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Omae H.,Tropical Agriculture Research Front TARF | Saidou A.K.,National Institute of Agronomic Research of Niger INRAN | Germaine I.,National Institute of Agronomic Research of Niger INRAN | Tobita S.,JIRCAS
Open Agriculture Journal | Year: 2015

We conducted on-farm participatory experiments over three years at six villages in the Fakara commune of Western Niger to demonstrate, verify, and evaluate the relevance of soil fertility management methods based on millet/cowpea intercropping. We tested six methods using one of three organic fertilizers (millet husks, manure, or neither) with or without mineral fertilizer and one using millet/hibiscus intercropping with millet husks. We evaluated farmers’ preferences by measuring the self-selected proportions of plots that farmers used for each condition. The results demonstrate the effectiveness of millet/cowpea intercropping; the application of mineral fertilizer, manure, and millet husks; and alternating-year application—all of them are affordable for farmers in the Sahel. Both the demonstration and farmerdirected trials made farmers aware of the effects of these methods. Farmers’ selection of methods depended on availability. The dissemination of agricultural methods mainly depends on the availability of input materials in the absence of other constraints such as money and accessibility. © Omae et al.; Licensee Bentham Open

PubMed | LANGEBIO, JIRCAS, University of Adelaide, Arizona State University and 3 more.
Type: | Journal: The Plant journal : for cell and molecular biology | Year: 2016

Phosphorus (P) is one of the essential nutrients for plants and indispensable for plant growth and development. P deficiency severely limits crop yield and regular fertilizer applications are required to obtain high yields and prevent soil degradation. To access P from the soil, plants have evolved high and low affinity Pi transporters and the ability to induce root architectural changes to forage P. Also, adjustments of numerous cellular processes are triggered by the P starvation response, a tightly regulated process in plants. With the increasing demand for food due to the growing population, demand for P fertilizer is steadily increasing. Given the high costs of fertilizers and in light of the fact that phosphate rock, the source of P fertilizer, is a finite natural resource, there is a need to enhance P fertilizer use efficiency in agricultural systems and develop plants with enhanced Pi uptake and internal P-use efficiency (PUE). In this review we will provide an overview of ongoing relevant research and highlight different approaches towards developing crops with enhanced PUE. In this context, we will summarize our current understanding of root responses to low phosphorus conditions and emphasize the importance of combining PUE with tolerance of other stresses, such as aluminum toxicity. Of the many genes associated with Pi deficiency, this review will focus on those that hold promise or are already at an advanced stage of testing (OsPSTOL1, AVP1, PHO1, OsPHT1;6). Finally, an update is provided on the progress made exploring alternative technologies, such as phosphite fertilizer. This article is protected by copyright. All rights reserved.

Ishizaki T.,Tropical Agriculture Research Front | Maruyama K.,JIRCAS | Obara M.,JIRCAS | Fukutani A.,Tropical Agriculture Research Front | And 5 more authors.
Molecular Breeding | Year: 2013

Dehydration-responsive-element-binding protein 1 genes have important roles in response to stress. To improve the drought tolerance of an upland rice cultivar NERICA1, we introduced ArabidopsisAtDREB1C or rice OsDREB1B driven by a stress-inducible rice lip9 promoter. Plants of some transgenic lines survived better than non-transgenic plants under severe drought. AtDREB1C transgenic plants had higher dry weights than non-transgenic plants when grown under moderate drought until the late vegetative growth stage. On the other hand, OsDREB1B transgenic plants had lower dry weights than non-transgenic plants under the same condition. Similar results were obtained under osmotic stress. The AtDREB1C transgenic plants headed earlier, had a larger sink capacity, and had more filled grains than non-transgenic plants. These results suggest that AtDREB1C expressed in NERICA1 improves not only survival under severe drought, but also growth and yield under moderate drought. © 2012 Springer Science+Business Media B.V.

