Poliploidização sexual em trevo vermelho

Because sexual polyploidization broadens genetic basis and supply plant breeders with more variability for the selection process, it can be useful in red clover breeding. This paper reports results of three crossing cycles, starting from a parental generation of tetraploid red clover plants (female parent), and diploids from the Quiñiqueli cultivar, selected for production of more than 1% of giant pollen grains (male parent) aiming to obtain tetraploid plants to be used in red clover breeding programs. Crosses in the next generations were performed by mutual cross-pollinations. Chromosome number chimerism and high pollen sterility were detected in F1, F2 and F3, but there was a trend towards increasing seed production and seed viability along the generations, probably due to successful competition between fertile and sterile gametes. The identification of fertile triploids, as well as their recurrent formation along the generations, indicates that triploid block is not complete in red clover, and that triploids may be successfully used as a bridge for the production of sexual polyploids.Porque a poliploidização sexual amplia a base genética e proporciona aos melhoristas maior variabilidade para o processo de seleção, ela pode ser uma ferramenta útil ao melhoramento de trevo vermelho. Com o objetivo de obter plantas tetraplóides que possam ser utilizadas em programas de melhoramento de trevo vermelho, este trabalho relata resultados de três ciclos de cruzamentos, partindo de uma população parental de plantas tetraplóides de trevo vermelho, como genitores femininos, e de diplóides da cultivar Quiñiqueli, selecionados para produção de mais de 1% de grãos de pólen gigantes, como genitores masculinos. Nas outras gerações, os cruzamentos foram realizados por polinizações cruzadas mútuas. Quimerismo para número cromossômico e alta esterilidade de pólen foram detectados em F1 , F2 e F3, mas houve uma tendência para aumento da produção e viabilidade das sementes ao longo das gerações, provavelmente devido à competição bem sucedida entre gametas férteis e estéreis. A identificação de triplóides férteis, assim como sua formação recorrente ao longo das gerações, indica que o bloco triplóide não é completo em trevo vermelho e que triplóides podem ser utilizados com sucesso para a produção de poliplóides sexuais

In vitro germination of pollen grains of three native species from Pampa biome with ornamental potential

The aim of this work was to verify the in vitro germination of pollen grains of Angelonia integerrima L., Campomanesia aurea O. Berg and Sesbania punicea (Cav.) Benth in different culture medium and temperatures. For this purpose, flower buds from which pollen was collected and sprayed on plates containing the three evaluated culture medium: M1 - agar and sucrose; M2 - agar, sucrose and H3BO3; M3 - agar, sucrose, H3BO3, Ca(NO3), MgSO4 and KNO3; and two incubation temperatures (20 °C and 30 °C). Data was subjected to analysis of variance after its transformation to square root and means were compared by Fisher’s test (LSD). For the three species, the temperature of 30 ºC provided the highest percentage of pollen grain germination. For A. integerrima, M1 and M3 promoted the highest germination percentages (40.7 % and 56.5 %, respectively). On the other hand, for C. aurea, M2 provided the highest germination average (43.7 %). At last for S. punicea, M3 was the one that provided the highest average (31.62 %). It was concluded that the evaluated species differ in micronutrient requirements for in vitro germination of pollen grains. The temperature of 30 °C was suitable for all three species.The aim of this work was to verify the in vitro germination of pollen grains of Angelonia integerrima L., Campomanesia aurea O. Berg and Sesbania punicea (Cav.) Benth in different culture medium and temperatures. For this purpose, flower buds from which pollen was collected and sprayed on plates containing the three evaluated culture medium: M1 - agar and sucrose; M2 - agar, sucrose and H3BO3; M3 - agar, sucrose, H3BO3, Ca(NO3), MgSO4 and KNO3; and two incubation temperatures (20 °C and 30 °C). Data was subjected to analysis of variance after its transformation to square root and means were compared by Fisher’s test (LSD). For the three species, the temperature of 30 ºC provided the highest percentage of pollen grain germination. For A. integerrima, M1 and M3 promoted the highest germination percentages (40.7 % and 56.5 %, respectively). On the other hand, for C. aurea, M2 provided the highest germination average (43.7 %). At last for S. punicea, M3 was the one that provided the highest average (31.62 %). It was concluded that the evaluated species differ in micronutrient requirements for in vitro germination of pollen grains. The temperature of 30 °C was suitable for all three species

