New disease-resistant cassava varieties introduced in Rwanda

Rwandan farmers lack improved cassava varieties resistant to the main cassava diseases; Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD). The diseases have affected cassava productivity, threatening the income and food security 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 by farmers,” said Dr Charles Bucagu, Deputy Director General of Agriculture, Research and Technology Transfer 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 clean, safe, and productive cassava seeds.

In partnership with RAB, IITA has been implementing a four-year project since 2017, which introduced new cassava varieties and seed quality management techniques to fight CBSD and CMD.

The CBSD Project implemented various approaches to curb the diseases. The project introduced up to 17 elite clones, with high dual tolerance to CBSD and CMD, each clone with about 200 tissue culture plantlets. Moreover, over 40,841 true cassava seeds were introduced.

Dr Athanase Nduwumuremyi from RAB holds a clean seed in a screen house.

“The project introduced both elite clones and biological seed that have directly and positively impacted the genetic diversity for CBSD/CMD dual resistance now and future 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,” said Dr Silver Tumwegamire, CBSD Control Project Leader.

The project also considered local varieties. Thirty selected accessions were sent to Kenyan Plant Health Inspectorate Services for virus cleaning, 19 were returned for integration into the seed system. Ten have already been used together with the new introduced elite clones to generate new breeding populations. Up to 11,261 biological seeds have equally been produced.

IITA introduced the semi-autotrophic hydroponic (SAH) technology at Rubona station to
increase the multiplication rates of tissue culture-derived plantlets.

IITA has introduced and built the capacity for Semi-Autotrophic Hydroponics at Rubona station in efforts to strengthen quality seed delivery. Two screen houses and five basic seed centers were established.

“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 seed 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.

Cassava is the second most grown crop and the fourth most consumed staple crop in Rwanda, 2018 official data indicate. It is among the priority crops promoted by the government to ensure food security and increased farmer income.

For more details about all the achievements of the CBSD Control project, please read through the following newsletters: