Produção de clamidósporos de Pochonia chlamydosporia em diferentes substratos

Clamidósporos são estruturas de sobrevivência do fungo nematófago Pochonia chlamydosporia. Objetivou-se, com este trabalho, avaliar diferentes substratos, teores de água e formas de inóculo para a produção in vitro de clamidósporos de P. chlamydosporia. Inicialmente, testaram-se os substratos grãos de milho triturado, grãos de arroz e casca de café e os tipos de inóculo meio líquido concentrado ou diluído (1:40) e discos de cultura, colonizados por P. chlamydosporia. Posteriormente, testou-se o substrato grãos de milho triturado suplementado ou não com caldo de batata com os inóculos do fungo nas formas de discos de micélio ou suspensão aquosa. As maiores produções de clamidósporos g-1 de substrato foram obtidas nos substratos grãos de milho triturado e casca de café, e as melhores formas de inóculo foram meio líquido diluído (1:40) e discos de micélio. A suplementação do substrato grãos de milho triturado com caldo de batata não aumentou a produção de clamidósporos do fungo e a melhor forma de inóculo do fungo foi a de discos de micélio. Além disso, testaram-se os substratos canjica, grãos de arroz, casca de café e fibra de coco, umedecidos com diferentes quantidades de água; o substrato casca de café umedecido por diferentes períodos; a casca de café enriquecida ou não com sacarose e farinha de arroz e o substrato grãos de arroz esterilizado no forno micro-ondas com diferentes quantidades de água. Apenas o substrato grãos de arroz, em todas as quantidades de água testadas, apresentou maior produção de clamidósporos. Não houve diferença na produção de clamidósporos no substrato casca de café umedecido por diferentes períodos e apenas quando a casca de café foi enriquecida com farinha de arroz, apresentou maior média de clamidósporos g-1 de substrato. Todos os tratamentos apresentaram grande produção de clamidósporos g-1 quando o substrato utilizado foi o de grãos de arroz tratados no forno de micro-ondas. O melhor meio de cultivo de P. chlamydosporia para a produção de clamidósporos foi o substrato contendo grãos de arroz.Chlamydospores are survival structures of the nematophagous fungus Pochonia chlamydosporia. The objective of this study was to evaluate different substrates, different contents of water and kinds of inoculum for the production of Pochonia chlamydosporia chlamydospores. The substrates evaluated were: milled maize, rice grains and coffee husk; all of them were inoculated with disks of culture, concentrated liquid media or diluted liquid media (1:40) colonized by P. chlamydosporia. Besides, the substrates milled maize, supplemented or not with potato broth, and inoculated with fungus disks or aqueous suspension were evaluated. Milled maize and coffee husk were the best substrates for chlamydospores production. The best inoculum kinds were disks of culture and diluted liquid media (1:40) colonized by P. chlamydosporia. The supplementation of milled maize with potato broth did not improve the production of chlamydospores, and the best inoculum form was disks of fungus. Moreover, it was also studied the substrates rice grains, coffee husk and coconut fibers with different rates of water; the substrate coffee husk moistened by different periods; the supplementation of coffee husk with rice flour or dextrose; and the substrate grains of rice sterilized in microwave oven with different rates of water. The substrate grains of rice, in all of the amounts of water tested showed increase in production of chlamydospores. There was no difference in the chlamydospores production of the coffee husk substrate, when moistened by different periods of time and only when it was supplemented with rice flour it showed higher mean of clamydospores per gram of substrate. All treatments evaluated showed higher production of chlamydospores in the substrate grains of rice treated in the microwave oven. The best substrate for the production of chlamydospores of P. chlamydosporia was the rice grains

How can dairies maximize their profits and properly remunerate their dairy farmers?

ABSTRACT The current pricing process of raw milk in Brazil discourages producers from improving milk composition, which affects both yield and quality of dairy products. Furthermore, small and medium-sized dairies face great difficulties when it comes to planning production. Thus, a linear programming model was developed to price the raw milk and determine the optimal mix (combination of quantities) of dairy products that maximizes total contribution margin (TCM) under daily scenarios of high (January) and low (July) raw milk supplies (summer and winter, respectively) by comparing optimal solutions with actual results. The TCM of optimal and actual mixes were higher in January due to the greater availability of raw material. Packaging was a limiting factor in the production of cheese in optimal mixes. The relationship between unit contribution margin (UCM) and the required amount of raw materials per product unit and resource availability is crucial to defining the mix of dairy products and TCM of the dairy. Casein and raw milk volume showed shadow prices. Under both scenarios, the calculated prices of raw milk were higher than the prices charged by the dairy and were higher in January. The proposed model remunerates the producers based on the quantity and quality of raw milk. The dairy can maximize its TCM by better planning its mix of products with the use of linear programming

