Análise da estabilidade de híbridos de sorgo granífero para rendimento de grãos na safrinha.

A interação GA freqüentemente observada para o caráter produtividade de grãos em sorgo granífero sugere a análise da estabilidade. Nesse sentido o objetivo do trabalho foi analisar a estabilidade de 25 híbridos de sorgo granífero avaliados em sete ambientes pela análise de Yates e Cochran (1938) que preconizam estabilidade pela não variação de rendimento diante das variações ambientais e as análises de Plaisted e Peterson (1959) e Wricke (1965) que preconizam a estabilidade pela variação coerente com a melhoria ambiental. Pela análise de Yates e Cochran (1938) apenas um indivíduo foi considerado estável, porém este apresentou baixa média de rendimento de grãos, já pelas metodologias de Plaisted e Peterson (1959) e Wricke (1965) dois híbridos se destacaram, o 0307689 pela alta estabilidade associada a uma alta média de rendimento de grãos, sendo um indicativo de adaptabilidade geral desse material e o híbrido 0307671 que apresentou grande contribuição para interação GA e média geral alta, sendo um indicativo de adaptabilidade específica. Pela correlação de Sperman foi observado que as metodologias de Plaisted e Peterson (1959) e Wricke (1965) ordenaram os híbridos de forma igual, com isso o uso simultâneo dessas análises é redundante, mas o uso de uma delas é interessante, apesar da divergência de filosofia. Os métodos de Plaisted e Peterson (1959) e Wricke (1965) foram parcialmente concordantes com o método de Yates e Cochran (1938), devido a sua correlação estatisticamente superior a zero, porém de baixa magnitude. Nenhuma metodologia se correlacionou com a média de produção de grãos, mostrando que a seleção não pode ser realizada exclusivamente pelos métodos de estabilidade, uma vez que espera-se encontrar indivíduos produtivos estáveis e outros instáveis, tanto em uma quanto na outra filosofia de estabilidade. Devido aos resultados e filosofia das metodologias de estabilidade, o uso da avaliação de produtividade simultaneamente com o método de Plaisted e Peterson (1959) ou Wricke (1965) se mostrou a melhor estratégia de seleção de híbridos superiores

Antenatal corticosteroid treatment for the prevention of peri-intraventricular haemorrhage in preterm newborns: a retrospective cohort study using transfontanelle ultrasonography

Objective: The objective of this study was to assess the correlation between antenatal corticosteroids and peri-intraventricular haemorrhage (PIVH) using transfontanelle ultrasonography, as well as to evaluate the risk factors for its incidence. Methods: We performed a retrospective cohort study using medical records of preterm newborns. The protocol for maternal corticoid administration for foetal lung maturation included dexamethasone 4 mg (intramuscular) 8/8 hours per 48 hours, with one cycle per week. The diagnosis of periintraventricular haemorrhage was based on transfontanelle ultrasonography, using the Papile's classification. The following risk factors for peri-intraventricular haemorrhage were assessed: birth weight, gestational age at delivery, type of delivery, newborn's sex, surfactant administration, premature rupture of membranes and previous history of infection during the current pregnancy. The student's t-test and chi-square test were used for statistical analysis. Results: Our sample population included 184 preterm newborns. Transfontanelle ultrasonography revealed peri-intraventricular haemorrhage in 32 (74.4%) and periventricular leukomalacia in 11 (25.6%) newborns. Grade I haemorrhage was found in 20 (62.5%), grade II in five (15.6%), and grade III in seven (21.8%) newborns, as in accordance with Papile's classification. Vaginal delivery (p = 0.010), birth weight <1500 g (p = 0.024), gestational age at delivery ≤32 weeks (p = 0.018), and previous history of infection during pregnancy (p = 0.013) were considered risk factors for peri-intraventricular haemorrhage in preterm newborns. Conclusion: Maternal corticoid administration for foetal lung maturation showed a protective effect against peri-intraventricular haemorrhage in preterm newborns. The risk factors for peri-intraventricular haemorrhage were determined

Growth and nutrient contents in lowland rice due to phosphorus and potassium fertilization.

In order to reach an optimum and sustainable production, growers must know the fertilizing potassium (K) and phosphorous (P) application rates. The present study aimed to determine the rice development in response to combined rates of P and K, on Plinthaquults (380-400 g kg-1 of clay), under high and low fertility conditions, in the tropical lowland plain of the Araguaia river, Brazil. Three field experiments were performed, each one consisting of a completely randomized factorial block design, with three replications. Treatments included a combination of six K2O rates (0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1 and 150 kg ha-1) with six P2O5 rates (0 kg ha-1, 30 kg ha-1, 60 kg ha-1, 90 kg ha-1, 120 kg ha-1 and 150 kg ha-1). No interaction effect between P and K rates was observed for the evaluated variables in any fertility level/year. Phosphorous application under low fertility conditions, as well as K under high fertility conditions, affect overall crop nutrition, tillering capacity, yield components and grain yield of lowland rice, though no effects were observed due to the P application in high fertility soils and K in low fertility soils. Under high fertility conditions, the grain yield increment rate due to the K application was 4.04 kg ha-1, whereas in the low fertility areas, such as recently cleared fields, a maximum yield of 7,161 kg ha-1 was achieved by applying 140 kg ha-1 of P

Genomic prediction of assitive and non-additive effects using genetic markers and pedigrees in pines breeding.

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