporating horticultural attributes according to the needs and preferences of clients and marketplace. The objective of this review was to present progress on genetic improvement of citron watermelon with emphasis on cultivar development with biotic and abiotic stress resistance and desired horticultural attributes. Further, the review highlighted genetic and molecular resources in citron watermelon and other cross compatible cucurbits that may aid in accelerated breeding and cultivar release. Finally, the paper summarized research focus areas with potential to enhance effective utilization of citron watermelon genetic resources for targeted breeding of this crop or related taxa such as dessert watermelon.