Fernando Irajá Félix de Carvalho

Plant height reduction in populations of triticale (X triticosecale Wittmack) by induced mutations and artificial crosses

Induced mutations by gamma radiation (0, 5, 10, 20 and 40 kR doses) and reciprocal crosses were tested as mechanisms of enhancing genetic variability for plant height in two triticale cultivars, BR4 and EMBRAPA18. The reciprocal crosses and all doses of radiation showed similar increase in genetic amplitude for this trait, being suitable for increasing variability in breeding programs. Genotypes showed different responses as the gamma ray doses were increased, expressing shorter plant height. The decision of using induced mutations or artificial crosses depends on the resources available and the selection method to be used

Evidence of vertical migration in the Ipanema bat Pygoderma bilabiatum (Chiroptera: Phyllostomidae: Stenodermatinae)

Migration is defined as a seasonal and cyclic population movement observed in all animal classes and studied mainly in vertebrates. A considerable part of the knowledge on migration comes from birds, for which migration is an important aspect of their biology. In the case of bats, females usually migrate larger distances than males in some species. The present study analyzes the seasonal occurrence of Pygoderma bilabiatum (Wagner, 1843) at different elevations, in order to test for a pattern that evidences migration, using data from the states of Espirito Santo, Minas Gerais, Rio de Janeiro, Sao Paulo, Parana, Santa Catarina, and Rio Grande do Sul, Brazil. A total of 529 specimens of P. bilabiatum were captured. Pygoderma bilabiatum seems to be more frequent at intermediate and high elevations (over 80% of all captures were made above 250 m a.s.l.) and at latitudes above 22°S, where rainfall is high (over 1,500 mm) and temperatures are mild (16-23°C). Sex ratio varied with elevation; it was skewed towards males at lower elevations (N = 9, r2 = 0.60, F = 12.311, p = 0.008, Sex ratio = 0.0004*elevation + 0.976), though females predominated at all altitudinal bands and in all states analyzed.

O uso de ácido giberélico em solução nutritiva na avaliação precoce de estatura de genótipos de trigo hexaplóide

Six hexaploid wheat genotypes with known height and giberellic acid sensibility, were used in a new method to test plant stature (rht genes) with giberellic acid nutritive solution. The plants were submitted to three periods of giberellic acid action: without giberellic acid, giberellic acid from 8th day after sowing (7 days) and giberellic acid just after sowing (15 days). The use of giberellic acid was efficient on selecting genotypes with different plant heights in all periods with giberellic tested.

Diferentes ambientes para avaliação da sensibiliade ao ácido giberélico em genótipos de trigo (Triticum aestivum L.)

This experiment was conducted to analyse different environments in lhe indentification of dv/arf genes m wheat througth lhe giberellic acid (GA) sensitivity reaction. The tests were conducted in 1995, in a greenhouse (GH), laboratory (LA) andfield (Ff) in Porto Alegre and Eldorado do Sul, RS, Brazil. Six genotypes with different heigth were evatualed in GH and LA by treatments with 0 and 100 GA ppm, and in lhe Fl, when plants had two tofour leaves in lhe treatments with 0, 100 and 1000 GA ppm. The heigth measurement was done 20 days after lhe aplication of GA in GH, 18 days in LA andfour-week evaluations in lhe FI. The identijication of GA sensitive genotypes was possible in ali environments. The heigth dijference between the treatments was used to compare the environments, and the targer difference were observed in GH and in the Fl. The genotype x environment interaction was not significam, demonstrating showing the possibility ofusing this identification test in thefield. Seven days after the tratment aplication the sensitive of GA genotypes could be detected througth height measurements and visual evaluation.

Estimativa da herdabilidade para os caracteres adaptativos ciclo e estatura de planta em aveia

Field experiments were conducted in 1993 and 1994 in Eldorado do Sul, RS aiming to increment the efficiency of artificial selection in oat for the adaptative traits heading date and plantheight. The heritability (h2) was estimated for 19 segregating populations conducted by the pedigree method and using linear regression as proposed by LUSH (1940). Measurements were taken weekly for heading date from 10 plants in each F3 segregant population during five subsequent weeks in 1993. Plant height was mesured 15 days after anthesis. In 1994, the F4 populations were measured for plant height and heading date. Different h2 values were obtained for each trait from the different segregating populations. The heritability values were from 0.19 to 0.59 for heading date and from 0.43 to 0.92 for plant height. The high h2 estimates as obtained for these two adaptative traits indicate that artificial selection can be succefully done in early generations.

