SCIENTISTS have identified the first ever genetic markers associated with resistance to two deadly cassava viral diseases in Tanzania’s grown varieties.
The International Institute for Tropical Agriculture (IITA), in a statement availed to the ‘Daily News’ yesterday, identified the two varieties as Namikonga and Albert.
Mostly grown by Tanzanian farmers, the varieties are capable of withstanding the devastating Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD), unlike other varieties.
A team of scientists that has been studying the varieties’ DNA has successfully identified the genetic markers linked to their resistance to each of the viral diseases. The markers can be used to speed up the often long and expensive conventional breeding for cassava varieties with dual resistance to the diseases. “We are very happy with the findings of our studies which are a result of over six years of research.
“It is an important milestone in the efforts to revive cassava production in East, Central and Southern Africa where the two diseases remain a serious problem, threatening the region’s food security,” said Morag Ferguson, a molecular breeder at IITA.
Ferguson said for West Africa, where there is great fear of CBSD spreading and with devastating effects on the food security, the markers can assist in pre-emptive breeding.
Namikonga and Albert, which are genetically related, have been grown by farmers in areas that are hotspots for the two viral diseases for many decades and have shown high resistance despite being subjected to the diseases for a long period.
Namikonga is tolerant to CBSD but highly susceptible to CMD while in contrast, Albert is highly susceptible to CBSD but resistant to CMD.
The international team, drawing scientists from Tanzania, Kenya, South Africa, and the United States, crossed the two Tanzanian varieties and studied a large population of the progeny over two seasons in two disease hotspots in the country.
“The studies have enabled us to better understand the location of genes we suspect are associated with resistance to CBSD in the DNA of the farmer-preferred cassava variety, Namikonga, and CMD in the variety Albert,” noted Ms Esther Masumba, the molecular breeder from the Ministry of Agriculture, Livestock and Fisheries.
She added, “Once validated,this will help speed up breeding through marker-assisted selection (MAS) which shortens the breeding cycle and reduces the offspring population that breeders have to work with.
Breeders will be able to quickly narrow down from the thousands of offspring to only those with the desired markers.” She was part of the research team and conducted the study as part of her PhD studies at the University of Pretoria, South Africa.
Most of the cassava breeding programmes in Africa use purely conventional breeding methods that are laborious and expensive due to long breeding cycles and the need for large field trials. The application of molecular markers in breeding and selection of crop varieties can both reduce breeding time and costs.
The research team will now continue to validate these markers for their applicability in marker assisted breeding (MAB).
COOPERATIVES
A cooperative is an organised group of like-minded producers who combine to form a farmers’ group or partnership. Members share responsibilities and any profit or loss. They speak with a single voice and can purchase feed, equipment, chicks, building material and other supplies more cheaply. Eventually storage facilities can be established and a supply shop set up. The group can also have a strategic plan to reduce competition between individuals, set prices for poultry products and generally work to help one another to establish an industry on a firm footing. Trainers should provide as much assistance as possible to the farmers in establishing a working group that will spearhead the formation of a cooperative. The cooperative may eventually expand into other areas of commerce where the farmers can trade other farm produce in addition to poultry.COMMUNITY OWNERSHIP
This is similar to, but less rigid than a cooperative and is run by a committee representing a district or village community. For example, the committee may be responsible for raising point - of - lay pullets. These they sell at 17 - 18 weeks to individual egg producers and the profits are distributed amongst the community. The committee might purchase and run an incubator, and sell the chicks for meat or egg production at different ages. Or the committee may manage a small broiler or egg farm along commercial lines. In both cases there is opportunity to buy large numbers of chicks and bags of feed. This is usually attractive to the supplier and cheaper for the community. The concept of community farming is to empower people, mainly women, who have no opportunity as individual poultry keepers, to improve their circumstances and to alleviate poverty. Once formed, It can be extended to bio-security programs, vaccination programs against diseases, purchase of medical and other supplies, marketing of meat birds and eggs, dissemination of information, training programs and exchanging information, and greater opportunity to obtain micro-credit. This is critical to allow expansion of the family enterprise. There is a key role here for the poultry trainer who can assist in orchestrating the group by providing advice and guidance.BE THE FIRST TO COMMENT
