# Behavior of Different Grafting Strategies Using Automated Technology for Splice Grafting Technique
###### Abstract  
Even though the splicing graft technique is relatively recent, it has become the most commonly used grafting method for solanaceae, and in particular, for tomato. Today, almost everyone has standardized the use of plastic or silicone grafting clips, equipped with manipulating wings and a frontal opening, to ensure proper bonding and allow for wound healing. Numerous factors influence the success or failure of the grafting process, factors such as the seedling varieties combined, climatic conditions, pre-graft and post-graft care, cutting point, cutting angle, pressure of the clips, blade edge, or substrate water content, among others. In this work, several alternatives in the graft assembly and coupling protocol were evaluated. Having studied the different working alternatives for grafting using a robotic system, two modes of joining order were analyzed. It has been shown that there are 20% more recorded successes if one first joins the graft seedlings and then places the grafting clip to guarantee their union. In addition, we studied the different orientation alternatives for the cutting line and the seedling union with respect to the clip opening--there were approximately 10% more successes obtained in grafts where the splice-union cutting line between the two plants faced the clip opening. tomato grafting; splice-grafting technique; agricultural robot; automated grafting; agricultural machinery; grafting clips; tube grafting; slant-cut grafting; Japanese top grafting +
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comes in response to increasing social awareness, and also to a growing interest in developing organic and integrated agriculture. Although, today, the fight and resistance to soil pests and viral diseases remains the main objective for applying this technique [12], there are other reasons and particularities justifying its use. It is a faster and more effective tool for selecting desirable crop characteristics than natural screening, selection processes, or species hybridization [13; 14]. Grafting increases the health and precocity of the plant, providing stronger and more vigorous root systems than in ungrafted plants, which leads to improved water and nutrient absorption [15; 16; 17]. Improved mineral nutrition can result in the significantly lower use of agrochemicals during cultivation [9], as well as better adaptability to environments where there is abiotic stress and potentially harmful and unfavorable conditions, such as water stress, thermal stress, and saline stress; there is also better performance in response to high heavy-metal concentrations [5; 12; 14; 18]. In addition, grafted plants provide higher productivity, with fruit that is significantly larger than that from ungrafted plants [19] while other fruit characteristics, such as their shape, skin color, flesh texture and color, or concentration of soluble solids, are negatively influenced by the rootstock, despite being generally assumed as hereditary stem characteristics [15]. Grafting is a common practice in high value-added cucurbitaceous and solanaceous crops [20]. There are two basic grafting methodologies: One is where the grafting process retains the two root systems, that of the rootstock and of the scion (tongue approach grafting, side grafting); and the other is that in which a shoot from the scion is joined to the rootstock plant (cleft grafting, hole grafting, splice grafting) [21; 22]. In the first case, less strict environmental conditions are required during the grafting period and the post-graft phase [23], but its application is complex in solanaceae, mainly because the plants are usually grafted very young when stem thickness is minimal (Figure 1). Splice grafting (also called slant-cut grafting, Japanese top grafting, or tube grafting) is currently the most common grafting method for tomato (_solanum lycopersicum_) worldwide [24]. The splice graft has a high success rate, is relatively simple to execute, and is even amenable to automation, so a large number of plants can be grafted in a short period of time [25].