8th INTERNATIONAL WHEAT CONFERENCE

eNhANCINg WheAT fIeLd PeRfoRmANCe ANd ReSPoNSe
To ABIoTIC STReSS WITh NoVeL gRoWTh-ReguLAToRy
ALLeLeS
Andy Phillips 1 , Peter Hedden 1 , Steve Thomas 1 ,
Ian Prosser 1 , Stephen Pearce 1 Margaret Boulton 2 , John
Snape 2 , Simon Griffiths 2 , Nadia Al-Kaff, 2
Andrey Korolev 2 , Robert Saville 2 and Martin Parry 1
Crop Genetic Improvement, Rothamsted research, Harpenden, Herts, AL52JQ, John Innes
Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK
E-mail Address of presenting author: martin.parry@bbsrc.ac.uk
The ‘Green Revolution’ that improved worldwide cereal yields from the 1960s was due
to a combination of new varieties of wheat and rice and the increased use of nitrogen
fertilisers and pesticides. An important feature of the new varieties was reduced height:
although originally introduced to allow the plants to tolerate high levels of fertiliser without
lodging, it was discovered that these new semi-dwarf varieties increased yield, as
harvest index was increased. These dwarf varieties of wheat carried an allele of the Rht-1
series of genes (“Reduced Height”) that made them insensitive to exogenously applied
gibberellin (GA). There are relatively few alleles of Rht-1 that have been widely used in
wheat, and predominantly just one in UK varieties, Rht-D1b. Changes in climate, agricultural
practise and possible restrictions in the use of growth-regulating chemicals may
mean that wheat varieties containing this gene are no longer capable of producing the
highest yield. Part of this programme is aimed at exploiting existing sources of variation
in wheat that alter GA signalling and therefore have different effects on height. We have
approached this by investigating existing Rht-1 dwarfing alleles and also novel dwarfing
loci identified through quantitative genetics. We have also discovered that dwarfing genes
that confer reduced height through changes in GA signalling also protect plants against
stresses such as drought, heat, or salt. This may become even more important as climate
change reduces the amount of rainfall in wheat-producing areas. From the literature it
was not clear whether the particular Rht allele (Rht-D1b) that predominates in UK varieties
is ideal for protecting wheat plants from stress. A second aim of this project has
been to test a range of genes affected in GA signalling for their effectiveness in protecting
plants from drought and other abiotic stresses.
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