Abstract: BRS 500 B2RF is a high-yielding cotton cultivar with transgenic resistance to lepidopteran pests and tolerance to the herbicide glyphosate. Additionally, BRS 500 B2RF has resistance to Ramularia leaf spot and partial resistance to root-knot nematode. It represents an important contribution to sustainable cotton production in Brazil.

Abstract BRS 369RF and BRS 370RF were developed by the EMBRAPA as a part of efforts to create high-yielding germplasm with combinations of transgenic traits. BRS 369RF and BRS 370RF are midseason cultivars and have yield stability, adaptation to the central Brazilian savanna, good fiber quality and tolerance to glyphosate herbicide.

Cotton cultivar BRS 335 is a midseason high-yield cultivar and has adaptation to the Northeast Brazilian savanna, yield stability, desirable resistance to main cotton diseases and good fiber quality. The cultivar BRS 335 meets growers' demands for competitive lint yield as well as fulfilling industrial textile requirements.

Dentre as doenças que incidem sobre o algodoeiro, o "tombamento" é considerado uma das principais, sendo causado por um complexo de fungos de solo e da semente, os quais, ocorrendo separadamente ou em combinação, podem ocasionar o tombamento de pré e pós-emergência das plântulas. Os principais agentes etiológicos do tombamento são Rhizoctonia solani Khun, Colletotrichum gossypii South e Colletotrichum gossypii South var. cephalosporioides Costa. O objetivo deste trabalho foi avaliar o efeito de diversos fungicidas, utilizados em tratamento de sementes de algodão, no controle de patógenos associados às sementes e/ou presentes no solo. Sementes livres de patógenos, não-inoculadas e inoculadas com Colletotrichum gossypii var. cephalosporioides(Cgc)), foram tratadas com tolylfluanid + pencycuron + triadimenol, carboxin + thiram e fluazinam + tiofanato metílico. No teste de emergência em areia, o tratamento testemunha inoculada com Cgc apresentou o menor índice de emergência. O maior índice de emergência ocorreu em sementes sem inoculação e tratadas com tolylfluanid + pencycuron + triadimenol. O tratamento mais eficiente no controle do tombamento de pós-emergência do algodoeiro, em substratos contendo Rhizoctonia solani, foi a mistura tolylfluanid + pencycuron + triadimenol. No campo, a maior incidência e severidade da ramulose, causada por Cgc, ocorreu em plantas provenientes de sementes não tratadas com fungicidas e inoculadas com Cgc. Nenhum dos fungicidas testados foi fitotóxico ao algodão.

The cotton seedling damping-off is a worldwide problem caused by a complex of soil-borne and seed-borne fungi, occurring separately or in combination, and cause pre- or post-emergence damping-off. The main etiological agents causing the damping-off are Rhizoctonia solani Khun, Colletotrichum gossypii South and Colletotrichum gossypii var. cephalosporioides. The aim of this work was to evaluate the effectiveness of many fungicides that have been used on the treatment of cottonseeds to control pathogens associated with seeds and/or presents in the soil. Cottonseeds free of pathogens, inoculated and non-inoculated with Colletotrichum gossypii var. cephalosporioides (Cgc), were treated with tolylfluanid + pencycuron + triadimenol; carboxin + thiram and fluazinam + thiophanate methyl. On the Growing on Test, the non-treated seeds inoculated with Cgc showed a lower level of emergence. The higher level of emergence occurred on non-inoculated seeds treated with tolylfluanid + pencycuron + triadimenol. The most efficient treatment in the control of post-emergence damping-off in substrates containing Rhizoctonia solani, was obtained with the mixture of tolylfluanid + pencycuron + triadimenol, followed by carboxin + thiram. In the field, the higher severity of ramulosis, caused by Cgc, occurred in plants from non-treated seeds inocculated with Cgc. None of the fungicides tested showed phytotoxity to cotton.

O objetivo deste trabalho foi determinar a herança da resistência do algodoeiro à doença-azul. Populações derivadas das variedades resistentes CD 401 e Delta Opal foram avaliadas em casa de vegetação, por meio da inoculação de pulgões virulíferos. A resistência à doença-azul do algodoeiro é condicionada por um gene dominante, tanto em 'DC 401' quanto em 'Delta Opal'.

The objective of this work was to determine the inheritance of cotton blue disease resistance by cotton plants. Populations derived from the CD 401 and Delta Opal resistant varieties were evaluated, through a greenhouse test with artificial inoculation by viruliferous aphids. Cotton blue disease resistance is conditioned by one dominant gene, both in CD 401 and Delta Opal varieties.

The objective of this work was to evaluate the efficiency of delinting time of cottonseeds through the electrical conductivity and the quantity of neutral sugars and uronic acids leaked from the seeds during imbibition in water, in function of the fractioning in water and the artificial ageing. The seeds were delinted with commercial sulphuric acid for 1.5 and 4.5 minutes, separeted according to the sedimentation fractions in water and submitted to artificial ageing for 0, 72 and 96 hours. Electrical conductivity, contents of neutral sugars and uronic acids were determinated from the exudate resulting from the seeds imbibition in relation different treatments. The results showed that the delinting time for 1.5 minutes provided higher values of electrical conductivity, higher contents of neutral sugars and lower contents of uronic acids in relation with delinted seeds.