Seedling production management of Shallots from seeds based on local wisdom technology

True seed shallot (TSS) has become an alternative material for shallot seeds to fulfil the lack of good-quality seed bulbs. Transplanting was the most popular TSS planting method for farmers. This technic uses seedlings as planting material. The seedling production was the most crucial stage in transferring technology from vegetative propagation (seed bulb) to generative propagation (TSS). This paper reviews the advantages and disadvantages of several seedling techniques and the strategy for selecting techniques and maintaining seedlings that are suitable to the specific conditions at the seedling site using local wisdom technology. Data and information were tracked and selected then organized in review writing paper. Analysed and data synthesis showed that several techniques could be used to produce shallot seedlings, including technical seedling, use of seedling media, seed treatment and seedling harvest arrangements. The selection of seedling techniques and maintenance management is influenced by several factors, including environmental factors of cultivation, capital availability, labour and other site-specific conditions. Seedling production can be developed as a new unit system (seedling grower) to produce excellent quality propagation material. The implications of this paper are expected to be used by seedling growers to improve the best practice of seedling production with local wisdom technology.


Introduction
Shallot (Allium cepa L. Aggregatum group) is a strategic and crucial vegetable in Indonesia because any changes in the price of shallots can affect national economic growth.Shallot is a vegetable with high economic value, most widely cultivated in almost all parts of Indonesia.It contributes significantly to most regions' economic development [1][2][3].The prices of shallots play an essential role in shaping the inflation rate in Indonesia [4][5][6].Efforts to maintain the availability and supply of shallots in the market are important strategies to maintain price stability and control inflation.
Low productivity is still a problem in shallot production in Indonesia, where in 2020, it was 1.815 million tons from a harvested area of 186.9 thousand hectares with average productivity of 9.71 tons ha - 1 [7].Shallot is a potential agricultural export commodity.Indonesian shallot exports reached US$ 13.74 million in 2020, an increase of 29.8% from the previous year with US$ 10.58 million [8].
Production and productivity of shallots still could be increased, considering that there is still a yield gap between productivity at the farmer level and the potential yield of new superior varieties that have been released.Several high-yielding varieties, such as 'Super Philip', 'Batu Ijo', 'Bauji' and 'Biru Lancor', have potential yields between 16-20 tons ha -1 [9].The main constraints in the production of shallots include high input costs, pests, and diseases [10].The use of good-quality seeds is one factor that determines shallots' productivity.Shallot cultivation generally uses bulbs as planting material, and nowadays, innovation to using seeds as planting material has been introduced to farmers [11].The availability of good-quality seeds is still an obstacle during the planting season.In the case of Central Java, the seed requirement was only fulfilled by about 35% [12].The seed was one component with the high cost of shallot farming production input.Several research results reported that the seed cost in shallot farming ranges from 30%-44.8% of the total cost of farming [13][14][15].Opportunities to improve farm cost efficiency can be achieved using True Seed of Shallot (TSS) as shallot seeds.The use of TSS seeds is economically feasible because it may increase the net income of 22-70-million-rupiah ha-1 also provides a profit of 224.8 million rupiahs per hectare with a B/C ratio of 4.4 in on-season [16] and provides a profit of 40 million rupiahs in the off-season [17] compared to seed bulb.This increase in income was obtained from a twofold increase in yield compared to seed bulbs and seed cost efficiency [18,19].These profits and increased income may attract farmers to adopt TSS technology.Pangestuti and Sulistyaningsih [20] stated that TSS could save 62.5% -80% of seed costs.Adiyoga et al. [3] reported a high potential for adopting TSS in production centres and new shallot development areas outside Java Island.It is necessary to develop efforts at the field level to increase TSS adoption by farmers.
Research information related to TSS has been widely reported, including the production of the mini bulb and planting media [21], TSS seeding techniques to produce seeds and mini bulb [22], TSS seedling media [23] nursery technique with array system and soil block [24]), the influence of seedling population and TSS seeding technique [25,26].Seeding was the most crucial stage for farmers in transitioning phase from using vegetative propagation (bulbs) to generative propagation (TSS) [27].Good seedling quality will affect growth after transplanting and crop yields [28].As a transitional technology, there are often obstacles to producing good seedling therefore farmers prefer to buy ready-to-plant seedlings.Producing ready-to-plant TSS seedlings has developed into a new business unit in the shallot seed system, as has emerged in West Nusa Tenggara and Brebes, Central Java.
Seedling production technology can be adapted to local wisdom technology where the nursery is carried out.The specific needs of this local wisdom are related to the use of planting media, nursery methods and nursery maintenance.This paper aims to explore the most optimal TSS nursery technology based on local wisdom technology.

