Robust seed systems, emerging technologies, and hybrid crops for Africa

Gaffney, Jim; Anderson, Jennifer; Franks, Cleve D.; Collinson, Sarah; MacRobert, John; Woldemariam, W.; Albertsen, Marc C.

doi:10.1016/j.gfs.2016.06.001

Cited by 32 publications

(26 citation statements)

References 49 publications

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“…Genetic male sterility could be used in the African market (i) to increase the feasibility of hybrid seed production, and (ii) to improve hybrid yield in commercial fields using blended male sterile:male fertile hybrids. A hybrid seed system built around GMS could provide more sustainable grain yield for farmers who currently rely on older, landrace varieties (Gaffney et al, 2016).…”

Section: Resultsmentioning

confidence: 99%

Genetic Male Sterility (Ms44) Increases Maize Grain Yield

et al. 2017

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During reproductive development in maize (Zea mays L.), the tassel and the ear compete for available nutrients, at the expense of ear development. The objective of this study was to determine if male sterility (MS) genes could be used to reduce the competition between developing reproductive organs and to improve ear and kernel development. Nitrogen (N) budget experiments conducted in the greenhouse revealed that, under N limiting conditions, the tassel continued to accumulate N prior to anthesis while the ear stopped accumulating N. This finding confirmed prioritization of N partitioning to the tassel at the expense of the developing ear during the critical period of kernel set. Genetic male sterile (GMS) genes were used to terminate pollen production. At anthesis, ear biomass of male sterile plants carrying the ms1 allele increased 92% compared with male fertile plants in a greenhouse experiment. In subsequent field testing, GMS (Ms44 allele) male sterile plants increased grain yield across six N rates between 0 and 170 kg ha−1 (784–2301 kg ha−1), three plant densities between 79,070 and 158,140 plants ha−1 (489–3706 kg ha−1), and in flowering drought stress environments (2768 kg ha−1), compared with male fertile plants. Yield was improved due to increased silk number per ear, kernel number per ear, and reduced barren plants. The dominant GMS allele, Ms44, can be used to produce completely sterile or 50:50 segregating male fertile:male sterile hybrid seed through the use of a transgenic maintainer line. Growing a blend of male sterile and male fertile plants can improve grain yield under a range of growing conditions, including those where drought and N limit crop yield.

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Section: Resultsmentioning

confidence: 99%

Genetic Male Sterility (Ms44) Increases Maize Grain Yield

et al. 2017

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“…Substantial investment has been made in hybrid breeding at CIMMYT since 2006 (Cairns et al, 2013b), and yields have significantly increased under abiotic stress (Masuka et al, 2017; Setimela et al, 2012). Although there remains many barriers to the successful implementation of hybrids in many regions of SSA (Gaffney et al, 2016), together these results suggest that hybrids may be economically more viable than OPVs, despite initial investments. These results are in agreement with recent studies in Kenya and Zambia.…”

Section: Discussionmentioning

confidence: 97%

Gains in Maize Genetic Improvement in Eastern and Southern Africa: II. CIMMYT Open‐Pollinated Variety Breeding Pipeline

Masuka¹,

Magorokosho²,

Olsen

et al. 2017

Crop Science

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Open‐pollinated varieties (OPVs) still represent a significant proportion of the maize (Zea mays L.) seed system in many countries of sub‐Saharan Africa. The International Maize and Wheat Improvement Centre (CIMMYT) has been breeding improved maize varieties for the stress‐prone environments experienced by most smallholder farmers in eastern and southern Africa for over 30 yr. Hybrid breeding is now the major focus of the CIMMYT breeding pipeline. However, OPVs are generated within the hybrid pipeline. This is the first study to document genetic gain for maize grain yield under both optimal and stress (random and managed drought, low nitrogen [N], and maize streak virus [MSV]) conditions within the CIMMYT eastern and southern African OPV breeding pipeline. Genetic gain was estimated using the slope of the regression on the year of OPV release in regional trials over a 12‐yr period (1999–2011). Open‐pollinated varieties were separated into two maturity groups, early (<70 d to anthesis) and intermediate‐late (>70 d to anthesis). Genetic gain in the early maturity group under optimal conditions, random drought, low N, and MSV was 109.9, 29.2, 84.8, and 192.9 kg ha−1 yr−1. In the intermediate‐late maturity group, genetic gain under optimal conditions, random drought, low N, and MSV was 79.1, 42.3, 53.0 and 108.7 kg ha−1 yr−1. No significant yield gains were made under managed drought stress for both maturity groups. Our results show continued improvement in OPVs for both yield potential and stress tolerance.

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“…Only one case included a large private sector seed multiplier, and that was for potato seed, which generally has more commercial demand and the seed commands a high price. With hybrid crops, private sector entry into seed systems is more feasible, whereas for roots, tubers, and bananas, in general, subsidy elements tend to prevail (Gaffney et al 2016). Marando Bora ("Better Vines") was a project designed to distribute healthy sweet potato seed to 150,000 farmers in Tanzania (Ogero, McEwan, and Pamba 2016).…”

Section: Seed Accessmentioning

confidence: 99%

Understanding root, tuber, and banana seed systems and coordination breakdown: a multi-stakeholder framework

Bentley¹,

Andrade-Piedra

Demo

et al. 2018

Journal of Crop Improvement

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Vegetatively propagated crop (VPC) seed tends to remain true to varietal type but is bulky, often carries disease, and is slow to produce. So VPC seed needs to be handled differently than that of other crops, e.g., it tends to be sourced locally, often must be fresh, and it is less often sold on the market. Hence, a framework was adapted to describe and support interventions in such seed systems. The framework was used with 13 case studies to understand VPC seed systems for roots, tubers, and bananas, including differing roles and sometimes conflicting goals of stakeholders, and to identify potential coordination breakdowns when actors fail to develop a shared understanding and vision. In this article, we review those case studies. The framework is a critical tool to (a) document VPC seed systems and build evidence; (b) diagnose and treat coordination breakdown and (c) guide decision-makers and donors on the design of more sustainable seed system interventions for VPCs. The framework can be used to analyze past interventions and will be useful for planning future VPC seed programs. ARTICLE HISTORY

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Robust seed systems, emerging technologies, and hybrid crops for Africa

Cited by 32 publications

References 49 publications

Genetic Male Sterility (Ms44) Increases Maize Grain Yield

Genetic Male Sterility (Ms44) Increases Maize Grain Yield

Gains in Maize Genetic Improvement in Eastern and Southern Africa: II. CIMMYT Open‐Pollinated Variety Breeding Pipeline

Understanding root, tuber, and banana seed systems and coordination breakdown: a multi-stakeholder framework

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