Interactive effects of genotype x environment on the live weight of GIFT Nile tilapias

ABSTRACT In this paper, the existence of a genotype x environment interaction for the average daily weight in GIFT Nile tilapia (Oreochromis niloticus) in different regions in the state of Paraná (Brazil) was analyzed. The heritability results were high in the uni-characteristic analysis: 0.71, 0.72 and 0.67 for the cities of Palotina (PL), Floriano (FL) and Diamond North (DN), respectively. Genetic correlations estimated in bivariate analyzes were weak with values between 0.12 for PL-FL, 0.06 for PL and 0.23 for DN-FL-DN. The Spearman correlation values were low, which indicated a change in ranking in the selection of animals in different environments in the study. There was heterogeneity in the phenotypic variance among the three regions and heterogeneity in the residual variance between PL and DN. The direct genetic gain was greater for the region with a DN value gain of 198.24 g/generation, followed by FL (98.73 g/generation) and finally PL (98.73 g/generation). The indirect genetic gains were lower than 0.37 and greater than 0.02 g/generation. The evidence of the genotype x environment interaction was verified, which indicated the phenotypic heterogeneity of the variances among the three regions, weak genetic correlation and modified rankings in the different environments.

Genetic parameters in female reproductive traits of Nile tilapia (Oreochromis niloticus)

ABSTRACT Genetic parameters for reproductive traits in female Nile tilapia were estimated in this study using Bayesian inference method. The data set presented information from 451 Nile tilapia females that were evaluated at two different places in Maringá - Paraná - Brazil (hapas of 1 and 10 m³) and at one location in Alfenas - Minas Gerais - Brazil. A spawning examination was conducted once a week from October 2012 to March 2013 for a total of 23 weeks of evaluation. Single-trait analyses for spawning success, multiple spawning, spawning frequency, and volume of eggs/female were performed by using the software MTGSAM Threshold. The heritability estimates were 0.14, 0.16, 0.53, and 0.08 for spawning success, multiple spawning, spawning frequency and volume of eggs/female, respectively, indicating it is possible to achieve a substantial genetic gain using these reproductive traits as selection criteria.

Desenvolvimento corporal e testicular em machos de codornas de corte e de postura de 25 a 360 dias / Body and testicular development in males of meat- and egg-type quails of 25 to 360 days

Codornas do tipo carne e tipo ovos foram analisadas para determinar o desenvolvimento reprodutivo, a puberdade e o início da senilidade. Para tal, 288 codornas (144 codornas de corte e 144 de postura) foram acompanhadas desde a eclosão até os 360 dias de idade. As aves foram distribuídas por idade em 18 grupos, sendo 8 codornas/grupo/tipo de codorna. Após 35 dias as codornas foram mantidas em condições de fotoperíodo de dias longos (17luz: 7escuro). O peso vivo e os valores morfométricos e histológicos testiculares foram determinados em cada período. Os dados obtidos foram analisados para determinar a curva de crescimento e o comportamento dos parâmetros analisados. O modelo que mais se adequou aos dados foi o modelo não linear de Gompertz (Y=A exp [-B e (-kt)]). O peso vivo e as características testiculares macro e microscópicas apresentaram comportamento alométrico entre si, sendo que, aproximadamente aos 60 dias os machos apresentaram-se sexualmente desenvolvidos, e estabilizaram o peso corporal por volta dos 100 dias. O testículo direito é mais cranial que o esquerdo e diferem em relação a comprimento e largura, porém não foi observada diferenças (P>0,05) para peso testicular. As codornas de corte apresentaram peso corporal e peso testicular maiores que as codornas de postura, porém as codornas de postura apresentaram peso relativo testicular maior. Durante todo o período analisado os machos puderam ser considerados sexualmente aptos. Os reprodutores apresentaram características sexuais ativas até os 360 dias de idade, representadas pelo tamanho testicular e pela atividade celular nos túbulos seminíferos.

Meat- and egg-type quails were analyzed to determine reproductive development, puberty and the onset of senility. For this purpose, 288 quails (144 meat- and 144 egg-type quails) were followed from hatch to 360 days old. The birds were distributed by age in 18 groups, 8 quails/group/type of quail. After 35 days quails were maintained under long daylength conditions (17L: 7D). The live weight and the macro and microscopical testicular characteristics were determined in each period. The data were analyzed to determine the growth curve and the behavior of parameters. The model that best fits the data was the non-linear Gompertz model (Y = A exp [-B and (-kt)]). Live weight and testicular morphometric parameters had an allometric behavior among themselves, and at approximately 60 days the males had sexually development, and body weight stabilized at about 100 days. The right testicle was more cranial than the left, differing in the length and width, but no difference in testicular weight (P>0.05) was observed. The meat quails had a larger body weight and testicular weight than the egg quails, but the egg-quail had a higher percentage of testes in relation to body weight. During the whole adult period the males could be considered sexually fit. Breeders had active sex characteristics until 360 days of age, represented by testicular size and by cellular activity in the seminiferous tubules.

