Thesis Abstracts
Cytochemistry of Rhodnius (Triatominae, Hemiptera) salivary glands
(Estudo citoquímico em glândulas salivares de triatomíneos do gênero Rhodnius)
Ana Paula Marques de Lima-Oliveira*
*1997. Departamento de Biologia, Instituto de Biociências, Letras e Ciências Exatas de São José do Rio Preto, São José do Rio Preto, SP, Brasil. Master's thesis. Orienting Professor: Maria Tercília Vilela de Azeredo Oliveira.
We describe the structure of interphasic nuclei (euchromatin, heterochromatin and nucleolus) and the distribution of acid and alkaline phosphatases and Mg2+-dependent ATPase activities in salivary gland cells of Rhodnius prolixus and R. neglectus. Lacto-acetic orcein, silver nitrate and toluidine blue were used to stain nuclear complexes, showing binuclear cells with polyploid nuclei and variation in chromatin texture. Lacto-acetic orcein and C-band strongly stained more heterochromatic corpuscles only in adult male nuclei of both species. The techniques of impregnation by Ag+ and variations of the critical electrolytic concentration clearly showed several nucleolar corpuscles in the two species and for both sexes. Phosphatase activity was more intense in the large than in the small lobules of the salivary glands, and also more than in the salivary duct. At the cellular level, these activities were most intense in the nucleolar corpuscles and in the nuclear membrane, demonstrated as a dark and dense precipitate. Acid and alkaline phosphatase reaction products were found in the nuclear corpuscles and cytoplasm of all salivary glands. In males and females of R. neglectus, ATPase activity was found in some regions of the salivary gland; in males the reaction product appeared in all nuclei, so it was impossible to demonstrate nucleolar corpuscles. ATPase activity was more intense in R. prolixus males than in females. Incubation medium without substrate, with an inhibitor (NaF) of phosphatase activity, absence of MgCl2 for ATPase and of MgSO4 for alkaline phosphatase, constituted the controls for enzymatic reactions. In the majority of controls, the reaction products were absent in the nuclei and in the cytoplasm. However, in nuclei of the glands treated with alkaline phosphatases, in the absence of substrate (sodium B-glycerophosphate), and in R. neglectus males tested for ATPase activity without MgCl2, very weak granulations were recorded. Analysis of the nuclear cytochemical characteristics of salivary gland cells of the two species showed no differences. At the nuclear level, males were distinguished from females by the presence of one or two heterochromatic corpuscles. The absence of these corpuscles in females could be due to the mechanism of sexual differentiation and gene inactivation by dose compensation. Presence of several nucleoli in the interior of nuclei and cytoplasmic metachromasy was associated with intense synthetic activity of gland cells. The phosphatase activities (acid, alkaline and ATPase) in the nucleoli, membranes and nuclear matrix of the salivary gland cells support the role of these enzymes in the transcription of RNAr molecules and biogenesis of ribosomes, transport of molecules among the cells, mechanisms of cell cycle regulation and replication of DNA.
Publication supported by FAPESP.
Cytogenetic studies of triatomines (Panstrongylus, Triatominae, Heteroptera)
(Estudos citogenéticos de triatomíneos (Panstrongylus, Triatominae, Heteroptera))
Esther Tartarotti*
*1998. Departamento de Biologia, Instituto de Biociências, Letras e Ciência Exatas de São José do Rio Preto, São José do Rio Preto, SP, Brasil. Master's thesis. Orienting Professor: Maria Tercília Vilela de Azeredo Oliveira.
A comparative study was made of two species of the genus Panstrongylus (P. herreri and P. megistus), with analysis of the different phases of spermatogenesis, the nucleolar cycle, nucleolar organizer regions (NOR), heterochromatin patterns of meiotic chromosomes and correlation of cytogenetic morphologies.
Cytological preparations of the testes were obtained by orcein lacto-acetic staining, silver nitrate impregnation, C-banding and HaeIII and AluI restriction endonucleasis banding of cell smears. The karyotypes of P. megistus and P. herreri were 2n = 18 + X1X2Y and 2n = 20 + X1X2Y, respectively. The most primitive species in the Heteroptera belong to the family Pentatomidae, with 2n = 14 chromosomes and XY males. Most of the other Heteroptera possess a chromosome complement with more chromosomes and are considered to be more recent. Thus, evolutionarily, P. herreri is a more derived species than P. megistus. These two species, as well as other Panstrongylus, do not have primary constrictions, suggesting that the chromosomes are holocentric, which corroborates the hypothesis of holocentric chromosomes in Heteroptera.
