The CSSA is a bimonthly peer-reviewed scientific journal, recognized as one of the premier showcases of agricultural scientific research. After careful consideration by a subset of the Crop Science Editorial Board and other member-scientists, the article was selected based on how it has advanced knowledge in the profession, the effectiveness of communication, methodology, originality, and impact.
“It is exciting to have validated low-cost methods that will allow many people around the world to take a hard look at the root of the problem. Fighting against drought is an uphill battle, and we have known for a very long time that roots would be our greatest ally in this fight. Up until now, we did not have any easy way of doing that. I truly hope that this recognition will prompt more work on roots.”
This study was funded by the Australian Grains Research and Development Corporation (GRDC) and CGIAR Research Program on Wheat (WHEAT) led by the International Maize and Wheat Improvement Center (CIMMYT).
Researchers demonstrate that CIMMYT’s
durum wheat lines can be grown, bred, and selected under zero tillage or
conventional tillage conditions without negatively affecting yield
New research published in Field Crops Research by scientists at the International Maize and Wheat Improvement Center (CIMMYT) responds to the question of whether wheat varieties need to be adapted to zero tillage conditions.
With 33% of global soils already degraded, agricultural techniques like zero tillage – growing crops without disturbing the soil with activities like plowing – in combination with crop residue retention, are being considered to help protect soils and prevent further degradation. Research has shown that zero tillage with crop residue retention can reduce soil erosion and improve soil structure and water retention, leading to increased water use efficiency of the system. Zero tillage has also been shown to be the most environmentally friendly among different tillage techniques.
While CIMMYT promotes conservation agriculture, of which
zero tillage is a component, many farmers who use CIMMYT wheat varieties still
use some form of tillage. As farmers adopt conservation agriculture principles in
their production systems, we need to be sure that the improved varieties
breeders develop and release to farmers can perform equally well in zero tillage
as in conventional tillage environments.
The aim of the study was to find out whether breeding wheat
lines in a conservation agriculture environment had an effect on their
adaptability to one tillage system or another, and whether separate breading
streams would be required for each tillage system.
The scientists conducted parallel early generation selection
in sixteen populations from the breeding program. The best plants were selected
in parallel under conventional and zero-till conditions, until 234 and 250 fixed
lines, were obtained. They then grew all
484 wheat lines over the course of three seasons near Ciudad Obregon, Sonora,
Mexico, under three different environments, — zero tillage, conventional
tillage, and conventional tillage with reduced irrigation – and tested them for
yield and growth traits.
The authors found that yields were better under zero tillage
than conventional tillage for all wheat lines, regardless of how they had been
bred and selected, as this condition provided longer water availability between
irrigations and mitigated inter-irrigation water stress.
The main result was that selection environment, zero-till
versus conventional till, did not produce lines with specific adaptation to
either conditions, nor did it negatively impact the results of the breeding
program for traits such as plant height, tolerance to lodging and earliness.
One trait which was slightly affected by selection under
zero-till was early vigor – the speed at which crops grow during the earliest stage
of growth. Early vigor is a useful adaptive trait in conservation agriculture
because it allows the crop to cope with high crop residue loads – materials
left on the ground such as leaves, stems and seed pods – and can improve yield
through rapid development of maximum leaf area in dry environments. Results
showed that varieties selected under zero tillage showed slightly increased
early vigor which means that selection under zero tillage may drive a breeding
program towards the generalization of this useful attribute.
The findings demonstrate that CIMMYT’s durum wheat lines,
traditionally bred for wide-adaptation, can be grown, bred, and selected under
either tillage conditions without negatively affecting yield performance. This
is yet another clear demonstration that breeding for wide adaptation, a decades-long
tradition within CIMMYT’s wheat improvement effort, is a suitable strategy to
produce varieties that are competitive in a wide range of production systems. The
findings represent a major result for wheat breeders at CIMMYT and beyond, with
the authors concluding that it is not necessary to have separate breeding
programs to address the varietal needs of either tillage systems.
This work was
implemented by CIMMYT as part of the CGIAR Research Program on Wheat (WHEAT).
Read more results and recommendations in the study, “Durum wheat selection under zero tillage increases early vigor and is neutral to yield” in Field Crops Research, November 2019.
In the highlands of Ethiopia and the oases of the Sahara this crop has been cultivated for thousands of years. Today, smallholder farmers still grow it on marginal lands to assure production for their own consumption. However, durum wheat is no longer just a staple crop for food security but has become a major cash crop. In fact, the pasta, burghul and couscous industry currently purchase durum grain at prices 10 to 20% higher than that of bread wheat. Africa as a whole imports over €4 billion per year of durum grain to provide the raw material for its food industry. Hence, African farmers could obtain a substantial share of this large market by turning their production to this crop.
“A participatory approach, that uses the farmers themselves to guide the breeding decisions helps hugely in achieving success. A simple example was for an advanced line that I really liked: the yield was very high, the grains very big, and it had very good disease resistance. Still, when I showed it to farmers they did not like it. The main reason was that it was too short, and they could not get enough straw to feed their livestock. This is but an example on how incorporating farmers’ opinions save me from investing a lot of efforts in releasing and promoting a variety that would have never made it to cultivation”.
Challenges and promises
New breeding technologies offer great promise for expanding the area of durum wheat production in SSA. However, this remains primarily dependent on the market ability to purchase these grains at a higher price to stimulate farmer adoption. Because of its industrial nature, durum wheat has often been disregarded by SSA policy makers in favor of bread wheat as a more direct “food security” approach. Considering that the most cultivated durum varieties are more than 30 years old, there is a significant genetic yield gap that could be filled through the release and commercialization of more modern varieties.
A significant effort has been made to expand the production of improved durum wheat cultivars to supply raw materials to the food industries. The pasta producers used to rely on massive importation of durum wheat grains, which was not a sustainable long-term business strategy due to high and volatile costs. Further, the purchase of foreign grains competed with other national priorities for the use of governmental hard currency stocks.
Meeting the industrial standards
Recent investments in the pasta industry are proving extremely promising in Ethiopia thanks to new food habits of the growing urban populations, which are looking for fast and tasty foods, while still cheap and nutritious. The Ethiopian Millers Association has eagerly explored the possibility to procure the needed raw material directly from local farmers to reduce production costs and increase competitiveness against foreign pasta imports. Unfortunately, the local production did not guarantee sufficient rheological grain quality to satisfy the industrial needs. In fact, grain of tetraploid landraces does not meet industrial standards in terms of color or protein quality.
Hence, specific incentives needed to be provided to farmers to obtain industrial-grade harvests. The scope of the Ethiopian-Italian cooperation project for the Agricultural Value Chain in Oromia (AVCPO) was to re-direct some of the already existing bread wheat production system of the Bale zone toward the more lucrative farming of durum wheat for the industry.
The process acted on the key elements required by the pasta industry to stabilize and self-sustain the value chain: (a) competitive price, (b) high rheological quality for conversion into pasta, (c) easy and timely delivery, (d) consistent stock of grains and predictable increases over years.
Using non-GM molecular breeding techniques, ICARDA’s scientists developed a set of durum wheat varieties that can withstand up to 40°C heat along the Senegal River basin. If scaled up, the technology offers potential to fight hunger and help farmers adapt to rising temperatures.
Click hereto read the report on the ICARDA web page.