TSS Seedling Production Techniques
Dried shallot seeds have ovoid to triangular shape, one side is convex, and the other tends to be flat with a black seed coat and a granular feature.Seed germination consists of 15 sub-stages, starting from the imbibition process, the release of the radicle, the emergence of cotyledons, the hook phase, the whip phase, the release of true leaves until the development of 3-4 true leaves with pseudo stems that are thickened indicating that the seedling is ready for transplanting [29].This seeding process takes place 4-6 weeks after sowing (WAS) but can also be extended to 8 MSS [30].
Seed nursery engineering expertise and a longer planting time (19-30 days) are common obstacles in TSS cultivation.The nursery technique to produce good seedling is an essential point in the TSS cultivation stage which needs serious attention.Adopting TSS as planting material faces obstacles in using seedling media and the type of nursery.The kind of planting media significantly affects the fertility of shallot seedling growth which is reflected in the plant height variable [21].According to Nabih et al. [31], more loose soil planting media resulted in better root growth than clay media.Allium's root development rate is crucial in influencing plant growth and formation.
TSS seeding can be carried out with several techniques: direct seeding on beds/"tabela" systems and seedlings with intermediate media, such as seedlings in nursery tanks, plastic pots, trays, and soil blocks.The most fundamental difference between these two techniques is the shape of the resulting seedling.Direct seedlings will produce ready-to-plant seedlings without seedling media (pulled seedling), while seedlings with intermediate media produce seedlings with built-in seedling media in the root section (Figure 1).The use of these two systems can be adapted to the preferences and suitability of the TSS planting site.The various nurseries and their advantages and disadvantages are presented in Table 1.Using soil blocks is currently one of the technological innovations in the nursery.The advantage of soil block media is that the seedling roots will not be damaged when transplanting because the soil block where the seedlings grow are directly planted in the field [32] (It will increase successful percentage of transplanting rate.Technically, soil block media can accelerate seedling age where 30 days of seedling yields higher bulbs weight than 45 days of seedling, but 45 days of the seedling is more economical because it has a B/C ratio and a higher marginal rate of return [33].Eko and Shoidah [34] reported that the seedling system using soil blocks was better than direct seedling in beds.This aspect is indicated by the components of growth and yield of shallots.However, seedlings from beds (direct seedling) were preferred by farmers in Purworejo Village, Ngantang, Malang, compared to seeds using trays or soil blocks.Seedling growth faster if use direct seedling than seedlings in trays or soil blocks.Growth in the field of direct seedling seeds from the beds was also more rapid, with a 100% growth percentage, while seeds from growth trays were slow, and the growth percentage was 85% [17].This result shows that the use of type of seedling will have different effect in different location.

TSS Management Based on Local Wisdom Technology
Seedling management is needed to ensure that seedlings that arrive at users/farmers are in optimum conditions for transplanting.Important aspects to consider in seedling management are the allocation of seedling area, the composition of the seedling media, number of seeds to be prepared, and the age of the seedlings.

Land required to produce seedlings
The allocation of land area for nurseries must be anticipated.This aspect is also needed if farmers do the nursery themselves.The size of land required for seedling production depends on the nursery system.The seeds planted in an array or spread without any spacing for direct seeding will require a land area of 400-700 m 2 per hectare [35], with 3-7.5 kg seeds.The number of seeds needed depends on the seed viability and the nursery system [11,20].Seedling systems using media, both plastic pots and soil blocks, require a smaller number of seeds with higher growth rate when transplanting than direct seedling systems.
The precise technique of the nursery will affect seedlings germination and growth of TSS seedlings because transplanting may not be successful due to root damage [34].Nurseries must pay attention to plant density.The high plant density can lead to competition of seedlings that could affect the yield, both the number and size of the bulbs produced, respectively.If the planting distance to small, there will be plants with stunted growth, either due to shade or competition for water, nutrients, and oxygen.Plant with small planting distance requires more intensive maintenance because of higher disease attacks, especially in the rainy season [36][37].