The sex chromosome system in Panstrongylus is the X1X2Y type and C-banding and restriction endonuclease experiments indicate that the X chromosomes of P. megistus and P. herreri have similar digestibility and positive and negative C-banding regions, suggesting a common origin by single X fragmentation, a well-accepted hypothesis. The X chromosomes are more fragile than the Y, and fragment survival is facilitated by post-reductional meiosis and the holocentricity of the chromosomes.
The sex chromosomes in P. megistus and P. herreri were positively heteropycnotic at early prophase and were maintained together during the confused stage. In metaphase I the heterochromosomes were peripherical, separated and isopycnotic, similar to the autosomes. In metaphase II the heterochromosomes were found within the autosome ring, which suggests pseudotrivalent formation and corroborates the post-reductional behavior of these chromosomes.
Cellular cyst formations were observed during spermatogenesis. The cells were enclosed in an involucrum of mesodermic origin and continued in this state until differentiation, subsequently being released in the testicle lymph. The spermatocytes divide many times in the cyst. These multiplications cause a volume reduction, which is resolved through energy supplied by polyploid nuclei. P. megistus and P. herreri present nuclei with a single heterochromatic corpuscule.
The P. megistus and P. herreri heterochromosomes showed nucleolar organizer activity with strong silver ion impregnations at meiotic prophase I. Ligations of one or two autosomes with the nucleolar region were also observed. The data suggest nucleolar fragmentation, since corpuscules and nucleolar fragments were observed within the cell from metaphase I on. It was also found that in these Heteroptera reactivation of post-meiotic rRNA synthesis occurs, probably related to cell differentiation.
Analysis of meiotic chromosomes with C-banding showed that P. megistus and P. herreri have interstitial and terminal bands on autosomes, a common pattern in Heteroptera. The terminal bands corroborate the hypothesis that in the holocentric chromosomes the heterocromatin is normally close to the telomeres. The sex chromosomes in P. herreri were totally heterochromatic during spermatogenesis and in P. megistus the X chromosomes changed between positive and negative banding. There was a correlation between positive C-bands and NOR in the sex chromosomes and spermatids in early differentiation.
Restriction endonucleases, HaeIII and AluI, in P. megistus and P. herreri, showed enzymatic patterns similar to C-banding, suggesting the same heterochromatin type in the coincident regions. However, some heterochromatin digestion patterns were distinct, for example, in P. megistus polyploid nuclei (HaeIII), P. herreri prophase I (HaeIII) and pachytene of both species (HaeIII and AluI). The P. herreri X chromosomes treated with HaeIII gave enzymatic digestions which suggest heterochromatin different from that of C-banding. In P. megistus these chromosomes were heterochromatic and also exhibited a pattern different from C-banding, in that the X chromosomes were heterochromatic. This work suggests that other elements besides recognition sites, such as chromatin wrappage degree and protein-DNA interaction, influence REs results, since P. megistus and P. herreri showed a distinctive digestion pattern in early spermatogenesis, but metaphase chromosomes were practically inaccessible to the action of endonucleases.
Publication supported by FAPESP.
Cytogenetics and embryology of Eupatorium intermedium DC and E. pauciflorum HBK (Compositae)
(Citogenética e embriologia de Eupatorium intermedium DC e E. pauciflorum HBK (Compositae))
Maristela Sanches Bertasso-Borges*
*1993. Instituto de Biociências, Letras e Ciências Exatas de São José do Rio Preto, UNESP, São José do Rio Preto, SP, Brasil. Master's thesis. Orienting Professor: James Robert Coleman.
The reproduction of Eupatorium intermedium DC and E. pauciflorum HBK (Compositae) was studied through an investigation of embryology, microsporogenesis and pollen grain formation, karyotypes, pollination frequency and seed production and germinability.
