Reação de genótipos de soja, milho e arroz de terras altas a Pratylenchus brachyurus

• Autor(a) principal: Rios, Anderli Divina Ferreira
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/5010
• topic: Glycine max; Zea mays; Oryza sativa; Resistência; Glycine max; Zea mays; Oryza sativa; Resistance; CIENCIAS AGRARIAS::AGRONOMIA

The Brazilian production of grain crop is 193.9 million tonnes. The area harvested in 2014, was 55 million hectares, which represents in increase of 4.2 % compared to 2013 (52.8 million hectares). Rice, corn and soybean crops are the three main products that together accounted for 92.5 % of the grain production and accounted for 85.5 % of the harvested. Together these three crops produced around 177 million tonnes in the 2013/2014 season . Among the major diseases of soybean currently in the Cerrado region, we highlight those caused by nematodes, especially Heterodera glycines and Pratylenchus brachyurus. The maize and rice are used in rotation succession withis soybean crops and are host to the nematode making the management of areas infested with this pathogen more complex. The use of resistance is one of the most important strategies for plant disease control due to its compatibility with other management practices and for not being harmful to the environment. The objective of this study was to evaluate the reaction of of soybean, corn and rice genotypes to the root lesion nematode in order to obtain sources of resistance that could be included in plant breedind or be readily used by the farmers. Nine experiments were performed in the present study. Three experiments were conducted with soybeans in a completely randomized design. The first (experiment I) was conducted in field conditions with seventy cultivars (treatments) and six replications. The second experiment (experiment II) was conducted under controlled with 26 cultivars and seven replications. The third experiment (experiment III) was conducted in naturally infested field with 12 cultivars and six replications with assessments at 30, 60 and 90 DAS and harvest at 131 DAS. For corn, two experiments were conducted, the first with 30 genotypes and seven replications. The second (experiment II) was conducted in field conditions with ten genotypes and six replications evaluated at 30, 60 and 90 DAS and harvest at 119 DAS. For the rice crop, four experiments were conducted, three under controlled conditions (experiments I, II and III) and one in the field (experiment IV). All four experiments were set as a completely randomized design with six replications. In the present study no genotypes of soybean, corn or rice were found as resistant to P. brachyurus but some had promising results. The soybean cultivars TMG 132 RR, Emgopa 313 RR, M-Soy 8360 RR and CD 237 RR, rice cultivars BRS 01600, BRS Primavera and BRS Monarca and the corn hybrids, P30K75 and P30S31 presented lower nematode population densities or reproduction factors (RF). The soybean cultivars P 98Y11, BRSGO 8560 RR and P 98Y51 and the corn hybrids AG 1051, P3862H and SHS 3031 showed tolerance to the nematode. Given the results presented here, it is necessary for the studies to be continued in order to obtain resistant genotypes and to identify other promising crops that can be used in rotation with soybeans in areas with high infestation by the nematode. Also its important to study the behavior of this nematode in ecosystems where these crops are cultivated. Genotypes that provided lower nematode population densities should be preferred for future research in order to identify resistance.