Key Concepts

The toolbox for working with root, tuber and banana seed systems is designed to help the user understand and support seed system development, to increase the availability, access, and quality of seed of improved varieties and landraces.

Root, tuber and banana crops are the foundation of tropical food security. These crops are much more important in developing countries than in the north. But the bulky seed is expensive to transport, spoils easily, and can harbor health problems from viruses to weevils. These challenges must be overcome as most of the world’s remaining population growth, and economic development, will happen in tropical countries. Wise investment in seed systems will depend on informed understanding of the seed, the crops and the people who produce, transform and eat them.  

Root, tuber, and banana crops are vegetatively propagated crops (VPCs). Farmers use roots, tubers, stems, suckers or vines as planting material. VPCs are unlike grain and legume crops that are planted with true, botanical or sexual seeds, which is almost always dry, durable and fairly lightweight 

Vegetative planting material, called seed on this website, is fresh and moist, rendering it bulky, perishable, and prone to carrying pests and pathogens. The multiplication rates are also lowdemanding large amounts of seed for small areas of land. But vegetative propagation allows the crop to multiply true-to-type. Because planting material is genetically identical to the parent plant, each generation is cloned from the previous one. Therefore, the breeding, multiplication and distribution of root, tuber and banana planting material is unlike that of true seed crops like grains, pulses and many vegetables. 

Good seed is healthy, in optimal physiological condition, without physical damage, and of the preferred variety. Access to quality seed is important for many reasons:  

  • First, roots, tubers, stems, suckers or vines are the start of a new crop and if the seed is of poor quality, the crop will be disappointing, and the yield will be low.  
  • Second, availability and access to good seed are key to conserving valuable landraces and to disseminating improved varieties with new genetic traits such as drought or disease resistance, and higher nutritional value.  

Projects that aim to improve yields, nutrition, market access, pest and disease management, for example, depend heavily on ensuring good seed for both women and men farmers, from the poorest to the not-so-poor 

A seed system can be defined as the network of seed users, the private food sector, extensionists, farmer organizations, specialized seed producers, traders, researchers, policymakers and other stakeholders involved in providing, managing, replacing, and distributing the seed of a particular crop in a certain area (adapted from Bentley et al. 2018).  

A well-functioning seed system ensures that farmers can get enough good seed, of the varieties they want, at the right time, and at affordable prices. A well-functioning seed  system avoids spreading pathogens and pests, and helps farmers adapt to local and global challenges, such as climate change, while complying with national seed regulations, and empowering disadvantaged social groups such as women, youth and ethnic minorities. 

To learn more about how the Toolbox can be used to improve seed systems, see the Toolbox User Guide. To see all our individual tools, visit the Tools page, or check out a list of past Results. We also provide helpful diagrams to show you how our tools can be applied along the project cycle and seed system.