Yellow passion fruit seed oil (Passiflora edulis f. flavicarpa): physical and chemical characteristics

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

Yield and nitrogen uptake of peanuts as affected by lime, cobalt, and molybdenum

Peanut response to lime has been associated to calcium (Ca) nutrition, but a higher nitrogen (N) uptake has been observed in limed plots probably due to an increase in molybdenum (Mo) availability. A two-year experiment was conducted to study the effects of Mo, cobalt (Co), and liming on peanut yields and N nutrition. Peanut seeds were treated with Mo and/or Co and grown in soil with base saturation about 13, 41, 57, and 71%. There was no effect of seed treatment with Co on peanut yields or N nutrition. Liming and Mo application increased N contents in the leaves. Nitrogen uptake was increased by Mo and liming in cv. Tatu and only by liming in cv. Tupa. Manganese (Mn) contents in the leaves were decreased by liming. The higher yields were observed when the Ca/Mn ratio in the leaves was above 25. In acid soils, low availability of Mo and Mn toxicity can impair N acquisition by peanut plants and decrease grain yields.

Yield and quality of carrot seeds, cv. Brasilia, as a result of plant population, gibberellic acid and stage of maturity

'Brasilia' is a cultivar of carrot with characteristics suiting cultivation under hot conditions but with problems in seed production, arising from the conflicting requirements of root and seed production. One solution is to select cultivars requiring vernalisation and then to use GA(3) to induce flowering where the climate prevents this. There is, however, little information on plant population, seed maturity and harvesting time on which to base such a procedure. Accordingly this research was carried out to study the physiological quality and production of the seeds in plant populations from 25,000 to 800,000 plants/ha, in the seed-to-seed method of cv. Brasilia in Anapolis, GO, Brazil. In each population, two harvest methods (from first and second orders of umbels, or selected harvest, and remaining orders, or total harvest) and two stages of maturity (brownish, or mature seeds, and yellowish, or immature ones) were also evaluated. Two trials were carried out, with and without gibberellic acid. Seed was evaluated for physical characters, germination, vigour, 1000-seed weight, water content, dry matter and productivity. Seed was produced in both experiments (with or without GA3 spraying). Mature seed showed germination at least 30% greater than immature, and seed from the selected harvest showed germination 16% greater than from the total harvest. In increasing plant population to 200,000 plants/ha, seed quality was not affected, but productivity increased.

EFFECT OF DROUGHT AND DEFOLIATION STRESS IN THE FIELD ON SOYBEAN SEED-GERMINATION AND VIGOR

Although drought and defoliation stress have been shown to reduce soybean [Glycine max (L.). Merr.] yield, little information has been published regarding their effects on soybean seed quality. Field experiments were conducted in 1986, 1987, and 1989 to evaluate the effect of drought and defoliation (1989 only) stress during soybean seed development on seed germination and vigor. Essex (MG [maturity group] V) and Union (MG III) were grown in 1986 and 1987, and Harper (MG III) and McCall (MG 00) in 1989. Moisture treatments were either well watered or drought stressed during seed development (R5 to R7). In 1989, a total defoliation treatment was also imposed at R6 as an additional stress factor. There were significant reductions in yield and yield components following drought stress in all 3 yr and following defoliation in 1989. Leaf conductance and transpiration also decreased in the drought stress treatments. There was no effect of drought stress on seed germination or seed vigor as measured by accelerated aging germination and the cold test across the four cultivars (determinate and indeterminate) and 3 yr. In 1989 slight changes in 3-d germination and conductivity occurred for some drought stress treatments. Most of this response, however, was related to increased occurrence of hard seed, which does not represent an indication of a change in vigor. Seed germination and vigor were significantly reduced for small, flat, shriveled, and underdeveloped seeds that only occurred following defoliation. These seeds represented a small portion of the seed lot that would normally be removed during conditioning. The data suggest that drought stress would have no effect on seed germination or vigor, unless the stress was severe enough to produce shriveled, flat, underdeveloped seeds.

Potential hydroponics systems for seed potato production in tropical conditions

In tropical conditions such as Brazil, depending on the local altitude, potatoes can be planted and harvested in every month of the year successively, which favors pest and disease incidence, especially aphids transmission viruses. Therefore, obtaining good yield depends on constant pest and disease control and quality potato seed acquisition. One of the main strategies to increase a healthier seed potato multiplication rate and production is the use of hydroponic systems, with or without substrates, in channels, pots or boxes. In 2005 and 2008, researches investigated several hydroponic systems with and without the use of substrates. In the hydroponic systems without substrate, the aeroponic system resulted in the highest multiplication rate, with 47 tubers plant-1 compared to NFT and DFT, 35 and 37 tubers plant-1, respectively. With the use of substrates, the pot system obtained better results, reaching 12 tubers plant-1, followed by the capillary system and boxes, with 8 and 7 tubers plant-1, respectively. Potato seed production was influenced by hydroponics systems. Among hydroponic systems with substrate, the pots were shown as the best option. However, higher yields were obtained in the hydroponics systems without substrate, with the aeroponic system that provided the best results.

Fatty acids and some antioxidant compounds of Psidium guajava seed oil

Physico-chemical characteristics, fatty acid and tocopherol compositions, total phenolic content and antioxidant activity of crude oil extracted from guava (Psidium guajava var. pomifera) seeds were investigated. Oil yield from the seeds was 14.0%. Data obtained for the analytical indexes compared well with those of others edible oils. The oil showed high levels of unsaturated fatty acids (88.1%), mainly linoleic acid (78.4%). The tocopherol and total phenolic contents in the oil amounted to 29.2 and 92.3 mg/100 g, respectively. The guava seed oil exhibited a great DPPH · scavenging activity showing EC₅₀ of 12.9 g oil/g [DPPH · ] -1 and antiradical efficiency of 7.9×10 -2 . Therefore, the potential utilization of the guava seed oil as a raw material of food, chemical and pharmaceutical industries appears to be favourable and provides the use of a renewable resource, adding value to agricultural products.

Dry matter yield and tillering of brachiarias sown at depths intercropped with corn

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

Effects on soil chemical attributes and cotton yield from ammonium sulfate and cover crops

Fertilizer use in no-till systems must be aligned with a correct interpretation of soil chemical attributes and crop demands. The objectives of this work were evaluate the effects of pre-sowing application of ammonium sulfate (AS) and of cover crops on the yields and soil chemical attributes of no-till cotton (Gossypium hirsutum L. r. latifolium Hutch) over two harvesting years. The experiment was arranged in randomized complete block design, with the plots in strips, and the variables were three cover crops (Raphanus sativus L., Avena strigosa L. and Avena sativa L.) and four AS doses (0, 150, 300, and 450 kg ha-1) applied over millet dry biomass. The cotton in the experimental plots was manually harvested on April 25, 2007 and April 24, 2008. The soil samples were collected between cotton rows in all plots on May 5, 2007 and May 12, 2008, at depths of 0.0-0.05, 0.05-0.10, and 0.10-0.20 m for soil fertility analyses. The increasing doses of AS induced lower soil pH, and calcium (Ca) and magnesium (Mg) levels in the superficial soil layer, as well as higher exchangeable aluminum (Al) and sulfur (S) levels until a depth of 0.20 m. Seed cotton yields increased with increasing AS doses.