Ignácio José de Godoy

Efeito da infestação de Enneothrips flavens moulton sobre o desenvolvimento de cultivares de amendoim

A field experiment was carried out during the 2001/2002 growing season, in Campinas and Pindorama, Sao Paulo State, Brazil, to evaluate the influence of Enneothrips flavens Moulton (Thysanoptera: Thripidae) on development of peanut cultivars. The treatments comprised three cultivars of the upright type (IAC Tatu ST, IAC 5 and IAC 22) and three of the runner type (Runner IAC 886, Tegua and IAC Caiapo), with and without insect control. The experimental design was a split plot in completely ramdomized blocks and six replications. Main plots consisted of control and no control of thrips, and the cultivars were the subplots. For the evaluations of thrips infestation, leaf samplings were made starting at 29 days after planting (DAP). Each sample consisted of ten young leaves per plot, at the stage prior to their opening. For the evaluation of the number of buds per plant, five plants per plot were harvested from 29 DAP to the maturity stage of each cultivar. To determine the dry matter content, five plants per plot were harvested at Campinas at 29, 56, 85, 99, 112 and 125 DAP, following artificial drying. At both locations, the mean number of thrips per leaflet peaked at 56-57 DAP; in Pindorama, an early peak occurred at 29 DAP. Depending on the cultivar, the lack of control of E. flavens reduced the number of buds per plant and the vegetative growth.

Identification of Fungus Resistant Wild Accessions and Interspecific Hybrids of the Genus Arachis.

Peanut, Arachis hypogaea L., is a protein-rich species consumed worldwide. A key improvement to peanut culture involves the development of cultivars that resist fungal diseases such as rust, leaf spot and scab. Over three years, we evaluated fungal resistance under field conditions of 43 wild accessions and three interspecific hybrids of the genus Arachis, as well as six A. hypogaea genotypes. In the first year, we evaluated resistance to early and late leaf spot, rust and scab. In the second and third years, we evaluated the 18 wild species with the best resistance scores and control cultivar IAC Caiapó for resistance to leaf spot and rust. All wild accessions displayed greater resistance than A. hypogaea but differed in their degree of resistance, even within the same species. We found accessions with as good as or better resistance than A. cardenasii, including: A. stenosperma (V15076 and Sv 3712), A. kuhlmannii (V 6413), A. kempff-mercadoi (V 13250), A. hoehnei (KG 30006), and A. helodes (V 6325). Amphidiploids and hybrids of A. hypogaea behaved similarly to wild species. An additional four accessions deserve further evaluation: A. magna (V 13751 and KG 30097) and A. gregoryi (V 14767 and V 14957). Although they did not display as strong resistance as the accessions cited above, they belong to the B genome type that is crucial to resistance gene introgression and pyramidization in A. hypogaea.

Flutuação populacional de Enneothrips flavens moul. em cultivares de amendoim

Six recently developed peanut cultivars, along with the commercially known cultivar Tatu, were evaluated for thrips infestation in field experiments carried out at the Instituto Biologico Experimental Station, State of Sao Paulo, Brazil, during the 1992/93 and 1993/94 growing seasons. The experiments were arranged in a completely randomized block design with seven treatments (cultivars IAC-Poitara, IAC-Oira, IAC-Tupa, IAC-Caiapo, IAC-Jumbo, Botutatu and Tatu) and four replications. Thrips evaluations were made at weekly intervals by counting the number of nymphs and adults in samples of forty leaflets per plot. The results of 1992/93 showed that the cultivars IAC-Caiapo and IAC-Jumbo, both of runner growing habit, were significantly less infested then the others. In the 1993/94 experiment, with a lower total thrips infestation, these cultivars were significantly less infested than the others, except when compared to the cultivar Tatu.

Capacidade fotossintética de genótipos de amendoim em ambiente natural e controlado

Photosynthetic capacity of runner peanuts (Arachis hypogaea L.) cv. IAC-Caiapo and cv. Runner IAC-886 was evaluated under controlled condition, in plants grown on pots maintained in a greenhouse, and in irrigated plants grown on soil-filled tanks made of concrete, and exposed to natural ambient condition. CO2 net assimilation rate (A) response in relation to photosynthetic photon flux density (DFFF) was better in controlled condition, but in both conditions the same maximum A of ca. 28 µmol m -2 s -1 was reached. Under controlled condition, light saturation was about 1,000 µmol m -2 s -1 , although under natural condition, saturation occurred at higher DFFF. Leaf temperature between 23 and 36°C did not affect A, and leaf to air vapor pressure difference caused partial stomatal closing, decreasing A, when above 3.0 kPa. Photosynthetic capacities of the two cultivars were similar. Both cultivars showed good adaptation to daily changes of environmental conditions that occur during summer, showing dynamic photoinhibition of photosynthesis in the beginning of the afternoon (13-14h), as revealed by a reversible decrease in the maximum quantum efficiency (Fv/Fm) of photosystem II.

