Baudron F.,CIMMYT |
Delmotte S.,French National Institute for Agricultural Research |
Delmotte S.,Wageningen University |
Corbeels M.,CIRAD - Agricultural Research for Development |
And 3 more authors.
Agricultural Systems | Year: 2014
Cereal residues represent a major resource for livestock feeding during the dry season in southern Africa. When kept on the soil surface instead of feeding them to livestock, crop residues can contribute to increasing soil fertility and maintaining crop productivity in the short- and the long-term. We explored these trade-offs for smallholder cotton-sorghum farming systems in the semi-arid Zambezi Valley, northern Zimbabwe. The analysis was done using simulation models at three scales, the plot, the farm and the territory, to simulate the effects of different sorghum residue allocations to livestock feeding vs. soil mulching, in combination with different application rates of mineral nitrogen fertilizer on crop productivity. The plot-scale simulations suggest that without N fertilization soil mulching has a positive effect on cotton yields only if small quantities of sorghum residues are used as mulch (average cotton yields of 2.24 ± 0.41 kg ha-1 with a mulch of 100 kg ha-1 vs. 1.91 ± 0.29 kg ha-1 without mulch). Greater quantities of mulch have a negative effect on cotton yield without N fertilization due to N immobilization in the soil microbial biomass. With applications of 100 kg N ha-1, quantities of mulch up to 3 t ha-1 have no negative effect on cotton yield. Results at farm-scale highlight the fundamental role of livestock as a source of traction, and the need to feed a greater proportion of sorghum residues to livestock as herd and farm sizes increase. Farmers with no livestock attained maximum crop production when 100% of their sorghum residue remained in the field, as they do not have access to cattle manure. The optimum fraction of crop residue to be retained in the fields for maximum farm crop production varied for farmers with 2 or less heads of cattle (80% retention), with 2-3 heads (60-80%), with 4 or more heads (40-60%). At the scale of the entire territory, total cotton and sorghum production increased with the density of cattle, at the expense of soil mulching with crop residues. The results of our simulations suggest that (i) the optimum level of residue retention depends on the scale at which trade-offs are analyzed; (ii) the retention of all of the crop residue as mulch appears unrealistic and undesirable in farming systems that rely on livestock for traction; and (iii) crop residue mulching could be made more attractive to farmers by paying due attention to balancing C to N ratios in the soil and by promoting small-scale mechanization to replace animal traction. © 2014 Elsevier Ltd. All rights reserved.
Liu L.,Chinese Academy of Agricultural Sciences |
Ikeda T.M.,Japan National Agriculture and Food Research Organization |
Branlard G.,French National Institute for Agricultural Research |
Pena R.J.,CIMMYT Mexico |
And 11 more authors.
BMC Plant Biology | Year: 2010
Background: Low-molecular-weight glutenin subunits (LMW-GS) play a crucial role in determining end-use quality of common wheat by influencing the viscoelastic properties of dough. Four different methods - sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), two-dimensional gel electrophoresis (2-DE, IEF × SDS-PAGE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR), were used to characterize the LMW-GS composition in 103 cultivars from 12 countries.Results: At the Glu-A3 locus, all seven alleles could be reliably identified by 2-DE and PCR. However, the alleles Glu-A3e and Glu-A3d could not be routinely distinguished from Glu-A3f and Glu-A3g, respectively, based on SDS-PAGE, and the allele Glu-A3a could not be differentiated from Glu-A3c by MALDI-TOF-MS. At the Glu-B3 locus, alleles Glu-B3a, Glu-B3b, Glu-B3c, Glu-B3g, Glu-B3h and Glu-B3j could be clearly identified by all four methods, whereas Glu-B3ab, Glu-B3ac, Glu-B3ad could only be identified by the 2-DE method. At the Glu-D3 locus, allelic identification was problematic for the electrophoresis based methods and PCR. MALDI-TOF-MS has the potential to reliably identify the Glu-D3 alleles.Conclusions: PCR is the simplest, most accurate, lowest cost, and therefore recommended method for identification of Glu-A3 and Glu-B3 alleles in breeding programs. A combination of methods was required to identify certain alleles, and would be especially useful when characterizing new alleles. A standard set of 30 cultivars for use in future studies was chosen to represent all LMW-GS allelic variants in the collection. Among them, Chinese Spring, Opata 85, Seri 82 and Pavon 76 were recommended as a core set for use in SDS-PAGE gels. Glu-D3c and Glu-D3e are the same allele. Two new alleles, namely, Glu-D3m in cultivar Darius, and Glu-D3n in Fengmai 27, were identified by 2-DE. Utilization of the suggested standard cultivar set, seed of which is available from the CIMMYT and INRA Clermont-Ferrand germplasm collections, should also promote information sharing in the identification of individual LMW-GS and thus provide useful information for quality improvement in common wheat. © 2010 Liu et al; licensee BioMed Central Ltd.
