2026/04/30 by Yaroslav Zaitsev · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Advances in Cucurbitaceae Research #Berry genetics and cultivation research #Powdery Mildew Fungal Diseases
paper · doi:10.5281/zenodo.19922046
openalex publication_date 2026/04/30 · openalex created_date 2026/05/01 · openalex updated_date 2026/07/01
First-generation interspecific pumpkin hybrids are a large-scale commercial product and are used as professional rootstocks for cucurbits(bio-rootstock). Due to their reduced specialization, the tissue and sap of these hybrids are highly compatible, and thanks to the large number of incorporated genes, these rootstocks adapt well to the signals received from the scion plant, producing the substances required by the scion. Interspecific pumpkin hybrids also have their drawbacks. F1 hybrids are often sensitive to cool climates and are not prone to rapid growth and flowering. Not all melon varieties are ideal for grafting. In cold climates, open ground, and areas with high virus and insect infestations, grafted plants may be more susceptible to disease. Rootstocks require watering and a mild, greenhouse-like climate. Under these conditions, they achieve vigorous growth and timely flowering, demonstrating conditional immunity to pathogens and nematodes. Adapting professional rootstocks to harsher climates or terroirs is impossible, as they do not produce viable seeds. Therefore, professional rootstocks are adapted to the conditions in which pure lines are grown, often in specialized greenhouses for hybrid production, except the initial adaptations of pure lines in the field. Therefore, producing interspecific pumpkin hybrids in the second generation can offer many advantages. Such a crop can be more fertile, especially if it is obtained by reverse hybridization from a fertile interspecific hybrid adapted as a pollen donor. Also, when producing a reverse hybrid, the hybrid's genetic diversity increases. Furthermore, when the resulting hybrids are further crossed with other hybrid lines, the genetic material of all lines will be combined into a common gene pool for the resulting pure line. Essentially, this is the classic formation of a complex new variety, but in this case, it is the formation of a new species(Synthetic population) —Moschata/Maxima. This variety, possessing nominal fertility, can cross-pollinate multiple times without deep cleavage or loss of quality, and after extensive selection, it can pupate(stabilize into a distinct variety) into a similar variety (or more accurately, species). Such an interspecific hybrid will likely be pollinated by its ancestor crops; establishing a stable species barrier requires many generations, and in the early stages, it is necessary to pollinate the crop manually or grow it away from other cucurbits. But the key factors are fertile offspring and adaptability(Adaptive breeding), as well as the potential for subsequent crosses with other cucurbits, such as squash, Ficifolia (Cucurbita ficifolia), or some rare pumpkin species. For example, introducing squash genes into a hybrid can improve compactness and speed growth and flowering, ideal for more northern latitudes. Such hybrids are not formed from varietal squash and pumpkins due to their genomic differences, but crossing hybrid interspecific forms offers the potential to produce a similar hybrid. Also, phycephalia and some other distantly related pumpkins do not form hybrids under natural conditions, but working with interspecific hybrids may offer the potential to produce a more robust hybrid, potentially a professional melon rootstock, with qualities unavailable to modern first-generation interspecific hybrids.