Avaliação de espécies silvestres e cultivares de amendoim para resistência a Enneothrips flavens Moulton

In Brazil, various pests are reported to infest peanut crop, being the thrips Enneothrips flavens the most important. Accesses of wild peanut species, anfidiploide and peanut cultivars were evaluated in field conditions at Pindorama, Sao Paulo State, at the agricultural year of 2007/2008. The experiment consisted of a complete ramdomized block design with 48 treatments and five replications. The material was sown in small bags under greenhouse conditions. Plantings were carried out in October/November 2007. Starting at 30 days after planting in the field, evaluations were done at 15-day intervals, in five closed leaves of each plant. The following data were obtained: presence or absence of thrips in each leaf; symptoms of thrips damage in recently opened leaves, based on a 1-5 scale where 1 = without damage, 2 = 1 to 25% of the leaf surface with damage (grooves and deformations), 3 = 26 to 50%, 4 = 51 to 75% and 5 = 76 to 100% of damage symptoms. The accesses with the least damages and insect presence were: VS 14957 (A. gregoryi), V13832 (A. stenosperma), V8979 (A. kuhlmannii), V9912 (A. kuhlmannii), V7639 (A. kuhlmannii) e VMiIrLbGv14309 (A. villosa). The most sensitive accesses were V12549 (A. hypogaea), Ac2562 (A. hypogaea) and the commercial A. hypogaea genotypes IAC Caiapo and IAC Runner 886.

Avaliação de cultivares de amendoim para resistência a Spodoptera frugiperda

This study aimed to identify peanut cultivars resistant to Spodoptera frugiperda by determining the degree of resistance through univariate and multivariate analyses. The genetic material under evaluation comprised cultivars of the upright growth habit (IAC 5, IAC 8112, IAC 22 and IAC Tatu ST) and runner growth habit (IAC 503, IAC 505, IAC 147, IAC 125, IAC Caiapo and IAC Runner 886), grown under field conditions. Individual first instar larvae were placed in Petri dishes, on humidified filter paper, and maintained under controlled conditions of temperature (25±2 °C), humidity (60±10%) and photophase (12 hours). Ten newly hatched caterpillars were arranged in a completely randomized design with five replications. New leaves previously washed with 1% sodium hypochlorite were provided daily. The duration (days), weight (mg) and viability (%) of larval and pupal periods, the sex ratio, adult longevity and adult female fecundity were evaluated. All data recorded were submitted to analysis of variance by F test, and treatments were compared by the Tukey test (p≤0.05). Additionally, clustering and principal components analyses were performed. The cultivar IAC 22, of upright growth habit, and Runner IAC 886, of runner growth habit, were the least favorable substrates for the insect development, indicating resistance to S. frugiperda.

Influência da época de semeadura no crescimento, produtividade e outros fatores de produção em cultivares de amendoim na região da alta paulista

ABSTRACT INFLUENCE OF SOWING TIME ON GROWTH, PRODUCTIVITY AND OTHER YIELD CHARACTERSOF PEANUT CULTIVARS IN THE ALTA PAULISTA REGION, STATE OF SAO PAULO, BRAZIL Field experiments were carried out during the crop growing seasons of 1989/90 and1990/91 in Adamantina, State of Sao Paulo, Brazil. The objective was to study the influenceof sowing time on growth, yield and other agronomic yield characters of four peanut culti-vars under the agroecological conditions of the Alta Paulista. The study used a split-plotexperimental design with six randomized blocks. The main plots were sowing times whereasthe subplots were the cultivars IAC-Oira, IAC-Poitara, IAC-Tupa and Tatu. Decrease in drymatter yield, pod number and yield per plant were observed in all cultivars, from the first tothe last sowing date, i.e., from September /October through March, respectively. Theexperimental results were related to the air temperature. The greatest pod yields were achievedwhen peanuts were sowed between late September and October. The cultivars IAC-Oira,IAC-Poitara and IAC-Tupa showed greater pod number and dry matter yield per plant thanthe cv. Tatu.

