278,081 research outputs found
Seed priming improves endosperm weakening, germination, and subsequent seedling development of Solanum lycocarpum St. Hil.
No full textSeed priming is a treatment to improve seed quality and plant growth upon germination and is applied widely to crop species to improve uniformity and yield. The present study aimed to establish a priming protocol for Solanum lycocarpum St.Hil., to improve germination of the dormant seeds and seedling development for in situ restoration, and to determine the mechanism underlying priming. Priming for 15 d at 15 degrees C in water delivered the optimal priming effect, resulting in the fastest and most uniform germination and a high final germination percentage compared with shorter treatments, higher temperatures and lower water potentials. Seedling development following priming was significantly improved. To determine the role of endosperm weakening during priming, the force required to puncture the endosperm and endo-B-mannanase activity were determined during priming and subsequent germination. Mechanical weakening of the endosperm and development of endo-B-mannanase activity appeared to contribute to the priming effect. Despite the difference in dormancy the mechanism behind priming is similar to that in tomato. Seedling production of S. lycocarpum, e.g. for in situ restoration, would benefit from priming.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Univ Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, BR-18603970 Botucatu, SP, BrazilUniversidade Federal de Lavras (UFLA), Dept Ciencias Florestais, Lab Sementes Florestais, BR-37200000 Lavras, MG, BrazilRoyal Bot Gardens Kew, Seed Conservat Dept, Ardingly RH17 6TN, W Sussex, EnglandUniv Estadual Paulista, Fac Ciencias Agron, Dept Prod Vegetal, BR-18603970 Botucatu, SP, BrazilCNPq: 484791/2007-
Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation
No full textEuterpe Mulls is a key ecological species in the Atlantic forest. However, illegal plant extraction has lowered its natural occurrence in many areas. A previous study showed that gibherellic acid (GA(3)) applied 12 days after sowing (DAS) increases the germination performance of this species, but the study did not find the reasons for this result. We reassessed the effects of the seed water content (51, 47, 43, and 39%) on the germination of this species. We hypothesised that after imbibition was initiated, the stage at which GA(3) is applied to the seed would he irrelevant, and the anatomical changes in the embryo that are caused by GA(3) would be observed more than 15 days after GA(3) application. We also investigated whether GA(3) induced seed reserve mobilisation. We observed the same percentage of germinated seeds regardless of the seed water content. However, the rate and time of germination were higher as the seed water content increased. GA(3) improved the germination performance independently of the date on which GA(3) was applied (0 or 12 DAS). This improvement was due to an embryonic cell expansion that was observed 60 DAS, rather than any seed reserve (carbohydrates and lipids) mobilisation that was caused by GA(3).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation
No full textEuterpe Mulls is a key ecological species in the Atlantic forest. However, illegal plant extraction has lowered its natural occurrence in many areas. A previous study showed that gibherellic acid (GA(3)) applied 12 days after sowing (DAS) increases the germination performance of this species, but the study did not find the reasons for this result. We reassessed the effects of the seed water content (51, 47, 43, and 39%) on the germination of this species. We hypothesised that after imbibition was initiated, the stage at which GA(3) is applied to the seed would he irrelevant, and the anatomical changes in the embryo that are caused by GA(3) would be observed more than 15 days after GA(3) application. We also investigated whether GA(3) induced seed reserve mobilisation. We observed the same percentage of germinated seeds regardless of the seed water content. However, the rate and time of germination were higher as the seed water content increased. GA(3) improved the germination performance independently of the date on which GA(3) was applied (0 or 12 DAS). This improvement was due to an embryonic cell expansion that was observed 60 DAS, rather than any seed reserve (carbohydrates and lipids) mobilisation that was caused by GA(3).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Determinants for Use of Certified Maize Seed and the Relative Importance of Transaction Costs
