Adaptabilidade e estabilidade de progênies de meios-irmãos de pinhão-manso em diferentes regiões do Brasil.

RESUMO: Programas de melhoramento do pinhão-manso (Jatropha curcas L.) intensificaram-se nos últimos cinco anos, tendo sido selecionadas, localmente, plantas em diversas regiões do Brasil. O objetivo deste trabalho foi quantificar a interação genótipos x ambientes da produção de grãos de pinhão-manso, avaliada em três regiões brasileiras, e o progresso genético obtido com a seleção. A partir de progênies de meios-irmãos, selecionadas pela Embrapa Semiárido e pela EPAMIG, foram instalados, no ano de 2008, três testes de progênies, nos municípios de Planaltina, DF, Nova Porteirinha, MG e Pelotas, RS, utilizando-se delineamento de blocos ao acaso, com três repetições e cinco plantas por parcela. Como testemunhas foram utilizadas sementes de plantas não selecionadas e um dos materiais genéticos comercializados no Brasil. A interação genótipo x ambiente foi significativa. Foram identificadas oito progênies de adaptabilidade geral, três progênies de baixa adaptabilidade, duas progênies de adaptabilidade específica a ambientes favoráveis e duas progênies de adaptabilidade específica a ambientes desfavoráveis, em diferentes regiões do Brasil. As estimativas de progresso genético indicam eficiência da seleção massal, com ganhos de 28, 76 e 177%, nos municípios de Planaltina, DF, de Nova Porteirinha, MG, e de Pelota, RS, respectivamente. Observa-se que os ganhos de seleção obtidos pelo método centroide são mais equilibrados entre ambientes e, por isso, preferíveis. As novas médias, estimadas com o plantio das progênies selecionadas, em toneladas por hectare, são de 2,34 ton.ha-1, em Planaltina, DF; de 2,37 ton.ha-1, em Nova Porteirinha, MG, e de 2,09 ton.ha-1 , em Pelotas, RS. ABSTRACT: Physic nut (Jatropha curcas L.) breeding programs have intensified in the past five years, locally selecting plants from various Brazilian regions. The objective of this study was to quantify the genotype x environment interaction of the physic nut grain production and the genetic progress obtained with the selection. From Half-sib progenies selected by Embrapa and EPAMIG, in 2008, three progeny trials were installed in the cities of Planaltina-DF, Nova Porteirinha-MG and Pelotas-RS, using a randomized block design with three replications of five plants per plot. Non-selected plant seeds and genetic material commercialized in Brazil were used as control. The genotype x environment interaction was significant for the J. curcas grain yield expression. We identified eight progenies of broad adaptability, three progenies of low adaptability, two progenies of specific adaptability to favorable environments and two progenies of specific adaptability to unfavorable environments of different Brazilian regions. Estimates of genetic progress indicate mass selection efficiency, with genetic gains of 28%, 76% and 177% in the Planaltina-DF, New Porteirinha-MG and Pelotas-RS, respectively. The genetic gains obtained by the centroid method were more balanced among environments, and therefore, preferable. The new means estimated with the cultivating of the selected progenies are: 2.34 ton.ha-1 in Planaltina-DF, 2.37 ton.ha-1 in Nova Porteirinha- MG and 2.09 ton.ha-1 in Pelotas-RS.

Environmental effect on sunflower oil quality.

Sunflower is one of the most important oilseed crops and produces a high-quality edible oil. Balance of fatty acids in standard sunflower oil shows preponderance of linoleic rather than oleic acid, and conditions during seed development, such as temperature, changes the oleic/linoleic ratio of the oil. This work aimed to evaluate the environmental effect on fatty acid profile in a group of standard and high oleic varieties and hybrids. Seeds were produced during regular season crop and during off-season crop featuring different temperatures from anthesis to maturity. Fatty acid composition was determined by gas chromatography. Levels of oleic acid, in standard oil genotypes, raised as the crop developed in warmer environment while levels of linoleic acid decreased, and the opposite was observed when the crop was grown under lower temperature. High oleic genotypes were less sensitive to environment switching and showed lower variation on fatty acid composition.

Biplot analysis of strawberry genotypes recommended for the State of Espírito Santo.

Most strawberry genotypes grown commercially in Brazil originate from breeding programs in the United States, and are therefore not adapted to the various soil and climatic conditions found in Brazil. Thus, quantifying the magnitude of genotype x environment (GE) interactions serves as a primary means for increasing average Brazilian strawberry yields, and helps provide specific recommendations for farmers on which genotypes meet high yield and phenotypic stability thresholds. The aim of this study was to use AMMI (additive main effects and multiplicative interaction) and GGE biplot (genotype main effects + genotype x environment interaction) analyses to identify high-yield, stable strawberry genotypes grown at three locations in Espírito Santo for two agricultural years. We evaluated seven strawberry genotypes (Dover, Camino Real, Ventana, Camarosa, Seascape, Diamante, and Aromas) at three locations (Domingos Martins, Iúna, and Muniz Freire) in agricultural years 2006 and 2007, totaling six study environments. Joint analysis of variance was calculated using yield data (t/ha), and AMMI and GGE biplot analysis was conducted following the detection of a significant genotypes x agricultural years x locations (G x A x L) interaction. During the two agricultural years, evaluated locations were allocated to different regions on biplot graphics using both methods, indicating distinctions among them. Based on the results obtained from the two methods used in this study to investigate the G x A x L interaction, we recommend growing the Camarosa genotype for production at the three locations assessed due to the high frequency of favorable alleles, which were expressed in all localities evaluated regardless of the agricultural year.

Análise funcional e potencial biotecnológico do gene DHN11 de macieira (Malus x domestica Borkh.)

A deficiência hídrica é o principal fator limitante à agricultura, causando significativas perdas de produtividade nas mais diversas culturas vegetais. Novas tecnologias agrícolas, tais como a geração de plantas geneticamente modificadas melhor adaptadas a condições adversas de cultivo, são necessárias. Em um estudo anterior do grupo caracterizando a família gênica das desidrinas (DHNs) em macieira (Malus x domestica Borkh.), foi verificado que o gene MdDHN11 possui níveis de expressão cerca de 6 mil vezes maior em sementes em relação a outros tecidos. Sugere-se que o acúmulo nos últimos estágios de desenvolvimento de sementes possua papel protetor na tolerância à dessecação. Além disso, as DHNs são proteínas caracterizadas por seu envolvimento na resposta a mudanças na disponibilidade de água, principalmente os causados por estresses abióticos.