Highland yellow single cross hybrid maize ears
Credit, CIMMYT.
Hybrid rice. Credit, IRRI.
The development of hybrid maize seed has had one of the greatest impacts on increasing the quantity of available food supply.[8] Hybrid rice – grown on more than 21 million hectares, or 13% of land devoted to rice globally – too has contributed substantially to global food production. Hybrid rice increases yields between 5% and 15% over inbred varieties and China’s “super” rice achieves yields of 12 tonnes per hectare or 8% to 15% more than other hybrid varieties.[9]
Hybrid seeds are usually an improvement over non-hybrids in terms of qualities such as yield, resistance to pests and diseases, and time to maturity.[10] In addition to qualities like good vigour, trueness to type, heavy yields and high uniformity, other characteristics such as earliness, disease and insect resistance and good water holding ability have been incorporated into most hybrids varieties. Hybridisation can also be very useful in developing seed varieties that are drought and pest tolerant, enabling adaptation to climate change or mitigating other risks. As these cultivars have higher yield potential, under the right inclusive markets and climatic conditions, they can contribute to the improvement of farmers’ income and asset accumulation as well as the improvement of their standard of living.[11]
Benefits and limitations
Yield Benefits
The advantage of growing hybrid seed compared to inbred, open-pollinated lines comes from the ability to cross the genetic materials of two different, but related plants to produce new, desirable traits that cannot be produced through inbreeding or selection. Hybridisation can also be very useful in developing seed varieties that are drought and pest tolerant, enabling adaptation to climate change or mitigating other yield penalising risks. Hybrid seed also produces plants that are uniform, and usually higher in yield. Yield benefits vary by crop and environment, but some notable examples include maize hybrids developed by the International Institute for Tropical Agriculture (IITA) in West and Central Africa in the 1980’s that by the early 1990’s were available with resistance to maize streak virus and out-performed open-pollinated varieties (OPVs) by 33% to 45%.[12]
Costs to Smallholder Farmers
The main disadvantage of hybrid seed, especially for smallholder or resource-poor farmers, is that they do not perform to the same standards when their seed is saved for future plantings. Hybrid seed typically produces high yields the first year, but the yield drops if the seed is recycled for a second year. The percentage yield loss that occurs in recycling depends on the type of hybrid and the growing environment.[13] As a result, if farmers wish to achieve the same yields and or characteristics from season to season, they must continually repurchase the same seed. For farmers in developing countries, this can often be expensive or challenging if seed markets and credit are unreliable or inaccessible.
Sustainable Seed Systems
A sustainable seed system will ensure that high quality seeds of a wide range of varieties and crops are produced and fully available in time, acceptable and affordable to farmers. However, farmers are not always able to fully benefit from the advantages of using improved seed.[14] Part of these challenges will not be addressed without the development and improved access to finance and markets, but reforms and improvements are also needed within research and breeding programmes. Seed systems are usually divided into formal and informal; the former consisting of the development of new varieties by trained plant breeders and multiplied according to set standards and the latter informal seed selection, multiplication and exchange by farmers.
Whilst the formal sector offers opportunities to create uniform, quality and reliable seed that offer greater yield or other desired benefits, these seeds can sometimes be cost-prohibitive. Informal systems are low cost and adaptable to farmer preferences and needs, and the use of multiple seed varieties on a farm can improve resilience to certain to shocks and stresses, but is limited in its ability to develop or widely disseminate new varieties.[15] As both approaches offer options for strengthening resilience against a variety of risks and uncertainties, and private seed companies have not demonstrated strong interest in producing seeds that are grown in small volumes, in remote areas or marginal areas, both systems should be strengthened.
Constrained research and development capacity
Developing sustainable seed systems includes the improvement of agricultural research and development for new seed varieties. The issues and progress in plant breeding vary widely across crops and countries but generally, there is a lack of national capacity in plant breeding, due to a low number of trained breeders, and limited capacity to develop robust delivery and extension systems.
Through support from international agricultural research centres and donors to national agricultural research organisations (NAROs), improved germplasm has been adapted to local conditions for a variety of African staple crops. Only recently have universities and private sector companies become more involved in varietal development. Collaboration between all these actors has led to the development of several varieties of major food crops, especially maize, sorghum and rice in sub-Saharan Africa. In 7 West African countries, for example, more than 131 crop varieties were released between 2002 and 2012.[16] Notable advancements in public-private partnerships for improving drought-tolerant maize varieties is the Water Efficient Maize for Africa (WEMA), a collaboration between the African Agricultural Technology Foundation (AATF), the International Maize and Wheat Improvement Center (CIMMYT) and Monsanto to provide germplasm and seed varieties royalty-free.
