**Tian Gong, Zachary T. Ray, Kylee E. Butcher, Zachary E. Black, Xin Zhao \* and Je**ff**rey K. Brecht**

Horticultural Sciences Department, University of Florida, Gainesville, FL 32611, USA; tiangong@ufl.edu (T.G.); ray.ztyler@ufl.edu (Z.T.R.); kbutcher@ufl.edu (K.E.B.); zackblack@ufl.edu (Z.E.B.); jkbrecht@ufl.edu (J.K.B.) **\*** Correspondence: zxin@ufl.edu; Tel.: +1-352-273-4773

Received: 15 August 2020; Accepted: 16 September 2020; Published: 24 September 2020

**Abstract:** Vegetable grafting has primarily been used in the commercial production of high-value crops in the Solanaceae and Cucurbitaceae families. In this study, we explored the feasibility of making a novel graft between pac choi (*Brassica rapa* L. var. *chinensis*) and daikon radish (*Raphanus sativus* L. var. *longipinnatus*) to create a plant with harvestable pac choi leafy vegetable above-ground, and a daikon radish taproot below-ground. 'Mei Qing Choi' pac choi (scion) was grafted onto 'Bora King' daikon radish (rootstock). Grafted pac choi–daikon radish plants did not show a decrease in SPAD value, canopy size, leaf number, leaf area, or above-ground weight compared with self-grafted pac choi plants. However, taproot formation was reduced in grafted pac choi–daikon radish plants, as shown by decreased taproot length, diameter, fresh weight, and dry weight compared with non- and self-grafted daikon radish plants. Surprisingly, grafting with radish increased the photosynthetic rate of the pac choi. This pilot study demonstrated the potential of creating a new pac choi–daikon radish vegetable product to help save growing space and minimize waste at consumption, as pac choi roots are not eaten and radish leaves are usually discarded. The inter-generic grafting between *B. rapa* var. *chinensis* and *R. sativus* var. *longipinnatus* could also provide a unique model system to help elucidate scion-rootstock synergy and above- and below-ground sink competition in horticultural crops.

**Keywords:** Brassicaceae; growth; mineral content; photosynthesis; rootstock; taproot
