SATrends Issue 94
September 2008
1. Short and sweet!
top

Improving staple crops in their centers of diversity tends to be a particular challenge for plant breeders. Sorghum in West Africa is such a case, where plant breeders struggle to contribute new varieties that combine superior yields with traits necessary for good adaptation and end-use or marketing, and thus add new and useful varietal diversity.

Wild species of Arachis Malian National Program researchers in short-internode "Dwarf" sorghum population selecting individual plants for variety development.

ICRISAT's sorghum breeders in West Africa introgressed 10-20% of exotic germplasm into local guinea race sorghums. Through careful selection for reduced plant height and good adaptation, breeding lines of a novel plant type were identified. Results indicated that the shorter stem-internodes of this material had significantly higher stover digestibility and stems were completely consumed, whereas the woody stems of traditional sorghum varieties are typically left uneaten by ruminants. These new dual-purpose varieties can therefore be used as roughage for feeding livestock as well as grain for human consumption.


To test whether these new lines have the much sought after improved grain yield, ICRISAT and the Institut d'économie rurale (IER) Mali Sorghum Program, local farmer organizations, and extension services organized farmer managed performance trials in 8-10 villages. Each farmer grew two replications of the trial with 16 entries, including his own control variety and a common researcher control. Technicians assisted farmers with the field layout and sowing. Farmers managed the trial as an adjacent field. Researchers evaluated the trials twice during the cropping season, and conducted the harvest with all other partners. Threshing was done under researcher supervision. Farmers and visitors from the villages evaluated the varieties throughout the growing cycle, and until after the threshing.

Analyzing the grain yields across locations confirmed that these new short-internode variety types indeed combined higher grain yield with improved stover quality. Two varieties, Kalaban from IER and ICRISAT's Nafalen 6, produced 25% higher grain yields on average across the whole spectrum of growing conditions sampled in this multi-location test (Figure1).

Wild species of Arachis Figure 1: Regression of variety grain yield means on site means for two new varieties (Kalaban and Nafalen 6) and two check varieties, Tieble, a released landrace variety, and the farmers' own local variety, in on-farm trials of semi-dwarf sorghum varieties, 2006, with repeatabilities of 0.45 or higher.

Farmers' initial assessments of these new varieties were not so positive as the panicles did not appear heavy, drooping less than traditional varieties with some grain discoloration from late rains. However, the yield figures were so convincing that farmers continue to work with us to improve the grain color. These varieties are now listed in the Malian National Variety Catalogue and farmer organizations have started marketing the seeds.

For more information contact: E.Weltzien@cgiar.org,F.Rattunde@cgiar.org or M. Diourte (IER).

2. Hybrids beat sorghum grain mold
top

Grain mold is the bane of crop growers throughout the humid tropical and sub-tropical areas around the globe. In India, which has the largest area under sorghum cultivation (9 million ha) in the world besides Africa, nearly 40% of sorghum is grown in the rainy season. Grain mold is an important biotic constraint during this season as it makes the grain unsuitable for food or feed.

Grain mold is caused by several non-specialized fungi including several species of Fusarium, such as F. proliferatum, F. thapsinum, F. verticillioides and F. nygamai, Curvularia lunata, Alternaria alternata and Phoma sorghina. Several strains of the Fusarium species produce toxins hazardous to human and animal health. Annual global losses due to grain molds have been estimated at US$130 million.

Efforts to breed for grain mold resistance combined with high grain yields have met with partial success. But scientists discovered that crop losses can be minimized by developing sorghum hybrids with grain mold resistance.

Wild species of Arachis Fig 1. A moldy sorghum panicle. Fig 2. A high yielding grain mold tolerant sorghum hybrid.

Nine sorghum hybrids developed at ICRISAT involving resistant/moderately resistant parental lines, were evaluated during the rainy seasons of 2006 and 2007 for grain mold reaction and grain yield potential using CSH 16, a popular grain sorghum hybrid as a control.

In the grain mold screening block, sprinkler irrigation without inoculation was used from the flowering stage to grain maturity to ensure high humidity conducive to grain mold infection. Panicle grain mold rating was noted at physiological maturity. The hybrid ICSH 28001 (Fig 2) was the best among the hybrids tested, with significantly higher grain yield (18%) and less grain mold incidence (25%) than CSH 16 with similar agronomic desirability. The other two hybrids ICSH 28002 and ICSH 28003 were on par with CSH 16 for grain yield but recorded significantly lower grain mold incidence. These hybrids need further testing to confirm their grain mold resistance and yield superiority over CSH 16. It is important to note that they all have white grain, a much-desired trait for food preparations.

Wild species of Arachis 1Panicle grain mold rating score taken on a 1-9 scale, where 1= <10% and 9= >75% moldy grain.

 

 

 

 

 

 

 

 

 

 

 

 

 

For more details contact: a.ashokkumar@cgiar.org, b.reddy@cgiar.org or r.sharma@cgiar.org

 

top
3. Farmers lead new cereal seed system

Farmer groups in West Africa are improving marketing of cereals and often facilitate loans for production inputs. These efforts can be complemented by making higher yielding, fertilizer responsive varieties more available. However reliable sources of new variety seeds remains an open question, since private seed industries are almost nil, and Public Agricultural Agencies are under funded and seek sustainable ways to operate.

Farmer organizations in Burkina Faso, Niger and in Mali have initiated collaboration with ICRISAT cereal breeders and national program scientists to identify suitable new varieties of sorghum and pearl millet for their areas. Organization members conduct and evaluate many small variety trials, and have thus identified a range of sorghum and pearl millet varieties that increase and stabilize yields.

Many participating farmers initially gave away seeds to fellow villagers who requested samples. Although this can work for sorghum, which is mostly self-pollinated and can maintain varietal purity, pure pearl millet seeds need to be produced in isolated fields. A farmer organization in Niger (Mooriben) was trained to produce quality pearl millet seed, and now produces seeds of new locally preferred varieties. Farmer organizations now make seed more widely available by selling 1 to 5 kg packets through local input shops, their offices, or at general meetings. The demand far outstripped supplies, and the next generation of seed production and distribution activities are now underway on a larger scale.

Pigeonpea on slopes AMSP farmers in Burkina Faso with their certified seed production.

Farmer organizations in Burkina Faso and Mali received training in marketing certified seed. The newest development is that they have also started selling sorghum seed directly to input traders and emerging seed companies anxious to build their input distribution network.

Two farmer organizations in Burkina Faso, Union de Groupement pour la commercialisation des Produits Agricole, Boucle du Mouhoun (UGCPA/BM) and Assotiation des paysans innovateurs (AMSP) collaborate with the National Research Center to produce foundation seed and certified seed. The foundation seed is produced with very close supervision of researchers, and this seed is distributed to other organization members for production of certified seed. This approach enables farmers to have access to a much larger range of varieties with local adaptation than can be provided strictly by the national system alone.

Thus, farmer organizations are vital partners in this early phase of formal seed-system development in West Africa, and they are beginning to play an important role in the dissemination of new cereal varieties.

For more information contact: E.Weltzien@cgiar.org,F.Rattunde@cgiar.org,B.IG.Haussmann@cgiar.org or kirsten.vom_brocke@cirad.fr