Microtubers production by using Temporary Immersion System (TIS) bioreactor to potato varieties

As the national potatoes growth has become lower from year to year, it is now known that the problems came from the lack of certified potato seed varieties and the minimum access to sophisticated technology to make a good potato variety. The solution that can be made is to utilize microtubers as an efficient factor. The purpose of this research is to find the most effective method in micro tubers cultivation in vitro by comparing the conventional tissue culture method and the Temporary Immersion System (TIS) bioreactor method to four different potato varieties (Granola L., Dayang Sumbi, Atlantic Malang, Maglia). This research uses a split-plot design with a completely randomized design by using two factorial. The result of this study shows that the microtubers in the multiplication and production step using the TIS bioreactor method has a higher average compared to the conventional tissue culture method. As the various details, Dayang Sumbi has the highest parameter such as most sprouts, primer roots, diameter, wet weights, and fastest time growth. Granola L. excel in planlet height and most tubers. Atlantic Malang in the most multiplication and nodus. Meanwhile Maglia excel in most leaves.

Factors Affecting Farmers' Decisions to Use Certified Granola Potato Seeds in Parbuluan District, Dairi Regency

Agricultural products, including potatoes, are still faced with several problems with fluctuations and quite high price sensitivity, mainly due to changes in demand and supply. Decreased (degenerative) production occurs because of the disease that accumulates in each generation of potato seeds and continues to be carried over to the next generation. So that certified potato seeds are needed to increase farmers' production. This study will analyze the influence of the factors of farmer age, education level, farming experience, productivity, seed price, land area, farmer group participation in influencing farmers' decisions to use certified potato seeds. From the total population of potato farmers as many as 365 farmers in Parbuluan District, Dairi Regency, North Sumatra, testing was carried out on 78 samples with the results that the variables of productivity, price, farmer group participation had a significant effect on the use of certified potato seeds, while the variables of age, education, experience, area Land does not have a significant effect on the use of certified potato seeds and productivity, price, farmer group participation, age, education, experience, and land area all influence farmers' decisions to use certified potato seeds. Keywords: Certified Potato Seed, Potato Farmer, Potato Production.

Kendala Adopsi Benih Bersertifikat untuk Usahatani Kentang

<p><strong>English</strong><br />Most potato farmers in Indonesia do not adopt certified potato seed. Relatively expensive price of certified seed is the main reason the farmers apply the seed produced by themselves. In general, prices of potato produced using certified seed and those produced using uncertified seed are relatively equal. The farmers who regularly apply certified seed are those having partnership with the potato processor. High risk of potato seed production discourages the certified seed producers to produce it in sufficient amount for market supply. Less cost of certified seed production and improved potato selling price will enhance farmers’ adoption of certified seed. The government needs to empower the farmers to produce quality seed by themselves through informal seed system development rather than they have to depend on commercial certified-seed produced by the formal seed industry.</p><p> </p><p><strong>Indonesian</strong><br />Adopsi benih kentang bermutu oleh petani kentang di berbagai daerah relatif rendah. Harga benih kentang bersertifikat yang relatif lebih mahal dibanding benih kentang yang dibuat sendiri oleh petani merupakan alasan utama petani tidak menggunakan benih bersertifikat. Harga kentang yang berasal dari benih buatan sendiri dibanding harga kentang yang berasal dari benih bersertifikat jika dijual ke pasar umum harganya relatif sama. Penggunaan benih kentang bersertifikat dilakukan petani terutama untuk kemitraan dengan prosesor kentang. Risiko tinggi dalam memproduksi benih kentang bersertifikat merupakan disinsentif bagi penangkar benih kentang untuk berproduksi dalam jumlah yang memadai. Kemudahan dalam menangkarkan benih bersertifikat dan membaiknya harga jual kentang akan meningkatkan adopsi petani terhadap benih kentang bersertifikat. Pemerintah juga harus berinisiatif agar petani secara mandiri bisa menghasilkan benih kentang bermutu melalui pengembangan sistem benih informal dan tidak harus bergantung pada benih kentang komersial yang dihasilkan industri benih formal.</p>

Incidence and Impact of Verticillium dahliae in Soil Associated with Certified Potato Seed Lots

Verticillium dahliae causes Verticillium wilt of potato and can be found in soil associated with potato seed tubers. The purpose of this research was to quantify V. dahliae in soil associated with certified seed tubers and determine if this potential inoculum source is related to disease development in the field. Approximately 68% of seed lots assayed contained V. dahliae-infested soil on seed tuber surfaces (seed tuber soil). Over 82% of seed lots contained V. dahliae in loose seed lot soil obtained from bags and trucks used to transport seed tubers. Most samples contained ≤50 CFU/g but some contained >500 CFU/g. Most isolates (93%) were vegetative compatibility group 4A. Populations of V. dahliae in stem sap increased with increasing inoculum densities in field soils only when V. dahliae concentrations in seed tuber soil were low. High concentrations of V. dahliae in seed tuber soil resulted in greater stem sap colonization when V. dahliae inoculum densities in field soil were low (P < 0.01) and resulted in greater pathogen inoculum densities in postharvest field soils (P = 0.04). Seed tubers contaminated with V. dahliae-infested soils may introduce the pathogen into fields not previously cropped to potato or recontaminate those which have received preplant management practices. Long-term management of V. dahliae requires reducing propagules in soil associated with seed lots.

The Occurrence of PVYO, PVYN, and PVYN:O Strains of Potato virus Y in Certified Potato Seed Lot Trials in Washington and Oregon

Totals of 960 and 286 certified potato seed lots from locations across North America were planted in trials in Washington and Oregon, respectively, in 2001 to 2003 and tested for strains of Potato virus Y (PVY). The incidence of PVYO-infected lots averaged 16.4 and 25.9% in the Washington and Oregon trials, respectively. There was a general trend of increasing incidence of the PVYO, PVYN:O, and PVYN strains during this period, as evidenced by more infected cultivars, sites of seed origin, and number of seed growers providing infected seed lots. In particular, there was a dramatic increase in seed lots with the PVYN:O strain from 2002 to 2003. PVYN:O, in contrast to PVYO, which only causes yield reduction, also causes internal and external damage to tubers, making them unmarketable. In 2003, PVYN:O occurred in seed lots originating in eight states and three Canadian provinces. The increased incidence of PVYN:O was likely due to the difficulty in differentiating this strain from PVYO. The prevalence of PVY in potato seed lots documented herein poses a threat to potato production in the United States and suggests that current measures to reduce the incidence of this virus are inadequate.

Incidence of Colletotrichum coccodes in Certified Potato Seed Tubers Planted in Washington State

Incidence of Colletotrichum coccodes in lots of certified seed tubers planted in Washington state, originating from nine western and midwestern states in the United State and two provinces in Canada, ranged from 0 to 90% in 1994 and 0 to 53% in 1995. In 1994, significant interactions between state/province and cultivar, and between seed grower and cultivar, were evident. In 1995, incidence of C. coccodes in seed lots did not vary significantly among states and cultivars. C. coccodes was not isolated from nuclear seed tubers and incidence of infected tubers was higher with higher seed generations. The fungus was isolated from the tuber periderm and outer medulla tissues and isolation frequency was greater from tuber stem ends than from either bud ends or lateral sections. Significantly greater stem infections developed in plants grown from seed tubers in which C. coccodes had been detected than in plants grown from seed tubers from which C. coccodes had not been isolated. This study confirms that C. coccodes is distributed among potato-production areas within seed tubers, and that seed tuber infection increases the incidence of early-season plant infection.