5. Diversity, Local and Formal Seed Supply

2000 ◽  
pp. 218-252
Keyword(s):  
1988 ◽  
Vol 53 ◽  
Author(s):  
N. Lust

The  study deals with the spontaneous resettlement of a fire area, after  destruction of 600 ha Scots pine forest. The following items have been  examined in particular: the composition of the tree species, the duration of  the regeneration period, the influence of the parent stand, the exposition,  the slope, the treatment, the fire regime and the social differentiation.      The resettlement took place very quickly and over a very short period.  Birch and Scots pine take up 95 % of the stem number. The regeneration result  is precarious, yet mostly good. The parent stand is favourable both to seed  supply and to microclimate, but only over a short distance. The Scots pine  prefers more open and dry areas, whereas birch needs more humidity.     Practice has shown that natural regeneration of Scots pine stands is  possible. The forest treatment, however, is very important. It determines not  only the immediate result of the regeneration, but also the composition and  the structure of the future stand.


2018 ◽  
Vol 69 (12) ◽  
pp. 1237 ◽  
Author(s):  
G. C. Wright ◽  
M. G. Borgognone ◽  
D. J. O Connor ◽  
R. C. N. Rachaputi ◽  
R. J. Henry ◽  
...  

Breeding for improved blanchability—the propensity of the testa (skin) to be removed from the kernel following rapid heat treatment—is a priority for improvement in the Australian Peanut Breeding Program (APBP). Easy removal of the testa by blanching is required for processing of peanuts into peanut butter and various other confectionary products. Thus, blanchability is an economically important trait in any newly released cultivar in Australia. A better understanding of the range of genetic variation, nature of inheritance and genotype×environment (G×E) interactions, and the development of a low-cost method to phenotype in early generations, could speed up breeding for this trait. Studies were conducted to develop a low-cost, rapid method utilising minimal amounts of seed to phenotype in early generations, along with an assessment of G×E interactions over a range of years and environments to derive optimal selection protocols. Use of a smaller kernel sample size than standard (50 vs 200g) was effective for accurately assessing blanchability in breeding lines and could allow selection in early generations (e.g. in seed produced from a single F2 plant where seed supply is adequate). G×E interaction for blanchability was shown to be very low. Genotypic variance explained 62–100% of the total variance for blanchability, assessed in two diverse germplasm pools including 107 accessions in the USA mini-core over three environments and multiple APBP breeding lines grown over nine different years–environments. Genotypic correlations between all environments were very high (~0.60–0.96), with heritability for the blanchability trait estimated to be very high (0.74–0.97) across the 13 trials. The results clearly demonstrate that effective selection for improved blanchability can be conducted in early generations and in a limited number of contrasting environments to ensure consistency of results.


1970 ◽  
Vol 6 ◽  
pp. 10-22 ◽  
Author(s):  
Bimal K Baniya ◽  
Radha K Tiwari ◽  
Pashupati Chaudhary ◽  
Surendra K Shrestha ◽  
Pushpa R Tiwari

Formal and informal seed supply systems of rice (Jumla, Bara and Kaski), finger millet and taro(Kaski) were studied in three ecosites of Nepal during 1999-2001 to understand the processes ofseed flow, seed production, seed selection and storage systems. A survey was conducted at 48 to96 households. Informal seed supply was the only system in Jumla and Kaski and formal systemexisted only in Bara. The main sources of seed were farmer's own saved seed (67-91%), seedfrom neighbors and relatives. Exchange of germplasm was the main basis of fulfillment fromother sources. All farmers obtained seed from their own village, while farmers introducedmaterials occasionally from outside village. Most of the farmers followed seed selection beforeor after crop harvest. Rice field selection and plant selection based on a fixed set of criteria wasthe common practice. Non lodged plants with more grain per panicle, bold grains, well-maturedand uniform plants, long panicle, true to type, good looking grains, free from diseases andinsects were the main rice seed selection criteria. All farmers from both sites stored rice seeds bylocal methods in the locally available containers. Mor and Mudkothi are the special strawcontainers to store rice seed in Bara. Dhara is a special mud structure used to store rice seeds inJumla. Finger millet seed supply system was mostly similar to that of rice seed system. Ninetyone percent farmers saved seed for their own use; however, many of them changed finger milletseeds lots or varieties regularly for their particular plot. Ears selection during harvest by setcriteria for seed purpose was the common practice. Farmers stored finger millet seed carefully insmall locally available containers and tried their best to maintain the quality of seed duringdifferent stage of seed production. Taro has diverse planting materials: cormels, corms witheyes, suckers and corm with small cormels. Taro planting materials management is totallyinformal and almost 89% farmers saved these materials for their use and replaced them mostlyafter 3 years. Farmers had fixed criteria of corms and cormels selection for planting purpose andfocus and more on disease free. Storage of planting materials was locally by using localmaterials and methods. Understanding of seed system in various crops helps to developconservation strategy.Key words: Seed flow; seed production; seed selection; seed storage; seed systemDOI: 10.3126/narj.v6i0.3343Nepal Agriculture Research Journal Vol.6 2005 pp.39-48


