55 research outputs found
Does cooperative membership increase and accelerate agricultural technology adoption? Empirical evidence from Zambia
No full textIn developing countries, agricultural cooperatives are increasingly being used to promote improved agricultural technologies and alleviate food insecurity and poverty. However, little is known about the role of agricultural cooperatives in accelerating the adoption of improved agricultural technologies. Using a comprehensive balanced household panel and varietal data, this study applied the difference-in-difference model to identify factors affecting farmers? decision to become cooperative members and the impact of cooperative membership on the adoption of improved maize, inorganic fertilizer and crop rotation. Furthermore, the study used the inverse probability weighted regression adjustment model to analyze the impact of cooperative membership on the speed of adoption of improved maize varieties. We found that cooperative membership increased the probability of technology adoption by 11?24 percentage points. Results further indicated that the average time to adoption was about 8 years, but it was shorter for cooperative members. The results showed that, on average, cooperative membership increased the speed of adoption of improved maize by 1.6?4.3 years. Generally, the results suggest the need for policies which promote farmer organizations such as cooperatives coupled with effective extension services for faster and greater adoption of improved technologies
Use of exotic germplasm to enhance the performance of local maize
No full textExotic maize germplasm has been used minimally in most maize breeding programmes in Zimbabwe and sub-Saharan Africa (SSA). The major reasons for this include challenges in adaptation and the general tendency by breeders to shun the dilution of their elite breeding material. Breeders often prefer the easier and more predictable option of recycling their elite materials. This has resulted in the loss of genetic diversity, development of breeding bottlenecks and subsequent possibilities of stagnating or deteriorating yield gain. The cost and time constraints, the generally high expectations imposed by industry, and the huge capital outlays required to introduce exotic germplasm further discourages its inclusion in local breeding programmes. Traditionally in most breeding programmes in SSA, exotic germplasm is incorporated through introgression with backcrossing to produce modified local inbred lines. The modified local inbred lines with minor exotic components are then used in the production of three-way hybrids for commercialisation. Only minor modifications to the elite germplasm are accepted by most breeders. The usefulness of an inbred in any breeding programme is dependent upon its performance in combination with other inbreds. In this study, the usefulness of inbred lines was investigated through the production and evaluation of F1 single-cross hybrids and F1 three-way hybrids. The general aim of this study was to illustrate quicker and easier ways of identifying usable exotic inbreds in local breeding programmes. The yield per se performance of each hybrid in different stress environments was used as the major reference for selection. This study also challenged and allayed the breeders’ fears concerning the use of exotic germplasm by identifying superior marketable hybrids without going through the lengthy process of backcrossing. Furthermore, the study demonstrated the huge potential of local x exotic crosses as sources of multiple pedigree starts. All hybrids in this study were evaluated in varied stress environments approximating the local farmers’ conditions of low phosphorus, low nitrogen, random stress, high density and optimal conditions. Two hundred and fifty temperate inbreds with expired Plant Variety Protection (ex-PVP) certificates from the United States of America (USA) were crossed with three CIMMYT single-cross testers: CML539/CML442 (A tester), CML444/CZL068 (B tester), and CML312/CML444 (AB tester) to produce three-way hybrids which were evaluated over eight sites. The best inbreds, which were identified for enhancing yield from heterotic group A (SS group) were LH159, LH214, LH23HT, LH213 and MM402A. The best combiners from heterotic group B (NSS group) were HB8229, W8304, LH198, PJH40 and LH190, and from the unclassified lines were PHR58, WIL500, PHK35 and ICI441. The Griffing diallel model 1 method 4 mating scheme was used to evaluate 18 local inbred lines in a local x local diallel scheme and nine selected exotic inbred lines in an exotic x exotic diallel scheme. The North Carolina design II (NCII) was used to evaluate 18 selected local inbreds in combination with 12 selected exotic lines. Highest yielding crosses from the local x local diallel were, L3 x L6 and L4 x L14, and from the exotic x exotic diallel were E7 x E1 and E1 x E9. Inbred lines with the highest GCA from the diallels were L16, L4, E1 and E9. The best crosses from the NCII were N28 x N16 and N21 x N4. Local inbred lines N19, N28 and N30 and exotic inbred N3, N8 and N16 had the highest significant positive GCA effects. Inbred lines from Mexico lowland tropics and Kenya produced the best hybrids in combination with local lines, suggesting them as the most promising future sources of usable germplasm. The leveraging of local single-crosses using exotic tropical germplasm produced 1860 hybrids which were evaluated across eight sites. The outstanding combinations of (local x local) x local hybrids were DJH141028, DJH153523, DJH152318, DJH152580, DJH166030, DJH167263, and DJH168087. The best combinations of (local x local) x exotic hybrids were DJH161178, DJH152183, DJH152552, and DJH168068. The (local x local) x exotic crosses produced equally competitive hybrids as compared to the (local x local) x local. The highest heterosis was generated between the combination of IITA inbred lines and CIMMYT single-crosses, identifying IITA germplasm as the most promising source of tropical exotic germplasm. Overall, this study identified exotic inbred lines that can be used in local breeding programmes to produce hybrids directly and provides an initial step in a possibly bigger and even more comprehensive screening and evaluation programme that can be funded to create a database for the performance of exotic inbred lines in local breeding programmes
