RESUMO
Cowpea (Vigna unguiculata spp unguiculata) is adapted to the drier agro-ecological zones of West Africa where it is a major source of dietary protein and widely used as a fodder crop. Improving the productivity of cowpea can enhance food availability and security in West Africa. Insect predation--predominately from the legume pod borer (Maruca vitrata), flower thrips (Megalurothrips sjostedti) and a complex of pod-sucking bugs (e.g., Clavigralla spp)--is a major yield-limiting factor in West African cowpea production. Dramatic increases in yield are shown when M. vitrata is controlled with insecticides. However, availability, costs, and safety considerations limit pesticides as a viable option for boosting cowpea production. Development of Bt-cowpea through genetic modification (GM) to control the legume pod borer is a promising approach to cowpea improvement. Cowpea expressing the lepidopteran-active Cry1Ab protein from Bacillus thuringiensis is being developed as a first generation Bt-cowpea crop for West Africa. Appropriate stewardship of Bt-cowpea to assure its sustainability under West African conditions is critical to its successful development. A first step in this process is an environmental risk assessment to determine the likelihood and magnitude of adverse effects of the Cry1Ab protein on key environmental protection goals in West Africa. Here we describe the results of an expert panel convened in 2009 to develop the problem formulation phase for Bt-cowpea and to address specific issues around gene flow, non-target arthropods, and insect resistance management.
Assuntos
Proteínas de Bactérias/genética , Endotoxinas/genética , Fabaceae/genética , Proteínas Hemolisinas/genética , Plantas Geneticamente Modificadas/genética , África Ocidental , Animais , Bacillus thuringiensis/genética , Toxinas de Bacillus thuringiensis , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Monitoramento Ambiental/legislação & jurisprudência , Monitoramento Ambiental/métodos , Fabaceae/crescimento & desenvolvimento , Fabaceae/parasitologia , Expressão Gênica , Fluxo Gênico , Interações Hospedeiro-Parasita , Hibridização Genética , Insetos/fisiologia , Controle Biológico de Vetores/economia , Controle Biológico de Vetores/legislação & jurisprudência , Controle Biológico de Vetores/métodos , Doenças das Plantas/genética , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/parasitologia , Medição de Risco/legislação & jurisprudência , Medição de Risco/métodosRESUMO
Cowpea is an important tropical crop. It provides a large proportion of the food resource for the African human population and their livestock. The yield and quality of cowpea have been dramatically improved through traditional breeding strategies for the past few decades. However, reports of heritability estimates for early growth of cowpea are rare. We designed a simple experiment to estimate the broad-sense heritability of early growth. We randomly selected 15 cowpea varieties among a total of 5000 cowpea accessions maintained in the cowpea breeding facility at the University of California, Riverside to examine the genetic determination of early growth of cowpea (measured as the height at day five after seeding). The estimated broad-sense heritability on the individual plant basis is 0.2190. However, the corresponding estimate on the plant mean basis (average of four plants) is 0.5198, which is very high for a quantitative trait. The high heritability may explain why traditional breeding for cowpea growth is so effective. Since the design of experiment and method of data analysis are novel, this report can serve as an educational note for students in the area of quantitative genetics and plant breeding.