New disease-resistant cassava varieties introduced in Rwanda

Rwandan farmers have lacked improved cassava varieties resistant to the main cassava diseases, namely Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD). The diseases have since 2014/15 affected cassava productivity, hence threatening the incomes and food security of many people in the country.

“There are two main diseases that attack cassava in Rwanda and the region, CMD and CBSD. The latter poses a serious threat because once cassava is infected with CBSD, root tubers spoil, leaving almost nothing to be consumed,” said Dr Charles Bucagu, Deputy Director General at the Rwanda Agriculture and Animal Resource Development Board (RAB).

The solution to both CMD and CBSD

The Government of Rwanda has been working with partners to find improved resistant varieties and ensure availability of clean cuttings to farmers.

In partnership with RAB, IITA has been implementing a four-year IFAD-funded CBSD Control project since 2017, which implemented a dual strategy of developing resistant varieties and clean seed delivery systems to fight CBSD and CMD.

The project introduced up to 17 elite clones (about 200 tissue culture plantlets) with high dual tolerance to CBSD and CMD. Moreover, 40,841 true cassava seeds were also introduced and promising elite clones have since been selected for advanced yield performance.

“Both elite clones and biological seeds have directly and positively impacted the genetic diversity for the present and future CBSD/CMD dual resistance breeding efforts in Rwanda. Several CBSD/CMD resistant and high yielding varieties that carry good consumer preference and other end-use traits have been identified for Rwanda,” highlighted Dr Silver Tumwegamire, CBSD Control Project Leader.

The project also collected and characterized 55 local germplasm, 30 of which were sent to Kenyan Plant Health Inspectorate Services for virus cleaning. Up to 19 have been returned for conservation and re-introduction into the clean seed system. Ten local varieties have been crossed with the introduced elite clones to generate new breeding populations. Up to 11,261 biological seeds have since been produced and will be germinated to select new clones that combine superior culinary traits with CBSD/CMD resistance.

IITA has introduced and built the capacity for Semi-Autotrophic Hydroponics at Rubona station to strengthen quality seed delivery. The facility complements the screen house infrastructure for pre-basic seed multiplication by RAB.

“Through the project, Rwanda has made gains in terms of resistant elite clones and biological seed all of which will enable us to identify high yielding cassava seeds and resistant varieties. It has also enabled us to make efforts to streamline the cassava seed value chain in Rwanda. Thanks to this project, we now have cassava seed standards to ensure seed quality control for cassava in Rwanda,” said Dr Athanase Nduwumuremyi, head of the cassava research and technology transfer program at RAB.

According to 2018 official data cassava is the second most grown and the fourth most consumed staple crop in Rwanda. It is among the seven priority crops promoted by the government to ensure food security and increased incomes among the farmers.

Follow the achievements of the CBSD Control project through the following newsletters:

• CBSD Newsletter

               French: https://bit.ly/2EG3IwM
               English: https://bit.ly/3jmPvnp

• CASS Newsletter

              French: https://bit.ly/3hCgURZ
              English: https://bit.ly/2YENNFZ