An Experimental Study on the Effect of Cutting Angle on the Growth of Grafted Watermelon Seedlings Using the One-Cotyledon Grafting Method

Abstract

The labor-efficient automation of grafting has been recognized as a key factor in the wider adoption of grafting. In growing cucurbits, the root pruned one-cotyledon grafting method is the most commonly used method with grafting machines. The cutting angle, which affects the matching of the rootstock and scion, is key to the survival of the graft seedling. In the production of cucurbit graft seedlings, the cutting parameters are established based on experience, leading to low grafting success. To determine accurate cutting parameters, the watermelon cv. ‘Zaojia84-24′ was used as the scion and the pumpkin cv. ‘Zhenzhuang’ was used as rootstock, and two one-way experiments investigating the cutting angle of the watermelon scion and the rootstock as factors were conducted. The cutting angle of the rootstock and scion had no significant effect on the xylem reconnection rate or the grafting survival rate. A larger cutting angle for the rootstock and scion led to a delay in the reconnection of the phloem. Different cutting angles for the scion significantly affected the growth of the scion after grafting. Compared with a scion graft cutting angle of 10° (SL), graft cutting angles of 14° (SM) and 20° (SS) led to significantly greater scion dry weights, with increases of 16.00% and 18.61%, respectively. Different cutting angles of the rootstock significantly affected the growth of roots after grafting. Compared with a rootstock graft cutting angle of 10° (RL), graft cutting angles of 17° (RM) and 27° (RS) led to significantly greater root dry weights, with increases of 29.33% and 22.54%, respectively. The results of this study can provide a reference for the design of cutting mechanisms for cucurbit grafting robots, improving the cutting precision of grafting robots.

Melon Robotic Grafting: A Study on the Precision Cutting Mechanism and Experimental Validation

“…Therefore, increasing the area of the healing contact surface of the rootstock and scion can improve the healing survival rate of grafted seedlings, which is generally measured by the length of the cut surface [19]. Liang et al analyzed the effect of different cutting angles (14 • , 17 • , and 27 • ) on the healing and survival of grafted seedlings from an agronomic point of view and found that smaller cutting angles were more favorable for grafting survival [26]. These results are similar to the results of the present study, where the length of the cut surface was longer for smaller cutting angles.…”

“…Liang et al investigated the effects of three cutting angles (14 • , 17 • , and 27 • ) of melon rootstock seedlings on the healing survival and later growth of grafted seedlings. The results showed that the smaller the cutting angle, the earlier the phloem reattachment occurs, and the greater the tensile strength of the scion-rootstock union during the healing period, the more favorable the grafted seedling survival rate [26]. The study did not consider the interaction of cutting angle with cut quality and cutting success, which need to be taken into account in the actual cutting process.…”

An Original UV Adhesive Watermelon Grafting Method, the Grafting Device, and Experimental Verification

“…For optimal rootstock grafting, the seedling age was set at 8 to 10 days, with the external morphology of the rootstock characterized by two spreading cotyledons and a stem thickness of about 3.5 mm, as depicted in Figure 14a. In contrast, the scion was sown three days earlier than the rootstock, displaying 2 to 3 leaves in its growth [39,40], as shown in Figure 14b. The designed spray grafting device was subjected to drawing, machining, module assembly, and control software development to integrate the spray grafting device as shown in Figure A5, which only requires one person to operate it.…”

Technical Scheme for Cutting Seedlings of Cyclocarya paliurus under Intelligent Control of Environmental Factors

“…Among cucurbit growers, the root pruned one-cotyledon grafting method, combined with the use of grafting machines, is the most commonly employed approach. However, success in grafting is not solely dependent on the use of machines; the cutting angle, which determines the compatibility of the rootstock and scion, plays a vital role in the survival and growth of the grafted seedling [27]. For example, Sun et al [37] explored the broken head rate and stubble break rate of potato seedlings by the automatic machine for cutting and raising potato seedlings.…”

“…Moreover, the method of producing seedlings from cuttings can make the plant growth speed very rapid. Compared with other seedling methods such as seeding, cuttings have better genetics and better survival rates [27]. Seedling production from cuttings must be provided with specific temperature, humidity, and photosynthetic active radiation (PAR) requirements.…”