Comparation of two pruning methods toward arabica coffee seedling growth

Coffee production success in Indonesia was strongly affected by culture technique, for instance, proper pruning. Pruning Arabica coffee seedling is one of techniques to boost productivity by cutting the plant shoots and stems. This study aims to determine the effectiveness of shoot pruning and 50% pruning on the growth of Arabica coffee seedlings. Data processing was carried out by statistical methods to compare or test the average data of two paired populations using the T test at a level of 0.05. Parameters observed were plant height, number of leaves, stem diameter and number of branches. The results of the arabica coffee seedling experiment with two treatments of pruning on the shoots pruning showed that the average plant height, number of leaves, and number of branches, was higher than pruning at the 50% pruning. Meanwhile, pruning 50% of stem diameter showed a higher average than pruning of shoots. It can be concluded that pruning of Arabica coffee seedlings, especially shoot pruning, has a better effect on the growth of arabica coffee seedlings.


Introduction
As The third biggest coffee producent in the world, Indonesia places coffee as one of prominent farming commodities, in 2017 where their export value ranked as the 4th biggest commodity after palm oil tree, rubber and coconut, reaching to 1.19 billion USD.
Coffee production in Indonesia in 2020 reached 753,491 ton from 1.2 million hectare field with productivity amount was up to 806 kg/ha, while in 2019, fixed production amount was 752,511 ton from 1,245,358 ha with productivity 803 kg/ha.Coffee production of Indonesia consists of 72% robusta, 27% arabica and 1% liberika [1].
Coffee production success in Indonesia was strongly affected by culture technique, for instance, proper pruning.Pruning Arabica coffee seedling is one of techniques to boost productivity by cutting the plant shoots and stems.This action is purposed to form plant by controlling and directing plant growth to keep their health, supposing to have shoots and branches apparent which support plant growth that might resulted in good seed productivity [2,3] Pruning experiment at coffee seedling phase is considered to prompt plant growth and productivity.Thus, seeds with good growth level can be obtained before moving them to the field.To study the effect of pruning on the growth of coffee seedlings, then an experiment was conducted.

Experimental method
This research is to examine the difference between two pruning methods of arabica seedling.The first treatment that fifteen coffee seedlings were pruned 50% of plant height (P1) and the second treatment that fifteen coffee seedlings were pruned on the shoots (P2).The result analysis of average comparison of two pruning methods (50% pruning and shoot pruning).The observation was carried out every two weeks.

Observation parameters
Every two weeks, observation after pruning was performed with parameters as follow: a.The observation by measuring plant height, started from apex of stem until the tip of leaves in every two weeks after mycorrhiza treatment during six times observation.b.The amount of perfect performed leaves was counted every two weeks after pruning treatment during six times observation.c.Measured at the middle of stems that appear on the ground surface every two weeks after pruning during six times observation.d.The amount of branches that have just grown were counted every two weeks during six times observation.

Results and discussion
The result of yield data from a few observation parameters; plant height, amount of leaves and branches diameter through T test showed that there was no any significantly different parameter for each parameter.Result analysis of average comparison of two pruning treatments on Arabica coffee towards several parameters from first observation until the 6th.Respectively, plant height parameters, the amount of leaves, the amount of branches and stem diameter was not significantly different.The average difference in pruning treatment for each parameter is shown in the figure 1,2,3 and 4. Those four figures above indicated that although statistically (T test) demonstrated no significant difference but overall, plant height, the amount of leaves, the amount of stems, the amount of branches for shoot pruning treatment were higher while 50% pruning only affected stem diameter which appears no significant difference or nearly same.Based on data of statistic test (T test) result, Arabica coffee seedling growth marked better effect on the coffee with shoot pruning treatment, proved by experiment result.Eventhough, statistically (T test), they were not significantly for each parameter but almost the seen amount of leaves and branches at shoot pruning of coffee plant seedling were higher than those with 50 % pruning which only affect stem diameter, making them look unobvious different or almost averagely same.Coffee plant pruning is aimed at regulating vegetative growth to generative phase to reduce leaves volume that finally lessen the transpiration.Thus, water kept in the ground can be directed for the need of branches easily to have better plant seedling growth both branches, shoots, leaves and stems [4].Based on observation result of Arabica coffee plants, the height addition mostly showed no significant difference between two average treatments (15.06 cm and 15.85 cm), as well as stem diameter average treatment (0.175 cm and 0.17 cm), those mean both direct or indirect pruning has yet to able to stimulate coffee seedling growth for height addition and stem diameter.Although, pruning is actually supposed to boost whole coffee seedlings growth but in fact, the effect of pruning remains unseen during the observation, in other words, pruning could not affect another growth.The observation result at highest number of leaves demonstrated that Arabica coffee seedling with shoot pruning treatment produced more leaves, 1.80 leaves than those with 50% pruning treatment which were only 20.65 leaves.While, the observation at the highest number of branches gained better growth at shoot pruning treatment as well, its amount was equal to the leaves one, that was 0.65 branch while along with 50% pruning, it produced 0.55 branch.These pointed that pruning has effect on the amount of formed branches and in sequence will affect the amount of leaves on the coffee plant.Pruning will promote lateral shoot since basically it is to break the domination of apical growth.At least, apical domination has impact on slower lateral growth.As long as apical shoots keeps existing, lateral shoot will be slow until certain distance from shot tip [4,5].
Shoot pruning will affect auxin flow to lateral shoots.Over auxin on the plant might create shoots dormancy which can slow the growth under shoot tip.It may happen, since the existence of lateral shoots stimulate branches to grow more.Shoot on the plants is apical meristem tissue which is considered as auxin production.In this part, cell division and magnification are very high, thus pruning around cut area can stimulate auxin translocation around them and stimulate new branches growth as well [5,6].Another stimulator compounds, for instance, synthesized sucrose and nitrogen compounds within the leaves then move to cut part.At certain limit, those accumulations will stimulate new branches formation [7,8].

Conclusion
Experiment results of Arabica coffee seedling with two pruning treatments can be concluded: shoot pruning indicated that most of height plant, amount of leaves and branches are higher than at 50% pruning, but stem diameter is marked higher than at shoot pruning.The conclusion is shoot pruning gives better effect on Arabica coffee seedlings.