Apical cuttings are the conventional practice in the floriculture industry; this is due to the fact that apical cuttings are younger than internode cuttings, which increase apical cuttings uniformity in rooting and growth rate as well as increased success rates.
Internode cuttings are more resistant to environmental conditions and therefore tend to have increased transportation stability. In addition, they’ve shown increased value to customers all through the value chain; facilitated work with rooting machinery, higher cuttings production per growing area, reduce pinching work time.
In order to combine the advantages of the latter with the high standards of uniformity and success rates of apical cuttings, extensive greenhouse experiments were conducted.
These experiments showed that for a wide range of crops internode cuttings can be used showing all advantages of lower node cuttings without harming uniformity and success rates as was hypothesized in the past.
The ornamental plant industry is very diverse and includes the production of floral crops such as cut flowers and cut foliage, flower bulbs, flowering pots as well as foliage plants and bedding plants. Global floral production value is estimated at USD 55bn. Floricultural includes -mother stock plant material of various forms such as tissue culture, cuttings, and seeds. Mother stock material, bred and produced by the horticultural companies is then sold to nurseries or growers who in turn sell the final product, – flowering pots, to retailers.
Globalization of the floriculture market in the last years arise new product requirements. Both, mother stock materials as well as final products are exposed to extreme conditions during long and distant shipments. In some cases plant material is transferred through more than 30 °C from origin to destination. Despite the rough conditions, final products are committed to increase standards of quality and uniformity in this developing industry.
Parental material such as seeds used in many agricultural sectors is very resistant to environmental conditions and allows great rooting and growth uniformity when primed. In floricultural plants, many varieties are propagated using cuttings, mainly apical cuttings. Cuttings of some varieties, especially those with non-woody stems are very sensitive to environmental conditions during transportation.
Uniformity is a very important character in the industry which allows standardization and automation of processes.
In addition, in the last years, there was an acceleration of automation in the floriculture industry in order to optimize and standardize production process. Robots are available for most stages of the process from rooting to packaging of final products.
Internode cuttings have some commonly known advantages through the value chain:
1. Transportation- these cuttings increased lignification thus improving stability of the cutting during transportation.
- Rooting-increased lignification facilitates application of the cuttings by rooting machinery
- Rooting stations – Produce more cuttings per growing area. Since both types of cuttings can be used by growers without jeopardizing uniformity and quality of the cuttings. This can double the number of cuttings produced per growing area.
- Growers- Save time and workforce on pinching. Internode cuttings are necessarily pinched cuttings. In this way, there is no need for pinching of the cuttings.
We compared the two types of cuttings in various crops for a wide range of properties.
We were able to show that the potential of internode cuttings was higher for the examined crops (See table 1 and figure 1). The following crops showed increased potential when planting secondary cuttings: Fuchsia (X3.1 compared to apical cuttings-See figure 2A), Gomphrena (X3.1 compared to apical cuttings-See figure 2B), Cuphea (X2.4 compared to apical cuttings-See figure 2C), Lobularia (X2 compared to apical cuttings-See figure 2D), Torenia (X2 compared to apical cuttings-See figure 2E), Nemesia (X1.6 compared to apical cuttings-See figure 2F), Verbena (X1.2 compared to apical cuttings-See figure 2G), Iberis (X1.2 compared to apical cuttings-See figure 2H). For Lobularia, Torenia, and Gomphrena this increased potential was also characterized by longer and more branched roots (See figure 3).
Starters originating from internode cuttings showed an increased growth rate compared to apical cuttings following their transplanting (See figure 4). This allowed internode cuttings to fill pots in a shorter period.
A shipment simulation was conducted to assess the susceptibility of different cuttings to shipping conditions. We were able to show, as we’d hypothesized, internode cuttings are less susceptible to shipping conditions resulting in lower losses of cuttings during shipment (See figure 5).
Table 1: Starting time of potential is earlier and the total potential is higher for pinched cuttings
Three apical or secondary cuttings from the designated crops were planted. Potential was assessed once a week for each plant. Measurement was conducted for 9 weeks. Average weekly potential for each of the cuttings types of each crop is presented. Ratios are calculated as the potential of internode cuttings divided by the potential of apical cuttings.
Figure 1: Total Potential of internode cuttings is higher compared to apical cuttings
Three apical or internode cuttings from a variety of each of the crops were planted. The potential was assessed once a week for each plant. Measurement was conducted for 9 weeks. Total average potential of 9 weeks for each of the cuttings types and crops is presented.
Figure 2: Internode cuttings potential starts earlier and shows increased quantities per week compared to apical cuttings
Three apical or internode cuttings from the designated crops were planted. Potential was assessed once a week for each plant. Measurement was conducted for 9 weeks. Average weekly potential for each of the cuttings types of each crop is presented.
Figure 3: Internode cuttings’ rooting is enhanced compared to apical cuttings
Three apical or secondary cuttings from the designated crops were planted. Representing pictures of the roots one and two weeks after planting of the cuttings are presented.
Figure 4: Starters originating from internode cuttings exhibit an increased growth rate
Three starters from either apical or internode cuttings were transplanted in pots. Representing plants were photographed in the designated times after plantings. Spread of the cuttings in the pot is compared.
Figure 5: Secondary cuttings showed increased susceptibility to shipment conditions in most – crops.
3 bags of 100 apical or secondary cuttings of the different crops were packed in a box. Cuttings went through the following treatment:
Following 72h, boxes were opened and damaged cuttings were counted. Damaged cuttings of each type were calculated as the mean number of damaged cuttings. Percent of damaged cuttings was calculated from the full quantity started the simulation.
Internode cuttings are known to have advantages compared to apical cuttings all through the value chain. The main reason internode cuttings are not widely used in the floricultural sector is the hypothesis those will have decreased and less consistent rooting and growing abilities making them unprofitable for use in the industry. In our results we were able to show that for some crops internode cuttings have preferred commercial properties compared to apical cuttings such as increased and earlier potential, extended roots and higher growing rates of starters making. Together with the time saved on pinching of the cuttings and the higher suitability of the cuttings to rooting machinery, internode cuttings of those crops are more profitable to all players through the value chain: cutting suppliers, cutting growers.
Internode cuttings also showed less susceptibility to varying temperatures which simulates shipping conditions it is important to note the results described in this article are preliminary results. The method should be assessed further by the different players in the value chain in order to further establish its advantages.