The root hemiparasitic weed Striga hermonthica is a serious constraint to sorghum grain production in the ECA. A genetic linkage map of sorghum of N13X E36-1 based -RIL populations are geared at  displaying  locations  of  candidate  striga  genes  hence  very  ideal  genotyping  striga  resistant varieties.

In this genotyping innovation, a linkage map was developed for RIL populations based on a cross between a Striga resistant sorghum line (NX13); and striga susceptible line (E36-1). To fine map QTLs  associated  with  Striga  resistant  genes  in  sorghum  and  to  reduce  the  confidant  intervals between the flanking markers, a saturated genetic linkage map for Striga resistance in sorghum was constructed thereby adding 27 SSR and 21 DArT markers to the previous map. A DArT Marker or diversity  arrays  technology  is  A  DNA  segment,  present  or  absent  in  a  defined  genomic representation, depending on the individual genotype. DArT enables analysis of the striga genomes
with no prior DNA sequence knowledge. 

Fine  mapping  is  an  important  tool  that  can  fast  track  the  generation  of  evidence  for  several combinations of markers or association of markers that support the existence of striga susceptibility genes in the region.

Where  in  the  sub-region  the  technology/innovation  developed  and  where  is  it  suitable  for  up scaling/promotion. Development and evaluation of the striga resistant lines was done in laboratories at ICRISAT and BeCA in Kenya.

The technology was validated using the base recombinant inbred line (RIL) population and in both cases, the markers linked to the same genomic region confirmed the marker association.

The  beneficiaries  of  this  technology  are  sorghum  breeders  and  researchers,  students  and biotechnology  companies.    Publication  of  research  findings  in  journals  was  used  to  reach  wider circulation globally among sorghum breeders and researchers.

Essential partners/stakeholders) to be involved in the further scaling out/up    
The key partners needed in the scaling up process are:

• Sorghum breeders    
• Researchers
• Students
• Biotechnology companies

The innovation has not reached other sorghum breeders in the region.

Challenges  encountered  in  respect  to  further  dissemination,  adoption  and  scaling  up/out  of the genetic linkage mapping

• This is basic research which calls for  of  awareness  among policy makers to facilitate sustained funding
• Availability of good molecular laboratory facilities
• Availability of large grounds for field testing

Recommendation for addressing challenges

• Create awareness among policy makers and end users on fine mapping innovation
• Forge collaboration linkages with laboratories in advanced countries

Lessons learnt

• Need  for  early  awareness  by  policy  makers  of  the  use  of  this  modern  tool  in  the development of striga resistant sorghum varieties.
• There is need for forge collaboration linkages with advanced laboratories for testing the fine mapping innovations.
• Social,  environmental,  policy  and  market  conditions  necessary  to  catalyse  genetic linkage mapping
• Programmes that increase policy makers awareness
• Conducive institutional mechanisms for variety release

Basic  costs  (local  currency  and  equivalent  US  $)  associated  with  utilization  of  the  fine  mapping innovation  
Not done
Estimated returns (local currency and equivalent US$) such as cost benefit or gross margin figures where applicable
Not done

Gender issues /concerns (if any) were considered in the fine mapping exercise
Was not part of the study
Gender issues/concerns  (if any) in the fine mapping exercise
Was not part of the study
Gender-related opportunities (if any), which enhanced or can enhance the genetic linkage mapping  
Was not part of the study

Success stories from beneficiaries attesting to the use of the genetic linkage mapping
None as yet
Methodology for development genetic linkage map  
Are well documented and are being published

Mohamed H Abdalla
Associate Professor, Agricultural Research Cooperation (ARC)
P.O Box 126
Khartoum, Sudan
Mob: +249-921934900
Email: abdalla_moh2002@yahoo.com; abdallamoh2002@gmail.com

Name and contact address of other partner organizations and key scientists or non-scientists

Dr. Rasha Ali
Associate, Agricultural Research Co-operation (ARC)
P.O Box126
Khartoum, Sudan
Email: yarashaya@gmail.com

Dr Tom C. Hash
Sorghum Breeder
ICRISAT
Pantecheru,
India
Email: c.harsh@cgiar.org

Dr Santie de Villiers
Senior lecturer
Pwani University
Department of Chemistry and Biochemistry
P.O Box 195-80108
Kilifi, Kenya
Tel: +254 729369758
E-mail: s.devilliers@pu.ac.ke
santiedevilliers@gmail.com

Dr. Dionysious (Dan) Kiambi
Executive Director
African Biodiversity Conservation and Innovations Centre (ABCIC)
P.O. Box 100882-00101, Nairobi, Kenya
Tel/Fax. 254-20-2330014
Mobile.254-731823394/704417920
Email:d.kiambi@abcic.org

ANNEX 1

The  red  parts  show  markers  (SSR)  that  were  added;  while  the  black  parts  show  the  DaRT  markers. The genes responsible for striga resistance are in the strigaresistant QTLs (circled portions).

ANNEX 2
Glossary of terms
ARC       Agricultural Research Corporation of Sudan
ECA        Eastern and Central Africa
MAS       Marker Assisted Selection
RIL          Population  Recombinant Inbred Line Population
QTL        Quantitative Trait Loci  
NX13       Striga resistant sorghum line
E36-1        Striga susceptible sorghum line
SSR Marker     Simple Sequence Repeat marker  
DArT Marker    Diversity Arrays Technology marker
ICRISAT        International Crops Research Institute for the Semi-Arid Tropics  
BecA            Biosciences East and central Africa