Seedling Media Composition
The precise seedling media's composition will also affect the germination and growth of shallot seeds from seed.High-quality seedling media will produce seeds with optimal growth.According to Sopha and Basuki [23], seedling media can affect bulb diameter because seedling media has limited nutrient availability, leading to nutrient competition between individual plants.In addition, the composition of the seedling media significantly affected the number of shallot bulbs.Thoriqussalam and Damanhuri's [38] showed that soil seedling media mixed with cocopeat and husk charcoal gave the best results from several other compositions.
Seedling media for TSS varied by utilizing the materials available at the site (specific location).The seedling media which produced the highest percentage of shallot growth, was a mixture of Andisol soil + horse manure 1:1 (v/v).However, the seedling media according to this recommendation was not available in Brebes, so as an alternative, farmers in Brebes used a mixture of Alluvial paddy soil, sand, and manure 1:1:1(v/v/v) with a growth percentage of 46.5% [23].In Lowokwaru -Malang, seedlings with seedling competition media soil: husk charcoal 2:1(v/v), soil: cocopeat: goat manure 2:1:1(v/v/v) and soil: cocopeat: husk charcoal 2:1:1 (v/v/v) resulted in good growth and production of shallots when compared to seedlings from soil only [38].Prahardini et al [17] mentioned that the nursery with beds carried out by farmers in the Karya Bhakti I Ngantang Farmers Group, Malang Regency, used a mixed loose soil: manure (compost): husk charcoal = 1: 1: 1 (v/v/v).Seedling media must contain organic matter.According to [39] organic matter as a seedling medium is crucial in increasing seedling growth because organic matter can improve soil's physical properties.According to [40], the growing media can affect the size of the plant and shallot bulbs.

Number of Seed for Nurseries
Adin [35] reported that the use 1 kg of seeds with an area of 100m 2 required Rp. 4.500.000 in cost, and if it is put into business, it will generate a profit of Rp. 5.500.000,00 in one seedling cycle.The appropriate age of seedling to be transferred from the nursery to the field is one of the determining factors for the success of shallot cultivation using TSS

Seedlings age
Seedlings age is an important factor affecting shallot yield.Good seedlings quality can produce better yields [41].The age of the seedling is usually related to the size of the seedlings; the older seedlings have a larger size compared to the younger seedlings.We have experienced that the tiny seedlings have difficulties adapting to the field condition after transplanting, resulting in a low number of plants growing.The seedlings age was also influenced by the maintenance technique in the nursery and environmental conditions.The same seedlings age may significantly differ in growth when planting in lowlands and highlands (data not shown, authors field experience 2019-2022).Seedlings growth in the lowlands had better performance than in the highlands.
The result of various research and the field experience of farmers/seed pickers (direct communication) showed that the optimum seedling age still varies between 4 and 8 weeks.According to [33] 30-45-days after sowing seedlings showed no significant growth in the field after transplanting.According to [42]), the optimum transplanting seedlings age in Solok -West Sumatra (an area vulnerable to climate change) is five weeks (35 days).Mariana [43] showed that the nursery age of 4 -6 weeks is a good nursery age range for shallot harvest.But according to [44], older seedlings (age 50 days or eight weeks) produced higher bulbs than young seedlings.In areas with low temperatures, there is an indication that the older seedling age will have less bulb aggregation than the younger seedlings [45][46].This condition indicates that the different locations may affect the optimum seedling age for growth and shallot production

Conclusion
TSS was a potential alternative technology to increase the availability of good quality shallot seeds in Indonesia.A crucial stage in TSS cultivation was the production of good-quality seedlings.There are various nursery techniques to produce good seedlings, such as direct and indirect seeding using intermediate systems such as seeding in germination trays, seeding with plastic pots, and seeding with soil blocks.Nursery management, such as setting the allocation of land area for the nursery, seed requirements, selection of planting media composition and seedlings age, can be adjusted to location with local wisdom technology to obtain good seedling quality and the best TSS growth in the field.

Figure 1 .
Figure 1.Variations of TSS nursery techniques. A. Seed directly on the bed; B. Seedling in the seedling tank; C. Seedlings on plastic pots; D. Seedling on soil blocks.

Table 1 .
Variations in the type of seedling, advantages and disadvantages, as well as local wisdom suitability