ABSTRACT
A obtenção de estimativas confiáveis de parâmetros genéticos, incluindo dados relacionados à variabilidade das populações sob melhoramento, é essencial para se elucidar a estrutura genética das populações e para se inferir sobre sua variabilidade genética e seu potencial de melhoramento. Nesse sentido, este trabalho teve por objetivo estimar parâmetros genéticos e a diversidade em progênies de Macaúba com base em características morfológicas e fisiológicas. Para o estudo, foram avaliadas características morfológicas e fisiológicas em 15 progênies de macaúba, em delineamento em blocos ao acaso com 5 repetições e 3 plantas por parcela, no espaçamento de 5x5m. Não houve variabilidade para a maioria das características fisiológicas no conjunto de progênies avaliadas. Porém, verificou-se variabilidade genética para os caracteres morfológicos avaliados. As famílias de macaúba agruparam-se em três grupos distintos quanto à diversidade genética, sendo a família CPAC-03 a mais divergente em relação às demais. A eficiência no uso da água e o comprimento de raquis foram as características que mais contribuíram para a dissimilaridade das famílias de macaúba.
.Obtaining reliable estimates of genetic parameters, including data related to the existing level of variability in breeding populations is essential to elucidate the genetic structure of populations and to infer their genetic variability and potential for improvement. Therefore, this study aimed to estimate genetic parameters and diversity in progenies from Macaw Palm based on morphological and physiological traits. For that, morphological and physiological traits were evaluated in 15 macaw palm progenies (established following a random block design with 5 repetitions and 3 plants per plot - 5x5m spacing). No significant genetic variability was observed for physiological traits in the evaluated progenies. However, for the morphological traits, the existence of genetic variability was evidenced. The macaw palm families were grouped into three distinct groups based on its genetic dissimilarity, being CPAC-03, the most divergent progeny to the others. The water use efficiency and the leaflet length were the traits that contributed most to the dissimilarity of the families.
.ABSTRACT
Rice blast, caused by Pyricularia oryzae, is the most important disease in rice worldwide. This study investigated the effects of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal-to-ambient CO2 concentration ratio [Ci/Ca], and transpiration rate [E]); chlorophyll fluorescence a (Chla) parameters (maximum photochemical efficiency of photosystem II [Fv/Fm], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]); concentrations of pigments, malondialdehyde (MDA), and hydrogen peroxide (H2O2); and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and lypoxigenase (LOX) in rice leaves. Rice plants were grown in a nutrient solution containing 0 or 2 mM Si (-Si or +Si, respectively) with and without P. oryzae inoculation. Blast severity decreased with higher foliar Si concentration. The values of A, gs and E were generally higher for the +Si plants in comparison with the -Si plants upon P. oryzae infection. The Fv/Fm, qp, NPQ, and ETR were greater for the +Si plants relative to the -Si plants at 108 and 132 h after inoculation (hai). The values for qp and ETR were significantly higher for the -Si plants in comparison with the +Si plants at 36 hai, and the NPQ was significantly higher for the -Si plants in comparison with the +Si plants at 0 and 36 hai. The concentrations of Chla, Chlb, Chla+b, and carotenoids were significantly greater in the +Si plants relative to the -Si plants. For the -Si plants, the MDA and H2O2 concentrations were significantly higher than those in the +Si plants. The LOX activity was significantly higher in the +Si plants than in the -Si plants. The SOD and GR activities were significantly higher for the -Si plants than in the +Si plants. The CAT and APX activities were significantly higher in the +Si plants than in the -Si plants. The supply of Si contributed to a decrease in blast severity, improved the gas exchange performance, and caused less dysfunction at the photochemical level.
