Species diversity helps farmers reap the potential of pulses

Assorted pulses. ©Bioversity International/C.Zanzanaini

By Devra I. Jarvis, Principal Scientist, Bioversity International

The common bean is an unsung hero, and especially important in East and Central Africa and parts of Latin America. As well as improving the fertility of the soil in which it grows and providing farmers with a reliable income stream, it is the most important plant-based protein source for the people of Uganda, providing between 20 and 25% of the protein of the local diet.

 In many cases, however, bean yields are lower than they could be. This presents clear opportunities for beneficial interventions and — especially pertinent in this International Year of the Pulses — demonstrates the value of considering the full potential of pulses.

In Uganda, for example, bean yields are consistently 20% lower than their possible levels, largely because of damage by pests and diseases. Some parts of Uganda bean yield losses of up to 25% as a result of attacks by Bean Fly, Angular Leaf Spot (ALS) or Anthracnose. Research undertaken by Bioversity International shows that when farmers grow three or more bean varieties in their fields their crops sustain significantly less damage than those on plots with few varieties, particularly in years when there is a high incidence of disease.

In Ecuador, the picture is different. Smallholder farmers already plant their beans in mixtures and generally stick to traditional varieties (almost 90% of the beans sown in Ecuador are of traditional varieties). Despite using few or no pesticides, these farmers suffer low levels of pest and disease damage — less than 3% in 2012. Yet work with farmer groups in bean trials revealed there was nonetheless room for improvement. 

Bioversity International’s Devra Jarvis and national partner from The National Agricultural Research Organisation (NARO) in front of Kiziba community seedbank, established in Uganda in 2010. ©Bioversity International/D.Jarvis

Our research showed that after enhancing the bean plant mixtures by adding more varieties to the mixture than were normally used, yields increased and in some cases doubled. In fact, the yields exceeded those from both normal mixtures and commercial varieties sown.  Moreover, that year was one of low rainfall, and while the enhanced mixtures outperform the normal mixtures many farmers had little or no harvest from their commercial monocultures that year.

Unsurprisingly, there was a threefold increase in the number of farmers wanting to try enhanced bean mixtures, following those results.

Bioversity International, renowned for its expertise in the use of intraspecific (within-species) diversity for managing pests and diseases, has been working alongside partners, farmers and national researchers in China, Ecuador, Morocco and Uganda since 2006, specifically to ascertain how diversity within a crop type can boost pest and disease management efforts. Pulses feature strongly in this research, which has focused on both modern and traditional varieties of common beans and faba beans, among other crops.

This line of exploration will be increased and extended during this Year of the Pulses, ensuring that the plant diversity expertise that is Bioversity International's hallmark can be put to good use in support of associated international efforts.

Here is what our research to date has identified:

  • Small holder farmers maintain substantial numbers of traditional varieties of pulses, shown to be resistant to major pests and diseases, temperature and rainfall extremes, poor soil conditions, and reduced cooking time.
  • Planting diverse varieties of a pulse can reduce vulnerability to epidemics and offers a risk management strategy for unpredictable rainfall and temperature.
  • Farmers have local preferences for growing pulses either in varietal mixtures (different varieties of the same pulse crop), or growing several varieties in different fields. Working with these preferences for mixtures or sets by enhancing them with resistant varieties can substantially reduce pest and disease damage to the more susceptible popular varieties.
  • Farmers need access to good quality, diverse seed at the right time, and in sufficient quantity. Ensuring diversity of seed sources, from community seed banks supplying traditional varieties to a range of suppliers of commercial varieties, can help meet farmers’ demands.
  • Good quality seed can be produced by improving traditional pulse varieties, through both conventional breeding and participatory crop improvement. Both processes can be enhanced with marker-assisted selection for identifying parent materials.
  • Innovative harvesting and processing technologies are needed to accommodate the requirements of a diversity of pulse varieties while reducing labour costs.
  • A key requirement for sustainable security in pulses is that local, national and international organizations and agencies undertake actions to strengthen local institutions to enable farmers to take a greater role in the management of their resources.
  •  Sustainability requires capacity and institutional building at “middle levels” e.g., local technical universities, extension colleges, and local or provincial research and education institutes (in addition to national level institutes and community-based ones).

As part of the 15-member CGIAR research consortium, Bioversity International is committed to promoting and improving the use of pulses throughout the food chain, enhancing the global production of pulses, encouraging crop rotation and other fertility enhancing techniques, and addressing existing challenges to trade. Alongside our national partners, we will also continue to research innovative harvesting and processing technologies and to support training and information dissemination via universities and technical institutes. This aspect reflects a key Bioversity International axiom:

“The decision to implement a particular action, and therefore its success, will depend on farmers and the farming community having the knowledge and leadership capacity to evaluate the benefits that this action will have for them.”

Bioversity International’s vision is that agricultural biodiversity nourishes people and sustains the planet. Pulses form a major component of this vision.  

About the Author
Devra I. Jarvis, an American national, joined Bioversity International in 1996. Devra’s career began in China researching the last 10,000 years of vegetation and climate change in south-western China through fossil and modern pollen records.  In 1991 she joined the UN World Food Programme (WFP) where she worked in development and relief food aid in China, Uganda and Rome.  In 1996, Devra returned to her biological research background to lead Bioversity International’s new programme on in situ conservation of cultivated and wild crop diversity.

Today, 15 years later, Devra is the principal scientist of the Agrobiodiversity and Ecosystem Services group. Her work here has made her an outstanding scientific leader for the cross-disciplinary scientific work needed to advance Bioversity International’s understanding of the assessment, management, use and value of crop biodiversity in the production systems of smallholder farmers. She provides scientific guidance to research programmes and scientists not only at Bioversity International but also numerous international foundations, universities and other research centres.

Contact: d.jarvis(at)cgiar.org

The views expressed here belong to the speaker and do not necessarily represent FAO’s views, positions, strategies or opinions.


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