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NOVAS VARIEDADES DE ALGODÃO OBTIDAS NO BRASIL: 15 ANOS DE COLABORAÇÃO ENTRE A COODETEC E O CIRAD

2005; EMPRESA BRASILEIRA DE PESQUISA AGROPECUÁRIA; Volume: 22; Issue: 2 Linguagem: Inglês

10.35977/0104-1096.cct2005.v22.8681

1678-3964

Jean-Louis Bélot, Ivo Marcos Carraro, Patricia C. de Andrade Vilela, Osmério Pupim, José Martin, Pierre Silvie, Catherine Marquié,

Rural Development and Agriculture

A Cooperativa Central de Pesquisa Agricola (Coodetec) e o Centro de Cooperacao Internacional em Pesquisa Agronomica para o Desenvolvimento (Cirad) desenvolveram no Brasil, em 1990, um programa de criacao de variedades de algodao para a America do Sul. A diversidade de pragas, doencas e invasoras dos sistemas de producao acarretaram a hierarquizacao dos objetivos de selecao, em cada regiao agroecologica e conforme o tipo de sistema de cultivo. Os principais objetivos visam introduzir fatores de resistencia a doenca-azul (de origem viral, transmitida pelos pulgoes), a bacteriose, a doencas fungicas (ramulose e ramulariose) e a nematoides. O mercado internacional requer aumento da produtividade e melhoria da qualidade da fibra. Utiliza-se um esquema de selecao genealogica a partir de populacoes intra-especificas, de ampla base genetica, que recorre amplamente ao uso de ferramentas da biologia molecular, o que permite aplicar metodos de selecao assistida por marcadores. Esse programa comercializou sete variedades, CD401 a CD407, abrangendo cerca de 15% do mercado de sementes brasileiras e 30% do mercado do Paraguai. Os sucessos comerciais dessas variedades deram a Coodetec a possibilidade de autofinanciar seu programa de pesquisa algodoeira, ao passo que o Cirad pode manter uma equipe pluridisciplinar no Cone Sul-Americano. Os novos desafios consistem em criar cultivares adaptadas a sistemas especificos de cultivo (plantio direto sob cobertura vegetal, algodao de segundo ciclo ou adensado) e participar, em breve, do lancamento, no Brasil, de variedades de algodoeiro geneticamente modificadas. Termos para indexacao: producao vegetal, metodos e tecnicas. BREEDING NEW COTTON VARIETIES IN BRAZIL: 15 YEARS OF COLLABORATION BETWEEN COODETEC AND CIRAD ABSTRACT Since 1990, Coodetec (Cooperativa Central de Pesquisa Agricola) and Cirad (Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement) have been developing a program in Brazil to breed improved cotton cultivars for South America. The objectives of cotton breeding are geared towards meeting the needs of specific agrosystems due to the broad range of different cotton pests and cropping systems–ranging from labour-intensive but relatively non-intensified systems in Southern Brazil and Paraguai to highly intensive and completely mechanised systems in the Central-Western Brazilian Cerrados region. The goal is to overcome the main constraints by introducing traits of resistance or tolerance to viral (blue disease), bacterial (bacterial blight) and fungal (ramulose and grey mildew) diseases and nematodes. Farmers are constantly striving to increase their cotton yields, especially in the current setting of highly fluctuating world market prices for cotton fibre, but it is even more crucial to enhance fibre quality since this product is targeted for export markets. Improved cotton cultivars are created using a pedigree-breeding schedule applied to populations obtained via broad-based intraspecific crossing of cotton varieties and lines from all over the world. The efficiency of this cotton improvement program could be boosted by taking advantage of a new molecular biology tool – marker-assisted selection – especially with respect to introgressing blue disease resistance characters. New cotton varieties can now be officially recommended on the basis of results obtained in a varietal and agronomic experimental network that spans eight Brazilian States (Parana, Sao Paulo, Mato Grosso do Sul, Minas Gerais, Goias, Bahia, and Mato Grosso) and Paraguai. Since it was founded, 15 years ago, this program has released a series of improved varieties, i.e. CD401 to CD407, which are all resistant or tolerant to blue disease and bacterial blight, CD405 being the most nematode-tolerant variety. The very early CD401 variety yields excellent fibre and has been very well received by smallholders, while CD406, with the most indeterminate growth cycle, is designed for intensive Cerrado cropping conditions. These varieties have accounted for around 15% of the Brazilian market and 30% of the Paraguaian market in 2003-2004 despite very tight competition from many other public and private breeder companies. This commercial success has enabled Coodetec to entirely self-finance its cotton research program and Cirad to set up a multidisciplinary team to deal with a broad range of new research issues. The challenge is now to breed and promote cultivars tailored to specific cropping systems (direct seeding, mulch-based, cropping systems (DMC), secondary crop systems called safrinha systems, and high-density cropping – Ultra Narrow Row Cotton) and to prepare for the imminent release of genetically-modified cotton varieties. Index terms: vegetal production, tools and methods. DE NOUVELLES VARIETES DE COTONNIER OBTENUES AU BRESIL: 15 ANS DE COLLABORATION ENTRE LA COODETEC ET LE CIRAD RESUME Au Bresil, la Cooperative centrale de recherche agricole (Coodetec) et le Centre de cooperation internationale en recherche agronomique pour le developpement (Cirad) ont developpe depuis 1990 un programme de creation de varietes de cotonniers pour l'Amerique du Sud. La diversite des bioagresseurs et des systemes de production a conduit a hierarchiser les objectifs de selection pour chaque grande region agroecologique et selon les types de systemes cotonniers. Les principaux objectifs visent l'introduction de facteurs de resistance a la maladie bleue (d'origine virale, transmise par les pucerons), a la bacteriose, a des maladies fongiques (ramulose et ramulariose) et aux nematodes. Le marche international exige une augmentation de la productivite, et l'amelioration de la qualite de la fibre. Un schema de selection genealogique a partir de populations intra-specifiques a large base genetique est utilise. Il recourt largement a l'utilisation des outils de biologie moleculaire, permettant la mise en oeuvre de selections assistees par marqueurs. Ce programme a commercialise sept varietes, CD401 a CD407, couvrant en 2004 pres de 15% du marche de semences bresilien et 30% du marche paraguayen. Les succes commerciaux de ces varietes permettent a la Coodetec d'autofinancer son programme de recherche cotonniere et au Cirad de maintenir une equipe pluridisciplinaire dans le cone sud-americain. Les nouveaux defis sont de creer des cultivars adaptes a des systemes de culture specifiques (semis direct sur couverture vegetale, coton de deuxieme cycle ou a forte densite) et de participer au lancement prochain au Bresil de varietes de cotonnier genetiquement modifiees. Termes d'indexation: Productions vegetales, methodes et outils.