Austeclínio Lopes de Farias Neto

Volatiles Mediating a Plant-Herbivore-Natural Enemy Interaction in Resistant and Susceptible Soybean Cultivars

Several studies have shown that herbivore-induced plant volatiles act directly on herbivores and indirectly on their natural enemies. However, little is known about the effect of herbivore damage on resistant and susceptible plant cultivars and its effect on their natural enemies. Thus, the aim of this study was to evaluate the attraction of the herbivorous pentatomid bug Euschistus heros and its egg parasitoid Telenomus podisi to two resistant and one susceptible soybean cultivars with different types of damage (herbivory, herbivory+oviposition, and oviposition). In a Y-tube olfactometer, the parasitoids were attracted to herbivory and herbivory+oviposition damaged soybean plants when compared to undamaged soybean plants for the resistant cultivars, but did not show preference for the susceptible cultivar Silvânia in any of the damage treatments. The plant volatiles emitted by oviposition-damaged plants in the three cultivars did not attract the egg parasitoid. In four-arm-olfactometer bioassays, E. heros females did not show preference for odors of damaged or undamaged soybean plants of the three cultivars studied. The Principal Response Curves (PRC) analysis showed consistent variability over time in the chemical profile of volatiles between treatments for the resistant cultivar Dowling. The compounds that most contributed to the divergence between damaged soybean plants compared to undamaged plants were (E,E)-α-farnesene, methyl salicylate, (Z)-3-hexenyl acetate, and (E)-2-octen-1-ol.

Genetic correlation between traits in the ESALQ-PB1 maize population divergently selected for tassel size and ear height

Full-sib and selfed (S1) progenies were obtained from sub-populations of ESALQ-PB1, divergently selected for tassel size (T+ and T-) and ear height (E+ and E-), and used for estimating genetic and phenotypic correlation coefficients between traits. The analyzed traits were: EW- total ear weight (g/plant), PH- plant height (cm), EH- ear height (cm), TB- tassel branch number and TL- tassel length. The highest genetic (rG) and phenotypic (rF) correlation was observed for the combination PH x EH, as expected, with average of 0.800 and 0.778, respectively over sub-populations and locations. It is apparent that divergent selection for tassel size did not affect greatly the correlation between PH and EH in the full sib progenies, but in the inbred progenies the correlation was smaller in the sub-population selected for larger tassels. Genetic correlation between PH and EH with tassel traits was always positive but ranged from 0.020 to 0.668 in Piracicaba and from 0.06 to 0.309 in Rio Verde. Genetic correlation between PH and EH with yield (EW) also was positive in the range of 0.087 to 0.503. EH showed higher correlation with EW in relation to PH x EW and differences were larger in the sub-populations divergently selected for ear height. Correlation between tassel traits with other traits was positive in most of instances and a lack of consistency was observed among sub-populations. Generally the coefficients of genetic and phenotypic correlation differed substantially from the estimates in the base population ESALQ-PB1 before divergent selection for tassel size and ear placement. Divergent selection affected the correlation between traits under unpredicted and varying magnitudes.

Análise de crescimento de girassol em Latossolo com diferentes níveis de saturação por bases no Cerrado

Growth analysis of sunflower in a Cerrado Oxisol with different levels of basis saturation Abstract - In order to study the growth cycle of five sunflower cultivars, four experiments were carried out under four levels of basis saturation (18%, 35%, 56% and 77%), obtained with the application of dolomitic limestone in an acidic Red Latosol, clay texture (Tipic Haplusthox). Weekly growth data were fitted using the Logistic, three parameters Weibull and four parameters Generalized Logistic (a special case of Richards function) functions. Among the models used, the Logistic function obtained was the best growth data fitting. The NLIN procedure of SAS statistical package was used for fitting the data through the interactive process of DUD method. Cultivars were grouped according to final size and growth rates by a cluster analysis using the complete linkage method and by the Euclidian distance. Sunflowers growth reduced in all cultivars at 18% basis saturation level. At 35% basis satu- ration level, the best results were achieved for cultivar M734. In other instances, the best growth results were obtained between 56% and 77%. For cultivars EMBRAPA 122 and M738, growth rates were reduced when basis saturation was increased to 77%. The cultivar EMBRAPA 122 presented initial higher growth rate and lower plant height at the end of vegetative cycle.

