Groundnuts also known as peanut is cultivated in semi-arid tropical regions which are located 40⁰ Celicius north and south of the equator including Uganda.
It is an important legume grown and consumed globally but mostly in Sub Saharan Africa.
In Uganda, most people enjoy the peanut butter, confectionary and paste made from raw seed used for cooking groundnut stew. In other countries especially those in the dry lands it is grown to produce feed for livestock.
Most farmers in Uganda are growing groundnut varieties which are red or tan in colour.
When Seeds of Gold visited the head of ground breeding programme at National Semi Arid Resources Research Institute (NaSARRI), Dr David Kalule Okello, we were welcomed by the well-tended gardens at the entrance while the main gate opens to an even larger groundnut farm. Kalule has also planted the crop in plastic containers in greenhouses.
Kalule says there are 1,050 groundnut varieties which are being bred at NaSARRI.
“These varieties have diverse features where others have purple stems, some grow vertically, others produce less pods and they are used as animal feed,” says Kalule.
There are a number of improved groundnut varieties which has been bred over time and released for farmer use. They are in series of R standing for Red and T for Tan colour.
They include Serenut1R which matures in 100-110 days with yield capacity of 2,500-3,700 per hectare and Serenut2T with same features.
Serenut3R matures between 90-100 days with yield rate of 2,500-2,900 per hectare and Serenut4T with the same features.
Serenut5R matures in 00-110 days with yield rate of 2,500-3,000 per hectare, Serenut6T matures in 90-100 days with same yield rate as the former. Serenute7T with maturity rate 100-110 days yielding 2,500-3,700 per hectare.
Others are Serenut9T, 10R, 11T, 12R, 13T and 14R with same features as the above. These varieties were released between 1998 and 2011 mainly looking at the yield ratio and maturity period.
Last year Kalule and his team released extra early maturing varieties Naronut1R and 2t which mature in less than 90 days.
Soil and moisture
The crop grows well in drained soils with moderate organic matter and under soil PH of 6.0-6.5.
The seed has high demand for water for good germination.
The crop grows under optimum temperature of 27-30 degrees Celsius for seed germination and 24-27 degrees for reproductive growth.
Rainfall between 450 -1250mm is required annually for good growth.
Small seeded varieties require 300-500mm while medium maturing require 1000- 1200mm rainfall.
Scientists recommend seed dressing by farmers before planting to avoid soil fungal damage.
The seed can be dressed with Mancozeb and Thiram fungicide.
The recent released varieties do not have the element of dormancy where once the seed is dried it fails to germinate.
Early land preparation is good for maximum moisture retention, planting and seed germination.
Farmers are advised to prepare the land six weeks before planting and this should be before the rains beginning to pour.
“The land can be tilled using hand hoe, ox plough or tractor depending on what the farmer can afford,” says Kalule.
Farmers are expected to plant at the onset of the rains, season per season. Before sowing seed, it has to be inoculated with Rhizobium inoculum bacteria which stimulates nodulation on the roots allowing the plant to produce its own nitrogen.
The seed must be sown in rows of 45cm by 30cm. Generally 150,000 plants are recommended per hectare. Crop rotation is recommended to avoid disease and pest infestation.
The crop does well in areas which are fertile and farmers can apply fertilisers upon testing the soil. Farmers can apply recommended amount of NPK and Calcium. For small seeded varieties farmers may apply 300 kilogrammes of calcium per hectare and 25 kilogrammes of Nitrogen, 100 kilogrammes for phosphorous and 50 kilogrammes of potassium.
Farmers are expected to weed their fields three weeks after planting and this must be done three times before the time for harvesting approaches. The first weeding must be done before flowering occurs. This is because the crop will give maximum yield if it is not competing with weeds. Farmers are expected to carry out hand weeding and this comes with the challenge of employing labour for farmers with a big plantation.
Pests and diseases
A larger number of fungal, viral, nematode and bacterial diseases have been reported attacking the crop.
The major one being groundnut rosette disease which is a viral disease spread throughout Sub Saharan Africa.
It is transmitted by aphids feeding on the crop thereby causing yellowing of the leaves leading to stunted growth and failing to yield.
This can be controlled by chemical spray and farmers planting timely as well as use of seed with resistance such as Serenut4T, 6T, 8R and 7T
Early and late leaf spot
These cause dark spots on the leaves leading to photosynthesis not taking place.
It affects the yield of the crop. Chemical spray is recommended and crop rotation.
This disease causes brown rust all over the plant’s leaves and severely infected leaves will turn necrotic causing 50 per cent yield loss. This can be controlled by removing infected plants and spraying with mancozeb and solution made from neem tree.
The major pests are aphids which inject toxins leading to whitening of the plant veins and chlorotic effects.
Others are leaf minor which leads to stunted growth, thrips causing delay in vine growth and termites which end up cutting stems of the plant. Farmers are expected to spray with recommended insecticides and crop rotation and early planting is a good practice too.
Groundnuts are stored both as unshelled pods and as kernels for different uses and both forms are vulnerable to attack by insects.
They include peanut bruchid beetles which attack unshelled seed by releasing its eggs on the pod walls making a hole to destroy the seed. Others are red flour beetle which feast on groundnut seed causing rust. This can be controlled through good post-harvest practices.
Harvesting and storage
Hand harvesting is recommended. Once the pods are plucked from the stem, it must be dried in a properly cured ground.
Direct sunshine drying must be avoided not to compromise the quality pod seed, the sunshine must be mild and use materials such as polythene sheets or mats for drying.
The harvested groundnuts must be kept where the temperature is not humid.