Embryological studies of E. intermedium were made on material collected from five plants of a natural population in the Parque do Estado de São Paulo, São Paulo, SP, Brazil. Ovules were fixed in FAA. Analysis of clarified ovules revealed the presence of dyads and tetrads of megaspores at frequencies which indicate that reductional meiosis is a regular feature of megasporogenesis. The megaspore of the chalazal region increases and undergoes three successive mitotic divisions to give raise to a mature polygonum type eight-nucleate embryo sac. Embryo formation precedes endosperm formation which originates from the fusion of a male nucleus and the central nucleus, which originated from the fusion of the two polar nuclei. Analysis of 878 ovules in initial stages of development and in pre-anthesis (buds estimated to be within 24 h of achieving anthesis, but still closed) revealed the absence of embryo and endosperm formation, which only occurred in anthesis after the stigmas were exposed. These observations indicate E. intermedium to be strictly sexual.
Analysis of microsporogenesis was done using the smear technique, with anthers from buds fixed in absolute ethanol:acetic acid (3:1) and stained in aceto-carmine. Paquitene chromosomes were normally extended and normal pairing was evident in later stages of prophase. The regular occurrence of 10 bivalents leads to the normal production of tetrads of microspores, the nuclei of which undergo two mitotic divisions to produce pollen grains which are tri-nucleate when released. The regularity of microsporogenesis and pollen formation indicates a high degree of male fertility in the material studied.
Karyotypic studies were made of root tips fixed in absolute ethanol:acetic acid (3:1), pretreated with 0.002 M 8-hydroxyquinoline and stained with aceto-carmine. Six cells of E. intermedium were analyzed. Metaphase chromosomes measured from 2.66 to 4.07 mm and were all submetacentric. Measurements of long arm, short arm and total length, as well as the determination of arm ratio, permitted the recognition of a complement composed of two identical genomes, thereby indicating E. intermedium to be diploid, 2n = 2x = 20.
Counts of pollen grains occurring on 90 stigmas revealed that 74.4% had at least one grain, with a mean of 4.4 grains. Germination tests which ran for 21 days revealed a 68.3% germination rate. Seed production, determined for seven plants, showed that of 1730 ovaries examined, only 2.8% contained embryos.
Eupatorium pauciflorum was collected from natural populations occurring in São José do Rio Preto, SP. Embryological studies showed the complete absence of dyads and tetrads of megaspores, which indicates the absence of reductive meiosis. The megasporocyte functions directly as the megaspore, its nucleus undergoing three mitotic divisions to form an unreduced polygonum type eight-nucleate embryo sac. Embryo formation precedes endosperm formation. The two polar nuclei invariably fuse and the endosperm originates from the resulting central nucleus.
An analysis of 2610 ovules from buds in the initial stages of development and pre-anthesis revealed that approximately 20% of the ovules already contained embryos. This proof of precocious embryony is strong evidence for the existence of agamospermy in E. pauciflorum. Two factors indicate that diplospory is involved: the non-reductive division of the megasporocyte and the absence of aposporic cells. Endosperm development is autonomous.
The generative tissue of the anthers completely degenerates before meiosis of microsporogenesis is initiated, which results in total masculine sterility.
Karyotype analysis in E. pauciflorum was based on a single root tip cell. The chromosomes were very small, varying from 1.07 to 1.74 mm, and submetacentric. Long arm, short arm and total lengths, as well as arm ratios, permitted the recognition of three identical genomes in the complement, which suggests E. pauciflorum to be autotriploid, 2n = 3x = 30.
Analysis of stigmas of E. pauciflorum revealed that only 1.6% had pollen grains (N = 125).
Germination tests with seeds collected from 10 plants showed higher germination rates at room temperature (33.4%) than in a germinator at 30°C (5%). Seed production was determined in 10 plants; 84.4% of 1650 ovaries produced seeds.
On the basis of these studies it is concluded that Eupatorium intermedium is a diploid, strictly sexual species and that E. pauciflorum is triploid and apomictic.
Publication supported by FAPESP.
Study of genomic stability of plasmid vectors in Aspergillus nidulans during a fermentation process
(Estudo da estabilidade genômica de vetores plasmidiais em Aspergillus nidulans durante um processo fermentativo)
Maria Florencia Terenzi*
* 1997. Laboratório de Genética, Departamento de Ciências Morfológicas, FORP, USP-RP, Ribeirão Preto, SP, Brasil. Master´s thesis. Orienting Professor: José Moacir Marin.
The production of penicillin-like substances by isolates of Aspergillus nidulans was first described by Foster and Karrow in 1945. Although it produces only small amounts of penicillin, the fungus A. nidulans has been employed as a model organism in studies of the genetics of penicillin production because its formal genetics is much better understood than that of Penicillium chrysogenum, the industrial producer of penicillin.