Sakaigaichi T.,National Agriculture Research Center for Kyushu Okinawa Region | Terajima Y.,National Agriculture Research Center for Kyushu Okinawa Region | Matsuoka M.,National Agriculture Research Center for Kyushu Okinawa Region | Terauchi T.,National Agriculture Research Center for Kyushu Okinawa Region | And 4 more authors.
Japanese Journal of Crop Science | Year: 2010

The growth and yield in the twice harvesting system (THS) were compared with those in once harvesting system (OHS) of two sugarcane varieties (KRFo93-1 bred for forage use and the leading commercial NiF8 for sugar production). The cumulative effective temperature was the highest in OHS, followed by the 1st crop in THS and the 2nd crop in THS in this order. The growth stage was younger as the cumulative effective temperature was lower in both varieties. The stem length was consistently longer in KRFo93-1 than in NiF8, and the differences in stem length between the two varieties was markedly significant in the initial growth period after ratooning and in the 2nd crops in THS including low temperature period. Fresh- and dry-matter yields averaged in the 1st and 2nd ratoon years in KRFo93-1 were 226 t/ha/yr and 56.1 t/ha/yr in OHS, respectively and 278 t/ha/yr and 57.7 t/ha/yr in THS. Dry matter productivity was higher in THS than in OHS in KRFo93-1 but was lower in THS than in OHS in NiF8. The mechanism of high yielding ability of KRFo93-1 in THS may be caused by the vigorous initial growth after ratooning and vigorous stem elongation in the low temperature period.

Sakaigaichi T.,National Agriculture Research Center for Kyushu Okinawa Region | Terajima Y.,National Agriculture Research Center for Kyushu Okinawa Region | Terauchi T.,National Agriculture Research Center for Kyushu Okinawa Region | Sugimoto A.,JIRCAS | And 2 more authors.
Japanese Journal of Crop Science | Year: 2010

The effect of dense planting in planting and ratooning cane of forage sugarcane variety, KRFo93-1, on the growth and yield was studied at farmers' fields in Nishinoomote, Kagoshima from 2007 to 2008. The planting density examined was 63.6 ×103 (control), 95.4×103 (1.5 times, dense planting) and 127.2×103 (2 times, dense planting) buds/ha. The number of stems increased with increasing planting density. The number of stems was the maximum at 63 days after planting (DAP) in 2007 and at 75 DAP in 2008 and it decreased thereafter. It was higher in 2007 than in 2008, which might be affected by the difference in the amount of solar radiation. Stem length was significantly longer in dense planting until 88 DAP in 2007 and until 102 DAP in 2008. The longer stem length may be due to the smaller tiller number per stool in dense planting. The vegetation cover ratio was significantly higher in dense planting. The average fresh-and dry-matter yields in 2007 and 2008 were higher in dense planting. The effect of dense planting was very large until 88 DAP in 2007 and until 102 DAP in 2008. Therefore, the yield-increasing effect of dense planting would be larger if the timing of harvest was earlier than in this study. Dense planting had a positive effect on the growth and yield of ratooning cane in dense planting.

Tanaka U.,Humanity | Ikazaki K.,Tokyo Metroplitan University | Shimizu T.,Humanity | Sasaki Y.,Humanity | And 2 more authors.
Proceedings of the 5th International Disaster and Risk Conference: Integrative Risk Management - The Role of Science, Technology and Practice, IDRC Davos 2014 | Year: 2014

Desertification remains as a serious problem despite commitments from the international community even after the ratification of UNCCD in 1994. Caused by daily livelihood activities for basic needs of local people, the problem becomes worse year by year under increasing demographic pressure to land resources and ecosystems in the Sahel, West Africa. The difficulty of desertification control is that it is to deal with while maintaining the causes. It suggests the necessity to innovate practical techniques effective both for desertification control and local livelihood improvement. We innovated 'fallow-band system', which reduced 60-70 % of wind erosion and increased 50-75 % of crop yield, without cost, materials and labour. The technique was extended to more than 400 households in 75 villages, 23 districts and 5 regions in Niger. During the extension phase, we demonstrated a modification of conventional extension method, by incorporating a component technique of social network survey. It was useful to identify and visualize the network of information and confidence, key persons (opinion leaders) and vulnerable households in a commune. Together with local people, we also designed a practical technique 'lines of Andropogon', which is effective for soil erosion control, water harvesting and income generation, by utilizing indigenous knowledge and local resources. Through the process of collaboration, we surely confirmed that local people work as partner to innovate practical techniques useful for desertification control and livelihood improvement.