Reproduction mode and apospory expressivity of selected hybrids of Paspalum notatum Flügge

Paspalum notatum Flüggé (bahiagrass) is the most important forage grass in the native grasslands of southern Brazil; the native germplasm is tetraploid and apomictic. Breeding to produce cultivars has been possible due to chromosome doubling of sexual diploid accessions, allowing hybridizations with apomictic genotypes, generating progenies with variability for agronomic traits and segregating for reproduction mode. The aim of this study was to determine the reproduction mode of selected hybrids derived from intraspecific crosses through cytoembryological analysis and to evaluate the level of apospory expres¬sivity. Eighty one tetraploid hybrids corresponding to 21 families of sexual and apomictic parents were generated and 28 most productive plants based on their superior agronomic performance in the field were evaluated. Sixteen hybrids were reproduced sexually and 12 of them were highly apomictic or facultative apomictic. Sexual hybrids may be used for further crosses in the breeding program while highly apomictic plants produce uniform progeny and become candidates of new cultivars to promote pasture diversification

Determination of the mode of reproduction of bahiagrass hybrids using cytoembryological analysis and molecular markers

The aim of this study was to determine the mode of reproduction of a hybrid progeny derived from intraspecific crosses of Paspalum notatum through cytoembryological analysis and use of RAPD (random amplification of polymorphic DNA) molecular markers. Cytoembryological analysis allowed identification of the mode of reproduction of 28 plants that were selected after agronomic productivity evaluations. Of these, 19 had embryo sac morphology compatible with an apomictic mode of reproduction and nine had embryo sac morphology compatible with a sexual mode of reproduction. Meanwhile, molecular marker analysis for 194 individuals showed 54 sexual and 140 apomictic plants; of the 28 plants analyzed by the two methods, ten results (35.7%) were in disagreement. In this paper, through cytoembryological analyses, a ratio of 1:2.1 of sexual to apomictic plants was found. The BCU 243 marker showed a stable pattern of amplification, but some results differed with cytoembryological analyses, demonstrating that these analyses are more reliable when determining the mode of sexual reproduction for the plants of P. notatum. Apomictic plants characterized in this work can be tested in the field to check their agronomic value and registration as plant varieties, while the sexual plants can be used as potential parents in future crosses

Reproductive analyses of intraspecific Paspalum notatum Flügge hybrids

Paspalum notatum is an important forage native to Southern Brazil and one of the most promising fodder species in terms of productivity, quality, resistance and growth speed. The objective of this study was to evaluate the reproductive mode and fertility of hybrid progenies resulting from artificial crosses among artificially duplicated sexual plants, selected intraspecific hybrids of the UFRGS breeding program and apomictic ecotypes of the species. The resulting F1 progenies were represented by 24 plants with high pollen viability (varying from 82.15 to 99.67%) and 1.2:1 segregation for the sexual: apomictic reproduction mode, indicating predominantly sexual hybrids, due to distorted segregation. In the apomictic plants, most chromosomes paired as bivalents in diakinesis. Since the low presence of abnormalities observed in the meiotic chromosome pairing and the high pollen viability of the hybrids, all plants were confirmed as promising parents for future crosses

