The differences in true seed shallot nursery growth due to effect of type and thickness media

. Currently, botanical seeds of shallots or the true seed shallot (TSS) are becoming more accessible. The problem is that seeding botanical seeds requires the proper media to support the seeds to grow healthy and produce tubers as qualified as that from tuber seeds. The study aimed to obtain the seedling media's type and thickness to support optimal TSS growth. The study was arranged in a factorial design with two treatment factors: media type and media thickness. The environmental design is a Split Plot, with the main plot being a media type consisting of soil (soil + organic fertilizer + husk charcoal) and cocopeat (cocopeat + organic fertilizer + husk charcoal) as sub-plots is the thickness of the planting medium, with two levels of 3 and 5 cm, with five replications. The results showed that based on shoot length, stem diameter, root length, and total chlorophyll content, it was found that soil and cocopeat media with a thickness of 5 cm gave the best vegetative growth as well as the chlorophyll content compared to soil and cocopeat media with a thickness of 3 cm. The results of this study provide information that using media with a thickness of 5 cm gives better seed growth than media of 3 cm.


Introduction
Shallots are a strategic vegetable commodity for the Indonesian population.The national need for shallots in 2020 reached 995,614 tons per year [1].National shallot production in 2020 was 1,815,445 tons from an area of 191,201 ha, with average productivity of 9.49 tons/ha.The fulfillment of shallot needs can be fulfilled from domestic production, especially from five production center provinces: Central Java, East Java, West Nusa Tenggara, West Java, and West Sumatra.The Java Island accounts for 75% of the total national shallot production.Indonesia has achieved shallot self-sufficiency, but there are still problems fulfilling shallot bulb seeds.The main problem in shallot seed production is the seed bulb production which requires 4-5 months of planting.The delaying of planting time often occurs due to the unavailability of the seed.The other problem is the high price of the seed and the transportation cost.The range of shallot price is Rp.45,000-60,000 per kg, not including the shipping cost.
Other Researchers state that there is an opportunity to increase the availability of shallot seeds and minimize production costs, namely through true shallot seeds (TSS).Using botanical seeds as onion seeds becomes an opportunity in the cost efficiency of seed production.Research results from Sumarni et al. [2] mentioned that the provision of onion seeds from TSS is more efficient than seeds from bulbs.Pangestuti and Sulistyaningsih [3] reported that seeding TSS with a mixture of media processed into soil blocks resulted in healthy and robust seedlings, and there was no stagnation of early growth after transplanting because the root of the seedlings was not disturbed.Soil block media is a mixture of media to meet the ideal media composition consisting of brown peat, lime, coarse sand or perlite, essential fertilizer, soil, and compost [4].
Currently, TSS is becoming more accessible However, for seeding botanical seeds, a specific planting medium to produce healthy seeds and comparable yield to plants from the bulb is needed.Agricultural waste, such as cocopeat and husk charcoal, is easy to obtain and becomes an alternative media to TSS seedling.Sopha [5] concluded that the use of onion botanical seed seedling media with a mixture of soil media + cocopeat + manure or soil + manure + husk charcoal resulted in the optimal vegetative growth as good as that was planted in a mixture of soil media + manure.According to Lestari & Shoidah [6], the growth of TSS sown in soil blocks or trays does not show a noticeable difference.Some agricultural waste such as compost, husk charcoal, cocopeat, and soil can be used as a mixture of seedbed media, with a composition of soil: compost: husk charcoal in a ratio of 1:1:1 [5,7].
Soilless culture systems that utilize organic waste media such as cocopeat or burnt husks also using polybags or pots have been widely used in the cultivation of commercial horticultural commodities such as melons [8]; tomatoes [9][10][11], orchids [12,13], anthurium [14].These studies show that cocopeat or husk charcoal can be used to substitute soil in various horticultural crops, and resulted in optimal plant growth.There is no research that examines the thickness and composition of cocopeat-based planting media without using polybags for true seed shallot, so the results of this study will be a novelty in terms of media type mixture, thickness and seedling system without polybags.
Based on existing problems and alternative solutions from other studies, an experiment was carried out to obtain the best mixture of seedbed media which can support onion seeds from botanical seeds (TSS) to get optimal growth.

Experimental design
The research was compiled in a factorial design with two treatment factors, the type of planting media and the thickness of the planting medium.The environmental design used is a Split Plot.As the main plot was the type of planting media consisting of two levels: soil media and cocopeat media, and the subplot was the thickness of the planting medium, with two levels, 3 and 5 cm.The experiment was compiled with five tests.

Time and place
The study was conducted in a screen house in the experimental garden of BPTP Central Java with a place height of 380 m above sea level.The study was conducted from September -December 2020.

Research implementation
The preparation of seedbed media: soil and cocopeat is mixed with organic compost and husk charcoal.For soil media (soil: compost: husk charcoal in the ratio of 1 : 1: 1) based on Sudaryono [15] and for cocopeat media (cocopeat: compost: husk charcoal in a ratio of 3: 2: 1) based on Azmi et al. [16] with modifications based on the result of the experience of potato seed breeder in Banjarnegara.The seedbed media was sterilized by steaming for 45 minutes mixed with a predetermined ratio and put into a seedbed tray with a size of 25x25 cm.Then the planting media was watered using a mixture of water and PGPR solution until reached field capacity.The TSS variety used for the experiment is Trisula.The amounts of seeds per tray was 1g.Harvest for transplanting was carried out at 40 DAS.

