Estimativa da produtividade de arroz irrigado por inundação em em função da temperatura do ar e da radiação solar

Foram desenvolvidas duas equações de estimativa da produtividade do arroz irrigado por inundação, para as variedades: IAC-242, IAC-100, IAC-101 e IAC-102, em função da temperatura do ar e da radiação solar, no período crítico de formação da produção, para a região de Pindamonhangaba (SP). Os valores de temperatura do ar e de radiação solar ótimos encontrados para as variedades foram, respectivamente, 25,0oC e 475 cal.cm-2.dia-1. O modelo agrometeorológico desenvolvido para previsão da produtividade da cultura que apresentou melhores resultados quando testado com dados independentes foi o que relacionou o menor desvio dos dois elementos climáticos em relação ao valor ótimo obtido através de uma equação de regressão linear múltipla. Os valores de produtividade estimados pelo modelo mostraram diferenças menores que 10% quando comparados com os valores obtidos no campo.Two regression equations were developed to estimate lowland rice yield as a function of air temperature and incoming solar radiation, during the crop yield production period in Pindamonhangaba, SP, Brazil. The following rice cultivars were used: IAC-242, IAC-100, IAC-101 and IAC-102. The value of optimum air temperature obtained was 25.0°C and of optimum global solar radiation was 475 cal.cm-2, day-1. The best agrometeorological model was the one that related least deviation of air temperature and solar radiation in relation to the optimum value obtained through a multiple linear regression. The yield values estimated by the model showed good fit to actual yields of lowland rice (less than 10%)

Successful xenogeneic germ cell transplantation from Jundia catfish (Rhamdia quelen) into adult Nile tilapia (Oreochromis niloticus) testes

Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2 months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20 days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70 days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n = 8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement. © 2016 Elsevier Inc