Trying to capture the lucrative but elusive $400 per tonne
returns of chickpea presents unique challenges for Western
Australian grain growers.
Western Australia's low overnight inland temperatures
interfere with early pod set in chickpea to cut yield by up to
15 per cent and so rob growers of over $60/ha. Attempts to avoid
cool conditions during flowering by delaying sowing pushes pod
fill into the dry weeks of October, where moisture is too scarce
to sustain good production.
This double jeopardy has prompted research at Western
Australia's Centre for
Legumes in Mediterranean Agriculture (CLIMA) to develop more
robust varieties that flower earlier and set pods while moisture
is abundant. These new varieties will also incorporate better
resistance to ascochyta blight.
"Western Australia is currently planting less than a sixth of
the area to chickpea that it could sustain, which represents a
lost opportunity given that the crop is our highest paying
pulse," University of Western Australia researcher , Heather
Clarke, said.
"However, with a new approach at CLIMA, we are developing
‘Eskimo varieties’ with a better cold tolerance."
Chickpea sets seed when a tube is sent from pollen’s landing
point on the flower’s reproductive surface to the egg 10mm
below. However, when the average daily temperature dips below 15°
C these tubes shudder to a stop before reaching the egg.
Previous attempts to breed varieties able to withstand cooler
temperatures involved observing chilling tolerant plants in the
field and attempting to bulk up these varieties.
Unfortunately, few chickpeas have chilling tolerance, making
this process of elimination time inefficient.
"To speed up the development of chilling tolerant varieties
for Western Australia producers we pollinate plants under
controlled low temperature stress and retain only the survivors
from generation to generation in the breeding program," Dr
Clarke explained.
"This approach takes much of the guess work out and helps
control other factors such as exposure to light, moisture and
humidity, which can interfere with reproduction."
Working with germplasm from India and Syria , with some
existing chilling tolerance, this Grains Research and
Development Corporation supported project has already developed
locally adapted lines which will tolerate average temperatures
of 13° C.
At this critical level, the extra two degrees in chilling
tolerance could result in pods setting two weeks earlier to
broaden the planting window for Western Australia growers.
In addition to chilling tolerance, some of the advanced lines
are also showing greater tolerance to ascochyta blight than
standard varieties such as Sona and Heera.
While these varieties undergo field evaluation before release
to Western Australian growers, Dr Clarke has also developed
molecular marker technology to help hasten the ongoing bid to
drive the tolerable temperature for chickpea even lower.
Successfully identifying markers linked to chilling tolerance
could help future researchers use gene maps to identify and
cross tolerant plants without the need to work through so many
generations in the glasshouse and field.