F
Dr. Anandi Bierman & Prof. Anna-Maria Botha-Oberholster
Stellenbosch University
ew people know that the wheat used for baking bread, biscuits and other cereal products, is
in fact, genetically, a particularly complex organism. Modern bread wheat or Triticum aestivum L. is a hybridization of three progenitor species
(Triticum monococcum, Aegilops tauschii and possibly
Aegilops speltoides) and contains the genetic complement of each of these progenitors within every wheat
cell. In addition to the large amount of DNA within every cell, wheat DNA is highly complex and consists of
large regions of repetitive pieces of DNA in between
which the genes that govern important traits are hidden. And it is this property that makes working with
wheat particularly challenging.
This cereal is targeted by a number of pests and pathogens among which Rusts, Fusarium headblight and the
Russian wheat aphid (RWA; Diuraphis noxia Kurdjumov)
are prominent problems in South Africa. Currently, research by the Cereal Genomics group in the Genetics
Department, at Stellenbosch University focus on improving RWA resistance and water stress tolerance.
Since with the predicted climate change, we anticipate
more drought spells that will affect yield. However,
improving wheat for the South African market is not a
new activity at Stellenbosch University. In fact, wheat
breeding dates back to 1898, when Dr. E.A. Nobbs
evaluated 378 wheat varieties for stem rust resistance
at Elsenburg and Robertson Experimental Stations,
making him the first wheat breeder in South Africa. The
next validated historical reports came from Prof. J.H.
Neethling, who released the wheat cultivars Union 17
and Union 52, in 1915, which were followed by Gluretty, Hoopvol, Koalisie, and especially Pelgrim, Vorentoe
and Sterling. Since then staff at Stellenbosch University
released many more wheat and triticale cultivars.
Russian wheat aphid is not only a pest in South Africa,
but since 1981 (three years after it was first reported in
South Africa) it has also been a problem in the USA and
many other countries. Currently, RWA can be found in
all wheat producing countries except Australia. At Stellenbosch, we study the interaction between the aphid
and wheat in an effort to provide solutions to this economically important pest. Research in this area is directly aimed at increasing local yields but, considering
the bigger picture the aim is to address global food
shortages by understanding and curbing the impact of
biotic stress factors, such as the aphid, on crops.