Developing dual-resistance cassava

Cassava root rot caused by CBSD. Photo by IITA.
Cassava root rot caused by CBSD. Photo by IITA.

This year, we moved closer to developing North Face Sale a few too mild properly and so forth!
cassava with dual resistance to Cassava Mosaic Disease (CMD) and Cassava Brown Streak Disease (CBSD) – the most devastating diseases of the crop in Eastern and Central Africa and the greatest threats to the food security and livelihoods of over 200 million people.

In Uganda, we selected eight clones with resistance to CMD and CBSD and other farmer-preferred traits. These clones, which are the first ones with dual resistance suitable to the mid-altitude areas of the Great Lakes regions, were sent to the Kenya Plant Health Inspectorate Services for cleaning and multiplication in preparation for regional distribution to national partners. An additional 41 yellow-fleshed clones, also with dual resistance to CMD and CBSD, are undergoing advanced evaluation.

This is the fourth year of trials for dual-resistance cassava for mid-altitudes in Uganda. The trials are being conducted in Mukono and Namulonge, considered hot spots of CBSD and CMD in the country. The breeding work started with over 5000 true seeds of parents with tolerance to CBSD from Tanzania that were sent to Uganda for crossing with IITA varieties that are resistant to CMD.

Cassava grown from the Tanzanian seeds were repeatedly subjected to high disease pressure along with susceptible varieties for comparison. From each growing season, only 10 percent of the crop was selected for the next stage. After four growing seasons, the field has been narrowed down to eight very promising varieties.

Similar dual-resistance evaluation was carried out in Tanzania. Eight clones that have resistance to both CMD andeducate North Face Jacket Sale yourself on the way th much CBSD were deliberately subjected to the diseases by grafting them with infected plants. Five of these clones are being evaluated on-farm, while 11 clones with dual resistance and high starch content – a preferred trait by farmers – are also being evaluated.

Cassava that survives these tests, thereby producing a true dual-resistant variety, can then be used for further disease-resistance breeding in other countries in the Great Lakes region such as Rwanda, Kenya, and DR Congo. Throughout the selection process, farmers were actively engaged to ensure that the varieties meet their preferences such as cooking taste, texture, and yield.