The plants of C. arabica do not naturally produce a large number of orthotropic sprouts, hindering clonal multiplication by cutting, which would be the simplest technique with a lower cost of production compared to other methods of vegetative propagation. An alternative form, used successfully in the propagation of eucalyptus, is propagation by minicutting, which consists of pruning the shoot apex of the plant, forming the ministumps, which in variable time interval emits the shoots that will be used to make minicutting. In C. arabica plants the number of shoots can be increased with the application of growth regulators and fertilizers. So, the purpose of this work was to verify the effect of growth regulators and foliar fertilizers on the emission and development of orthotropic shoots of C. arabica. The experiment was installed in a randomized complete block design, with ten treatments composed by growth regulators and fertilizers: T1 (Control); T2 (Stimulate + Sturdy + Enervig); T3 (Stimulate + Vitakelp + Biozyme); T4 (Tiba + Sturdy + Enervig); T5 (Tiba + Vitakelp + Biozyme); T6 (Brs + Sturdy + Enervig) T7 (Brs + Vitakelp + Biozyme); T8 (Stimulate); T9 (TIBA); T10 (Brs-Brassinoesteroid), each plot consisting of two plants. Biometric and physiological parameters were evaluated for the ministumps, as well as the biometric parameters of the shoots and plant survival. The results showed that there was no influence of the treatments on the biometric parameters of the ministumps. A greater number of orthotopic sprouts were obtained in treatments with the TIBA growth regulator, as well as a greater plant survival of the minicuttings, after 25 days of transplanting in a greenhouse. It was concluded that TIBA treatments influenced the production and quality of clonal minicuttings of C. arabica.
The production of quality seedlings is the first step in the process of forming a good quality coffee. C. arabica cultivars are propagated sexually and due to their morphological characteristics, they undergo a very long process of material selection, usually requiring more than 25 years for the characteristics of interest of the cultivars to be stabilized [
The vegetative propagation of C. arabica is justified for the immediate exploration of F1 hybrids, representing a great saving of time by reducing the number of selection cycles to obtain lineages, guaranteeing the uniformity of the population and maintenance of the genetic gain obtained in the selection [
The clonal propagation by cutting, traditionally used in the C. canephora, did not succeed in the clonal propagation of C. arabica. Although no anatomical barriers are found for the rooting of C. arabica cuttings from orthotropic sprouts [
Other authors [
An alternative form of clonal propagation is propagation by minicutting. In this technique, minicuttings are taken from ministumps in clonal mini-clonal hedges, usually established inside greenhouse [
The benefits of mini-clonal hedges range from reduced space, greater control of plant health, and environmental control, which may influence the adhesion of seedlings from cuttings, as the field plants suffer from climate conditions, among other factors controlled in the nurseries at propagation by minicutting [
The number of orthotropic shoots in coffee plants can be increased with the application of growth regulators. TIBA (2,3,5-triiodobenzoic) is an inhibitor of polar auxin transport, acting directly on the apical dominance of the plant [
The brassinosteroids (BRs) are polyhydroxy steroidal lactones that occur naturally in plants, influence various developmental processes, such as germination and seed vigor, flowering and dormancy of buds and seeds in certain crops [
Stimulate® is a commercial product of Stoller do Brasil Ltda., Containing plant regulators and traces of chelated mineral salts. Its constituent plant regulators are indolebutyric acid (auxin) 0.005%, kinetin (cytokinin) 0.009% and gibberellic acid (gibberellin) 0.005%. This product reveals that it is able to assist in breaking dormancy of the lateral buds in some cultures [
The nutritional status of ministumps and shoots in vegetative propagation by minicuttings has been pointed out as one of the main factors in adventitious rooting of minicuttings, but few studies have been conducted aiming at the characterization of the effects of specific nutrients [
The objective of this work was to evaluate the influence of growth regulators and foliar fertilizers on sprouting and rooting of minicuttings of C. arabica.
The experiment was conducted at the State University of Northern Fluminense Darcy Ribeiro―UENF, in the municipality of Campos dos Goytacazes―RJ, located at 21˚48' latitude, 41˚20' long at an altitude of 11 m. The average annual temperature is 24˚C, with average annual precipitation of 1023 mm.
The experimental design was a randomized block with 10 treatments, with 4 blocks with 2 plants per block, totaling 80 experimental units. The treatments were elaborated from the combination of growth regulators and commercial fertilizers: T1 (Control); T2 (Stimulate + Sturdy + Enervig); T3 (Stimulate + Vitakelp + Byozime); T4 (Tiba + Sturdy + Enervig); T5 (Tiba + Vitakelp + Byozime); T6 (Brs + Sturdy + Enervig); T7 (Brs + Vitakelp + Byozime); T8 (Stimulate); T9 (TIBA); T10 (Brassinosteroid).
The foliar fertilizers used had the following compositions: Sturdy: (Nitrogen [N] 86.4 g/L; Phosphorus [P2O5] 432.0 g/l; Complexing agent-MEA 20%; Biozyme TF: Nitrogen [N] 20.7 g/l, Potassium [K20] 60 g/l, Boron [B] 0.96 g/l, Iron [Fe] 5.9 g/l, Manganese [Mn] 12 g/l, Sulfur [S] 25.2 g/l, Zinc [Zn] 29.1 g/l, Total organic carbon 42.0 g/l); Enervig: (Copper [Cu] 17.02 g/l, Manganese [Mn] 17.02 g/l, Iron [Fe] 22.02 g/l, Zinc [Zn] 33.92 g/l); Vitakelp: (Nitrogen [N] 180.0 g/l; Potassium [K20] 12.0 g/l; Algae Extract and Amino Acids).
Seedlings from the “Catuaí Vermelho IAC 99” were used to make the ministumps in cylindrical vases of 17 × 22 × 16 cm. The substrate used to fill the pots was Basaplant. Irrigation and cultural treatments were performed according to the recommendations of [
The apical meristem of the seedlings broke after the six months of age, and the height of the seedlings was standardized in 15 cm. Growth regulators and foliar fertilizers were applied 10 days after the apical meristem was broken and ministumps, and the treatments were repeated every 30 days.
The following variables were evaluated biometric: number of leaves; height of the plants; diameter of the neck; weight of dry matter of the aerial part and weight of dry matter of the roots, measured in digital analytical balance, after the material was dried in an oven at 70˚C for 72 hours. The root system was evaluated for volume, length and root diameter determined after root scanning and subsequent analysis of the images in the WinRHIZO program. The leaf green color intensity was also measured using a Portable Chlorophyll Meter SPAD-502 “Soil Plant Analyzer Development” (Minolta, Japan), where three readings were taken along the plant and the average was used to compose each repetition.
The number of shoots was measured; number of shoots leaves; length of shoots, measured from the base of the orthotropic branch to the apex of the branch; diameter of the shoots; dry matter weight of the shoots after the material was dried under study at 70˚C for 72 hours and fresh matter weight of the shoots measured in analytical digital scale.
The data of the index of glue were evaluated according to the methodology applied by [
IPG ( % ) = Number of pickets per plot × 1 00 Number of cuttings planted per plot
The data collected were submitted to analysis of variance, in which the means of the treatments were studied by the Tukey test (p < 0.05).
According to the analysis of variance of the biometric and physiological of the ministumps, for each of the parameters evaluated are shown in
F values | ||||
---|---|---|---|---|
Variation source | Fresh weight (g) | Initial number of leaves | SPAD | Initial diameter (cm) |
Treatments1 | 1.441ns | 0.7258ns | 0.3583ns | 0.4106ns |
Overall Average | 6.7322 | 9.7625 | 44.8362 | 2.8430 |
CV (%) | 29.078% | 14.892% | 9.706% | 12.175% |
F values | ||||
Variation source | Dry Weight (g) | Final Diameter (cm) | Final Height (cm) | Final number of leaves |
Treatments1 | 0.3826ns | 1.6742ns | 1.8749ns | 0.5922ns |
Overall Average | 2.4355 | 2.297 | 12.610 | 9.4125 |
CV (%) | 21.401% | 18.049% | 10.083% | 13.715% |
**significant at the level of 1% of probability by the F test; *significant at the level of 5% of probability by the F test; nsnot significant (p > 0.05) by the F test.
