Mutation Breeding for Resistance to Striga Parasitic Weeds in Cereals for Food Security


Soil and Water Management & Crop Nutrition The parasitic weeds Striga asiatica and S. hermonthica are major biological constraints to cereal production in most of sub-Saharan Africa and semi-arid tropical regions of Asia. Yield losses are mainly in maize, millet, sorghum and upland rice and most severe on marginal lands of subsistence farmers. The unique biology of Striga, tightly adapted to its crop hosts, limits control options. Because subsistence farmers either cannot afford or do not have access to inputs, host plant resistance is a vital part of Striga control. Resistance traits, however, are lacking in most cereal varieties sown in Striga prone areas. This CRP proposes the use of physical mutagenesis and associated screening technologies to broaden the genetic base of resistance. The project seeks to combine expertise in field and laboratory screening to enhance mutation breeding to timely develop or adapt screening packages to generate novel sources of Striga resistance. Initial focus will be on sorghum and rice because of their importance to food security and amenability to mutation breeding techniques. Screening packages will be optimized for laboratory, screen-house and field to identify resistant mutants to Striga asiatica and S. hermonthica.

Soil and Water Management & Crop Nutrition The mechanisms of discovered resistance reactions among the mutagenized populations will be determined through laboratory co-culture of the cereal with Striga. This will allow pyramiding of different mutations containing incompatible alleles into single varieties with durable resistance. Accelerating techniques such as rapid cycling of crop generation and efficiency enhancing technologies of doubled haploid, genomics and molecular markers will be adapted in the CRP as appropriate. Up to ten research contracts are expected to be awarded and five no-cost agreement holders from advanced laboratories and research institutes with recognized expertise in the targeted technologies will be invited to share their experience with the contract holders and contribute to the development and validation of the planned technical packages. In addition, it is foreseen that two technical contracts will be awarded for services in advanced areas such as marker development and advanced efficiency enhancing technologies and mutant characterization.

Nuclear Component:

Mutant populations will be developed using physical mutagens such as X-ray, gamma-ray and possibly ion beam.

CRP Overall Objective:

To support generation of novel sources of variation, using mutation breeding, by developing efficient screening protocols for Striga resistance in cereals for building research capacity and improving food security in Member States.

Specific Research Objectives:

  • To generate genetic diversity to develop resistant/tolerant varieties to Striga infestation.
  • To develop, optimize, validate and disseminate robust screening protocols for mutant populations for resistance/tolerance to the parasitic weed Striga in major cereal crops.
  • To integrate and adapt efficiency enhancing techniques in the mutation breeding processes.
  • To improve capacity in efficient mutation breeding for resistance to parasitic weeds in cereals.

Project Officer:

A.M.A. Ghanim and L. Jankuloski