The influence of abiotic stress on CIMMYT provitamin A elite maize germplasm
No full textMicronutrient malnutrition, including vitamin A deficiency, affects more than half of the world population, having a major effect on children less than five years old, pregnant and lactating women. The problem is significant in sub-Saharan Africa (SSA) where people subsist mostly on white maize which lacks vitamin A. Vitamin A deficiency is responsible for a number of health disorders that include poor vision and reproduction, and supressed growth and immunity. Biofortification of staple food crops such as maize with β-carotene can be a sustainable approach to address dietary vitamin A deficiency. Orange maize contains high levels of β-carotene, making it an important crop for combating vitamin A deficiency. The SSA region is also prone to various abiotic stresses that impact negatively on maize productivity. To ensure food security in the region, there is a need to breed highly nutritious maize cultivars adapted to the major abiotic stresses experienced in the region. To breed increased provitamin A hybrids, it is important to understand the mode of gene action affecting grain yield and β-carotene expression, and the heritability of β-carotene concentration under the prevailing stresses. There is also a need to determine the stability of provitamin A germplasm for grain yield and nutritional traits such as β-carotene under these stress conditions. In this study, 22 elite provitamin A inbred lines and five yellow drought tolerant inbred testers were crossed following a line × tester crossing design. Thirty hybrids had sufficient seed for replicated trials out of a potential of 110. The 30 hybrids and five checks were evaluated in Zimbabwe under optimum conditions, random drought stress, managed drought stress, combined drought and heat stress, low N stress and low P stress in 2014 and again in 2015. There was significant variation between hybrids for grain yield for all environments, except grain yield under low nitrogen stress. There was a significant interaction between year, environment and genotype for grain yield but no interaction was observed for grain texture. Inbred lines were highly heterotic for grain yield, especially under stress conditions. Narrow sense heritability for grain yield was more than 50% under optimal conditions, managed drought stress, combined and drought and heat stress and low P stress. AMMI and GGE analyses showed that genotype by environment interaction (GEI) was a very important source of maize grain yield variability. The environments were grouped into one mega-environment. The highly significant correlations between the environments suggest that testing can be done in only one environment. Hybrid environment, year and GEI effects for β-carotene were highly significant. Beta-carotene concentration was higher under optimum than under stress conditions and was highly significantly correlated with grain yield. Heritability for β-carotene was very high; 97% and 90% under optimum and 70% and 94% under managed drought stress in 2014 and 2015 respectively. General combining ability for β-carotene was significant and specific combining ability was not, emphasising the importance of additive gene action in the expression of the trait. Provitamin A hybrids had β-carotene concentration in the expected range (5-12 μg g-1) for first generation medium to high provitamin A maize genotypes. Lines 6, 7 and 8 can be used for breeding hybrids suitable for all environments except for managed stress conditions. Testers 1 and 2 were ideal for breeding for optimum conditions, managed drought stress, tester 2 for random drought stress and tester 3 for low P stress. Line 8 contributed consistently positively to grain yield, line 3 was favourable under managed drought stress and combined drought and heat stress, lines 6, 7, 8 and 9 were desirable under low N, 6, 7 and 8 under optimum conditions, 4, 6, 7, 8, and 10 under random drought stress, and 3, 8 and 10 under managed drought. The best performing and most stable genotypes for both grain yield and β-carotene can be distributed to SSA farmers for production. These hybrids will go a long way to alleviate vitamin A malnutrition among resource poor households in the region
Characterization of Maize Production in Southern Africa: Synthesis of CIMMYT/DTMA Household Level Farming System Surveys in Angola, Malawi, Mozambique, Zambia and Zimbabwe
No full textWe are very grateful for the financial support of the BMGF and HGDF that made all the studies and this synthesis
possible. We are also very grateful for the leading national partners; namely, Manuvanga Kiakanua (Angola), Samson
Katengezah and Julius Mangisoni (Malawi), Rafael Uaiene (Mozambique), Thomson Kalinda (Zambia), and Shamiso
Chikobvu (Zimbabwe), for the indulgence and commitment they have shown in undertaking the national level
surveys.