The time elapsed between the application of growth regulators and foliar fertilizers and the final evaluation of the experiment was 90 days. This period was probably short for growth regulators and fertilizers to induce a significant effect on the biometrics of the plants analyzed. Another factor that may have contributed to these results is the quality of the seedlings used, since they were acquired in a certified nursery and had good visual characteristics (size and color of the appropriate leaves and sprouts).
In
According to the results obtained in
In relation to the number of shoots, the treatments (T5, T4 and T9) that received the TIBA growth regulator showed higher sprouting averages, the other treatments did not differ among themselves, being statistically similar to the T1
F Values | ||||
---|---|---|---|---|
Variation source | Variation Root length (cm) | Surface area (cm2) | Root volume (cm3) | Root density (g/cm3) |
Treatments1 | 1.9916ns | 1.0295ns | 1.5074ns | 1.1873ns |
Overall Average | 136.0237 | 13.39075 | 1.2322 | 11.4445 |
CV (%) | 17.111% | 9.223% | 23.361% | 23.641% |
**Significant at the level of 1% of probability by the F test; *significant at the level of 5% of probability by the F test; nsnot significant (p > 0.05) by the F test.
F Values | |||||
---|---|---|---|---|---|
Variation source | Diameter of shoots (cm) | Length of shoots (cm) | Number of shoots | Fresh weight of shoots (g) | Dry weight of shoots (g) |
Treatments1 | 3.7730** | 2.8354** | 13.1148** | 0.8427ns | 0.3722ns |
Overall Average | 2.3772 | 1.3992 | 5.400 | 2.895 | 0.8220 |
CV (%) | 10.588% | 31.961% | 28.130% | 44.112% | 37.651% |
**Significant at the level of 1% of probability by the F test; *significant at the level of 5% of probability by the F test; nsnot significant (p > 0.05) by the F test.
(control). These results corroborate with the data obtained by [
The application of brassinosteroids did not prove to be efficient in the formation of shoots in coffee plants. These results corroborate with those found by [
It was observed that T1 (control) presented a higher average length of shoots compared to treatments T2, T4, T5, T7 and T8, but did not differ from other treatments. It can be verified that the length of the shoots can be related to the number of shoots per ministumps, since, the witness had a lower number of shoots, but a longer length of shoots, and the treatments T5 and T4, which presented higher averages as to the number of shoots significantly lower mean values than the control group (
It is verified that T10 had higher shoot size averages when compared to T4 and T5, not differing from the other treatments. This result may be associated to the lower number of shoots obtained in treatment 10, which in relation to T4 and T5 were respectively 291% and 325% lower, another possibility is that the brassinosteroids has influenced the development of shoot diameter, corroborating with results obtained by [
According to the data obtained in the experiment, we conclude that:
1) The production of minicuttings from axillary buds of arabica coffee is possible, since both orthotropic shoot production and rooting were obtained.
2) The TIBA growth regulator positively influences the production of minicuttings of arabica coffee.
3) The technique of seedlings production in mini-clonal hedges can be an interesting technological innovation, since it can be used to reduce the generation time, and the possible exploitation of F1 descendants.
Cavalcanti Filho, P.F.M., Baitelle, D.C., Freitas, S. de J., da Silva, W.S., dos Santos, P.C., Rodrigues, W.P., Freitas, S. de P., de Jesus Freitas, I.L., Locatelli, T., Verdin Filho, A.C. and Miranda, G.B. (2018) Effect of Growth Regulators in Production and Rooting of Coffea arabica L. Minicuttings. American Journal of Plant Sciences, 9, 628-636. https://doi.org/10.4236/ajps.2018.94049