Innovative Technologies in the Breeding of Sorghum for Striga resistance and drought tolerance

Striga-parasitizing-rain-fed-sorghum-in-Sudan

Striga remains one of the key biotic constraints affecting cereal grain production in Africa, particularly in the semi-arid areas. The striga weed parasitizes sorghum, maize, millet, teff, sugarcane, cowpea, and rice. The current solution for managing striga is cultural, chemical, biocontrol measures and using resistant lines. Cultural measures include crop rotation, intercropping, trap-cropping and catch cropping. Chemical measures include fertilizers, herbicides, soil sanitation, while biocontrol measures include insects and fungus. The resistant lines that have been developed and used by farmers easily succumb to infection probably due to different ecotypes of Striga while other Striga management options have been proven expensive and cannot be afforded by most African farmers.

The option we now have is to continue improving the current resistant and tolerant lines by introgressing a gene for immunity that is available in wild sorghums. We are using an integration of modern array of biotechnological approaches to obliterate constraints due to drought and Striga parasitism in sorghum. Marker assisted breeding was used to develop Striga and drought tolerant Sorghum in Sudan and these lines have been taken up by the national agricultural research systems to advance them for commercial release in Rwanda, Uganda, Kenya, Tanzania, Sudan and Eritrea.

The lines were developed at the agricultural research corporation in Sudan. While advancing these lines we are also using other biotechnological approaches. We are using a transcriptional profiling approach to identify and validate gene products in Striga and Sorghum that are essential to their early post-penetration development and subsequent growth and differentiation on susceptible sorghum. This process will speed up the process of Striga resistance gene identification and help us better understand the molecular mechanism of Striga parasitism on sorghum.

We are also using transgenic approaches to impart tolerance to drought. In addition, we are using knowledge of marker assisted breeding, Striga phenotyping and genetics to obtain novel sources of Striga resistance and drought tolerance genes from wild relatives of sorghum by mapping advanced backcross populations derived from wild relatives of sorghum and farmer preferred sorghum varieties (FPSV). Finally, we are characterizing the nutritional and industrial technological properties of Striga resistant and drought tolerant varieties. This article details the methodologies being used to develop Striga resistant and drought tolerant sorghum lines for Africa.