Doses de regulador vegetal em sistema de semeadura convencional e direta sobre a produtividade, teor de nutriente nas folhas e nas sementes e qualidade fisiológica das sementes de três cultivares de feijão

Pós-graduação em Agronomia - FEIS

Épocas de semeadura de cultivares de feijoeiro no período de inverno sob diferentes palhadas no cerrado: produtividade e qualidade fisiológica de sementes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adubação com fósforo e potássio para produção e qualidade de sementes de soja

O objetivo deste trabalho foi avaliar os efeitos da adubação com fósforo e potássio na produção e na qualidade de sementes de soja. Foram realizados experimentos em dois anos agrícolas, em delineamento de blocos ao acaso, em arranjo fatorial 5x3, com cinco doses de fósforo (0, 40, 80, 120 e 160 kg ha‑1 de P2O5 como superfosfato triplo), três de potássio (0, 50 e 100 kg ha‑1 de K2O como cloreto de potássio) e quatro repetições. Foram avaliados: produtividade, número de sementes por planta, número de vagens por planta, peso de mil sementes, germinação, vigor (envelhecimento acelerado, condutividade elétrica e lixiviação de potássio), e teores de P e K na folha e na semente. A produtividade, o peso de mil sementes e a produção de vagens e de grãos por planta aumentaram linearmente com a adubação fosfatada. O aumento na produtividade foi de 17,6%, no primeiro ano, e de 39,7% no segundo. As doses de P, no entanto, não interferiram na germinação e no vigor das sementes. A adubação potássica não altera a produtividade nem a concentração de K nas sementes, mas pode melhorar a germinação, sem interferir no vigor.

Intercropping soybean and palisade grass for enhanced land use efficiency and revenue in a no till system

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito da adubação potássica e da época de colheita na produtividade de canola

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Optimizing row spacing and plant population arrangement for a new short-height castor genotype in fall-winter

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diversidade genética em linhagens avançadas de soja oriundas de cruzamentos biparentais, quádruplos e óctuplos

The aim of this study was to analyse the genetic diversity and agronomic performance of a group of advanced and superior strains of soybean, derived from biparental, four-way and eight-way crosses, in order to identify future promising and superior combinations. The experiment was carried out in the experimental area of the Paulista State University, Julio de Mesquita Filho, Jaboticabal Campus, in the state of Sao Paulo, Brazil. The characteristics under evaluation were: number of days to flowering, plant height at flowering, number of days to maturity, plant height at maturity, height of the first pod, number of branches, number of pods per plant, agronomic value, lodging, one hundred seed weight and seed yield., The Mahalanobis distance and the relative contribution of each characteristic were used to calculate the phenotypic distances. Among the genotypes analysed, 19 strains displayed high productivity, being superior to the controls (V-max, CD 216, CD 219 and Conquista). The greatest distance found was between strains JAB 41 and JAB 17 (279.81), followed by JAB 40 and JAB 17 (261.38) and between JAB 40 and JAB 22 (255.46). There were six groups formed using the Ward method, indicating the presence of genetic variability among the tested strains. Increasing the number of parents had no effect on the increase in genetic diversity between the strains, and was not the factor responsible for the grouping or not of the genotypes under test.

Sistemas de aplicação de subdoses de glifosato e regulador de crescimento em algodoeiro

