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Scientists develop new bean varieties
Farmers scout for pests on their bean garden. Photo/Lominda Afedraru
What you need to know:
- Scientists with expertise in bean breeding contend that bean productivity is limited by biotic and abiotic constraints such as diseases, pests, poor soil fertility and drought.
Beans are considered essential in sub-Saharan Africa including Uganda and statistics indicate that in East Africa alone, they are the second most traded commodity and a meal is often considered incomplete without them.
Bean production in sub-Saharan Africa is largely done by small scale farmers predominantly by women for both household food security and cash.
In Uganda bean research to develop varieties by farmers is done by scientists from the National Agricultural Research Institute (Naro).
Background
Scientists with expertise in bean breeding contend that bean productivity is limited by biotic and abiotic constraints such as diseases, pests, poor soil fertility and drought.
One of the major interventions being pursued by regional bean research networks to address bean productivity in smallholder systems is enhancing the use of adapted varieties.
Based on bean agro-ecological adaptions and market demand similarities across several African countries, a regional breeding programme based on regional constraints and variety demand was introduced by the Pan-African Bean Research Alliance (PABRA) in 1996.
Through the alliance, national bean research programmes in agricultural research institutes in partnership with the International Center for Tropical Agriculture (CIAT) have developed a range of farmer preferred bean varieties with useful adaptation and consumer preferred traits.
Through this alliance, countries share germplasm and variety evaluation data that accelerate the release process, often leading to simultaneous release of a variety in several countries.
Uganda’s bean gene bank is located at the National Research Laboratories (NaRL) in Kawanda.
Seeds of Gold had the initiative to interact with the scientists in the bean breeding value chain and below are the details.
Genetic diversity
Dr Clare Mukankusi Mugisha the global lead of common beans at the Alliance of Bioversity International and CIAT explains that there are 37,000 accessions of beans at the global bean collection in Colombia and the 3,000 gene bank in Uganda.
She contends that as a breeder, she relies on genetic diversity to make progress.
If one bean variety is lost forever then scientists might never know how its unique attributes could have helped those engaged in the bean value change and it would be a problem for future generations to tackle specific challenges.
Current breeding initiative
Dr Mukankusi and her team have bred parent varieties for disease and pest resistance tolerant to drought but they are now breading beans which can cook faster and with Iron and Zinc nutrients.
The breeding started in 2018 and crossing the various lines began last year meaning they will be trough in 2027.
It will take them five cycles to complete the process and each cycle takes a period of two years.
What the team does is select bean varieties which are fast cooking say white beans and cross the pollen to other varieties such as Narobean 4 and 5 to come up with lines that can cook faster
The cross is done conventionally using its flowers where stigma is picked from one flower and crossed to the anther for pollination to take place.
The date for crossing is marked and during harvest the scientist will select those that have performed well for further crossing until they obtain what is desired.
Once the beans are harvested, there is the process of cooking it using Madison cooker in the laboratory to establish how fast it cooks.
The time the scientists are promoting is 30 minutes maximum for cooking.
The breeding process is participatory and farmers are engaged in the entire process because once the breeder seed is taken up by Naro scientists, they are tested in various agro ecological zones to establish how they will perform in the various selected places.
Gene bank
Andrew Kaggwa, a research Associate at CIAT explains that the gene bank contains bean varieties from a range of countries within Africa and from the main gene bank in Colombia.
Scientists across the region use them to improve bean varieties.
There are varieties from Rwanda which scientists collected during the time of genocide to keep to avoid extinction and after the insurgence, scientists from Rwanda where able to access these varieties which they have since bred and multiplied for farmer use.
The team uses a machine called Photo box to characterise seeds.
The collection at the gene bank is kept under a specific temperature which is cooler and this can enable the beans stored to remain viable for 50 years and others can last 20-30 years and they are replaced.
Released varieties
The team has released several varieties according reginal tests in the country and elsewhere, some large seeded, medium seeded and small seeded mainly consumed by people in northern Uganda.
Some of the varieties are accessed from local community seed banks especially those traditional varieties.
Most of the varieties released are out with the farmers with the recent promotion of Naro bean 6 which contains Iron and Zinc and is it mature faster. It is being grown most by farmers in Mayuge district.
It is also resistant to the root rot disease which is major disease ravaging beans in farmer fields.
Other varieties adopted are Narobean 1, 2, 3 4C and 5C with latter two being climbing beans mainly grown in Western Uganda.
varieties
One of the major interventions being pursued by regional bean research networks to address bean productivity in smallholder systems is enhancing the use of adapted varieties.