Inbreeding in two maize subpopulations selected for tassel size

O presente trabalho foi baseado na avaliacao de progenies de irmaos germanos e S1 da populacao de milho (Zea mays L.) ESALQ-PB1 depois de seis ciclos de selecao divergente para tamanho do pendao. Os seguintes caracteres foram analisados: altura da planta, altura da espiga, numero de ramificacoes do pendao, comprimento do pendao e peso do pendao. Para todos os caracteres, as unidades experimentais foram medias de tres plantas por parcela. As progenies foram avaliadas em onze experimentos (blocos completamente casualizados) com tres repeticoes em Piracicaba ¾ SP, Brasil. As medias das progenies endogâmicas (m1) e nao endogâmicas (m0) foram usadas para estimar a depressao por endogamia (I = m1 ¾ m0) e a contribuicao de homozigotos (m0 + a*) e heterozigotos (d*) para a media populacional. Considerando os cinco caracteres sob estudo, a depressao por endogamia variou de 1,9 to 15,9% mas somente para altura da planta foi detectada significância para aquele efeito. Os caracteres da planta exibiram maior depressao do que os caracteres do pendao; e o numero de ramificacoes do pendao parece ser mais sensivel a endogamia do que os outros caracteres do pendao. Com excecao de altura da planta, foi evidente que a depressao por endogamia foi maior na subpopulacao selecionada negativamente para tamanho do pendao (T¾). As estimativas de A = m0 + a* e d* indicam um menor efeito dos desvios de dominância para todos os caracteres, quando comparados com a contribuicao dos homozigotos. Foi detectada variabilidade significativa entre progenies na maioria dos casos.

BRS Celeste: nova cultivar de soja para o sistema de produção de grãos no cerrado

Maintenance or improvement of technology to soybean cultivation is necessary to reach economical productivity in the Brazilian Savannah, where it has shown to be superior to that obtained in the South of Brazil. New cultivars are among the contributions of research to high crop performance and yield stability. The soybean cv. BRS Celeste is an alternative to suit growers demand. It belongs to the same maturity group of cv. BR/EMGOPA 314 (Garca Branca), although it has higher yielding and shows resistance to the main diseases, especially stem canker (Diaporthe phaseolorum f. sp. meridionalis).

Caracterização de genótipos de soja na região dos Cerrados quanto à reação à podridão vermelha da raiz, causada pelos fungos Fusarium tucumaniae e Fusarium brasiliense

A podridao vermelha da raiz de soja vem crescendo em importância, a cada ano, no Brasil, com aumento substancial de participacao nas perdas de produtividade. Na regiao dos Cerrados, sao escassos os dados de campo sobre a reacao de cultivares a doenca. Assim, este trabalho teve como objetivo a caracterizacao, em campo, de uma serie de genotipos de soja, quanto a resistencia a podridao vermelha da raiz, em solos naturalmente infestados. Foram testados 71 genotipos de soja, sendo 16 do ciclo de maturacao precoce, 28 do ciclo de maturacao medio e 27 do ciclo de maturacao tardio, em quatro localidades, no entorno do Distrito Federal. O delineamento experimental foi o de blocos ao acaso, com quatro repeticoes. A caracterizacao foi realizada por meio dos niveis de incidencia e severidade dos sintomas foliares. Genotipos com altos niveis de resistencia a doenca foram observados nos tres grupos de maturacao, em cultivares e linhagens em fase final de melhoramento.

BRS Celeste - new soybean cultivar to the grain production system of the Brazilian savannah

Maintenance or improvement of technology to soybean cultivation is necessary to reach economical productivity in the Brazilian Savannah, where it has shown to be superior to that obtained in the South of Brazil. New cultivars are among the contributions of research to high crop performance and yield stability. The soybean cv. BRS Celeste is an alternative to suit growers demand. It belongs to the same maturity group of cv. BR/EMGOPA 314 (Garca Branca), although it has higher yielding and shows resistance to the main diseases, especially stem canker (Diaporthe phaseolorum f. sp. meridionalis).

PHYSICAL QUALITY OF SOILS UNDER A CROP-LIVESTOCK-FOREST SYSTEM IN THE CERRADO/AMAZON TRANSITION REGION

EN: Integrated crop-livestock-forest (iCLF) systems have gained prominence in the past decades as an alternative of sustainable land use, particularly in regions in which there is pressure against agricultural expansion in protected ecosystems such as the Brazilian Amazon. In this context, the objective of this study is to evaluate the effects of one year of use of the iCLF system in the Cerrado/Amazon transition region to determine its impact on soil quality compared to other traditional land uses in the region (planted forest, crop, forage, and native forest). The results indicated that the iCLF system did not jeopardize the soil physical quality, and only the crop land use affected the soil physical attributes. The land uses with the lowest impact on the physical condition of the soil were the iCLF system and the planted forest. | PT-BR: Os sistemas de integracao lavoura-pecuaria-floresta (ILPF) tem ganhado destaque nas ultimas decadas como uma alternativa de uso sustentavel das terras, especialmente em regioes onde existe pressao contra a expansao agropecuaria sobre ecossistemas protegidos, como e o caso da Amazonia Brasileira. Neste contexto, o objetivo deste trabalho foi avaliar os efeitos apos um ano da adocao de sistema ILPF em regiao de transicao Cerrado/Amazonia, buscando verificar suas consequencias sobre a qualidade do solo em relacao a outros usos da terra tradicionais na regiao (floresta plantada, lavoura, pastagem e mata nativa). Os resultados nao indicaram efeitos negativos do sistema ILPF sobre a qualidade fisica do solo, que somente foi impactada negativamente no tratamento lavoura. Dos usos da terra avaliados, os de menor impacto sobre a qualidade fisica do solo foram o sistema de integracao lavoura-pecuaria-floresta e a floresta plantada.