-The objective of this work was to evaluate yield and average fruit weight of strawberry cultivars Albion, Camarosa, Festival and Oso Grande, in two closed hydroponic systems (gutters and grow bags), using coconut fibre as substrate. The experimental design was of randomised blocks, divided into strips, with five replications. The hydroponic systems did not differ significantly as to yield, with advantages, such as savings in water and fertilizer and reduced environmental impact, over open systems. The most productive cultivar was Festival, followed by Oso Grande, with average yields of 6.99 kg m -2 and 5.56 kg m -2 respectively. The cultivars with the greatest fruit weight were Oso Grande and Albion, having averages of 11.8 and 11.1 g respectively, with the former being significantly superior to the latter. The highest yield (7.4 kg m -2 ) was obtained from the cultivar Festival under the gutter system. The Ibiapaba region has conditions which are favourable to strawberry production in relation to precocity (harvesting starts in the 6th week of growth) and production continues throughout the year; however there is a need to test new cultivars and to improve the cultivation techniques with an aim to producing larger-sized fruit.

Fusarium wilt, caused by the soil-borne fungus Fusarium oxysporum f. sp. cubense (Foc), is considered one of the most destructive diseases of bananas. Paradoxically, knowledge of the genetics of the pathogen population in the Americas is very limited. In this study, a collection of 178 monosporic isolates from several banana producing regions, located in different climatic zones along a South to North transect in Brazil, was formed to assess the genetic structure of the population of Foc. The isolates underwent pathogenicity tests, PCR diagnosis for the detection of Tropical race 4 and screening to SIX homologs. The VCG of 119 isolates was determined by pairing against 17 testers. A group of 158 isolates was selected for microsatellite genotyping. There was moderate diversity of Foc in Brazil. Eight VCGs were identified: 0120, 0122, 0124, 0125, 0128, 01215, 01220, and 01222, of which 78% of isolates belong to a single VCG, while 22% of isolates belong to complexes of VCGs. The distribution of VCGs is uneven and independent of the banana genotype. VCGs were correlated with homologs of the SIX genes and varied according to geographic regions. Four SSR loci were polymorphic and on average 7.5 alleles were detected per locus. Thirty-five multilocus genotypes (MLGs) were identified. There was no association between VCG and MLGs and no genetic structure of the population of Foc in Brazil was detected.

No abstract

Fusarium wilt, caused by the soilborne fungus Fusarium oxysporum f. sp. cubense ( Foc), is considered one of the most destructive diseases of bananas in Brazil. In this study, a collection of 194 monosporic isolates from several banana-producing regions located in different climatic zones along a south-to-north transect in Brazil was formed to assess the genetic structure of the population of Foc. The isolates underwent pathogenicity tests, PCR diagnosis for the detection of tropical race 4, and screening of SIX homolog genes that produce putative effector proteins. The vegetative compatibility group (VCG) of 119 isolates was determined by pairing against 17 internationally known VCG-tester strains. A group of 158 isolates was selected for simple sequence repeat (SSR) genotyping. There was moderate diversity of Foc in Brazil. Eight VCGs were identified: 0120, 0122, 0124, 0125, 0128, 01215, 01220, and 01222, of which 78% of isolates belong to a single VCG, whereas 22% of isolates are assigned to multiple VCGs, belonging to complexes of VCGs. The distribution of VCGs is uneven and independent of the banana genotype. The isolates of a VCG shared a similar profile of SIX homologs, but there was no association with geographic region. Four SSR loci were polymorphic, and, on average, 7.5 alleles were detected per locus. Thirty-five multilocus genotypes (MLGs) were identified. There was no association between VCG and MLGs, and no genetic structure of the population of Foc in Brazil was detected.

Resumo As mudanças climáticas são uma ameaça para o setor agrícola. O objetivo do estudo foi avaliar a influência da temperatura e radiação ultravioleta (UV) no desenvolvimento in vitro de isolados de Trichoderma spp. Os experimentos foram conduzidos no Laboratório de Patologia Pós-Colheita, da Embrapa Agroindústria Tropical (Fortaleza - CE). Avaliou-se a influência da temperatura de incubação (30, 35 e 40 °C) no crescimento micelial, bem como na esporulação (conídios.mL-1) e na germinação (%) dos conídios dos isolados de Trichoderma spp. (T. asperellum - SF 04, Quality WG®; T. harzianum - IBLF 006, Ecotrich WP®; e T. harzianum ESALQ - 1306, Trichodermil 1306). Para a avaliação da influência da UV, as placas de Petri contendo os isolados fúngicos foram expostas à luz em diferentes intervalos de tempo (0, 2, 4, 6 e 8 minutos) e obteve-se a germinação relativa. O isolado mais sensível à temperatura foi T. asperellum (SF 04), no qual, a temperatura de 35 °C apresentou menor área de crescimento micelial e menor germinação relativa (38,4%). O isolado T. harzianum (ESALQ 1306) apresentou a menor porcentagem de conídios germinados a 30 °C (63%), porém, teve o maior número a 35 °C (100%). A radiação UV diminuiu a germinação dos conídios e os isolados que apresentaram maior germinação relativa ao final do período de exposição foi T. asperellum (SF 04) e T. harzianum (ESALQ 1306). Estes resultados podem demonstrar uma maior capacidade de adaptação do isolado T. harzianum (ESALQ 1306) às condições extremas de temperatura.