2020 ◽  
pp. 82-85
Author(s):  
M.S. Nagendra ◽  
P. Selvaraju ◽  
R. Jerlin ◽  
K. Ganesamurthy ◽  
N. Senthil

Identification and characterization of crop varieties are crucial for ensuring the genetic purity of seeds. The present investigation was carried out to identify suitable chemical methods that are fast, reliable and easy for seed analysts, breeders and seed producers for identification of a variety. Twenty-five popular rice varieties in the seed supply chain of Tamil Nadu were subjected to phenol, modified phenol, NaOH, aroma, gelatinization temperature (alkali spreading value), GA3 and 2,4-D tests. The results of the experiment revealed that phenol and modified phenol tests changed the colour of TKM 9 and TRY 1 variety to brown but no colour change was observed in the variety I.W. Ponni variety. The NaOH test is useful for the identification of TKM 9 variety as it changed the colourless solution to red. GA3 and 2,4-D tests characterized the varieties based on the shoot growth into two and three groups respectively. However, all the variety lacked aroma and exhibited a high gelatinization temperature.


2019 ◽  
Vol 14 (1) ◽  
pp. 19
Author(s):  
I Nyoman Adiasmara Giri ◽  
Sari Budi Moria Sembiring ◽  
Gigih Setia Wibawa ◽  
Haryanti Haryanti

Teripang pasir, Holothuria scabra merupakan salah satu komoditas perikanan yang mempunyai nilai ekonomi tinggi di Asia. Populasinya di alam semakin menurun karena aktivitas penangkapan secara berlebihan. Untuk mengantisipasi menurunnya stok teripang di alam, maka perlu segera dilakukan pengembangannya melalui kegiatan budidaya. Di samping ketersediaan benih, pakan merupakan salah satu faktor yang sangat menentukan keberhasilan budidaya teripang. Penelitian ini bertujuan mendapatkan formulasi pakan buatan yang tepat untuk mendukung pertumbuhan teripang pasir. Empat pakan percobaan dengan formula berbeda, sebagai perlakuan, dibuat dalam bentuk pelet kering. Pakan diformulasi menggunakan tepung Sargassum sp., tepung Ulva sp., tepung Gracilaria sp., yang dikombinasi dengan tepung kedelai dan tepung beras dengan proporsi berbeda. Pada percobaan-1, benih teripang (hasil pembenihan) ukuran 14,4 ± 6,5 g ditebar dalam delapan buah bak berukuran 2 m x 1 m x 0,6 m dengan kepadatan 100 ekor/bak. Teripang diberi pakan percobaan dengan frekuensi satu kali sehari selama lima bulan. Pada percobaan-2, benih teripang ukuran 7,0 ± 1,6 g ditebar dalam delapan buah keramba jaring apung berukuran 1 m x 1 m x 1 m yang diletakkan di tambak dengan kepadatan 50 ekor per jaring. Teripang diberi pakan percobaan dengan frekuensi satu kali sehari selama empat bulan. Hasil percobaan menunjukkan pakan buatan yang diformulasi menggunakan tepung Sargassum sp., tepung Ulva sp., tepung kedelai, dan tepung beras dapat mendukung pertumbuhan dan sintasan teripang pasir, baik yang dipelihara dalam bak maupun dalam jaring apung di tambak. Sintasan teripang tidak dipengaruhi oleh pakan percobaan (P>0,05). Pakan buatan dengan komposisi bahan 30% tepung Sargassum sp., 35% tepung Ulva sp., 4% tepung kedelai, dan 18% tepung beras menghasilkan pertumbuhan terbaik dan dapat diaplikasikan pada pemeliharaan teripang pasir.Sandfish, Holothuria scabra is a highly valued sea cucumber product in Asian markets. Current exploitation has reduced its wild stock to an alarming level. In order to alleviate the over-exploitation to its wild population and provide a reliable supply of market demands, the aquaculture technology of sandfish has to be developed and perfected. Feed is one of the important factors for a successful sea cucumber aquaculture, besides seed supply. The aim of this experiment was to obtain an appropriate feed formulation to support the growth of sandfish. Four experimental diets (dry pellet) were formulated using seaweed meal of Sargassum, Ulva, and Gracilaria, combined with soybean meal and rice flour, each with different proportions. In experiment-1, cultured sandfish juveniles with an initial weight of 14.4 ± 6.5 g were stocked into eight concrete tanks (2 m x 1 m x 0.6 m) with a density of 100 juveniles/tank. In experiment-2, sandfish juveniles with an initial weight of 7.0 ± 1.6 g were stocked into eight floating net cages (1 m x 1 m x 1 m) erected in a pond with a density of 50 juveniles/cage. The sandfish juveniles were fed once daily with the experimental diets for five and four months for experiment-1 and experiment-2, respectively. Results of the experiment showed that diet formulated with Sargassum, Ulva, and soybean meals and rice flour produced good growth and survival of sandfish, both reared in concrete tanks and in floating net cages. The experimental diets did not affect the survival of sandfish (P>0.05). Formulated diet containing 30% Sargassum meal, 35% Ulva meal, 4% soybean meal, 18% rice flour, and 6% ‘lap lap’ flour gave the best growth and could be applied for grow-out of sandfish.