Population structure and genetic diversity of maize inbreds derived from tropical hybrids

The objectives of this study were to identify the population structure and to assess the genetic diversity of maize inbreds. We genotyped 81 microsatellite loci of 90 maize inbreds that were derived from tropical hybrids and populations. The population structure analysis was based on a Bayesian approach. Each subpopulation was characterized for the effective number of alleles, gene diversity, and number of private alleles. We also performed an analysis of molecular variance and computed a measure of population differentiation (FST). The genetic distances were computed from the similarity index of Lynch and the dissimilarity measures proposed by Smouse and Peakall. The cluster analyses were based on the unweighted pair-group method using arithmetic averages and Tocher method. The clustering efficiency was assessed by the error rate of the discriminant analysis. We also performed a principal coordinates analysis. The population structure analysis revealed three tropical heterotic pools, which have been used by worldwide and Brazilian maize seed companies. The degree of genetic differentiation and of intra- and inter-population genetic diversity for these tropical heterotic pools are comparable to that observed for temperate and subtropical heterotic pools. The higher allelic frequency variation within each tropical heterotic pool and the high genetic diversity between the inbreds were evidence of heterotic groups within the main tropical heterotic pools

Freqüência de irrigação em meloeiro cultivado em solo arenoso Irrigation frequency in melon crop cultivated in sandy soil

O objetivo deste trabalho foi avaliar o efeito de cinco freqüências de irrigação na produtividade e na eficiência do uso da água em meloeiro cultivado sob fertirrigação por gotejamento em solo arenoso de Tabuleiro Costeiro do Piauí. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos e seis repetições. Os tratamentos foram: F1, F2, F3, F4 e F5, correspondentes às freqüências de irrigação de 0,5, 1, 2, 3 e 4 dias, respectivamente. A freqüência de irrigação influenciou as produtividades comercial e total do meloeiro. As maiores produtividades totais (70,73 t ha-1; 77,99 t ha-1 e 64,21 t ha-1) e comerciais (67,20 t ha-1; 63,88 t ha-1 e 53,67 t ha-1) foram obtidas com as freqüências de 0,5 e de 1 dia, respectivamente. Com aplicações menos freqüentes, houve redução significativa (P<0,01) nas produtividades comercial e total do meloeiro. O peso médio de frutos não foi influenciado pelas freqüências de aplicação de água. A maior e a menor eficiência de uso de água, 24,40 kg m-3 e 14,14 kg m-3, foram obtidas com F1 e F5, respectivamente. As freqüências de irrigação de duas vezes por dia, diária e a cada dois dias, são as recomendadas para o meloeiro cultivado em solo arenoso sob fertirrigação por gotejamento. A eficiência de uso da água no meloeiro é maior quando as freqüências de irrigação são maiores.<br>The objective of this work was to evaluate the effect of five irrigation frequencies in the productivity and efficience of water use of melon crop cultivated under fertirrigation by drip irrigation in a sandy soil of the Coast Plains of Piauí, Brazil. The experiment was allocated in a randomized complete block design, with five treatments and six replications. The treatments were: F1, F2, F3, F4 and F5, irrigation frequency of 0.5, 1, 2, 3 and 4 days, respectively. The irrigation frequency affected the marketable and total yield of the melon crop. The highest total (70.73 t ha-1; 77.99 t ha-1 and 64.21 t ha-1) and marketable (62.20 t ha-1; 63.88 t ha-1 and 53.67 t ha-1) yields were obtained with the frequencies of 0.5 and 1 day, respectively. It was observed that for the leastest frequent of water applications there was a significative reduction (P<0.01) of the marketable and total fruit yield of melon crop. The average fruit weight was not affected by the frequency of water application. The highest and the lowest efficiency of water use, 24.40 kg m-3 and 14.14 kg m-3, were obtained with the frequencies of F1 and F5, respectively. The irrigation frequency twice a day, daily and two days are indicated for melon crop cultivated in sand soil by drip irrigation. The efficiency of water use for the melon crop is higher when the irrigation frequencies are higher