Langyintuo A.S.,Alliance for a Green Revolution in Africa AGRA |
Mwangi W.,CIMMYT Zimbabwe |
Diallo A.O.,CIMMYT Zimbabwe |
MacRobert J.,CIMMYT Kenya |
And 2 more authors.
Food Policy | Year: 2010
Following the liberalization and restructuring of the seed sector, the maize seed industry in eastern and southern Africa has witnessed a proliferation of private seed companies. Whereas the total number of registered maize seed companies in major maize producing countries increased four-fold between 1997 and 2007, the quantity of seed marketed barely doubled suggesting that the seed production and deployment environment is less than perfect.A study involving over 92% of all seed providers in east and southern Africa in 2007 showed that a number bottlenecks affect the entire maize seed value chain. The lack of access to credit constitutes a significant barrier to entry. Until governments and development partners make credit available to seed entrepreneurs directly or through risk sharing arrangements with commercial banks, national seed companies will not grow leaving the seed sector monopolized by the regional and multinational seed companies. In addition, the transfer of genetic materials between public and private sectors should be improved to allow easy access by seed companies to suitable and adapted varieties. To allow for rapid regional spillovers of varieties released in one country to similar agro-ecologies in different countries, the implementation of the harmonized regional seed laws and regulations should be expedited. Finally, the best strategies that increase the adoption of improved maize varieties should be explored and implemented to enhance seed demand. © 2010 Elsevier Ltd.
Baudron F.,CIMMYT Ethiopia |
Sims B.,FAO Mechanization Consultant and Engineering for Development |
Justice S.,CIMMYT Nepal |
Kahan D.G.,CIMMYT Ethiopia |
And 7 more authors.
Food Security | Year: 2015
The need for sustainable intensification in Eastern and Southern Africa (ESA) is widely recognized as a requirement to achieve food security with minimum negative social and environmental consequences. In current Research & Development programs, much emphasis is placed on increasing the efficiency with which land, water and nutrients are used, whereas farm power appears to be a ‘forgotten resource’. This is a major concern when farm power in ESA countries is declining due to the collapse of most tractor hire schemes, the decline in number of draught animals and the growing shortage of human labour. A consequence of low levels of farm mechanization is high labour drudgery, which makes farming unattractive to the youth and disproportionally affects women. Undoubtedly, sustainable intensification in ESA will require an improvement in access to farm power. In this paper, we suggest this can be achieved through the use of small, multipurpose and inexpensive power sources such as two-wheel tractors (2WTs) coupled with the promotion of energy saving technologies such as conservation agriculture (CA), whilst ensuring the profitability for farmers, service providers and other private sector actors in the supply chain. We argue that appropriate mechanization in Africa, a paradigm largely abandoned three decades ago, may be re-examined through the combination of these three elements. © 2015, Springer Science+Business Media Dordrecht and International Society for Plant Pathology.
Shamanin V.P.,Omsk State University |
Morgunov A.I.,CIMMYT Turkey |
Manes J.,CIMMYT Mexico |
Zelenskii Y.,CIMMYT Kazakhstan |
And 2 more authors.
Russian Journal of Genetics: Applied Research | Year: 2011
Commercial cultivars, breeding material, and near-isogenic Sr gene lines of spring common wheat were tested for resistance to the Siberian population of stem rust races in an experimental field of the Omsk Agrarian University and to virulent race Ug99 at the Institute of Plant Pathology in Kenya (Africa). Resistant material was selected for breeding in West Siberia. The genetic value of populations developed by a shuttle breeding program among scientific institutions of Kazakhstan, West Siberia, and the International Maize and Wheat Improvement Center (CIMMYT), Mexico, is proven. © 2011 Pleiades Publishing, Ltd.