Potential impact of scaling adaptation strategies for drought stress: a case of drought-tolerant maize varieties in Tanzania


 Drought-tolerant maize varieties (DTMVs) offer hope as an adaptation strategy for farmers facing increasing frequency of droughts in sub-Saharan Africa (SSA). However, these varieties are not yet widely cultivated, and the potential economic benefits not fully understood. Using predicted potential levels of scalability of DTMVs, we assess the potential economic impacts of investing in drought-tolerant maize varieties in Tanzania. The study uses household production and consumption data from major regions in Tanzania. The results from the economic surplus model indicate that by 2032, the adoption of DTMVs could generate between US$ 373 million and US$ 499 million in cumulative benefits for both producers and consumers. Such benefits could potentially lift up to 1.6 million people out of poverty by 2032. It is estimated that consumers would get 40% of the benefits and producers 60%, with the largest benefits occurring in the major maize-producing regions of Mbeya, Rukwa, Ruvuma, Mwanza, Arusha, and Kagera. Consumers in Dar es Salaam would also benefit significantly from the price reductions resulting from increased production. The largest returns on investment would occur in Dodoma, Geita, Simiyu, Singida, and Kagera. These findings justify the investment of both public and private funds to support the scaling of DTMVs in Tanzania.

CIMMYT is implementing a product-oriented breeding program targeted at improving maize 178 varieties for the mid-altitude areas of eastern and southern Africa that are prone to drought and 179 other stresses. As depicted in Figure 2- 193 A major factor in the scaling of DTMVs relates to the capacity of the seed system's institutions 194 to produce foundation seed. CIMMYT has partnered with relatively small seed companies in 195 the scaling of DTMVs; such seed companies lack the capacity to produce foundation seed, and 196 may be unable to maintain the genetic purity of seed, which can lead to seed contamination.

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This means that they have to rely constantly on partners such as CIMMYT for their supply of 198 breeder seed in order to produce foundation seed. In order to address this constraint, and as a way of improving the sustainability of the scaling 202 efforts, CIMMYT's interventions aim to strengthen the capacities of different actors along the 203 seed value chain, including by offering training to breeders in the NARS and seed companies 204 on various aspects of seed production. CIMMYT provides training to breeders and technicians 205 on new breeding tools, to enable them to produce quality seed, maintain parental inbred lines, 206 manage germplasm, maintain seed, and conduct hybrid male sterilization and de-tasseling 207 practices. Seed companies are also trained in conducting seed estimates by applying seed road 208 -Seed companies -Improved variety testing and release to embed preferred traits in DTMVs while maintaining their performance under stress conditions -Increased production of DTMV varieties Agro-dealers capacity enhanced through: -Affordable pricing, -Sales promotion -Brand positioning through multi-stakeholder collaborations -DTMV feedback processing Increased farmer awareness of DTMVs Better access to DTMVs seed by farmers DTMV seed being affordable to farmers   Agro-dealers are also trained in business management, seed storage, and marketing. Such  and to seed at affordable prices 1 . Under this framework, we address the question of whether a 246 potential adopter is aware of the existence of DTMVs, has access to seed, and has access to 247 seed at a price that is affordable. In addition to identifying the households that are aware of 248 DTMVs, we identify households with physical access to seed, and those with access to 249 affordable seed. We then extend the ATE adoption framework proposed by Diagne and    Therefore, as well as understanding the differential benefits between producers, it is important 291 to distinguish the differential benefits between different regions as well. We then adopt the 292 horizontal multimarket model, with the initial quantity equilibrium set by balancing total 293 production across all regions with total consumption across all regions including exports. In  In the economic surplus model, the key parameter affecting changes in price and economic 318 surplus is the cost reduction per unit of output due to adoption, or the k-shift (Alston et al.,  The study uses both primary and secondary data. Primary data is from a household adoption

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The results of the predicted adoption rates with and without ATE correction for different 506 population awareness of DVDs, seed availability, and seed affordability, population selection 507 biases, and adoption gaps are presented in Table 5-1. The awareness of DTMVs in the study 508 area sample in Tanzania was estimated to be 27%, whereas the sample adoption was 10%. The 509 predicted adoption rate for the full population after correcting heterogeneity in awareness of 510 DTMVs was 39%. This is higher than the observed sample adoption rate because of the low 511 levels of diffusion of DTMVs among the farming community. This indicates that if the entire 512 population of maize farmers were aware of DTMVs, the effective demand for DTMV seed 513 would have increased from 0% to 39%, resulting in an adoption gap due to lack of DTMV 514 exposure of 29%.

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Correcting for heterogeneity in awareness and availability of physical seed combined, the 517 predicted adoption rate for the full population is 46%. This means that if, in addition to being 518 aware of DTMVs, all farmers had DTMV seed physically available to them, the effective 519 demand for DTMV seed would have been 46%.The corresponding estimate of the adoption 520 gap of 34% resulting from non-availability of seed can, therefore, be interpreted as the seed-521 access gap, which is the potential demand loss due to non-access to seed (Donstop et al., 2013), 522 and which also suggests that there is scope for scaling the cultivation of DTMVs in Tanzania  The cost of seed can prevent potential adopters from adopting DTMVs. After correcting for 532 heterogeneity in awareness, seed availability, and access to affordable seed combined, the 533 predicted DTMV adoption rate for the full population is 52%. The corresponding estimate of 534 the adoption gap resulting from lack of awareness, access to seed, and access to seed at an 535 affordable price combined is 43%, and is significant at the 5% level. These adoption gap 536 estimates imply that there is still potential for scaling DTMVs adoption, once awareness and 537 seed accessibility constraints are addressed.  The third scenario assumes symmetric exposure and universal access to seed that is at an 562 affordable price. Under this scenario, the government would incur additional expenditure as a 563 result of offering seed price support to those who were unable to purchase seed at prevailing 564 seed market prices. Under this scenario, the total benefits from the scaling of the DTMVs have 565 a present value of about US$ 499 million. The consistently higher benefits are attributable to 566 the yield benefits accruing from scaling the cultivation of DTMVs from 46% in the second 567 scenario to 52% in the third scenario. Producers' benefits increase by 1 percent to 61 percent 568 due to the price support that they enjoy from the government, while the internal rate of return, 569 though high, declines from 118% in the second scenario to 96% in the third scenario due to the 570 cost incurred by the government in administering a targeted smart seed-subsidy program. With a conservative assumption that the yield benefit is 15% (instead of 19%), under the 39% 579 maximum-adoption scenario, the total benefits would amount to US$ 294 million, with a 580 benefit/cost ratio of 1.9 (

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As earlier expressed, about 35% of the maize produced in Tanzania is traded between maize-599 surplus and maize-deficit regions, with Dar es Salaam being the major maize-deficit region.

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The results for the horizontal multimarket model are presented in Table 5  any partial data recorded to be removed from the records. This way, the survey was consistent 665 with CIMMYT-IREC policies and those generally applied in low-risk social science research.

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The respondent's participation in the study was voluntary. It ensured the concealment of their 669 identity, and the respondent were informed that their identity would not be known in any study 670 report or publications. Respondents were assured that their household information would be 671 kept strictly confidential and will not be shared with any third party.