Interação de genótipos de milho vs locais, anos e épocas de semeadura

This work aims to evaluate the G x E interaction and its unfolding in simple and complex part, in order to study the best locations and sowing dates for evaluation of genotypes grain yield of maize, at Jaboticabal-SP and Campo Alegre de Goiás-GO. Four experiments were carried out in randomized blocks design with three replications and 17 genotypes where 13 are experimental synthetic, three varieties and a commercial hybrid. Two seasons of cultivation were evaluated for each location. Environmental stratification was measured by the traditional method of Lin (1982) and the dissimilarity has been estimated by the method of Cruz & Castoldi (1991), in addition to the Pearson correlation coefficient between environments pairs. The results showed that there was disagreement between the methods used. Breeding programs must prioritize evaluations in years and locations to the detriment of different sowing dates in order to discriminate the best genotypes and make precise recommendationsO objetivo desta pesquisa foi avaliar a interação G x A e seu desdobramento em parte simples e complexa, a fim de estudar quais os melhores locais e épocas de semeadura para avaliação de genótipos de milho, quanto à produção de grãos nas cidades de Jaboticabal-SP e Campo Alegre de Goiás-GO. Foram conduzidos quatro experimentos no delineamento de blocos casualizados com três repetições e 17 genótipos sendo 13 sintéticos experimentais, três variedades e um hibrido comercial. Foram avaliadas duas épocas de cultivo para cada local. A estratificação ambiental foi mensurada pelo método tradicional de Lin (1982) e a dissimilaridade ambiental foi estimada pelo método de Cruz e Castoldi (1991), além da correlação de Pearson entre os pares de ambientes. Os resultados demonstraram que houve discordância entre os métodos utilizados. Nos programas de melhoramento, devem-se priorizar avaliações em anos e locais distintos, em detrimento de épocas de semeadura diferentes, a fim de discriminar os melhores genótipos e fazer as recomendações precisas dos mesmo

Genetic variability in popcorn synthetic population

The Brazilian popcorn has low genetic variability and the successful development of advanced lines, new popcorn cultivars with high grain yield (GY) and expansion volume (PE) is dependent on parental selection and precise determination of heterotic groups. The aim of this study was to evaluate genetic variability and identify heterotic groups in synthetic populations of popcorn, using diallel crosses. Thus, nine synthetic populations were crossed using complete diallel scheme. The GY and PE traits of 36 hybrids and reciprocals were evaluated in a randomized complete block design with 72 treatments and two replicates in two years. The effects of non-additive genes were the most important in the genetic control of these traits, indicating a favorable situation to produce hybrids. The reciprocal effect is mainly due to non-maternal effects for GY and PE. The highest GY values were obtained for the 02 x 08, 04 x 09, 05 x 09, and 01 x 09 crosses and the highest PE were obtained for the 07 x 01 and 03 x 04 crosses. The exploitation of synthetic populations from S3 lines can be an alternative to increase the genetic variability for grain yield and popping expansion in popcorn breeding programs.

Correlation and path analysis of agronomic and morphological traits in maize

ABSTRACT The efficiency of selection can be broadened for certain traits using estimative of genetic parameters, which are fundamental for plant breeding. The estimative of genetic parameters allows identifying the nature of the action of genes involved in the control of quantitative traits and evaluates the efficiency of different breeding strategies to obtain genetic gains. Therefore, this study aimed to verify the variability and correlation between morphological and agronomic traits in synthetic maize populations, in order to practice indirect selection. Thirteen populations were evaluated in field experiments at Jaboticabal- SP and Campo Alegre de Goiás-GO, using randomized block design, for lodging (LOD), culm breakage (CB), plant height (PH), ear height (EH) and grain yield (GY). The 13 populations were also sown in 1 kg-plastic bags under black shade cloth, using a randomized complete block design with nine replications, for evaluation of the morphological traits: main root length (MRL), root fresh matter (RFM), root dry matter (RDM), average root diameter (ARD), root surface area (RSA), root tissue density (RTD) and shoots dry matter (SDM). The trait GY exhibited genetic variability enough to be effective if used for selection. The selection on the morphological traits is indicated on RDM, due to the ease in obtaining data and its accuracy, high correlation with all morphological traits and association with GY. The simultaneous selection based on RFM and RDM, for gains in GY, can be performed. The highest direct effect on GY was identified in LOD and CB, being indicated for indirect selection

Genética na escola

Humans has always been interested in genetics for many years, and their study is very important for developing better plants and animals. In 2008 it was added to the curriculum of the Brazilian high school some issues about genetics. Unesp of Jaboticabal has several courses in which genetics is a compulsory subject. For this reason, the project Genetics at School was developed to transmit practical knowledge of genetic to third year high school students. The topics covered for the classes will be: reproduction of the species (sexual and asexual), heredity, Mendel's laws, sex-linked inheritance, blood incompatibility groups, genetic code: DNA and RNA, paternity tests (electrophoresis), biotechnology and genetically modified organisms, genetic improvement and "general curiosities", being taught through classes with the aid of powerpoint and other resources. During the first half, as well as preparation of lessons and teaching materials, schools consultation was made to check availability and interest, and these four signaled positively. In the second half the lessons related to the proposed topics will be taught from September.O homem sempre se interessou pela genética desde muitos anos, e seu estudo é muito importante para desenvolvimento de plantas e animais melhores. No ano de 2008 foi adicionado ao currículo do ensino médio brasileiro alguns assuntos sobre genética. A Unesp de Jaboticabal possui vários cursos em que genética é disciplina obrigatória. Por esse motivo, foi elaborado o projeto Genética na Escola para transmitir conhecimentos práticos da área aos alunos do terceiro ano do ensino médio. Os temas abordados para as aulas serão: reprodução das espécies (sexuada e assexuada), hereditariedade, Leis de Mendel, herança ligada ao sexo, grupos sanguíneos e incompatibilidade, código genético: DNA e RNA, testes de paternidades (eletroforese), biotecnologia e os organismos geneticamente modificados, melhoramento genético e "curiosidades gerais", sendo ministrado por meio de aulas com auxílio de Datashow e outros recursos. Durante o primeiro semestre, além da elaboração das aulas e materiais didáticos, foi feita consulta às escolas para verificar interesse e disponibilidade e, destas, quatro sinalizaram positivamente. No segundo semestre serão ministradas as aulas referente aos temas propostos, a partir de setembro.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES