ICRISAT Archival Report 2006 - The seedlings of success in the ...

SSR markers that are polymorphic between cultivated and wild sorghums. The frequencies of the SSR markers will
be used as a measure of gene flow.
Determine the distance of pollen flow:
This activity is being conducted at two locations, Kenya and South Africa in 2006 and 2007. A well adapted variety
will be planted in the center of the field in a 20 x 20 m plot as a source of pollen. From the center of the field in eight
directions four rows of A-lines with similar maturity to the adapted variety will be sown. Seed set on the A-line
was/will be recorded in a one-meter quadrant covering all the four rows at 10 meter-intervals up to a maximum of
100m. The presence of plants with seeds will be used to detect distance of pollen flow. The frequency of outcross
seed will be used to determine the outcrossing percentage at various distances.
A trial was established at the Dominion farm in Yala, Nyanza Province, Kenya in April 2006. The pollen source was
a locally adapted sorghum variety (Nahandavo) while the female rows were ms lines (ATX 623 and ICSA88006).
Preliminary results indicate that mean outcrossing rates were high at short distance from the pollen source and the
rate decreased as we move further from the pollen source; beyond 40 m, outcrossing rates were below 1%;
outcrossing rates and pollen flow distance were high downwind than upwind. This trial will be repeated at the same
site next season. A similar trial was planted at the University of Limpopo farm, South Africa on 28-29 November,
2006. The trial is being conducted in collaboration with the Department of Agriculture, Limpopo Province and the
University of Limpopo. The pollen source was a locally adapted variety (SDS 6013) while the female rows are ms
lines (A150, A8607, SDSA 27). Data is being collected during this 2007 by a University of Limpopo graduate
student who intends to write a MSc thesis on this information
S Mwangi and MA Mgonja
Milestone C.2.3.4: Hybrid fitness determined between cultivated/wild and weedy sorghum types from at least two
ESA countries by 2009
Hybrids produced from crop-wild sorghum crosses must persist in the wild if there is to be continued gene exchange
in future. The possible generation of “superweeds” after fitness enhancing genes escape from transgenic crops to
wild populations is a risk that is often discussed, but rarely studied (Halfhill et al, 2002). This study aims to evaluate
the fitness of sorghum crop-wild hybrids for fitness parameters under field conditions.
This activity will be conducted at two sites in Kenya to evaluate the performance of cultivated, wild/weedy and
crop-wild/weedy hybrid sorghums under field conditions.
Four cultivated varieties (IS 8593, KARI mtama 1, Gadam Hamam, Seredo) and two wild/weedy sorghum were
planted in the crossing block at Kiboko in November 2006. Crossing between cultivated and wild/weedy sorghum
will be made. The hybrids and parents will be evaluated for fitness and agronomic performance.
MA Mgonja and SG Mwangi
Milestone C.2.3.5: Fitness of F1, F2, BC1F1 crop-wild hybrids and their wild and cultivated parents evaluated in 2
experimental stations (Eastern and Coastal provinces) by 2008 (FS, SdV, DK + KARI + University of Hohenheim
Artificial, reciprocal crosses are planned between cultivated and wild sorghum varieties to assess the rate of crop-toweed
genetic introgression (and vice versa) and to determine the hybrid fitness resulting from such crosses. Two
agro-ecological zones, low- and mid-elevation, have been selected and seed from the collection conducted in mid
2006 was planted at both locations for this purpose. A total of 64 crosses will be made (16 crosses in each of the 4
Sorghum growing areas) and these will be advanced to the F2 and BC1F1 stages in 2007.
F Sagnard, S de Villiers and D Kiambi
Milestone C.2.3.6: Documentation for the risk/safety assessments on the environment needed when actual GM will
be presented for regulatory approval initiated by 2009
A document is being prepared on: The significance of gene-flow through pollen transfer in sorghum and
implications at centre of diversity using other crops as examples. The document will be prepared in collaboration
with the ABS Project regulatory affairs consultant, Dr Willy de Greef.
MA Mgonja and SG Mwangi
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