Sorghum Research Brief
Sorghum is a drought-tolerant crop hence it’s grown in drier areas. Sorghum research started in the East Africa community in the late 1950s. When later the East Africa community separated into Kenya, Uganda, and Tanzania, sorghum research continued in Kenya in the late 1970s. Sorghum in Kenya is grown in western, northern Rift Valley, eastern, and some parts of Central. The research objectives in sorghum research are; increased yield, drought, disease and pest tolerance, earliness, seed color, and marketability. The main activities involve germplasm acquisition, characterization and maintenance, development of breeding populations, development of improved sorghum varieties, and sorghum agronomic recommendations for the different growing areas.
The development of new varieties is done mainly through conventional breeding and sometimes through marker-assisted selections. Most of the varieties which have been released are open-pollinated varieties but recently hybrid breeding has been undertaken by Dr C. K. Kamau.
Sorghum Constraints being addressed
i). Low yields due to the use of local cultivars by farmers who mature late hence are affected by the short rainy seasons which are characteristic of the semi-arid areas
ii).Diseases. The common sorghum diseases are leaf spot, rust, leaf blight, anthracnose, ergot, head smut, and covered kernel smut. Sorghum-covered Kernel smut is the most damaging disease in dry areas.
iii). Pests. Birds, Sorghum shoot ﬂy(Antherigona varia), Stem borers(Busseolafusca), aphids, bollworm, and Aphids. Birds are the main cause of crop loss in sorghum. Storage pests are weevils
iv). Few processing and utilization technologies hence reduced consumption.
v). Low marketability of brown and red sorghums
Vi). Labor intensity in harvesting and threshing. Due to lack of mechanization technologies in sorghum production.
High local demand for over 30,000 metric tonnes of white sorghums by the brewing industry
Demand of sorghum for processing of animal feeds
Climate change scenario which is affecting the production of other cereals such as maize in the arid and semi-arid areas
Early maturing, high yielding, market preferred varieties
1. Sorghum varieties
i) KARI Mtama 1
This is a tall variety with cream white grain. The average yield is 3.8 tons/ha. It matures in three and a half to four months thus it may not tolerate very dry areas. It can grow in Eastern, Baringo, parts of Central and Western Kenya.
Gadam is a short variety with chalky white grain. The average yield is 3.15 tons/ha. It is a very early maturing variety, it matures in two and a half to three months. It is highly drought tolerant hence suitable for moderately dry and very dry areas in the upper eastern and lower eastern Kenya
The variety has medium-height plants and the grain is brown in color. The average yield is 2.7 tons/ha. The plant matures within three months. It is fairly drought tolerant. It can be grown in moderately dry eastern and western Kenya.
The variety has medium-height plants and the grain is brown in color. The average yield is 2.25 tons/hand the maturity time is three months. It is a drought-tolerant variety that can grow in eastern and western Kenya.
2. Sorghum production recommendations for increased yields
i).The effect of growth enhancers, Zinc foliar fertilizer application on white sorghum grain yield, and Stover weight
Growth enhancers can be used at (25-50 ppm)/ha + 2% zinc soil-applied or top-dressed to increase sorghum production in semi-arid lands.
Zinc application at 4% Zn soil applied as zinc sulfate should be used to increase sorghum productivity in semi-arid lands of eastern Kenya because the soils are deficient in zinc.
It is advisable to apply zinc at the topdressing stage of sorghum and should be applied on the soil around the crop base to avoid leaf scorching as this can reduce yield although more data is required on this observation.
ii). Appropriate sorghum legume rotations for increased sorghum productivity in semi-arid Eastern Kenya
Based on observed Gadam sorghum grain yield following a legume crop, shorter maturity N26 green gram variety is the best legume type for rotation with sorghum in the semi-arid lower eastern Kenya.
Gadam sorghum with fertilizer application (22 + 25 kg N and P/ha), timely thinning and weeding at 3 to 4 weeks after crop emergence are the best practices in the semi-arid lower eastern Kenya with a potential yield of 1.2-1.7 t/ha of grain.
iii)Bird menace management recommendation for sorghum
Over 90% sorghum grain yield can be salvaged if harvested at the soft dough stage (cream white). Overall, the highest sorghum yield loss was at the full cream grain stage, 20 days after the grain turned green.
It is recommended that farmers should harvest grain sorghum early to avoid damage by birds where these are a challenge. A full sunny day will provide the shortest drying period, while a cloudy or humid day could lead to grain rotting.