We would like to appreciate the support we received from CIMMYT’s Southern Africa Regional Office staff while
organizing and undertaking “Data Analysis and Report Writing” workshop to speed up finalization of the country
level reports that ended up very successfully. This report has benefited from the valuable comments of different
colleagues. We are particularly grateful to the comments and suggestions of Dr Menale Kassie and Dr Surabhi
Mittal of Socioeconomics program at CIMMYT. Their meticulous reviews have made the report much more
readable. We also appreciate the contributions of Dr Hugo De Groote and Mrs Janin Trinidad who are
coordinating the working paper publication in the Socio-Economics Program of CIMMYT. This report was finally
edited and formatted by Mr Wandera Ojanji, Science Editor at CIMMYT Kenya. We thank him for his excellent
work.
This report is presented without a thorough peer review with the main purpose of making data and information rapidly
available to research teams and partners in the Drought Tolerant Maize for Africa (DTMA) project and for use in
developing future, peer-reviewed publications. Readers are invited to send comments directly to the corresponding
author(s). The views expressed in this report are those of the authors and do not necessarily reflect opinions of
CIMMYT, other partners, or donors. All errors and viewpoints in this report remain to be ours and are not shared
with any individual or institution
Genetic studies on sorghum seedling tolerance to heat and development of a rapid screening technique
No full textFailure of seedling establishment is a major factor limiting crop production of Sorghum (Sorghum bicolor L. Moench) in the semi and tropics where soil surface day temperatures can exceed 50°C. Improvement of seedling heat tolerant genotypes would reduce crop losses due to insufficient plant populations. The objectives of this study were to develop a simple, repeatable and effective screening procedure to consistently estimate seedling heat tolerance and to gather information on the expression of heterosis for seedling heat stress, determining the individual parental contribution and to estimate additive, dominance and epistatic effects for seedling heat tolerance by utilizing generation means analyses of populations developed from a specific set of parents. Two experiments were conducted, one to develop screening procedures to determine heat recovery indices (HRI) of seven genotypes by subjecting seedlings grown in a in dark growth chamber at 30°C to direct heat shock in a controlled temperature water bath at 50°C for 0, 10, 20 and 30 minutes returning them to them 30°C growth chamber then measuring recovery at successive intervals. The second experiment estimated genetic parameters of MU in hybrids of four lines of varying MU crossed with three tester lines, and, evaluating the derived F1, F2, F3, BC1 and BC2 families for generation means analysis. Exposure at 10 minutes and 30 minutes gave the best separation between genotypes for MU. The technique of using 10 minutes exposure at 50°C, and measuring coleoptile length after 32 hours of recovery is an effective method to determine seedling heat tolerance that can be used to screen a large number of genotypes. Generation means analyses showed additive and dominance effects contributed to coleoptile elongation under normal conditions, but only additive effects were significant in recovery growth. Epistatic effects were present in both conditions. General combining ability (GCA) effects for HRI were highly significant under all conditions but specific combining ability effects were negligible. These results offer an opportunity for improving plant population of sorghum in tropical areas with high seedling mortality
Assessment of the effectiveness of maize seed assistance to vulnerable farm households in Zimbabwe
No full textThe publication describes outcomes of a study to assess the effectiveness of a large-scale crop seed relief effort in Zimbabwe during 2003-07. Aims of the effort, which was supported by the British Department for International Development (DfID) and coordinated by the Food and Agricultural Organization (FAO) regional office in Harare, included broader diffusion of open-pollinated maize varieties (OPVs), as opposed to hybrids. Based on the findings of the study, the authors recommend that, to increase benefits to vulnerable groups, participants in such efforts should effectively disseminate information on selecting and recycling seed, supported by training and field demonstrations, and should target relatively well-endowed farmers initially. Recommendations also included promotion of OPVs by commercial seed companies and developing a simple, farmer-friendly system for naming varieties.Agricultural development, Technical aid, Farm income, Food production, Maize, Open pollination, Hybrids, Zimbabwe, Crop Production/Industries, International Development,
Sustainable intensification of low-input agriculture systems in the Eastern Province of Zambia: implementation, progress and achievements
No full textAssessment of the effectiveness of maize seed assistance to vulnerable farm households in Zimbabwe
No full textThe publication describes outcomes of a study to assess the effectiveness of a large-scale crop seed relief
effort in Zimbabwe during 2003-07. Aims of the effort, which was supported by the British Department for
International Development (DfID) and coordinated by the Food and Agricultural Organization (FAO) regional office
in Harare, included broader diffusion of open-pollinated maize varieties (OPVs), as opposed to hybrids. Based on
the findings of the study, the authors recommend that, to increase benefits to vulnerable groups, participants in such efforts should effectively disseminate information on selecting and recycling seed, supported by training and field demonstrations, and should target relatively well-endowed farmers initially. Recommendations also included
promotion of OPVs by commercial seed companies and developing a simple, farmer-friendly system for naming
varieties
- …