The aim of this project was to evaluate the maintenance, during a fermentative process, of a exogenous DNA introduced by different plasmids through genetic transformation.
The chosen process was the one usually used for penicillin production and we used different pH and temperatures to evaluate their influence in the plasmid loss by the transformed strains. The conidia recovered after fermentation were harvested and plated on either non-selective or selective medium to determine the mitotic stability of the transformants, and the presence of plasmid was confirmed by DNA-DNA hybridization (Southern blot).
Through this analysis system it was possible to verify the high frequency of the vector (plasmid) and exogenous information maintenance in transformed strains.
Research supported by CNPq. Publication supported by FAPESP.
Karyological variability and chromosomal evolution in lizards of Gymnophthalmidae and Gekkonidae (Squamata) families: evidence based on differential staining and fluorescent in situ hybridization (FISH)
(Diversidade cariotípica e evolução cromossômica em lagartos das famílias Gymnophthalmidae e Gekkonidae (Squamata): evidências baseadas em coloração diferencial e hibridação in situ fluorescente (FISH)
Katia Cristina Machado Pellegrino*
*1998. Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brasil. PhD thesis. Orienting Professor: Dr. Yatiyo Yonenaga-Yassuda.
Thirteen microteiid lizard species of family Gymnophthalmidae and two species of Gymnodactylus from the family Gekkonidae, one of them with two subspecies, were cytogenetically analyzed after conventional and differential staining (Ag-NOR staining, C- and replication R-banding). Comparative R-banding analysis and fluorescent in situ hybridization (FISH) of telomeric sequences were also performed in order to study the karyotype differentiation of the microteiid genus Leposoma and the gekkonid Gymnodactylus geckoides amarali.
The following species from the family Gymnophthalmidae were investigated: Anotosaura vanzolinia (2n = 46, 22M + 24m), Bachia bresslaui (2n = 46, 18M + 28m), Bachia dorbignyi (2n = 32, 18M + 14m), Cercosaura ocellata and Colobosaura modesta (2n = 42, 18M + 24m), Leposoma guianense, L. oswaldoi, Neusticurus bicarinatus, Pantodactylus albostrigatus and Placosoma cordylinum (2n = 44, 20M + 24m), L. scincoides (2n = 52), Placosoma glabellum (2n = 58) and Nothobachia ablephara (2n = 62 to 64) from seventeen different Brazilian localities.
An extensive karyotypic variability was detected among the microteiid species with variation in the diploid number from 2n = 32 in Bachia dorbignyi up to 2n = 62, 63, 64 in Nothobachia ablephara. The variability, which allowed the establishment of species-specific karyotypes, included differences in the number and morphology of chromosomes due to fusion/fission centric, pericentric inversions and other more complex rearrangements; number and location of NORs; amount and distribution of constitutive heterochromatin, and also presence of supernumerary chromosomes. Extreme variability was detected among the karyotypes of species belonging to the same genus, as observed in Bachia, Leposoma and Placosoma.
The following species from the family Gekkonidae were studied: Gymnodactylus geckoides amarali (2n = 38 to 41/42) from the cerrado of the States of Goiás and Mato Grosso in Central Brazil; Gymnodactylus geckoides geckoides (2n = 40) from caatinga of the States of Paraíba, Sergipe, Alagoas and Bahia in Northeastern Brazil, and Gymnodactylus darwinii (2n = 38 and 2n = 40) from the Atlantic forest of five different continental islands of the State of São Paulo in Southeastern Brazil, and from two localities in the States of Bahia and Alagoas. The variation in diploid number detected in G. g. amarali resulted from a chromosomal polymorphism in the pair 1 (2n = 38, 39, 40) involving centric fusion and presence of supernumerary chromosomes, which occurred in mosaicism (2n = 41/42). In G. darwinii, a geographical karyotype differentiation between specimens from island (2n = 38) and continental populations (2n = 40) was found.
