# Behavior of Different Grafting Strategies Using Automated Technology for Splice Grafting Technique
## 3 Results and Discussion
Similarly, we can conclude that there are statistically significant differences between the orientation combinations of the joint surfaces between the seedlings with respect to the grafting clip opening (Table 2). Orientating the seedlings by placing the union surface in front of the vertical clip opening (S) resulted in a greater success rate than orientating the graft by positioning the union surface with either the rootstock or scion in front of the clip opening. This difference in success, around 10% higher, is possibly due to the conventional clips used being prepared to make a clamping force in that determined orientation, compared to the other orientation alternatives. Sometimes, the failures reported were mainly due to the direction of tightening exerted by the clip sides, where the proper directional pressure was not applied, to keep the graft surfaces in intimate contact, or there was not a sufficient level of pressure. Moreover, because of the lack of protection in the clip opening area, the pointed end is free and sometimes loses contact with the other seedling surface. In a similar way, failures were classified and grouped into five categories, according to the origin that gave rise to the failed graft (Figure 9). For the strategy of junction orientation S, most failures were due to the stem tip bent over on itself or scratches and chafing in guiding and positioning the stem into the clip. The total failure rate was slightly higher than 10% for S. For junction orientation FR and FS, these failures are still the most important, but there is an increase in failures due to pinching off the stems by the clip, as these are slightly separated before tightening, and the lateral opening of the graft clip is limited. The total failure rate was higher than 25% for FR and FS alternatives. Consequently, the best grafting strategy tested to carry out the splicing graft was order-dependent; that is to say, positioning the seedlings first, and then fitting the grafting clip. It also depends on the seedling orientation, placing the union line perpendicular to the clip opening (Figure 10). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Orientation**} & \multirow{2}{*}{**N**} & \multirow{2}{*}{**Grafts**} & \multirow{2}{*}{_Mean (Success)_} & \multirow{2}{*}{_Variance_} & \multirow{2}{*}{**St. Error_} & \multirow{2}{*}{**95\% CI**} & \multicolumn{2}{c}{**Grouping**} \\  & & & & & & & **(Tukey’s HDS)** \\ \hline
**Side (S)** & 12 & 300 & 89.67\% & 0.00135 & 0.1150 & (0.8278; 0.9655) & a \\
**Front R (FR)** & 12 & 300 & 77.33\% & 0.00267 & 0.1198 & (0.7045; 0.8422) & b \\
**Front S (FS)** & 12 & 300 & 76.67\% & 0.00075 & 0.1167 & (0.6978; 0.8355) & b \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison between the average successes of the different orientations tested. Grouping of comparisons applying Tukey’s HSD test (honestly significant difference). Significance level \(p<0.05\). Figure 9: Distribution of unsuccessful grafts according to different cause, depending on the orientation in which the process is undertaken. Fail type 1: Stem tip bent over on itself. Fail type 2: Scratches in guiding and positioning. Fail type 3: Separation between stems (not well-joined). Fail type 4: Pinching off the clip. Fail type 5: Other non-appreciable failures in the grafting process. It is evident that manual grafting has several problems: (1) Skilled workers are required, which increases the cost of grafted plants [50]; (2) large volumes of labor are required in short periods of time, requiring a large production scale; (3) frequently, grafted plants present a low quality of the union as a result of the manual and repetitive process, under extreme conditions of the working environment (high temperature and humidity), in order to fulfil the objective of an intensive production.