Scientific World

African farmers develop their own cultivars Nerica – New Rice for Africa is the name of the great biotechnological success in rice breeding. What scientists created in the lab using modern methods, namely hybrids of African rice and Asian rice, had already come into being decades ago by chance in West African fi elds.

When scientists of the Africa Rice Background Center (AfricaRice, formerly WARDA) in Cotonou, created the rice cul- Hybrids are individuals that arise from a crossing of parents of the same species, dif- tivar Nerica (New Rice for Africa) in the ferent species or subspecies. In , inbred lines are generally crossed to mid 1990s by hybridising African rice produce F1-hybrids, and the broader genetic source material of the parents results in () and Asian rice (Oryza yield increases (an effect known as heterosis). The hybrids referred to in this article are sativa), it was considered a biotechno- not F1-hybrids, but the stabilised progeny of crosses between African and Asian rice. logical sensation. Scientists of Wagenin- The advantages of Nerica in comparison with African and Asian rice: higher yield, gen University (the Netherlands) have shorter growth duration, resistance to local stresses and higher protein content than since discovered hybrids of African rice traditional rice varieties. and Asian rice in that are genetically different from Nerica and came into being totally independently two rice species are not capable of are early and drought tolerant, which of the scientifi c development that led to crossbreeding. Part of the mystery as is why they were preferentially grown Nerica. These hybrids are the product to how the hybrids came into being and dispersed by the farmers. of a spontaneous crossing of the two anyway no doubt lies in the enor- species. The farmer hybrids presumably mous tracts of West African rice crop- arose from the parent species Oryza land. Somewhere within this immense n W Warsars ppromotedromoted sselectionelection glaberrima and ssp. indica, crop production area, the supposedly whereas Nerica arose from Oryza glaber- impossible crossing of the two species The fi rst hybrids presumably came rima and Oryza sativa ssp. japonica. took place. A group of new genotypes into being in -Bissau and/or thus came into being in West Africa Sierra Leone, long before the wars in Farmers grow both African and through in-fi eld hybridisation. These these countries started. Sierra Leone Asian rice together in expansive areas genotypes are relatively well suited for was battered by civil war from 1991 to of West Africa. As a general rule, the production on nutrient-poor soils, and 2002, whereas the Portuguese Colonial War raged in Guinea-Bissau from 1963 through 1974.

Many farmers went into hiding dur- ing the war in Sierra Leone, which made it impossible to clear new cropland in the forests. Trees would have had to have been felled, leaves and small branches would have been burned, and the rising

Man harvesting a fi eld of Nerica rice. Other than theses cultivars, the hybrids discovered by Dutch scientists in Africa are the product of a spontaneous crossing

Photo: laif of two rice species.

42 Rural 21 – 01/2010 Scientific World

smoke would have led the rebels directly soils. But unlike African rice they have to the villages. Instead of developing a white or brown seed colour, which Imprint new land, the farmers thus planted their is important in these countries, since Rural 21 – rice in the same fi elds year after year. farmers prefer white seed colour. The The International Journal Every year more nutrients were removed seeds of African rice are red. for Rural Development from the soil, and production became Published by: more and more diffi cult. Because the DLG-Verlags-GmbH farmer hybrids grow relatively well on n N Newew relationshiprelationship bbetweenetween Frankfurt, Germany nutrient-poor soils, they were cultivated ffarmersarmers andand scientistsscientists Advisory council: with increasingly greater frequency dur- Dr Albert Engel, GTZ; ing the war years. The scientists from Wageningen are Dr Reinhard Grandke, DLG; Manfred Hochwald †, Welthungerhilfe; now advocating a new orientation of Dr Christoph Kohlmeyer; Karl-Martin The Portuguese Colonial War pro- the relationship between the scientifi c Lüth, DLG; Dr Hansjörg Neun, CTA; moted the dispersal of the hybrid cul- community and local farmers. The new Dr Stefan Schmitz, BMZ; tivars. Many farmers fl ed from Guinea- fi ndings show that African farmers are Dr Beate Wilhelm, InWEnt Bissau to southern Senegal and to playing an active role in the improve- Editor in chief: Gambia, carrying the hybrids in their ment of seed. The hybrids bred by Silvia Richter baggage. With the severe decline in them could be used as the foundation [email protected] rainfall in Gambia and southern Sen- for new scientifi c developments. A Phone: +49-30-39848857 egal in the early 1970s, the local farm- wide range of rice varieties with differ- Editorial staff : ers began planting the hybrids of the ent characteristics is needed to meet Angelika Wilcke, [email protected] refugees from Guinea-Bissau. In gen- the agro-ecological and socio-eco- Ines Buck, [email protected] eral the farmer hybrids grown in South nomic needs of farmers in Africa and Editorial offi ce: Senegal, Gambia and Guinea Bissau are around the world. The genetic poten- DLG-Verlags-GmbH Eschborner Landstraße 122 drought tolerant (although there is one tial of rice can only be fully exploited 60489 Frankfurt, Germany exception) and they inherited from the through new forms of cooperation Translated by: African rice the ability to grow on poor between scientists and farmers! (ib) Christopher Hay Tazir International Services More information: Distribution, advertising: DLG-Verlags-GmbH Study: Evidence for the Emergence of New Rice Types of Interspecifi c Hybrid Dr. Michaela Roland Origin in West African Farmers’ Fields: Eschborner Landstraße 122 www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0007335 60489 Frankfurt, Germany [email protected] Layout: Petra Obermeier In brief Printed by: GREISERDRUCK GmbH & Co. KG n IInsectnsect netsnets impregnatedimpregnated mmoreore on the market within the next few Karlsruher Straße 22 eeffff eectivelyctively years. (Bayer CropScience AG) 76437 Rastatt, Germany Researchers at Bayer CropScience Rural 21 is published six times per year. have found a way to incorporate n MMaizeaize ggenomeenome ddecodedecoded The subscription rate is 49.– Euro (Germany), 51.– Euro (international) deltamethrin, the company’s WHO- A team of 150 scientists led by Wash- and 8.30 Euro per issue, plus postage. recommended active ingredient for ington University in St. Louis, Missouri All rights reserved. The contents may mosquito net impregnation, into poly- (USA), has deciphered the genetic code not be translated, reproduced in propylene fi bre. Announced by Bayer of the maize plant. “Over 32,000 genes whole or in part, nor may information CropScience in November 2009, the were predicted, of which 99.8 percent be passed on to third parties without result is a new textile fi bre which can were placed on reference chromosomes”, permission of the publisher. Please direct all corres pondence to the editor be used to make impregnated mos- write the scientists in the November in chief. quito nets that are softer, stronger and 2009 issue of Science. “These analyses The opinions expressed by the authors remain effective for longer than con- inform and set the stage for further inves- are not necessarily those of the pub- ventional nets. The new product, which tigations to improve our understanding lisher or the editor. The editor retains will be sold under the brand name of the domestication and agricultural the right to make editorial changes. LifeNet, is expected to be launched improvements of maize.” (AFP/Science)

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