The comparative R-banding analysis, associated with FISH of telomeric sequences, provided evidence for possible mechanisms involved in the chromosomal evolution of Leposoma guianense and L. oswaldoi, with 2n = 44 karyotypes including 20 biarmed macrochromosomes and 24 microchromosomes, and L. scincoides with 52 acrocentric and subtelocentric chromosomes of decreasing size. The elucidation of the rearrangement involved in the polymorphism of pair 1 in G. g. amarali was possible as well. The presence of interstitial telomeric bands (ITBs) after FISH at the pericentromeric regions of biarmed chromosomes of L. guianense, L. oswaldoi and G. g. amarali, found to be involved in pericentric inversions and Robertsonian rearrangements, was interpreted as remnants of ancestral telomeres at the chromosomal rearrangement sites. Centric fusion was considered to be the most probable rearrangement involved in the karyotype differentiation of the species of Leposoma and in the origin of the polymorphism of pair 1 in G. g. amarali.
Publication supported by FAPESP.
Evaluation of the clastogenic effect of the herbicides Atrazine, Metolachlor and Atrazine + Metolachlor, through the micronucleus test in Rattus norvegicus
(Avaliação do efeito clastogênico dos herbicidas Atrazine, Metolachlor e Atrazine + Metolachlor, através do teste de micronúcleos em Rattus norvegicus, linhagem Wistar)
José Cavalcanti da Silva*
*1997. Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil. Master's thesis. Orienting Professor: Salvador de Carvalho.
The clastogenic effect of Atrazine, Metolachlor and Atrazine + Metolachlor was evaluated through the micronucleus test in Wistar rats (Rattus norvegicus). These herbicides were applied at doses of 80, 50 and 25% of LD50, for 24, 48 or 72 h. Two thousand polychromatic erythrocytes were analyzed for each animal. The results were analyzed with the c2 test. From each herbicide evaluated it was detected a superior frequence of micronucleus in the polychromatic erythrocytes, with small variations, suggesting that different doses in different times were innocuous. In polychromatic erythrocytes of bone marrow from rats treated with Atrazine using the highest dose, equivalent to 80% of LD50, in all times, a statistically significant increase in the frequence of micronucleus was observed. On the other hand, when using lower doses, both 50 and 25% of LD50, no statistically significant increase in micronucleus frequence was observed. The results of evaluations of the mixture Atrazine + Metolachlor showed a statistically significant increase in the frequence of micronucleus in all doses and times studied. This fact indicates a clastogenic effect of this mixture. After the statistical analysis, it could be said that Atrazine presents clastogenic effect when a concentrated dose (80% of LD50) is used, whereas Metolachlor does not present clastogenic potential in any dose and any time observed. Atrazine + Metolachlor presented clastogenic effect in all doses and times evaluated. Evidently, there is a synergistic effect of the products, but it is difficult to affirm if Atrazine or Metolachlor is more important.
Evaluation of mutagenic and/or recombinogenic activity of extracts of barbatimão (Stryphnodendron adstringens, Mart.) in germ and somatic cells of Drosophila melanogaster
(Avaliação da atividade mutagênica e/ou recombinogênica do barbatimão (Stryphnodendron adstringens, Mart.) em células germinativas e somáticas de Drosophila melanogaster)
Neila Coelho de Sousa*
*1997. Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brasil. Master's thesis. Orienting Professor: Salvador de Carvalho.
Stryphnodendron adstringens Mart. is a medicinal plant which grows in the Brazilian savanna (cerrado) and is commonly known as barbatimão. Barbatimão is used in alternative medicine in treating diarrhea, hemorrhage, leucorrhea, urethral and vaginal catarrh, scurvy, gastric ulcers and other diseases. Its use is based on the astringency produced by the high tannin content, mainly in the stem bark, from which the therapeutic extract was obtained for this research. The seeds of the plant are toxic for cattle and abortive in rats.
This extract was analyzed for its clastogenic, mutagenic and/or recombinogenic potential in test using germ and somatic cells from Drosophila melanogaster. The RING-X-LOSS test in germ cells evaluates clastogenic effects, shown as total loss of the ring-X chromosome, mosaicism, partial loss of the Y chromosome or non-disjunction. This test uses two mutant strains with specific genetic markers designated ring-X (males) and ywsn3 (females). In order to obtain response from cells in different spermatogenesis stage and to know if the compound has a direct (spermatozoid) or indirect (young and adult spermatids) action, the adult males were treated with different concentrations of the extract (100, 75 and 66%) and crossed through the brooding method.
The results were not statistically significant when compared to the negative control concerning the clastogenic events, and, also, there were no statistically significant addings in total loss of the ring-X-loss chromosome frequencies concerning the induced cells in different spermatogenesis stage.
The wing spot test (somatic mutation and recombination test) is used to analyze the mutagenic and recombinogenic effects induced by the therapeutic extracts, detecting point mutation, deletion, non-disjunction, mitotic recombination and, possibly, genic conversion. It employs males from the mwh marker strain and females from the flr and ORR; flr strain. Standard cross, which uses low metabolic cells (direct action), and improved cross, with high metabolic cells (indirect action), were performed. The therapeutic extract concentrations were the same used in the RING-X-LOSS test. The results obtained, through the wing analysis in both crosses, were statistically nonsignificant when compared to the negative control. The results of this test did not allow to classify this compound as having a direct or indirect action. In this way, the phytotherapic compound barbatimão (Stryphnodendron adstringens) showed to be ineffective in the induction of clastogenic, mutagenic and/or recombinogenic events, when analyzed through the RING-X-LOSS and wing spot tests, in Drosophila melanogaster germ and somatic cells, respectively.
Reproductive biology study of yellow passion fruit (Passiflora edulis f. flavicarpa Deg.)
(Estudo da biologia reprodutiva no maracujá amarelo (Passiflora edulis f. flavicarpa Deg.))
Margarete Magalhães de Souza*
* 1998. Laboratório de Melhoramento Genético Vegetal, Centro de Ciências e Tecnologias Agropecuárias, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, Brasil. Master's thesis. Orienting Professor: Telma Nair Santana Pereira.
The yellow passion fruit (P. edulis f. flavicarpa Deg.) is a very important crop to Brazil, mostly for juice production. It has the central north of Brazil as the distribution center. The objective of this research was to study gamete development. The reproductive biology (microsporogenesis, micro-gametogenesis, pollen viability and megagametogenesis) was studied. This study was conducted in an open population grown in Campos dos Goytacazes, RJ. Microsporogenesis and microgametogenesis were normal, as observed in most Angiosperms. The microspore mother cell produced the microspore after meiosis and cytokinesis, which after mitosis became a pollen grain. All the pollen grains were round, engorged with starch and stained well with I2KI reaction. Pollen viability was higher than 80%, even 24 h after anthesis. Megagametogenesis, the formation and development of the embryo sac, was studied in bud flowers collected at different stages, fixed in FAA, cleared in methyl salicylate and observed with a confocal microscope. The ovule of passion fruit is crassinucellate, bitegmic, and anatrophus. The passion fruit ovules exhibited the Polygonum type of gametophyte development. A functional megaspore after three successive mitotic divisions resulted in an eight-nucleate megagametophyte: the egg apparatus at the micropylar end, two polar nuclei at the central cell, and three antipodals at the chalazal end. The egg apparatus was formed by an egg cell and two synergids, each with a filiform apparatus. Starch grains were observed on the central cell of the embryo sac.
Publication supported by FENORTE /UENF.
Diallel analysis of combining ability in dry bean (Phaseolus vulgaris L.) adapted to northwest Paraná State, Brazil
(Análise dialélica da capacidade combinatória de cultivares de feijão (Phaseolus vulgaris L.) adaptados ao noroeste Paranaense)
Marco Antonio Aparecido Barelli*
* 1997. Pós-Graduação em Agronomia, Universidade Estadual de Maringá, Maringá, PR, Brasil. Master's thesis. Orienting Professor: Maria Celeste Gonçalves-Vidigal.
A diallel cross was produced in Phaseolus vulgaris L. to determine general combining ability (GCA) and specific combining ability (SCA), and to identify superior parents and hybrids to be recommended in Paraná State, Brazil. Six cultivars of dry bean (LPSPI 93-17, LPSPI 93-19, FT-Nobre, Aporé, Rudá and Campeão-1) and all possible F1's among them were evaluated using Griffing's analysis (1956), Method II, Model I. Non-additive effects were predominant in the genetic control of days to emergence and plant height. Additive effects were primarily involved in the genetic control of days to flowering, first pod height, number of pods per plant, number of seeds per plant and weight of 50 seeds. Pod length, number of seeds per pod and grain yield showed similar importance for additive and non-additive effects. Combining ability estimates revealed that FT-Nobre and Rudá are indicated for intrapopulation breeding methods. On the other hand, the combinations LPSPI 93-17 x FT-Nobre, LPSPI 93-17 x Aporé, LPSPI 93-19 x Rudá and FT-Nobre x Aporé are indicated for interpopulation breeding methods.