Hitsuda K.,Japan Development Service Co. | Toriyama K.,Japan International Research Center for Agricultural science | Subbarao G.V.,JIRCAS | Ito O.,JIRCAS
Soil Science Society of America Journal | Year: 2010

Critical micronutrient concentrations in soils and plants have not been clearly determined for marginal soils where deficiencies are likely to occur. The objective of this study was to develop a reliable method for assessing micronutrient deficiency in soils and plants. Soybean plants [Glycine max (L) Merr,] were grown in the A and B horizons of two Brazilian Ustoxes and watered with a complete nutrient solution (i.e., control) or solutions lacking one of the following micronutrients: Mn, Zn, B, or Cu. Soybean plants were repeatedly grown in the same soils until maturity. The cumulative frequency of deficient plants where the relative seed dry weight was significantly decreased was recorded. Tne percent relative cumulative frequency (PRCF) is calculated as: cumulative frequency + total number of tested plants x 100. A linear-plateau regression line was fitted to the PRCF as a function of the micronutrient concentrations in the soil, the uppermost mature leaf, or seed. Critical concentrations (mgkg-1) for deficiency indicated as transition points of regression lines are: 6.4 for Mn (reference), 1.0 for Zn, 0.2 for B, and 0.2 for Cu in the sou (Mehlich-I extraction for Mn, Zn, and Cu; hot 0.005 mol L-1 BaCl2 extraction for B): 63 for Mn, 34 for Zn, 25 for B, and 4 for Cu in the uppermost mature leaf: 55 for Mn, 42 for Zn, 14 for B, and 5 for Cu in seeds. Thus, this determination method can clearly identify the critical values for micronutrient deficiency in soils and in plant tissues. © Soil Science Society of America, 5585 Guilford Rd., Madison WI 53711 USA All rights reserved.

Agency: GTR | Branch: BBSRC | Program: | Phase: Research Grant | Award Amount: 200.62K | Year: 2012

Zinc (Zn) is an essential nutrient in micro-quantities for all living organisms. Deficiencies limit crop production in many parts of the world, and Zn is often deficient in the diet of humans subsisting on staple-food crops, causing severe health problems. An important strategy for dealing with this is to breed crops that are efficient in taking up Zn and concentrating it in edible plant parts. Rice is one of the main crops being targeted because of its global importance and the prevalence of Zn deficiency in populations subsisting on rice. However rice is unusual in its Zn relations compared with other cereals in two respects. First, it is mainly grown in submerged soils, and because of the peculiar biogeochemistry of submerged soils, Zn deficiency in the crop is widespread, affecting up to 50% of rice soils globally. Second, as a result of inherent physiological differences, little Zn is remobilized from existing plant reserves to grains during the grain filling growth stages, as in other cereals, so that Zn uptake appears to be one of the main bottlenecks limiting rice grain Zn contents. Research has shown that grain Zn concentrations in rice - already low compared with other cereals or pulses - are further reduced in Zn deficient soils, and large fertilizer additions are needed to overcome this. Dietary and crop Zn deficiency are inevitably linked in areas with low Zn soils, as in most parts of Asia where rice is the staple. Enhancing the Zn uptake capacity of rice varieties will therefore be crucial to increasing grain contents. It will also be important to understand long-term sustainability of growing high grain Zn rice under inherently Zn-limited conditions, and what can be done to avoid problems in the future. Current research at the International Rice Research Institute (IRRI) is using classical plant breeding combined with molecular biological markers for useful plant traits to develop rice varieties with high grain Zn contents and improved yields on Zn-deficient soils. Research is also underway to enhance grain Zn through agronomic means, including fertilizer and water management. However progress in these activities, and in understanding long-term sustainability issues, is constrained by our poor understanding of the mechanisms underlying genotype differences, and of the dynamics of plant-available Zn in the soil within the growing season and longer term. In recent research by members of the project team, we have shown that three key mechanisms enhance growth of rice seedlings in Zn deficient soil: (a) secretion from roots of Zn-chelating compounds called phytosiderophores and subsequent uptake of chelated Zn in the rhizosphere, (b) maintenance of new root growth, and (c) prevention of root damage by oxygen radicals linked to high bicarbonate concentrations. Studies with a limited set of genotypes suggest that Zn loaded into grains mostly comes from Zn uptake during the reproductive stages rather than by re-translocation from vegetative tissue. The mechanisms listed above in relation to seedling growth may also assure adequate Zn uptake during the reproductive phase. However, this has not been systematically investigated so far, nor have any genes related to reproductive-stage Zn uptake been tagged. The proposed research addresses these knowledge gaps with an interdisciplinary approach linking fundamental research on soil biogeochemistry, molecular physiology and genetics with applied work on agronomy and plant breeding, with a conceptual framework provided by mathematical modelling. Our goal is to develop genotypes and management practices for growing high Zn rice in Zn deficient soils, suitable for resource-poor farmers. This will encompass agronomic interventions based on understanding of limiting factors for Zn uptake and translocation, and breeding approaches based on understanding of genetic factors controlling key tolerance mechanisms.

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