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Ierna A.,CNR Institute of Neuroscience | Tenorio J.,Centro Internacional Of La Papa Cip
Journal of Horticultural Science and Biotechnology | Year: 2011

The influence of pre-sowing treatments in a solution of potassium nitrate and potassium phosphate (0.118 M KNO 3 + 0.090 M K 3PO 4; K + K) at -1.0 MPa for 5 d, or in 1,500 mg l -1 gibberellic acid (GA 3) for 1 d, on the characteristics of emergence and on seedling growth in 12 true potato seed (TPS) crosses was studied.The trials were carried out at two sites in Peru: La Molina and San Ramon. The latter site was characterised by having a higher maximum temperature and higher minimum and maximum relative air humidities. The nature of the TPS cross was the major factor determining seedling performance. Both pre-sowing treatments increased the percentage of emergence compared to untreated seed. These positive effects were most noticeable in TPS crosses characterised by having prolonged seed dormancy. At San Ramon, where the climatic conditions were less suitable for the germination of TPS, the effects of both pre-sowing treatments were more evident than at La Molina. The K + K pre-sowing treatment resulted in a shorter mean time for emergence and higher seedling vigour compared to the GA 3 treatment. The ability of either pre-sowing treatment to improve the emergence and seedling vigour of TPS crosses characterised by having prolonged seed dormancy under high-temperature conditions may be of practical value for promoting TPS technology in tropical regions.

Rapidel B.,CIRAD - Agricultural Research for Development | Rapidel B.,Tropical Agriculture Research and Higher Education Center | Ripoche A.,CIRAD - Agricultural Research for Development | Allinne C.,CIRAD - Agricultural Research for Development | And 8 more authors.
Agronomy for Sustainable Development | Year: 2015

Agroecosystems represent 38 % of global land use. Agroecosystems are located close to human settlements and are managed to produce food and fibers, traded in markets. Agroecosystems also produce other goods and services essential to human beings, such as climate regulation, flood mitigation, and landscape amenity. Economists and ecologists have developed the ecosystem services framework to foster the provision of these non-commercial services. Scientists can therefore help decision makers to develop sustainable ecosystems by studying ecosystem services. Here, we analyze the trade-offs of ecosystem services of farming systems. We discuss case studies of mixed perennial crops. The set of ecosystem services provided by these agroecosystems depends on their composition, structure, and management. Complex rule-based management will be required if winegrowers are to maintain an adequate set of ecosystem services across contrasting climatic years. Innovations including cover crops in banana systems can fulfill most of the objective set but will rely on increased farm labor. We then discuss the advantages, challenges, and opportunities to include the description of relations between ecosystem services in cropping system design. We propose to extend the yield gap analysis to ecosystem services, as a service gap analysis. This extension faces methodological questions about the potential provision of a service in a region. We conclude on the challenges that need to be faced if we want to use ecosystem services trade-offs to improve the contribution of agricultural systems to human well-being. © 2015, INRA and Springer-Verlag France.

Sanchez T.,Aereo | Ceballos H.,Aereo | Dufour D.,Aereo | Dufour D.,CIRAD - Agricultural Research for Development | And 6 more authors.
Food Chemistry | Year: 2014

Efforts are currently underway to improve carotenoids content in cassava roots through conventional breeding as a strategy to reduce vitamin A deficiency. However, only few samples can be quantified each day for total carotenoids (TCC) and β-carotene (TBC) contents, limiting the gains from breeding. A database with >3000 samples was used to evaluate the potential of NIRS and chromameter devices to predict root quality traits. Maximum TTC and TBC were up to 25.5 and 16.6 μg/g (fresh weight basis), respectively. NIRS predictions were highly satisfactory for dry matter content (DMC, R2: 0.96), TCC (R2: 0.92) and TBC (R2: 0.93). NIRS could also distinguish roots with high or low cyanogenic potential (R2: 0.86). Hunter color parameters could also be used for predictions, but with lower accuracy than NIRS. NIRS or chromameter improve selection protocols, allowing faster gains from breeding. Results also demonstrate that TBC and DMC can be improved simultaneously (required for the adoption of biofortified cassava). © 2013 Elsevier Ltd. All rights reserved.

Rodriguez-Delfin A.,Agrarian National University | Posadas A.,Centro Internacional Of La Papa Cip | Leon-Velarde C.,Centro Internacional Of La Papa Cip | Mares V.,Centro Internacional Of La Papa Cip | Quiroz R.,Centro Internacional Of La Papa Cip
Acta Horticulturae | Year: 2015

An experiment was performed to determine the uptake of macronutrients and yields in plants from four sweet potato cultivars ('Huambachero', 'Toquesita', 'Jewel' and 'Camote Sal') grown during summer-fall at the Hydroponics Module of the Universidad Nacional Agraria La Molina, Lima, Peru. Plants were grown in quarry sand and watered with nutrient solutions containing three different N, P and K concentrations (mg L-1): 1) 125-20-200, 2) 175-40-250 and 3) 225-60-300. Tuber root development began at 35 days after transplanting and the total crop cycle was 130 days. The highest plant dry weight, tuber root dry weight and yield (tuber root fresh weight) were obtained with the 125-20-200 mg L-1 treatment. The nutrient solution containing the highest N, P and K concentration (225-60-300 mg L-1) produced the lowest growth and yield in the four evaluated cultivars. Being a forage cultivar, 'Camote Sal' did not produce tuber roots. There were significant differences in the dry tuber root weight and the total dry weight between the commercial root ('Huambachano' and 'Jewel') and the forage ('Camote Sal') cultivars, among the commercial tuber root cultivars and, between the forage and the double purpose ('Toquesita') cultivars. There were significant differences found among cultivars in the P, and K uptake in leaves and in the N, P, K, Ca and Mg uptake in tuber roots. N uptake was similar in leaves and tuber roots, but there was a higher P and K uptake in tuber roots than in leaves. There was a higher Ca and Mg uptake in leaves than in tuber roots. The highest P uptake in leaves and tuber roots was obtained in the 'Jewel' and 'Toquesita' cultivars respectively. The highest K uptake in tuber roots was observed in 'Huambachero'. Higher N, P, and K levels decreased the total dry weight, the dry tuber root weight and the tuber root fresh weight.

Orbegozo J.,Centro Internacional Of La Papa Cip | Roman M.L.,Centro Internacional Of La Papa Cip | Rivera C.,Centro Internacional Of La Papa Cip | Tovar J.C.,Centro Internacional Of La Papa Cip | And 5 more authors.
Revista Peruana de Biologia | Year: 2014

The Oomycete Phytophthora infestans (Mont.) de Bary, the causal agent of the disease known as late blight, is primarily responsible for the decreased in production performance and potato crops worldwide. The integration of the complete R genes sequences in the potato genome using Agro-transformation appears an alternative to be considered in the fight against this pathogen. The Rpi-blb2 gene (R gene) from the wild species Solanum bulbocastanum Dunal shows a broad resistance to isolates of P. infestans, making it an important candidate for plant breeding studies. This paper reports the integration of the Rpi-blb2 gene into potato var. Désirée genome by Agrobacterium tumefaciens - mediated transformation system, the molecular characterization of 29 events transformed and whole plant infection with isolate POX67 of P. infestans from Peru. Désirée events [Rpi-blb2] 4 and Désirée [Rpi-blb2] 30, showed a substantial resistance to P. infestans infection confirming complete transfer of the Rpi-blb2 gene from a wild species to a cultivated species by genetic transformation. © Los autores.

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