2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Suko Ismi

Application technology for grouper seed production was conducted by dissemination activities, aimed for dissemination technology in several places having aquaculture prospects in order to facilitate seed supply. The research was conducted  in 2012 collaborated with the Department of Fisheries and Maritime Affairs Lamongan Regency and Fisheries Academy  of Sidoarjo. Application technology for grouper seed production was conducted in Tunggu village, Paciran district, Lamongan, East Java. Grouper seeds which maintained were tiger, cantik, and cantang. Seed productions were performed from egg to juvenile with size of ±3.0 cm,in which the eggs  were transported from hatchery in Bali and larval rearing was conducted based on the produced technology. The results showed that survival rate of tiger grouper was 8.3%, cantang grouper was 11,6%, and cantik grouper was 12.4%.  The results showed that R/C ratio was >1, in which the business was profitable. The technology can be applied to the community and grouper seed production  can support aquaculture activities. Keywords: Grouper seed, production, technology, R/C ratio, aquaculture


2011 ◽  
Vol 47 (1) ◽  
pp. 137-157 ◽  
Author(s):  
FLORENT OKRY ◽  
PAUL VAN MELE ◽  
EDWIN NUIJTEN ◽  
PAUL C. STRUIK ◽  
ROCH L. MONGBO

SUMMARYThis paper analyses the organization of the rice seed sector in Guinea with the overall objectives to assess how organizational settings affect seed supply to small-scale farmers and to suggest institutional changes that would favour seed service and uptake of varieties. Data were collected in Guinea, West Africa, using focus group discussions with extension workers, farmers, representatives of farmers’ associations, agro-input dealers, researchers and non-governmental organization (NGO) staff, and surveys of 91 rice farming households and 41 local seed dealers. Findings suggest that the current institutional settings and perceptions of stakeholders from the formal seed sector inhibit smallholder farmers’ access to seed. Seed interventions in the past two decades have mainly relied on the national extension system, the research institute, NGOs, farmers’ associations and contract seed producers to ensure seed delivery. Although local seed dealers play a central role in providing seed to farmers, governmental organizations operating in a linear model of formal seed sector development have so far ignored their role. We discuss the need to find common ground and alternative models of seed sector development. In particular we suggest the involvement of local seed dealers in seed development activities to better link the formal and the informal seed systems and improve smallholder farmers’ access to seed from the formal sector.


Sign in / Sign up

Export Citation Format

Share Document