Tomato Rootstock Enhances Vegetative Growth and True Fruit Growth of Potato Scion

To improve the probability of flowering and fruit set in potatoes ( Solanum tuberosum L.) under low-altitude, low-latitude conditions in the Sichuan Plain, China, heterografting was employed using tomato ( Solanum lycopersicum L.) as rootstock and potato as scion. This approach aimed to enhance potato fruit set success and hybrid breeding efficiency. Four potato cultivars, 'Chuanyu No. 10', 'Chuanyu No. 56', 'Chuanyu No. 18' and 'Mila', were grafted onto tomato rootstock. Observations and measurements were conducted on scion flower and fruit development, vegetative growth of the aboveground plant parts, and nitrogen (N), phosphorus (P), and potassium (K) content. Grafted plants exhibited significantly greater plant height and stem diameter compared to non-grafted controls, indicating enhanced vegetative growth. Analysis of aboveground tissues revealed significantly higher nitrogen and phosphorus content in grafted plants than in controls. Hybridization results demonstrated that grafted plants achieved higher fruit set rates and produced true seeds with larger fruit diameters compared to controls. Although the yield of true seeds per fruit was higher in grafted plants, the weight of individual true seeds did not differ significantly from controls. Heterografting potato scions onto tomato rootstock promoted both vegetative and reproductive growth in potato. Grafted plants accumulated higher levels of nitrogen and phosphorus, resulting in taller and more robust growth. Concurrently, heterografting facilitated flowering, fruit set, and true seed development in the potato scion, thereby enhancing hybrid breeding efficiency.