Exploration and identification of morphological characters of local Samosir shallot (Allium ascalonicum L.) accessions for sustainable agriculture

Samosir local shallots are a superior local resource commodity with a very distinctive taste and aroma, more pungent and fragrant, the color is redder and shiny. Currently, Samosir local shallots are experiencing a shortage therefore exploratory research is needed to obtain sources of quality planting material for sustainable agriculture. The objective of the research was to explore and identify the morphological characters of Samosir local shallots accessions at Bakti Raja District. The research method was carried out using a descriptive exploratory method. The results showed that the Samosir local shallots from all the accessions observed had cylindrical leaves with holes, with dark green leaf color, medium leaf size, low leaf density, umbrella-like flower shape, white flower color and purple/white bulb color. There is diversity in the shape of the bulb, namely Siunong-unong Julu accession, Simangulampe 1 and Simangulampe 2 have a globe tuber shape, while Simamora 1 accession has broad elliptic leaf shapes, Simamora 2, Simamora 3, Simamora 4 Marbun Tonga Dolok, Tipang 1 and Tipang 2 has a broad oval shape. Tipang 2 accession had the highest weight of 100 dry shallot bulbs, Simangulampe 1 and Simangulampe 2 accessions had the highest tuber diameter.


Introduction
Shallot (Allium ascalonicum L.) is a horticultural commodity that plays an important role as a flavoring agent, a mixture of ingredients for the food industry and a source of biopharmaceuticals, because of its bioactive compounds such as flavonoids, saponins, allicin, aliin, essential oils, and quercetin [1].In shallots, quercetin has anti-diabetic, anti-osteoporosis, anti-cancer, antioxidant, anti-diarrheal, hypoallergenic and antibacterial properties [2].
Samosir local shallot is a superior commodity whose fame has begun to decline, so it needs attention.The advantages are a very distinctive taste and aroma, fragrant and more pungent, redder and shiny color, less air content, although the size is smaller than other onions, and a high selling price in the market.Until now, the supply of local Samosir shallot seeds is still carried out through tubers and is not yet available in the form of botanical seeds/TSS.
The cultivation of shallot usually is done by using bulbs as planting material.The main problems are the high cost of providing seed tubers (40% of the total production cost), the lack of assurance of seeds due to bulb-borne pathogens such as Colletotrichum sp., Fusarium sp., Alternaria sp., and viruses from the plant of origin, as well as the high volume of seedlings.requires expensive warehouse storage and transportion [3].The alternative to overcome the problem is to use True Shallot Seed (TSS) as planting material.
Samosir Regency and the areas around Lake Toba from the 1970s to 2005 have been known as the main producing areas shallots in North Sumatra where the varieties planted are varieties Samosir local.The government's introduction of imported shallots into the Samosir region has the potential to increase the scarcity of the local shallot population.Therefore, it is necessary to prevent the extinction of local Samosir shallots, through inventory, characterization and evaluation of local Samosir shallot plants, in order to save shallot local resources as well as hopefully can developed into botanical seeds which are proven to be superior when compared to bulbs as planting material.Shallot cultivation from TSS needs to be developed, because it has the advantage of increasing tuber yield up to two times (26 tons/ha production), less seed volume (seed needs around 7,5 kg/ha compared to bulbs around 1.5 t/ha) rage, cheaper of cost transportation, healthier and stronger because it is virus free, bigger tubers [4,5], longer seed storage (1-2 years) while bulbs as planting material can only be stored 4 months [6,7].
In order to obtain the best planting material, it is necessary to first know the characteristics of Samosir local shallots in production centers, so that data on the morphological characteristics of Samosir local shallots will be obtained for further development.Research on the identification of morphological characters of local Samosir shallots is still rarely carried out.Previous research has studied gamma ray radiation and its effect on the morphological, physiological and production characteristics of local Samosir shallots [8,9], the genetic profile of shallots from Samosir Island using SSR analysis [10], the effect of soil texture on shallot production Samosir [11], genetic diversity of shallot from several location in North Sumatera using RAPD markers [12].
Based on the background above, the research aims to obtain information regarding morphological characterization of existing Samosir local shallots can be used as superior seeds with high productivity, as an ingredient in the formation of TSS.

Place and time of research
This research was carried out in Bakti Raja District, Regency Humbang Hasundutan, North Sumatra Province in June-August 2023.

Research tools and materials
The tools used are questionnaires, digital caliper, ruler/meter, digital scales, envelopes, data books, stationery and cameras.The material used is local shallot Samosir found at survey site in Bakti Raja District.