CHUVA E PREVISÃO DE ÉPOCAS DE PULVERIZAÇÃO PARA CONTROLE DAS MANCHAS FOLIARES DO AMENDOIM

Foram realizados experimentos de campo, em Ribeirao Preto e Pindorama (SP), no ano agricola de 1996/97, com o objetivo de avaliar o uso da chuva na previsao de epocas de pulverizacao para racionalizar o controle da mancha-preta e da mancha-castanha em amendoim. Cada experimento constituiu-se de cinco tratamentos, em blocos ao acaso com cinco repeticoes, utilizando-se, em todos os experimentos, o cultivar Tatu. Os tratamentos empregados foram: (A) testemunha, sem controle das doencas; (B) quatro pulverizacoes em datas fixas, a cada 14 dias, com inicio aos 42 dias apos a semeadura; indicacao de pulverizacao apos a ocorrencia de dois (C), quatro (D) ou seis (E) dias com chuvas diarias >2,5 mm, consecutivos ou nao, com monitoramento da chuva no periodo entre o 35o e o 90o dia apos a semeadura. As pulverizacoes foram realizadas com chlorothalonil, na dosagem recomendada. Para avaliar o desempenho dos tratamentos, mediram-se: indice de severidade (I%), em amostragens semanais realizadas a partir do quarto decendio apos a semeadura, sendo a intensidade das doencas durante o ciclo estimada pela area sob a curva de progresso de cada doenca (ASCPD), bem como sua soma (ASCPDT). Tambem se avaliaram os indices de producao: produtividade (kg.ha-1), rendimento em sementes (%) e massa de 200 sementes. Segundo os resultados dos experimentos, os tratamentos com indicacao de pulverizacao apos a ocorrencia de dois ou quatro dias com chuva >2,5 mm, revelaram dados semelhantes ao tratamento com pulverizacoes fixas, nos itens: intensidade de doenca (ASCPDT) e produtividade da cultura. O desempenho desses tres tratamentos foi superior a testemunha e aquele com indicacao de pulverizacao apos a ocorrencia de seis dias com chuva >2,5 mm. Devido a ocorrencia de elevado numero de dias com precipitacao pluvial no periodo, foi possivel, nos dois experimentos, apenas a reducao de uma pulverizacao no tratamento D em relacao ao tratamento com pulverizacoes fixas. No C, a recomendacao de pulverizacao com fungicidas foi praticamente semelhante ao de pulverizacoes fixas.

Ocorrência de Tetranychus ogmophallos Ferreira & Flechtmann (Acari: Tetranychidae) em Amendoim no Estado de São Paulo

High mite infestations were observed during two consecutive years (1999 and 2000) in peanut fields of cultivar IAC-Caiapo, at the Adamantina Experiment Station of Instituto Agronomico de Campinas (IAC). The mites were identified as Tetranychus ogmophallos Ferreira & Flechtmann, and the symptoms consisted of an initial silver-like chlorosis on leaves, progressing to formation of a great ammount of web structures covering the plants. For a preliminary evaluation of the damage, two 1.000 m2 plots were marked during the 1998/99 field growing. One was not treated with pesticide and the other was chemically sprayed for mite control. In both plots, pod harvesting was done at three intervals, and pod yield within each plot was estimated as the average of harvesting intervals. Comparison between treated and untreated plots indicated a 76,5% yield reduction due to mite infestation. T. ogmophallos has been previously known from Arachis pintoi, a wild peanut species, but no report of its occurrence on cultivated peanut (Arachis hipogaea) was known.

Potencial produtivo de linhagens de amendoim do grupo ereto precoce com e sem controle de doenças foliares

YIELD POTENTIAL OF UPRIGHT EARLY MATURING PEANUT LINES WITH AND WITHOUT CONTROL OF FOLIAR DISEASES Eleven peanut lines and the cultivar IAC-Tatu-ST, of the upright early maturing group (Arachis hypogae subsp. fastigiata, Waldron), were evaluated for pod yield, shelling percentage and average kernel weight in six field experiments carried out at the Ribeirao Preto and Pindorama Experiment