Innovations in Dryland Agriculture

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ment (site × season) can dominate the responses but management (tactical agron-
omy) and interactions with the environment can account for much more of the yield
variance than genotype or its interactions with either environment or management
(Anderson 2010 ).
In the Australian dryland environments since about 2000, average grain yields
have either reached a plateau or become much more variable from season to season
(Fig. 1 ). For example, in Western Australia, the season-to-season range of average
wheat yield was about 0.8 t/ha before 2000 compared to about 1.7 t ha-1 in the new
millennium. The reasons proposed for this increased variability range from increased
variability in rainfall (climate change) to inappropriate application of inputs, espe-
cially N fertilisers, according to seasonal conditions (tactical management).
Breeding advances, often underpinned by physiological research, have made
major contributions to yield improvement in the Australian wheat crop (Fischer and
Wall 1976 ; Siddique et al. 1989 ; Loss and Siddique 1994 ; Evans 1987 ; Passioura
2006 ). Further improvements have been attributed to the interactions that exist
between breeding and agronomy or management (Anderson and Impiglia 2002 ;
Hochman et al. 2009 ; Cooper et al. 2001 ; Passioura and Angus 2010 ; Sadras and
Lawson 2011 ; Richards et al. 2014 ). Improved transpiration efficiency (Evans 1987 ;
Passioura and Angus 2010 ), competitive ability against weeds (Palta and Peltzer

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1950-1959 1960-1969 1970-1979 1980-1989 1990-1999 2000-2009

Decade

Mean yield (t/ha

) Broadleaf (hormone)

herbicides

Desiccant herbicides

Grass selectives

Reduced tillage

Semi-dwarf

cultivars

Early sowing

No till

First leaf rust epidemic

Lime, gypsum

Herbicide

resistance

50% received a premium for

quality

Increasing N and K fertilizer use

Lupin rotation

Fungicide sprays

Pasture legumes

Wheat Yield trend in Western Australia

Fig. 3 Some practices associated with average wheat yield improvement in Western Australia,
1950–2000 (After Anderson et al. 2005 )

W.K. Anderson et al.