Research method
The method used in the research is a survey method, namely identify the agronomic characteristics of shallots in Bakti Raja District directly in the field.The research was carried out in 3 stages which includes exploration and identification of morphological characteristics of shallots local Samosir in Bakti Raja District.In the first phase, exploration for local Samosir shallots was carried out at planting centers in the Bakti Raja District area (Humbang Hasundutan Regency), covering 5 villages namely Siunong unong Julu, Simamora, Simangulampe, Marbun Tonga Dolok and Tipang.A total of 10 accessions of local Samosir shallots were used to observe morphological characters.These accessions were collected from various places in the form of living plant collections.
In the second stage, observations were made of the morphological characters and shallot cultivation techniques at the sampling locations.At this stage the characterization and identification of morphological (visual) characters of local shallot Samosir accessions in Bakti Raja.The third stage, namely the data analysis technique carried out is descriptive statistics.
Data observation was carried out by observing qualitative morphological characters at the location including leaf characters (shape, size, color, density), flowers (shape, color), tubers (shape, color) using International Plant Genetic Resources Institute (IPGRI) descriptors.

Result and discussion
Based on the exploration of local shallots from Samosir at Bakti Raja, 10 accessions were found consisting of 1 accession in Desa Siunong unong Julu, 4 accessions in Desa Simamora, 2 accessions in Desa Simangulampe, 1 accession in Desa Marbun Tonga-Dolok and 2 accessions in Desa Tipang.All accessions in the research are in the highlands with an altitude of more than 900 m above sea level (Table 1).The soil pH for each accession ranges from 4.37 -5.10, which is classified as acid soil, while the wind speed at the research location is classified as weak because it is < 5.4 km/hour according to the Beaufort Scale [13].The local Samosir shallots from all the accessions observed all have hollow cylindrical leaf shapes, with dark green leaf color, medium leaf size, low leaf density, umbrella-like flower shape, white flower color and purple/white bulb color.There is diversity in the shape of the bulb, namely the Siunong-unong Julu accession, Simangulampe 1 and Simangulampe 2 have a globe bulb shape, while the Simamora 1 accession has broad elliptic leaf shapes, Simamora 2, Simamora 3, Simamora 4, Marbun Tonga Dolok, Tipang 1 and Tipang 2 has a broad oval shape (Table 2).This difference could be due to kinship distance, apart from taking samples at different ages also cause the occurrence of differences in qualitative data results.
The color characteristics of each tuber accessions have the same character is purple/white.This is line with previous research which stated that the color uniformity bulbs thoroughly for each the accession is dark purple or lilac in color bright [14].
Figure 1 shows the phenotypic leaves, flowers and bulb.Each observation parameter has different morphological characteristics.In general, shallots are propagated vegetatively using bulbs that will produce the same characters as their parents.Shallots that are spread in Indonesia are thought to have a high level of diversity.Knowledge of genetic diversity is very important in breeding programs, because this is the basis for further crop development.Exploration and identification are the main activities in the breeding program by gathering and assembling all available sources of genetic diversity.Then proceed with the characterization of all the traits possessed by the source of genetic diversity which can be used as basic information to continue the breeding program.Morphological markers can be measured visually based on the qualitative characters possessed by plants such as the shape and color of leaves, flowers, bulb and seeds, where these characters are controlled by simple genes and are slightly influenced by environmental factors.In general, morphological markers are used to induce genetic variation between cultivars, species or population accessions in germplasm characterization [15,16].

Table 2. Identification of local Samosir shallot characters for each accession.
Leaf (hollow cylindrical shape, dark green, medium size, low density) Flower (like an umbrella, white color) Bulb (broad oval shape, purple/ white color) Bulb (globe shape, purple/white color) Bulb (broad elliptic shape, purple/white color)  The weight of 100 dry bulbs of local Samosir shallots varies for each accession (Table 3).The Tipang 2 accession had the highest weight of 100 dry shallot bulbs (557.40 g), while the Simamora 2 accession had the lowest weight of 100 dry shallot bulbs (292.97 g).Simangulampe 1 and Simangulampe 2 accessions had the highest tuber diameter (23.94 mm) while the Siunong unong Julu accession had the lowest tuber diameter (22.92 mm).Bulb formation shallots depend heavily on the results of photosynthesis are translocated to the bulbs which influence the quality of the bulbs which are characterized by the weight of 100 dry bulbs and bulb diameter.Table 3. Production and bulb diameter of each shallot accession.

Conclusion
The Samosir local shallots from all the accessions observed had cylindrical leaves with holes, with dark green leaf color, medium leaf size, low leaf density, umbrella-like flower shape, white flower color and purple/white bulb color.There is diversity in the shape of the bulb, namely the Siunong-unong Julu accession, Simangulampe 1 and Simangulampe 2 have a globe bulb shape, while Simamora 1 accession has broad elliptic leaf shapes, Simamora 2, Simamora 3, Simamora 4 Marbun Tonga Dolok, Tipang 1 and Tipang 2 has a broad oval shape.Tipang 2 accession had the highest weight of 100 dry shallot bulbs (557.40 g).Simangulampe 1 and Simangulampe 2 accessions had the highest tuber diameter (23.94 mm).

Figure 1 .
Figure 1.The phenotypic appearance of 10 accesions of local Samosir shallot in Bakti Raja District.

Table 1 .
Altitude, wind speed, and soil pH for each shallot accession.