Pós-graduação em Agronomia - FEIS

Poda apical para produção de frutos e sementes de abóbora

The tip pruning stimulates the emission of lateral shoots, thus can produce higher number of flowers, fruits and seeds. This work aimed to evaluate the effect of apex pruning on fruit and seed production in pumpkin. The treatments consisted of plants without pruning, with pruning in the sixth, eighth and tenth node of main stem. The experimental design was a randomized block, with six replications. It was studied a line of pumpkin of the Germplasm Bank of the Universidade Estadual Paulista/Faculdade de Ciências Agronômicas. The characteristics evaluated were: number of branches per plant and fruit position in branches of the plant production (number and weight) of fruits per plant, fruit yield, fruit average weight, fruit length and diameter, seed weight per fruit, seed yield and quality (germination test, first count, thousand seed weight, emergence, speed of emergence and accelerated aging). There was a significant difference only for number of secondary branches per plant and thousand seed weight, with larger values for plants that have not been pruned. It was obtained high average of germination (94%) and good fruit (16.9 t ha-1) and seed (148 kg ha-1) yield. The apex pruning does not influence the production of fruits and seeds, as well as the physiological seed quality in pumpkin.

Uso de aguas residuales urbanas en el riego de colza (Brassica napus L.) con destino a biocombustible

El aceite de colza es comestible pero también puede utilizarse en la producción de biodiesel. Cuando el destino es el energético, el cultivo puede regarse con aguas residuales urbanas o cloacales. La mayor proporción del uso de éstas en el mundo ocurre en regiones áridas donde otras fuentes de agua son escasas, situación que se plantea en los oasis irrigados de Mendoza. En este trabajo se comparó el rendimiento de un cultivar invernal de colza regado con agua cloacal (AC) y agua subterránea (AS), y su potencial para producir biodiesel. La experiencia se llevó a cabo en una planta de tratamiento de agua cloacal de Obras Sanitarias en el departamento Tunuyán (33° 32’ 89’’ S; 69° 00’ 80’’ O; 859 m snm). El rendimiento de semilla de AC fue significativamente mayor que el de AS (7690 y 3886 kg/ha, respectivamente). La cantidad de biodiesel factible de producir por cada hectárea de cultivo asciende a 2800 kg en el tratamiento AC y a 1400 kg en AS. El uso de aguas residuales urbanas genera un nicho interesante para la producción de biocombustibles, utilizando un recurso hídrico con limitaciones para producir alimentos.

Residual effect of synthetic Zn chelates on the availability of this metal in different soils under waterlogged conditions.

Adding Zn improves crop growth, increases seed yield and also positively affects nutritional quality. After Zn fertilization, there is normally a period of several years in which residual effects provide an adequate supply of Zn to successive crops. Immediately after the application of Zn sources water-soluble Zn slowly but continually decreases. Various factors, including time and moisture conditions, affect the aging process and modify the solubility of the metal in soil and therefore its availability. In previous experiments, we studied the residual effect of synthetic chelates, obtained that the amounts of potentially available Zn decreased in the second cropping year due to aging processes. The present study was undertaken to verify variations in the residual effects of applying four different synthetic Zn sources

Conservation implications of the reproductive biology of the endangered vine Ipomoea microdactyla Griseb. (Convolvulaceae)

A plant's reproductive biology exerts a significant influence on both population persistence within changing environments and successful establishment of new populations. However, the interaction between extrinsic (i.e. ecological) and intrinsic (i.e. genetic) factors also is an important driver of demographic performance for plant populations. It is light of this that I performed a multidisciplinary investigation of the breeding system, seed and seedling establishment dynamics, and population genetic structure of the endangered Caribbean vine Ipomoea microdactyla Griseb. (Convolvulaceae). The results from the breeding system study show individuals from Florida, USA and Andros Island, Bahamas to be self-incompatible. Plants from the two regions are cross-compatible but there is evidence for outbreeding depression in their progeny. Significant regional differences were found in floral traits and progeny traits that suggests incipient speciation for the Florida populations. The results from the seed and seedling establishment dynamics experiment demonstrate that the restoration of small populations in Florida via seed and seedling augmentation is a successful strategy. The demographic performance of the outplanted individuals was driven significantly by ecological factors (e.g. herbivory) rather than by genetic factors which emphasizes that the ecological context is very important for successful restoration attempts. The results from the population genetic study using an analysis of molecular variation (AMOVA) reveal significant differences in genetic variation among individuals from Florida, Andros, and Cuba. A Bayesian analysis of population genetic structuring coincided with the previous AMOVA results among the three regions. The Mantel test indicated significant 'isolation by distance' for these regional populations implying restricted gene flow over relatively short distances. Overall, the Florida populations had the lowest measures of genetic diversity which is most likely due to the effects of both colonization founder events and habitat fragmentation. The results of my study highlight the value of performing multidisciplinary studies in relation to species conservation as knowledge of both extrinsic and intrinsic factors can best guide decisions for species preservation.