Biologia de Agistemus brasiliensis Matioli, Ueckermann & Oliveira (Acari: Stigmaeidae) e sua potencialidade de predação sobre Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) / Biology of Agistemus brasiliensis Matioli, Ueckermann & Oliveira (Acari: Stigmaeidae) and its predation potential on Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae)

O presente trabalho objetivou estudar a biologia de Agistemus brasiliensis Matioli, Ueckermann & Oliveira nas temperaturas de 15; 20; 25; 30 e 35°C, alimentada com Brevipalpus phoenicis (Geijskes) e pólen de Thypha sp. em condições de laboratório. Tabelas de vida de fertilidade foram calculadas para determinar os parâmetros biológicos. A temperatura ideal para o desenvolvimento de A. brasiliensis foi 29°C. Os valores de T (ciclo de vida - dias), R0 e r m, na temperatura de 30°C, foram de 13,95; 16,25 e 0,20, respectivamente. A potencialidade de predação de A. brasiliensis foi estudada para as densidades populacionais de 5; 10; 20; 40 e 60 adultos de B. phoenicis a 29°C, em arenas de 3 cm de diâmetro, sobre frutos de laranja-pêra. A densidade de 20 ácaros foi suficiente para que o predador consumisse seu número máximo de presas (7,6 ácaros por dia). Densidades acima de 40 ácaros da leprose proporcionaram 4,7 ovos por dia, em comparação aos 2,5 ovos por dia obtidos na densidade de 20 ácaros da leprose.

The present work aimed to study the biology of Agistemus brasiliensis Matioli, Ueckermann & Oliveira at the following temperatures, namely 15, 20, 25, 30 and 35°C, fed with Brevipalpus phoenicis (Geijskes) and Typha pollen, in laboratory conditions. Life tables were calculated to evaluate the biological parameters. The optimal development of A. brasiliensis took place at 29°C. The values of T (time of generation - days), R0 and r m at 30°C were, 13.95, 16.25 and 0.20, respectively. The prey consumption of A. brasiliensis was studied at the densities of 5, 10, 20, 40 and 60 leprosis mite females per cage (3 cm in diameter) on citrus fruits at 29°C. The maximum prey, namely 7.6 B. phoenicis females per day, were consumed at a density of 20 leprosis mites. At densities of above 40 leprosis mites per cage, A. brasiliensis oviposits 4.7 eggs per day, in comparison to 2.5 eggs per day at 20 mites per cage.

Capacidade de colonização de Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) em cercas-vivas, quebra-ventos e plantas invasoras / Colonization capacity of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) on plants used as hedge, windbreak and on weeds

The objective of this work was to evaluate the Brevipalpus phoenicis (Geijskes) settling capacity on common species of hedge and windbreak plant species as well as weeds normally foundaround or in citrus orchards. The study was conducted in laboratory and greenhouse, using 11 plant species (treatments): Hibiscus sp., Malvaviscus mollis, Grevillea robusta, Mimosa caesalpiniaefolia, Bixa orellana, Euphorbia splendens, Bidens pilosa, Commelina benghalensis, Sida cordifolia,Ageratum conyzoides and Citrus sinensis. A completely randomized block design was used, with five replicates. For each experimental unit composed of one plant in a pot, 100 females of B. phoenicis were transferred from a lab rearing. Evaluation was carried out 45 days after transference of the mites to the weeds and 60 days after their transference to the hedge and windbreak plant species. Leaves were cut for evaluation of the totals of development stages. Counts were transformed in ln(x+5) and analyzed bymeans of F test. The results were compared using Tukey test (P <_ 0.05). The most favorable hedge and windbreak plant species for the development of mites, in decreasing order, were: M. mollis (6,342 mites),Hibiscus sp. (2,546), B. orellana (2097), G. robusta (1,485), and M. caesalpiniaefolia (776). No mites were found on E. splendens. Regarding the weeds, the results were: B. pilosa (2,238), C. benghalensis (920), S. cordifolia (738), and A. conyzoides (684). In C. sinensis, 3,116 mites were found. Except for E. splendens, all plant species were shown favorable to the B. phoenicis population growth. The presence of these plants in citrus orchards can represent a threat to the crop.

Este trabalho teve como objetivo avaliar a capacidade de colonização do Brevipalpus phoenicis (Geijskes) em espécies de cercas-vivas, quebra-ventos e plantas invasoras mais freqüentesem pomares cítricos. O ensaio foi conduzido em laboratório e casa-de-vegetação, utilizando-se 11 espécies vegetais (tratamentos): Hibiscus sp., Malvaviscus mollis, Grevillea robusta, Mimosa caesalpiniaefolia, Bixa orellana, Euphorbia splendens, Bidens pilosa, Commelina benghalensis, Sida cordifolia e Ageratum conyzoides e Citrus sinensis. Adotou-se o delineamento estatístico deblocos casualizados, com cinco repetições. Para cada unidade experimental, constituída de uma plantaenvasada, foram transferidas 100 fêmeas de B. phoenicis provenientes de uma criação estoque. Decorridos 45 dias após a transferência dos ácaros para as plantas invasoras e 60 dias para as cercasvivas e os quebra-ventos, estas tiveram suas folhas destacadas e seus ramos repicados para avaliação dos totais de estágios de desenvolvimento. Os dados relativos às contagens foram transformados em ln(x+5) e analisados pelo teste F. As médias foram comparadas pelo teste de Tukey (P <_ 0,05). As cercasvivas e quebra-ventos mais favoráveis ao ácaro, em ordem decrescente, foram: M. mollis (6.342 ácaros), Hibiscus sp. (2.546), B. orellana (2.097), G. robusta (1.485) e M. caesalpiniaefolia (776). Nenhum ácaro foi encontrado em E. splendens. Com relação às plantas invasoras, foram: B. pilosa (2.238), C. benghalensis (920), S. cordifolia (738) e A. conyzoides (684). Em C. sinensis foram contados 3.116 ácaros. Com exceção de E. splendens, todas as plantas mostraram-se favoráveis ao crescimento populacional de B. phoenicis. A presença destes nos pomares cítricos pode representar uma ameaça à cultura.