Canola, Rapeseed, and Mustard: For Biofuels and Bioproducts - Industrial Crops: Breeding for BioEnergy and Bioproducts - page 140

rapeseed including triazine tolerance, glufosinate tolerance, glyphosate tolerance,
and imidazolinone tolerance in B. napus canola/rapeseed as well as imidazolinone
tolerance in B. juncea canola have been developed and commercialized in Canada
[ 63 ]. Triazine-tolerant and glyphosate-tolerant B. napus canola cultivars have also
been developed and commercialized in Australia [ 64 ]. Australia also developed and
grows imidazolinone-tolerant canola and, more recently, Roundup Ready canola in
some Australian states [ 65 ]. Biotechnology created herbicide-tolerant canola occu-
pied 26 % of global canola production area (8.2 m ha of 31 m ha total) in 2011 [ 66 ].
The development of synthetics, varietal associations, and hybrids in B. napus
using genetic male sterility systems, nuclear male sterility systems, and cytoplasmic
male sterility systems is a more recent major breeding achievement which signif-
icantly increased seed yield in B. napus canola/rapeseed grown in Canada starting
in 1989 and elsewhere in the world shortly thereafter [ 1 , 43 ]. The development of
hybrids in B. juncea has also been successful in India [ 67 ].
Target Traits and Current Breeding Goals
There are several common target traits and current breeding goals applicable to all
Brassica oilseeds and all areas of world production. These include increased seed
yield; enhanced yield stability; adaptation to local environments; improved seed
quality, oil quality, and meal quality; herbicide tolerance; as well as improved
abiotic and biotic stress (disease and insect) resistance [ 1 , 16 , 43 , 46 ]. Because of
variation in the current state of development of different Brassica oilseed species,
different growing conditions throughout the world, different weed spectrums,
varying abiotic and ever-changing biotic threats to production, constantly evolving
market requirements and opportunities, and differing resources available to differ-
ent Brassica breeding programs, the relative importance of these breeding targets is
oilseed species, location, and time specific [ 43 ]. Increasing seed yield in B. juncea
and B. rapa was a primary breeding target in India; however, there was shift in the
early 1990s to equal emphasis on improving seed yield and seed quality [ 46 , 68 ]. In
contrast, in the western world, breeding for seed, oil, and meal quality were primary
target traits in B. juncea , B. napus , and B. rapa starting in the 1970s [ 16 , 69 ]. The
emphasis in breeding targets in the western world has now shifted to improving
seed yield and yield stability while maintaining seed quality [ 43 ]. For B. carinata ,
canola quality is a target trait for crop researchers in Spain, while increasing erucic
acid content is a target for Canadian researchers [ 43 ]. While breeding for biotic
stress resistance such as disease resistance is a common target, the important
diseases vary in different parts of the world, with blackleg a major disease in
Australia, Canada, and Europe, while sclerotinia stem rot is the major disease in
China [ 46 ]. Similarly, breeding for abiotic stress tolerance is a common target;
however, important stresses range from frost in Canada, northern Europe, and the
highlands of China to drought, heat, and salt in India [ 46 ].