02656naa a2200205 a 450000100080000000500110000800800410001910000190006024500830007926000090016252020010017165000110217265000140218365000140219770000180221170000200222970000170224970000160226677301680228216557842010-04-14       2009    bl uuuu     u00u1 u    #d1 aRIBEIRO, L. R.  aDiscrimination of banana genotypes for Fusarium wilt resistance in greenhouse.  c2009  aAmong the major constrains to banana breeding for Fusarium wilt resistance is the long period necessary for evaluations in the field and the lack of an effective method for early detection of resistant genotypes. This work aimed to establish a screening method for Fusarium wilt resistance under greenhouse conditions and to validate its reliability by challenging cultivars with different levels of resistance. In a firts step, two types of substrates (vermiculite and washed river sand) and three inoculum sources (conidial suspension from 1- week-old colonies grown in potato dextrose agar (PDA), conidial suspension produced after stress of 1-week-old colonies and Foc-colonised corn meal-sand (CMS) medium) were studied by inoculating 45-day-old plantlets of 'Silk' (AAB, susceptible) in a double-tray system. Symptoms were observed in plants grown in both substrates, but highest incidence occurred in washed river sand. Low infection rates were observed when using conidial suspension from PDA-grown colonies. By contrast, inocula from stressed colonies and CMS caused consistent symptom expression. Using washed river sand as substrate and inoculum from PDA-grown stressed colonies and/or Foc-colonised CMS, plantlets of the cultivares 'Tropical' (AAAB) and 'Thap Maeo' (AAB) (field intermediate resistance) were challenged. Plantlets of 'Silk' and 'Grande Naine' (AAA) were used as susceptible and resistant controls, respectively. While the incubation period in Silk was 13 days after inoculation (dai), in 'Tropical' and 'Thap Maeo' initial symptoms were only observed at 17 dai. No symptoms were observed in 'Grande Naine'. The disease progress evaluated based on external symptoms and rhizome discoloration scales allowed cultivars discrimination according to resistance levels. Since experiments were repeated three times with similar results, our research suggests that the method here described could be suitable for early detection of banana genotypes resistant to Fusarium wilt.  aBanana  aFusariose  aGenótipo1 aAMORIM, E. P.1 aCORDEIRO, Z. M.1 aSILVA, S. O.1 aDITA, M. A.  tIn: ISHS/PROMUSA BANANA SYMPOSIUM, 2009, Guangzhou, China. Global perspectives on asian challenges: programme and abstracts. Guangzhou: ISHS: Promusa, 2009. p. 46.