Progênies híbridas de grama forquilha : avaliações agronômicas

Paspalum notatum Flüggeis one native forage grasses of southern Brazil. Through intraspecific hybridization, is possible generating progenies with variability for agronomic traits.The objective of this work was to evaluate 24 hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes.The hybrids were obtained from crosses among sexual and apomictic clones, and were vegetative propagated in a greenhouse until the transplant to the field. The agronomic traits evaluated were: total green mass (TGM), leaf dry mass (LDM), stem dry mass (SDM), inflorescence dry mass (IDM), dead mass (DeM), total dry mass (TDM),growth habit (GH). Correlations between plant diameter (PD), number of tillers (NT), total dry matter (TDM), plant height (PH), total green matter (TGM), leaf dry matter (LDM), stem dry mass (SDM), number of inflorescences (NINF) and inflorescence dry matter (IDM) were performed using the Pearson correlation coefficient. The hybrids had great variability in all agronomic characteristics measured. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than othergenotypes. The hybrid KF4 too had greater LDM; KF1 and KF4 were the colder tolerant. These genotypes were selected for evaluations, such as seed production, fertilizer use efficiency, animal performance, and for new crosses. The high correlation of the total dry mass with the other forage components will be useful for indirect select criteria in bahiagrass improving strategies.Paspalum notatumFlügge é uma gramínea forrageira nativa do sul do Brasil. Hibridizações intraespecíficas geram progênies com variabilidade para características agronômicas. O objetivo deste trabalho foi avaliar 24 híbridos e selecioná-los pelas características agronômicas superiores, bem como analisar correlações entre características forrageiras que possam auxiliar na seleção de genótipos. Os híbridos foram obtidos através dos cruzamentos entre clones sexuais e apomíticos, e foram propagados vegetativamente em casa de vegetação até o transplante para o campo. As características agronômicas avaliadas foram: massa verde total (MVT), massa seca das folhas (MSF), massa seca do caule (MSC), massa seca da inflorescência (MSI), material morta (MM), massa seca total (MST), hábito de crescimento (HC). As correlações entre diâmetro da planta (DP), número de perfilhos (NP), massa seca total (MST), altura da planta (Alt), massa verde total (MVT), massa seca das folhas (MSF), massa seca do caule (MSC), número de inflorescências (NINFL) e massa seca das inflorescências (MSINFL) foram realizados utilizando o coeficiente de correlação de Pearson. Os híbridos tiveram grande variabilidade em todas as características medidas. Em três anos de avaliações, os híbridos KD9, KF1, KF4 e KD5 produziram maior MST; KF4 apresentou maior MSF; KF1 e KF4 foram os mais tolerantes ao frio. Esses genótipos foram selecionados para avaliações de produção de sementes, eficiência no uso de fertilizantes, desempenho animal e para novos ciclos de cruzamentos. A alta correlação da massa seca total com outros componentes da forragem será útil para critérios de seleção indireta em estratégias de melhoramento da grama forquilha

Cytogenetic characterization of Angelonia integerrima Sprengel, a native species with ornamental potential

Angelonia integerrima Sprengel is a native species of the state of Mato Grosso do Sul and the Southern region (Paraná, Santa Catarina and Rio Grande do Sul) of Brazil, with features such as an unusual appearance and color of the flowers, indicating an ornamental use. To optimize the use of this species and to fill in gaps regarding its cytogenetic characterization, this study determined the chromosome number, meiotic index and pollen viability of plant individuals of four A. integerrima populations. All plant individuals of the four populations had 2n = 20 chromosomes. Still, the meiotic index of most analyzed plant individuals exceeded 90%, while pollen viability of all plant individuals was higher than 80%. These data suggest considerable cytological stability of the analyzed A. integerrima plant individuals, which may favor the selection of future genotypes for commercial purposes or their use in conservation and breeding programs of the species

Hybrid progenies of Bahiagrass: agronomic evaluation

Paspalum notatum Flügge (bahiagrass) is one of the most common native grasses found in southern Brazil and have become one of the most promising forage species considering their value for beef cattle production in the tropics and subtropics. The breeding program has been possible through intraspecific hybridization among sexual and apomictic clones, generating progenies with variability for agronomic traits. Hybrid materials with superior agronomic performance can be selected, registered and protected to be made available as a commercial cultivar. The objective of this work was to evaluate 24 intraspecific hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than other genotypes. The hybrid KF4 too had greater leaf dry matter; KF1 and KF4 were the more cold tolerant. These genotypes were selected for new cycles of hybridization and field evaluations, such as seed production, fertilizer use efficiency and animal performance. The high correlation of the total dry mass with the other forage components might be useful for indirect select criteria in bahiagrass improving strategies.Paspalum notatum Flügge is one native forage grasses of southern Brazil. Through intraspecific hybridization, is possible generating progenies with variability for agronomic traits. The objective of this work was to evaluate 24 hybrids and select them for the superior agronomic traits, as well analyze correlations between forage traits that can assist in the selection of genotypes.The hybrids were obtained from crosses among sexual and apomictic clones, and were vegetative propagated in a greenhouse until the transplant to the field. The agronomic traits evaluated were: total green mass (TGM), leaf dry mass (LDM), stem dry mass (SDM), inflorescence dry mass (IDM), dead mass (DeM), total dry mass (TDM), growth habit (GH). Correlations between plant diameter (PD), number of tillers (NT), total dry matter (TDM), plant height (PH), total green matter (TGM), leaf dry matter (LDM), stem dry mass (SDM), number of inflorescences (NINF) and inflorescence dry matter (IDM) were performed using the Pearson correlation coefficient. The hybrids had great variability in all agronomic characteristics measured. Based on the three years of evaluation, hybrids KD9, KF1, KF4, and KD5 produced higher total dry mass than other genotypes. The hybrid KF4 too had greater LDM; KF1 and KF4 were the colder tolerant. These genotypes were selected for evaluations, such as seed production, fertilizer use efficiency, animal performance, and for new crosses. The high correlation of the total dry mass with the other forage components will be useful for indirect select criteria in bahiagrass improving strategies

