Relação entre tricomas foliares de genótipos de feijoeiro comum, Phaseolus vulgaris L. e resistência a Diabrotica speciosa Germar, 1824 (Coleoptera: Chrysomelidae)
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Data
2005-08-01
Autores
Paron, Maria José Fachini de Oliveira [UNESP]
Lara, Fernando Mesquita [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Editora da Universidade Federal de Lavras (UFLA)
Resumo
Considerando que a pubescência foliar pode afetar a preferência alimentar do inseto, com o presente estudo objetivou-se verificar a influência da pilosidade dos folíolos na resistência de genótipos de feijoeiro a D. speciosa. O experimento foi conduzido em delineamento experimental inteiramente casualizado, com seis tratamentos e oito repetições. Os tratamentos foram seis genótipos de feijoeiro: Emgopa Ouro e IAPAR 57, do centro de domesticação Mesoamericano (MA) e Jalo Precoce, Goiano Precoce, PR 10595142 e PR 10595146 do centro de domesticação Andino (AN). Cada parcela foi constituída por um vaso com 1,2 Kg de solo e uma planta encerrada em um telado individual. No 25º dia após o plantio, em cada telado foram liberados dez adultos de D. speciosa, após jejum de 24 horas, durante 72 horas. Os danos sofridos foram estimados de acordo com a área consumida em cada genótipo. Os tricomas das folhas dos genótipos foram contados usando microscópio estereoscópico (40x), com uma escala micrométrica sobre 1 cm² de área da superfície abaxial (AB) e adaxial (AD), contando-se os tricomas unciformes e aciculares presentes em cinco folhas de cada genótipo. O genótipo IAPAR 57 (MA) foi o preferido no teste de alimentação, enquanto os genótipos andinos foram menos consumidos por adultos de D. speciosa. Os genótipos apresentaram variabilidade quanto ao número de tricomas, tanto aciculares quanto unciformes, em ambas as superfícies, abaxial e adaxial. Os genótipos andinos não diferiram quanto ao número de tricomas unciformes na superfície adaxial. O somatório do número de tricomas aciculares e unciformes na superfície abaxial dos genótipos sugerem relação inversa entre esta característica e a área consumida por D. speciosa.
Considering that foliar pubescence may affect insect feeding preference on plant genotypes, the purpose of this study was to evaluate the influence of leaflet pubescence on resistance of common bean genotypes to D. speciosa. The experiments were conducted in a completely randomised design, with six treatments and eight replicates. The treatments were six common bean genotypes, Emgopa Ouro and IAPAR 57, from Mesoamerican domestication center (MA), Jalo Precoce, Goiano Precoce, PR 10595142 and PR 10595146 from Andean domestication center (AN). Each replicate consisted of one pot with 1.2 kg soil and a plant placed in a individual cage. The genotypes were submitted to feeding test 25 days after planting, when ten adults of D. speciosa, starved for 24 hours, were released for 72 hours in each cage. Damage was estimated by area of foliage consumed on each genotype. Trichomes on both the abaxial (AB) and adaxial (AD) leaf surfaces were counted using a stereomicroscope (40 X), on 1 cm² area, with the hooked and straight trichomes being counted on five leaflets/genotype. The MA genotype IAPAR 57 was the most preferred on feeding test, while the AN genotypes were less eaten by Dispeciosa. The genotypes showed variability aceading to density of trichomes on both surfaces. Andean genotypes showed no difference in unciform trichome densities on AD surface. The total number of straight and hooked trichomes on AB leaf surface suggests inverse relation between this characteristic and the area consumed by Diabrotica speciosa.
Considering that foliar pubescence may affect insect feeding preference on plant genotypes, the purpose of this study was to evaluate the influence of leaflet pubescence on resistance of common bean genotypes to D. speciosa. The experiments were conducted in a completely randomised design, with six treatments and eight replicates. The treatments were six common bean genotypes, Emgopa Ouro and IAPAR 57, from Mesoamerican domestication center (MA), Jalo Precoce, Goiano Precoce, PR 10595142 and PR 10595146 from Andean domestication center (AN). Each replicate consisted of one pot with 1.2 kg soil and a plant placed in a individual cage. The genotypes were submitted to feeding test 25 days after planting, when ten adults of D. speciosa, starved for 24 hours, were released for 72 hours in each cage. Damage was estimated by area of foliage consumed on each genotype. Trichomes on both the abaxial (AB) and adaxial (AD) leaf surfaces were counted using a stereomicroscope (40 X), on 1 cm² area, with the hooked and straight trichomes being counted on five leaflets/genotype. The MA genotype IAPAR 57 was the most preferred on feeding test, while the AN genotypes were less eaten by Dispeciosa. The genotypes showed variability aceading to density of trichomes on both surfaces. Andean genotypes showed no difference in unciform trichome densities on AD surface. The total number of straight and hooked trichomes on AB leaf surface suggests inverse relation between this characteristic and the area consumed by Diabrotica speciosa.
Descrição
Palavras-chave
Pubescência, preferência alimentar, resistência de plantas, feijão, Fabaceae, Pubescence, feeding preference, host plant resistance, common bean, Fabaceae
Como citar
Ciência e Agrotecnologia. Editora da Universidade Federal de Lavras (UFLA), v. 29, n. 4, p. 894-898, 2005.