Identification of novel drought-tolerant-associated SNPs in common bean (Phaseolus vulgaris)

Common bean (Phaseolus vulgaris L.) is a leguminous in high demand for human nutrition and a very important agricultural product. Production of common bean is constrained by environmental stresses such as drought. Although conventional plant selection has been used to increase production yield and stress tolerance, drought tolerance selection based on phenotype is complicated by associated physiological, anatomical, cellular, biochemical, and molecular changes. These changes are modulated by differential gene expression. A common method to identify genes associated with phenotypes of interest is the characterization of Single Nucleotide Polymorphims (SNPs) to link them to specific functions. In this work, we selected two drought-tolerant parental lines from Mesoamerica, Pinto Villa, and Pinto Saltillo. The parental lines were used to generate a population of 282 families (F3:5) and characterized by 169 SNPs. We associated the segregation of the molecular markers in our population with phenotypes including flowering time, physiological maturity, reproductive period, plant, seed and total biomass, reuse index, seed yield, weight of 100 seeds, and harvest index in three cultivation cycles. We observed 83 SNPs with significant association (p < 0.0003 after Bonferroni correction) with our quantified phenotypes. Phenotypes most associated were days to flowering and seed biomass with 58 and 44 associated SNPs, respectively. Thirty-seven out of the 83 SNPs were annotated to a gene with a potential function related to drought tolerance or relevant molecular/biochemical functions. Some SNPs such as SNP28 and SNP128 are related to starch biosynthesis, a common osmotic protector; and SNP18 is related to proline biosynthesis, another well-known osmotic protector.

Grain yield and seed quality of soybean selected for high protein content

The objective of this work was to evaluate the effects of selection for high protein on seed physiological quality and grain yield of soybean. Four populations of BC1F4 and four of F4, each from a cross between a commercial variety and a line bearing high protein seeds, were used. The high protein content selection has a tendency to affect negatively the seed physiological quality. Estimates of correlation coefficients between protein content and grain yield were mostly negative but varied among populations. It is possible to obtain lines with high protein content, keeping the grain yield and the seed physiological quality of their respective recurrent progenitors.

Mining wheat germplasm collections for yield enhancing traits

The material in genebanks includes valuable traditional varieties and landraces, non-domesticated species, advanced and obsolete cultivars, breeding lines and genetic stock. It is the wide variety of potentially useful genetic diversity that makes collections valuable. While most of the yield increases to date have resulted from manipulation of a few major traits (such as height, photoperiodism, and vernalization), meeting future demand for increased yields will require exploitation of novel genetic resources. Many traits have been reported to have potential to enhance yield, and high expression of these can be found in germplasm collections. To boost yield in irrigated situations, spike fertility must be improved simultaneously with photosynthetic capacity. CIMMYT's Wheat Genetic Resources program has identified a source of multi-ovary florets, with up to 6 kernels per floret. Lines from landrace collections have been identified that have very high chlorophyll concentration, which may increase leaf photosynthetic rate. High chlorophyll concentration and high stomatal conductance are associated with heat tolerance. Recent studies, through augmented use of seed multiplication nurseries, identified high expression of these traits in bank accessions, and both traits were heritable. Searches are underway for drought tolerance traits related to remobilization of stem fructans, awn photosynthesis, osmotic adjustment, and pubescence. Genetic diversity from wild relatives through the production of synthetic wheats has produced novel genetic diversity.