A preference for maize
Maize is the most important cereal crop in sub-Saharan Africa. Africa produces 6.5% of maize globally, but accounts for 30% of worldwide consumption. Eastern and Southern Africa consumes 85% of its production for food, whilst Africa as a whole consumes 95%, compared to other regions of the world that use maize primarily as animal feed.[17] Although many other crops continue to be culturally important, offer more nutrients or strategies for diversification and resilience, maize receives the majority of attention from agricultural research and breeding programmes.[18] Recently, however, there has been growing attention to breeding other cereals such as millet and sorghum.
Plant breeding has large fixed costs and long (5-20 years) and uncertain payoffs. Typically, only a large company or a subsidised public entity can afford to assume these risks.[19] In addition, many types of seed are easy to reproduce. Though, some seeds are difficult to harvest or store such as many vegetable seeds, others do not maintain their yield advantage if saved, as is the case with hybrid maize. Many self-pollinating crops including wheat, rice, groundnuts, and potatoes maintain their genetic characteristics over many generations. This explains why farmers generally will purchase vegetable and hybrid maize seed, but often use saved seed for other crops.[20] In addition to the difficulty for a company to recover its breeding costs when farmers save and re-use seed, limited consumer demand for other types of seed varieties from the formal sector also constrains investments in neglected crops and environments.
Adoption
In a number of countries, the use of hybrid cultivars in sorghum and maize production has been increasing, for example in Nigeria, Kenya and Zambia.[21] Rates of adoption, however, vary by country, region and farm typology and size. In Kenya, hybrid seed is more widely adopted by commercial rather than small-scale farmers.[22] The use of hybrid technology is also considerably higher in the South African commercial farming sector than in the smallholder sector.[23] In contrast, hybrid cultivars dominate agricultural food production systems of small-scale farming sectors in Zambia and Zimbabwe.[24]
One study[25] noted that hybrid technology is likely to be adopted more extensively by farmers that have large farms. Farmers who have access to farming support services also tend to swiftly adopt new technology. In Kenya, for example, farmers’ access to credit, input supply and extension services enhanced the adoption of their new hybrid maize.[26] Another study found that gender and literacy levels affect adoption of new seed technologies. Although women constitute the majority of the subsistence farming community, men are more likely to adopt hybrid sorghum. Farmers with some level of education adopt the hybrid cultivars more than those without years of schooling. However, in other studies this has not been found to be a strong predictor of use.[27] Distance to roads, access to transport infrastructure and farm size are found to influence the scale of hybrid seed planted by smallholder maize growers most significantly.[28] Further, the majority of farmers with membership in cooperatives use hybrid sorghum. Therefore, access to agricultural organisations may also have an impact on the farmer adoption of technology. In Kenya, cost was cited as the strongest barrier to hybrid seed adoption.[29]
Plant breeder rights and farmer ownership of seeds
As genetic resources have assumed increasing scientific and (especially) commercial value, debates over access to and ownership of genetic resources have intensified. Seed is basic to crop production and thus food security and rural development. The sustainable availability of good-quality seed is therefore an important development issue.[30] Trends emerging in the commercial seed industry which has become increasingly concentrated and now integrated into the pharmaceutical and chemical industries under the classification of ‘life-sciences’ companies generates concern among users. The concern is that corporate control over seed markets and genetic resources will disadvantage farmers no longer able to access, afford or save seed and lead to further consolidation of the farm sector in both developed and developing countries. Seeds have, therefore, also become an issue in debates on equity.[31]
Economic Impacts
The advantages of hybrids come at a price, because the performance of seeds diminishes in subsequent generations, requiring annual purchasing to maintain performance. Despite this reoccurring cost, the influence of hybrid seed on income and assets is favourable for smallholder maize growers in Kenya[32] and Zambia.[33]
Although smallholders in Kenya, particularly in less favourable areas, have been reluctant to adopt hybrid maize varieties, well adapted varieties can be profitable in terms of yield and yield stability even in marginal areas under low input conditions.[34] Further, those that do not adopt the technology, can be considered disadvantaged.[35]
In Zambia, the use of maize hybrids is associated with higher values of household income, assets, farm and processing equipment, livestock, and lower levels of deprivation compared to non-adopting farmers.[36] For every kilogram of hybrid maize seed planted, total household income increased by ZMK 32,230 (US$6,000) on average. Since this is considerably more than the price of hybrid seed in Lusaka ZMK 4,300 – 12,000 (US$0.59 – 1.65), hybrid maize proved profitable for Zambian smallholder farmers. If this profitability continues, returns will build productive assets and lessen the severity of poverty.[37]