Dissimilaridade entre ecótipos de Andropogon lateralis submetidos a diferentes frequências de desfolha e alturas de corte

Andropogon lateralis Nees is a native grass of southern Brazil and is one of the most frequent specie found in native grasslands. The species is widely distributed and has a high degree of phenotypic plasticity, which makes it highly adaptable to different edaphoclimatic conditions and management. This study aimed to evaluate the behavior of twelve ecotypes of A. lateralis, collected in different regions of the state of Rio Grande do Sul and cut to three different heights and subjected to two different defoliation frequencies. From September to February, the ecotypes were evaluated for total dry matter, leaf and stem yields. In addition, total, vegetative and reproductive tillers and plant height were measured. These characteristics are important for the selection of superior genotypes in terms of genetic variability and forage production. Total dry matter and leaf dry matter are characteristics with agronomic importance and they showed the highest correlation (r = 0.77), enabling an indirect selection for one of these characteristics. The natural selection of plants resulted in distinct structural, morphological and productive characteristics with heterogeneity that allows the selection and grouping according to the characteristics, ecotypes with superior agronomic characteristics can be included in breeding programs.Andropogon lateralis Nees é uma gramínea nativa do sul do Brasil e uma das espécies mais frequentes na flora dos campos nativos da região. Possui ampla distribuição e alto grau de plasticidade fenotípica, tornando-o adaptável as condições edafoclimáticas e a práticas de desfolha. Este estudo teve como objetivo avaliar a dissimilaridade entre doze ecótipos de A. lateralis N., coletados em diferentes regiões do Rio Grande do Sul, submetidos a duas frequências de desfolha e três alturas de corte. No período de setembro a fevereiro, os ecótipos foram avaliados quanto à produção de matéria seca total, de lâminas foliares e de colmo. Além disso, foram medidos o número de perfilhos totais, vegetativos e reprodutivos e a altura das plantas. Essas características são importantes para a seleção de genótipos superiores em termos de variabilidade genética e produção de forragem. A matéria seca total e a matéria seca foliar são características com importância agronômica e apresentaram a maior correlação (r = 0,77), possibilitando uma seleção indireta para uma dessas características. A seleção natural das plantas resultou em características estruturais, morfológicas e produtivas distintas com uma heterogeneidade que permite a seleção e agrupamento de acordo com as características, ecótipos com características agronômicas superiores podem ser incluídos em programas de melhoramento

Caracteristicas fisicoquimicas de frutos de Myrcianthes pungens (O.Berg) D. Legrand