Observation parameters
Observations for media include the nutrient content of planting media (soil and cocopeat), pH, C-Organic content, N-total, P2O5, K2O, and Cation Exchange Capacity (CEC).The seed growth observed includes the length of shoots and the number of leaves from 15 DAS every three days until 25 DAS.At the harvesting time (42 DAS), the observation includes the length of the shoots, the number of leaves, the diameter of the stem, and the length of the roots, chlorophyll a, chlorophyll b, and chlorophyll total of leaves.

Results and discussion
The results showed that the media used both soil and cocopeat had almost the same nutrient content.The difference was found in the parameters of N-total content and Cation Exchange Capacity (CEC) (Table 1).The results of the chemical analysis of soil and cocopeat media showed that the actual nutrient content of the two media was very similar.It means that cocopeat has a sufficient level of fertility and is not different from soil media to support plant seed growth.Description: N = neutral, AM = slightly sour, S = medium, T = high, ST = very high There was no significant interaction between the type and the thickness of the TSS planting media either at 15 DAS, 18 DAS, 21 DAS, and 25 DAS.The shoots in the treatment of soil planting media are longer than that in the cocopeat media both in 3 cm and in 5 cm thickness media (Table 2).The number of leaves of plants grown in soil media was significantly higher than in cocopeat media.The fertility of the media does not influence the initial growth of TSS yet.Whereas water availability is needed during the germination process to activate the enzymes that play a significant role in seed germination [17], At 18 DAS, there was no significant interaction between the type and thickness of the media for shoot length and the number of leaves of TSS seedling.The shoot length of the 3 cm thickness media, significantly longer than that in the 5 cm thickness media.Moreover, plants in soil media produce longer shoot lengths and more leaf numbers than in cocopeat media (Table 2).At 18 DAS, the influence of the environment and fertility of the media has begun to affect the seedbeds' growth.According to Rosliani et al. [18], the type of planting media is very noticeable, it can be seen from the change in the plant size especially plant height.Changes in plant growth might be due to the number and kinds of nutrient content in the growing medium.Koesriharti and Istiqomah [19] also reported that the availability and absorption of nutrients in the growing media significantly affect the growth and development of a pakcoy, including the nutrients uptake which is limited by nutrients that are in a minimum state.
At 21 and 25 DAS, there was no significant interaction between the type and thickness of the TSS seedling media on the shoot length.The shoot length of plants in the 5 cm media was significantly longer than the shoot length of plants in the 3 cm media.At 25 DAS, the number of leaves with soil media of 5 cm remained significant compared to the three other treatments.Meanwhile, the number of leaves on the soil media with a thickness of 3 cm indicates the greatest number of leaves.Description: (-) indicates no real interaction between treatments.The value followed by the same letter in the same column indicates no noticeable difference on Duncan's multiple range test with an α 0.05 At 42 DAS, there were significant interactions between the type and thickness of the growing media of bud length and total chlorophyll (Table 3).The growth of bud length and total chlorophyll at 42 DAS was inversely proportional to each other; that is, the longer the shoot, the smaller the total chlorophyll content, and the shorter the shoot, the greater the chlorophyll content remains.It was indicated that chlorophyll formed on longer shoots is less than that of the chlorophyll formed in the shorter shoot.Description: (-) indicates no real interaction between treatments.The value followed by the same letter in the same column indicates no noticeable difference on Duncan's multiple range test with an α 0.05.
A total chlorophyll affects the function of chlorophyll a and b in the leaves.Chlorophyll b serves as a photon-capturing antenna of sunlight, and chlorophyll a serves as an absorber and channeler of energy from chlorophyll b to be passed to the center of photosynthesis action.If the amount of chlorophyll a dan b is less, then the photosynthesis at plant leave is not optimal and will affect the subsequent process of plant growth.
Results of this study showed that soil seedling media with a thickness of 3 cm resulted in the lowest total chlorophyll content in the plant.On the other hand, soil seedling media with a thickness of 5 cm resulted in the highest total chlorophyll content in the plant.The total chlorophyll content in the 3 cm cocopeat planting media was not different from the 5 cm soil media due to the higher properties of cocopeat in holding water.When the humidity of the media is maintained, the chlorophyll biosynthesis process in the leaf tissue becomes more optimal.Irawan and Kafiar [20] reported that cocopeat media has a higher moisture content than soil media or husk charcoal.It was also reported by Pratiwi [21] that cocopeat has advantages as a planting media, such as the ability to bind water (water holding capacity).

Conclusion
Based on shoot length, stem diameter, root length, and total chlorophyll content, it was found that soil and cocopeat media with a thickness of 5 cm gave the best vegetative growth as well as the chlorophyll content, compared to soil and cocopeat media with a thickness of 3 cm.The results of this study provide information that using media with a thickness of 5 cm gives better seed growth than media of 3 cm.

Table 1 .
Formatting sections, subsections, and subsubsections.The results of the analysis of the nutrient content of the soil planting medium and cocopeat.

Table 2 .
The length of the shoots and the number of leaves of the seedbed TSS with different types and thicknesses of the growing medium aged 15, 18, and 21 DAS.

Table 3 .
The shoot length, the stem diameter, the length of the root, chlorophyll content of the leaves in the seedbed of TSS with differences in the type and thickness of the planting medium age 42 DAS.