No full textThe rising world prices for major tradable staples such as maize have been a concern for sub- Saharan countries such as Kenya which are maize deficit countries. Maize is a major staple food for over 80 percent of Kenya’s population. Kenya relies on maize for up to 40 percent of its dietary energy supply and is accordingly searching for ways to increase maize productivity. Maize productivity has been rising in the last decade manly as a result of the use of improved germplasm and fertilizer. However, the proportion of farmers using these technologies is low and the aggregate productivity in maize is low compared to other countries and its potential. Previous studies on input adoption have often assumed the existence of perfect supply and product markets, tending to ignore the important but significant role played by institutions as well as the role of transaction costs associated with market exchange. This study makes use of qualitative information from institutions and actors in seed input value chains as well as quantitative information collected from a sample of 150 farmers, in the Moist Transitional Maize Zones of Kenya. A two stage regression model was applied to analyze determinants of adoption and factors affecting degree of adoption of certified improved maize seed. The results show that as farmers adopt certified seeds, they incur higher transaction costs than non adopters, rural infrastructure, social capital such as membership in groups and trust play an important role in the decision of whether or not to use certified seed.Crop Production/Industries,
Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation
No full textEuterpe Mulls is a key ecological species in the Atlantic forest. However, illegal plant extraction has lowered its natural occurrence in many areas. A previous study showed that gibherellic acid (GA(3)) applied 12 days after sowing (DAS) increases the germination performance of this species, but the study did not find the reasons for this result. We reassessed the effects of the seed water content (51, 47, 43, and 39%) on the germination of this species. We hypothesised that after imbibition was initiated, the stage at which GA(3) is applied to the seed would he irrelevant, and the anatomical changes in the embryo that are caused by GA(3) would be observed more than 15 days after GA(3) application. We also investigated whether GA(3) induced seed reserve mobilisation. We observed the same percentage of germinated seeds regardless of the seed water content. However, the rate and time of germination were higher as the seed water content increased. GA(3) improved the germination performance independently of the date on which GA(3) was applied (0 or 12 DAS). This improvement was due to an embryonic cell expansion that was observed 60 DAS, rather than any seed reserve (carbohydrates and lipids) mobilisation that was caused by GA(3).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Estadual Paulista, UNESP, Dept Bot, Inst Biociencias, BR-13506900 Rio Claro, SP, BrazilUniv Estadual Paulista, UNESP, Dept Bot, Inst Biociencias, BR-13506900 Rio Claro, SP, BrazilFAPESP: 06/02820-1FAPESP: 08/00125-0CNPq: 471452/2008-
Wheat and barley seed system in Syria: farmers' varietal perceptions, seed sources and seed management
No full textA total of 206 wheat and 200 barley farmers were interviewed in northeastern Syria to understand farmer perceptions and practice relating to modern varieties, seed sources and seed quality. Wheat farmers had better awareness and grew modern varieties (87%), applied fertilizers (99.5%), herbicides (93%), seed treatment (90%) or insecticides (41%). In contrast barley growers had low awareness (36%) and use (0.5%) of modern varieties, herbicides (4%), insecticides (3%) and fertilizers (56%). Grain yield, grain size, food quality and tolerance to lodging, drought and frost were the agronomic characteristics farmers sought from new wheat varieties. For barley, grain yield, grain size, grain color, feed quality, marketability and tolerance to diseases and drought were the key traits sought. The informal sector-seed retained from the previous harvest or obtained from neighbors or local traders/markets-was the main source of seed for both wheat and barley. Most farmers practiced onfarm seed selection, cleaning, treatment, separate storage or quality assessment of seed that was obtained locally. Farmers’ perceptions and preferences of new varieties/technologies and their seed sources and seed management practices must be taken into account in any efforts to develop or to strengthen seed sector developmen
Effect of time of fungicide application on the second harvest seed yield of five cocksfoot (Dactylis glomerata L.) cultivars