EFEITO DO ACAMAMENTO ARTIFICIAL EM GENÓTIPOS DE TRIGO DE PORTE ALTO E BAIXO

Grain yield advantage of genotypes of shortstature over tall genotypes is explained by the reduction of lodging in short plants. This study was conducted with the objective to determine the effects of three different times of artificial lodging over the tall genotype IAC-5 and its almost-isogenic lines IPF 55243, IPF 55244 and IPF 55245 which carry the genes Rht1, Rht2 and Rht1 + Rht2, respectively. Artificial lodging was applied using strings that mainteined the plants lodgeded in the stages of booting, anthesis and grain at milk state. The effects of lodging on grain yield were similar to all genotypes independently of plant height. The major effect of the lodging was observed during anthesis and increased the number of sterile spiqueletes by spike, decreased the number of total spikelets by spike, decreased the number of grain by spike and grain yield. Genotypes with genes for short plant height had superior grain yield than tall genotypes.

Herança da estatura de planta e do comprimento da panícula principal no cruzamento entre Avena Sativa L. e Avena Sterilis L.

The wild species Avena sterilis L. has been widely used for crossing with cultivated oat. The high affinity between them enables an increase in genetic variability and transference of important agronomic genes. However, undesirable characters such as great plant height and length of the panicle can be transferred to progenies. These characters were analysed to evaluate the genetic variability and inheritance in crossing between Avena sativa L. and Avena sterilis L. Estimates of phenotypical and genetical variances were high while the environmental variance was low, providing a high broad sense heritability. The additive gene effect was the most important for explaining the genetic variation for both characters.

Characterization for plant height and flowering date in the biological species oat

4 ABSTRACT - The use of wild oat races in artificial hybridization with cultivated oat ( Avena sativa L.) has been used as a way of increasing the variability. This work aimed to identify the variability for plant height and flowering date of groups of cultivated oat genotypes, wild introductions of A. fatua L. and segregating populations of natural crosses between A. sativa and A. fatua. Wide genetic variability was observed for both traits in the groups and between them. The wild group of A. fatua L. showed high plants with early maturity, but in the segregating group there was reduced plant height and early maturity. The wild introductions of A. fatua L. studied in this work can be used in oat breeding programs to increase genetic variability by transferring specific characters into the cultivated germ plasm.

Genetics of in vitro organogenesis and precocious germination of wheat embryos

As bases geneticas da germinacao precoce de embrioides de trigo e organogenese in vitro foram estudadas utilizando-se seis genotipos brasileiros e suas geracoes F1, F2, BC1F1 e BC2F1, atraves da analise de media de geracoes. Quatro pais e um conjunto de F1x92s tambem foram analisados em um experimento dialelico. Os resultados indicam que ambos caracteres sao determinados por uma complexa acao genica, ocorrendo efeitos aditivos, de dominância e epistaticos. Foram obtidos valores altos para as estimativas de herdabilidade no sentido amplo, o que indica uma forte determinacao genetica, embora este parâmetro nada informe sobre a magnitude da acao aditiva. Considerando a complexidade do controle genico, espera-se que maiores ganhos geneticos sejam obtidos selecionando para os caracteres em geracoes avancadas de populacoes segregantes. Os baixos valores de correlacao entre ambas caracteristicas e embriogenese somatica e regeneracao de plantas (dados apresentados em trabalho anterior) indicam a possibilidade de obtencao de genotipos recombinantes.

Variabilidade genética para teor de proteína bruta em grãos de aveia

The increased use of oat grains as human food has stimulated plant breeders to select genotypes with high grain quality. This work aimed to identify and characterize genetic variability for total grain protein in cultivated oat and introductions of A. fatua L., A. sterilis L. and hybrid populations from A. sativa L. x A. sterilis L.. The results showed a large genetic variability for the trait in the studied groups. Differences among cultivated oat genotypes may be attributed to different genetic constitution. A. sterilis L. group showed high protein content specially with the introduction of I-325. Genotypes from A. fatua L. showed similar low levels of protein probably because the narrow range of regions sampled in this study. Some hybrids from A. sativa L. x A. sterilis L. showed high protein content and acceptable agronomic traits.