Inheritance of common bean (Phaseolus vulgaris L.) resistance to Colletotrichum lindemuthianum (Sacc. et Magn.) Scrib. races 69 (epsilon) and 453 (zeta)
(Herança da resistência do feijoeiro (Phaseolus vulgaris L.) às raças 69 (epsílon) e 453 (zeta) de Colletotrichum lindemuthianum (Sacc. et Magn.) Scrib.)
Juliana Parisotto Poletine*
* 1997. Pós-Graduação em Agronomia, Universidade Estadual de Maringá, Maringá, PR, Brasil. Master's thesis. Orienting Professor: Maria Celeste Gonçalves-Vidigal.
The differential varieties of common bean (Phaseolus vulgaris L.) Michelite, Dark Red Kidney, Perry Marrow, Cornell 49242, AB 136, PI 207262 and G 2333 were crossed in all possible combinations to study resistance inheritance to antracnose. The F1 and F2 generations were obtained under greenhouse conditions. The plants were inoculated using a brush moistened with a 1.2 x 106 spores/ml water spore suspension approximately 18 days after germination. They were kept in an approximately 100% relative humidity chamber at 18oC and with a 12-h photoperiod for five days. After incubation the plants were transferred to suitable environments, where they stayed until assessment. Visual assessment was carried out eight to ten days after inoculation for symptoms of resistance or susceptibility reaction to the 69 (epsilon) and 453 (zeta) Colletotrichum lindemuthianum races. A scoring scale where the plants were considered resistant (scores 1 and 2) or susceptible (scores 3 to 5), depending on the severity of the disease, was used. The action of six independent dominant resistant genes (present in the following varieties, Dark Red Kidney, gene A (Co1); Cornell 49242, gene Are (Co2); PI 207262, gene Mex2 (Co4); AB 136, gene Q (Co6) and G 2333, genes Co7 and one identified in this study (named Co8)) was suggested to explain the results obtained for 69 (epsilon) race; any one of these genes gives resistance. Besides these genes, resistance is also obtained with the interaction among two dominant genes, X and Y, which act as complementary factors. Resistance to 453 race (zeta) is explained by the action of five dominant genes present in the varieties Dark Red Kidney, gene A (Co1); Cornell 49242, gene Are (Co2); AB 136, gene Q (Co6) and G 2333, genes Co7 and Co8, as well as the complementary factors Z and W.
Color inheritance and development of a yellow tomato mutant in the F1 and F2 generations
(Herança de cor e desenvolvimento de um mutante amarelo de tomate nas gerações F1 e F2)
Elizanilda Ramalho do Rêgo*
*1997. Laboratório de Melhoramento de Hortaliças, Departamento de Fitotecnia, Universidade Federal de Viçosa, Viçosa, MG, Brasil. Master's thesis. Orienting professor: Fernando Luiz Finger.
Inheritance of yellow color in a mutant tomato was studied by following changes in the F1, F2 and backcross generations. Growth, nutritional value and carotenoids were estimated throughout fruit development. Isozyme studies were made of leaves, flowers, roots and mature green and ripe tomatoes. Red color was found in all F1 fruits and when backcrossed with the normal red parent. Inheritance of red color was monogenic based on segregating generations with complete dominance for red. Yellow fruits had low b-carotene, lycopene and vitamin C content; however, the hybrid showed intermediate total carotenoid concentration and heterosis for vitamin C quantity in the fruit. Both the yellow mutant and the F1 had a low pH compared with normal red fruits. Chlorophyll A was reduced in mature green fruits of mutant and F1 plants; in yellow ripe tomatoes total chlorophyll, chlorophyll A and B were also reduced, while in the red hybrids only chlorophyll B was at a low level. Total carotenoid and chlorophyll contents of both leaves and flowers were similar in all genotypes. Fresh and dry matter, and diameter of pericarp and fruit increased with fruit development. On the other hand, there was a reduction in soluble solid and dry content. Isozymes showed differences in activity in each tissue, but they were similar across genotypes.
Publication supported by CNPq.
Publication Dates
-
Publication in this collection
23 Feb 1999 -
Date of issue
Sept 1998