No full textThe effects of time of fungicide application on seed yield and its components were determined for second harvest plots of three New Zealand (Grasslands Wanan, Grasslands Kara, Grasslands Tekapo) and two Japanese (Akimidori, Makibamidori) cocksfoot (Dactylis glomerata L.) cultivars. Tebuconazole (188 g a.i. ha-1) was applied either at ear emergence, at ear emergence plus anthesis, and anthesis plus 10 days post anthesis. Disease incidence was <1% for all cultivars, but fungicide treatments significantly increased the percentage green area of the flag leaf, leaf two and leaf three, plus the stem. Seed yield was significantly increased by the ear emergence fungicide application in cv. G. Wana, G. Tekapo and Makibamidori, and by the ear emergence plus anthesis applications in cv. G. Wana, G. Kara, Akimidori and Makibamidori. These yield increases ranged from 14% (cv. G. Kara) to 43% (cv. Makibamidori), and were associated with increased floret site utilisation and increases in thousand seed weight, although these responses were not consistent for all treatments or cultivars
Soil seed bank dynamics in Mediterranean urban vegetation fragments
No full textConservation of biodiversity in urban vegetation fragments is of increasingly high importance with growing urbanisation globally, particularly so in the biodiversity hotspot of the Mediterranean southwest of Western Australia. Relationships between fragmentation (connectivity, fragment size, time since isolation) and urban disturbances (weed invasion, human disturbance, rubbish) relative to the soil seed bank of a representative sample of Perth’s urban woodland fragments (N=36) were examined. In total, 182 seedling types comprising 57 invasive, 105 native and 20 unknowns were identified. Approximately 65% of the 21,770 seedlings counted were native, 33% invasive and 2% unidentified. The average soil seed bank seedling density was 2,787 germinates per m2. Community analysis (ordination) showed that the soil seed bank composition correlated with fragment age. Subsequent quantitative analysis (linear regression) did not find evidence for species or functional trait groups being vulnerable to decline due to isolation or fragment age, indicating that species extinction is not evident within Perth’s urban fragments. More invasive annual herbs were found within older fragments and the soil seed banks of smaller fragments were found to have lower native species abundance compared to larger fragments. A positive relationship was found between the number of footpaths within a fragment and the abundance of annual invasive herbs within the soil seed bank. High weed cover in a fragment resulted in high weed presence within the soil seed bank. It was also found that high weed cover did not necessarily indicate low native species diversity or abundance within the soil seed bank, suggesting caution in using weed cover to classify sites as suitable/unsuitable for topsoil transfer in restoration activities. The soil seed bank of the study sites contained a diverse range of native species, indicating that topsoil from these areas may be useful in restoration of degraded sites
Performances of the 1,000-seed-weight and oil-content traits in lines DH-G-42 and DH-7-9.
No full textSeed-weight and oil-content of two extreme B. napus lines DH-G-42-8 and DH-7-9-6 were selected (in bold).</p
A field experiment on bargaining for seed reveals bias against women agripreneurs: Summary of findings and policy recommendations
No full textThis policy note summarizes results from a Lab-in-the-field experiment1 in eastern Uganda, where a representative sample of 760 smallholder maize farmers were given the opportunity to bargain over a bag of maize seed from either a male or female seller. Specifically, we test whether the gender of the seed seller impacts the seed buyer’s negotiation strategies and the eventual outcomes in bilateral price negotiations. The findings reveal that buyers confronted with a female seller were less likely to accept the seller’s initial offer price and responded with a lower counter price compared to farmers faced with a male seller. Negotiations, on average, took one additional round when the seller was a woman and resulted in a transaction price that was almost 9 percent lower. These results relate to previous research with agro-input dealers in Uganda which showed that female managed/owned agro-input shops are perceived less favorable in terms of quality of seed sold and price competitive ness. Policies and programs working to advance women’s empowerment through agribusiness need to recognize these gendered biases, and increase investment in public campaigns, extension and training to change attitudes towards women entrepreneurs.Non-PRIFPRI5; 3 Building Inclusive and Efficient Markets, Trade Systems, and Food Industry; 4 Transforming Agricultural and Rural Economies; G Cross-cutting gender themeInnovation Policy and Scaling (IPS); Transformation StrategiesCGIAR Gender Platfor
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