O guabijuzeiro produz frutos com potencial para exploração comercial, porém poucos estudos foram conduzidos. O objetivo deste trabalho foi caracterizar frutos de guabijuzeiros coletados em diferentes locais do Rio Grande do Sul. Os frutos de 13 acessos foram avaliados, em duas safras, quanto à massa fresca (MF), diâmetro longitudinal (DL) e equatorial (DE), cor, rendimento de polpa (RP), sólidos solúveis totais (SS), acidez total (AT) e Vitamina C. Na primeira safra o acesso G1 destacou-se em MF (6,89 g), DL (19,4 mm) e DE (22,3 mm); já na segunda safra os melhores resultados para MF foram obtidos com os acessos P1 (4,93 g) e BG2 (4,80 g), para DL com os acessos P1 (17,86 mm) e BG2 (17,40 mm) e DE com os acessos BG2 (20,25 mm) e P1 (20,17 mm), enquanto para o RP, as médias foram de 53,18 e 53,0%, na primeira e segunda safras, respectivamente. A cor predominante da casca foi a cinza. O teor de SS apresentou média de 15,8 e 15,1 °Brix na primeira e segunda safras, respectivamente. Para AT, as médias foram de 0,15% e 0,18%, na primeira e segunda safras, respectivamente. Para as relações SS/AT as médias foram de 108 e 91, na primeira e segunda safras, respectivamente. Para os teores de Vitamina C o acesso G1 se destacou na primeira (42,3 mg/100 g de polpa) e segunda safras (41,9 mg/100 g de polpa). Portanto, alguns acessos apresentam potencial para serem propagados visando à utilização em coleções e programas de melhoramento genético.The guabijuzeiro produces fruits that have potential for commercial exploitation, but few studies have been conducted. The objective of this work was to characterize fruits of guabiju trees collected in different places in Rio Grande do Sul. The fruits of 13 accessions were evaluated, in two harvests, for fresh mass (MF), longitudinal (DL) and equatorial diameter (DE), color, pulp yield (RP), total soluble solids (SS), total acidity (TA) and vitamin C. In the first harvest, G1 accession stood out in MF (6.89 g), DL (19.4 mm) and DE (22.3 mm); in the second harvest, the best results for MF were obtained with accessions P1 (4.93 g) and BG2 (4.80 g), for DL with accessions P1 (17.86 mm) and BG2 (17.40 mm) and DE with accessions BG2 (20.25 mm) and P1 (20.17 mm), while for the RP, the averages were 53.18 and 53.0%, in the first and second harvests, respectively. The predominant color of the bark was gray. The SS content averaged 15.8 and 15.1 °Brix in the first and second harvests, respectively. For AT, the averages were 0.15% and 0.18%, in the first and second harvests, respectively. For the SS/AT ratios, the averages were 108 and 91, in the first and second harvests, respectively. For the levels of Vitamin C, accession G1 stood out in both evaluations, the first harvest (42.3 mg/100 g of pulp) and the second harvest (41.9 mg/100 g of pulp). Therefore, some accessions have the potential to be propagated for use in collections and genetic improvement programs.El guabijuzeiro produce frutos que tienen potencial de explotación comercial, pero se han realizado pocos estudios. El objetivo de este trabajo fue caracterizar frutos de guabiju recolectados en distintas localidades de Rio Grande do Sul. Los frutos de 13 accesos fueron evaluados, en dos cosechas, para masa fresca (MF), diámetro longitudinal (DL) y ecuatorial (DE), color, rendimiento de pulpa (RP), sólidos solubles totales (SS), acidez total (TA) y Vitamina C. En la primera cosecha, el acceso G1 se destacó en MF (6,89 g), DL (19,4 mm) y DE (22,3 mm); en la segunda cosecha, los mejores resultados para MF se obtuvieron con los accesos P1 (4.93 g) y BG2 (4.80 g); para DL con los accesos P1 (17.86 mm) y BG2 (17.40 mm) y DE con los accesos BG2 (20,25 mm) y P1 (20,17 mm), mientras que para la RP los promedios fueron 53,18 y 53,0%, en la primera y segunda cosecha, respectivamente. El color predominante de la corteza fue el gris. El contenido de SS promedió 15,8 y 15,1 ° Brix en la primera y segunda cosecha, respectivamente. Para AT, los promedios fueron de 0,15% y 0,18%, en la primera y segunda cosecha, respectivamente. Para las relaciones SS/AT, los promedios fueron 108 y 91, en la primera y segunda cosecha, respectivamente. En cuanto al contenido de Vitamina C, el acceso G1 se destacó de los demás en la primera (42,3 mg/100 g de pulpa) y en la segunda cosechas (41,9 mg/100 g de pulpa). Por lo tanto, algunos accesos tienen el potencial para propagarse y para uso en colecciones y programas de mejora genética