ABSTRACT
The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a limiting factor in soybean production in the North Central region of the USA. The objectives of this work were to identify sources of resistance to A. glycines in 14 soybean genotypes, and also document changes in total protein, peroxidase, and chlorophyll in response to aphid feeding. A reduced number of A. glycines was observed on the genotypes UX 2569-159-2-01 and UX 2570-171- 04, indicating the presence of antixenosis and/or antibiosis. UX 2569-159-2-01 expressed the highest level of resistance; whereas, UX 2570-171-04 had moderate levels of resistance to A. glycines. Chlorophyll content was relatively unaffected by A. glycines, except for a reduction in UX 2569-159-2-01 infested plants at 5 and 15 days after infestation (DAI). No changes were detected in total protein content between infested and control plants for the genotypes analyzed; however, peroxidase activity was higher in infested UX 2570-171-04 at both 5 and 10 DAI. This improvement in peroxidase content in infested UX 2570-171-04 may be playing multiple roles in the plant tolerance.
Subject(s)
Aphids , Glycine max/physiology , Herbivory , Animals , Chlorophyll/analysis , Genotype , Peroxidase/metabolism , Soybean Proteins/analysis , Glycine max/geneticsABSTRACT
Rice (Oryza sativa L.) is considered one of the most important crops in the world, and the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Crambidae), is among the key pests damaging the crop in the Americas. The objective of this work was to identify rice genotypes as a source of resistance to D. saccharalis. Rice plants were infested in the greenhouse and subsequently evaluated for damage, larval weight and survival, and stem size. The cultivars 'Bonança', 'Caripuna', 'IR 42', 'Canela de Ferro', 'SWA Norte', 'BR IRGA 409', 'Pepita', 'Serra Dourada', 'Araguaia', 'Xingú', 'Tangará', and 'Soberana' showed antibiosis antixenosis, or both to D. saccharalis. These cultivars may be used as donor sources in the breeding program and used directly by Brazilian farmers as a component of rice-integrated pest management.
Subject(s)
Antibiosis , Herbivory , Moths/physiology , Oryza/physiology , Animals , Brazil , Genotype , Larva/physiology , Moths/growth & development , Oryza/geneticsABSTRACT
Avaliou-se o comportamento de genótipos de feijoeiro sob infestação de Bemisia tabaci (Genn.) biótipo B em condições de campo, nas épocas de cultivo "da seca" e "das águas". Utilizaram-se os genótipos IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRS-Pontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 e Z-28. Adotou-se o delineamento de blocos casualizados com 14 tratamentos e três repetições. As avaliações foram realizadas semanalmente, contando-se o número de ovos e de ninfas de B. tabaci biótipo B em dez folíolos por parcela. Na safra "da seca" os genótipos menos ovipositados por B. tabaci biótipo B foram IAC-Una e LP 02-130 e os mais ovipositados foram os genótipos Z-28 e Pérola. As menores presenças de ninfas de mosca-branca foram observadas em LP 98-122 e FT-Nobre e as maiores em LP 01-38, Pérola e Z-28. Para a safra "das águas" os genótipos não diferiram entre si em relação ao ataque de B. tabaci biótipo B. Os fatores da produção apresentaram diferença estatística somente na safra das secas.
Bean genotypes were evaluated under the infestation of Bemisia tabaci (Genn.) biotype B under field conditions in the dry and rainy season. The genotypes used were IAC-Tybatã, IAC-Una, FT-Nobre, Pérola, LP 98-122, LP 02-130, LP 01-38, LP 9979, BRSPontal, BRS-Requinte, BRS-Triunfo, BRS-Grafite, CV-48 and Z-28. The experiment was arranged in randomized blocks with 14 treatments and 3 replications. The evaluations were made on a weekly basis by counting B. tabaci biotype B eggs and nymphs on 10 leaflets per plot. In the dry season the least oviposited genotypes by B. tabaci biotype B were IAC-Una and LP 02-130, while the most oviposited were Z-28 and Pérola. The least presence of nymphs of whitefly was observed on LP 98-122 and FT-Nobre, and the most on LP 01-38, Perola and Z-28. For the rainy season the genotypes did not differ in relation to the attack of B. tabaci biotype B. The yield factors presented a statistical difference only in the dry season.
