Arbuscular mycorrhizal fungi as mitigating agents of salt stress in Formosa papaya seedlings

The objective of the present study was to evaluate the effect of mycorrhization on the nutritional, hydric and biochemical components of papaya seedlings, Carica papaia L., from the Formosa Group, Hybrid Tainung Nº 1, submitted to irrigation with saline water. The research was conducted at the Federal Institute of Paraíba, Sousa Campus, from March to December 2018. The experimental design used completely randomized blocks, with treatments arranged in a 4 x 5 factorial scheme, referring to the fungi species: Gigaspora candida, Acaulospora scrobiculata, Dentiscutata heterogama and without mycorrhizae, and the five salt concentrations in irrigation water: 0.0; 10.0; 20.0; 30.0 and 40.0 mmolc L-1 in four repetitions. The characteristics evaluated were: relative water content, water saturation deficit, membrane damage, photosynthetic pigments, concentration and accumulation of nitrogen, phosphorus, potassium, sodium and the relationship between potassium and sodium concentrations in leaf tissue. The species D. heterogama and G. candida presented the highest rates of leaf hydration and the lowest damage to biomembranes at all saline levels. Mycorrhizae increased the absorption of N and P, especially from 30 mmolc L-1 of salt. A greater relationship between potassium and sodium concentrations was evidenced in seedlings mycorrhized with D. heterogama.The objective of the present study was to evaluate the effect of mycorrhization on the nutritional, hydric and biochemical components of papaya seedlings, Carica papaia L., from the Formosa Group, Hybrid Tainung Nº 1, submitted to irrigation with saline water. The research was conducted at the Federal Institute of Paraíba, Sousa Campus, from March to December 2018. The experimental design used completely randomized blocks, with treatments arranged in a 4 x 5 factorial scheme, referring to the fungi species: Gigaspora candida, Acaulospora scrobiculata, Dentiscutata heterogama and without mycorrhizae, and the five salt concentrations in irrigation water: 0.0; 10.0; 20.0; 30.0 and 40.0 mmolc L-1 in four repetitions. The characteristics evaluated were: relative water content, water saturation deficit, membrane damage, photosynthetic pigments, concentration and accumulation of nitrogen, phosphorus, potassium, sodium and the relationship between potassium and sodium concentrations in leaf tissue. The species D. heterogama and G. candida presented the highest rates of leaf hydration and the lowest damage to biomembranes at all saline levels. Mycorrhizae increased the absorption of N and P, especially from 30 mmolc L-1 of salt. A greater relationship between potassium and sodium concentrations was evidenced in seedlings mycorrhized with D. heterogama

Biometrics, physiology, production, and quality of Cantaloupe melons grown with saline waters under semi-arid conditions

Brazilian Northeast region emerges as both producer and exporter relevant of cantaloupe melon to several countries; however, this region is vulnerable to salinization problems due to it is inserted in a semi-arid area. This study aimed to evaluate the biometrics, physiological, production and quality of new cantaloupe melon hybrids cultivated with different saline waters under semi-arid conditions. The experiment was conducted using a drip irrigation system in a split-plot randomized design. The plot was different irrigation water electrical conductivity (ECw) levels: 0.5, 2.0, 3.5, and 5.0 dS m-1, while the subplot was two new cantaloupe melon hybrids: Zielo and SV1044. Plant biometrics (stems and leaves analysis), plant physiology (solutes accumulation and gas exchange in leaves), fruit production (number, weight, and yield), and fruit quality (physical and chemical analysis) were investigated. Stem length, leaf numbers, leaf area, and shoot dry mass decreased when ECw increased from 0.5 to 5.0 dS m-1. Also, there was an increase of Na and Cl concentration and reduction of K concentration in leaves due to ECw increase. Gas exchange reduction, losses in fruit numbers, weight, yield, and in quality were observed with the ECw increase. It is possible to conclude that the ECw increase salinizes the soil and increases Na and Cl concentration in plants causing reduction in gas exchange, in growth, and in fruit production and quality. However, the response of cultivated hybrids regarding salinity may be different, as in our study that the Zielo hybrid was less affected by the increase in ECw.Brazilian Northeast region emerges as both producer and exporter relevant of cantaloupe melon to several countries; however, this region is vulnerable to salinization problems due to it is inserted in a semi-arid area. This study aimed to evaluate the biometrics, physiological, production and quality of new cantaloupe melon hybrids cultivated with different saline waters under semi-arid conditions. The experiment was conducted using a drip irrigation system in a split-plot randomized design. The plot was different irrigation water electrical conductivity (ECw) levels: 0.5, 2.0, 3.5, and 5.0 dS m-1, while the subplot was two new cantaloupe melon hybrids: Zielo and SV1044. Plant biometrics (stems and leaves analysis), plant physiology (solutes accumulation and gas exchange in leaves), fruit production (number, weight, and yield), and fruit quality (physical and chemical analysis) were investigated. Stem length, leaf numbers, leaf area, and shoot dry mass decreased when ECw increased from 0.5 to 5.0 dS m-1. Also, there was an increase of Na and Cl concentration and reduction of K concentration in leaves due to ECw increase. Gas exchange reduction, losses in fruit numbers, weight, yield, and in quality were observed with the ECw increase. It is possible to conclude that the ECw increase salinizes the soil and increases Na and Cl concentration in plants causing reduction in gas exchange, in growth, and in fruit production and quality. However, the response of cultivated hybrids regarding salinity may be different, as in our study that the Zielo hybrid was less affected by the increase in ECw

Macro and micronutrient accumulation in watermelon

The expansion of crop productivity such as watermelon can be reached by providing adequate nutrition in quantity and when plants need it most. It is known that well-nourished plants better resist biotic and abiotic stresses, being determinants for more sustainable management. In this sense, the objective of the present study was to evaluate the plant growth, the rate of nutrient absorption, the proportion of absorption, and estimate the quantity of exported nutrients by watermelon fruits. The experiment was implemented in randomized block design with eight treatments (phenological phases) - 33 and 40 (growth), 47 and 54 (flowering), 61 and 68 (filling), 75 and 82 (maturation) days after planting (DAP). Each evaluation consisted of plant collection for dry mass, macro, and micronutrient analysis in the shoot (leaves and stems), fruits, and the entire plant. The period between 61 and 68 DAP was the one with the highest plant dry matter increment. The accumulation of macronutrients in the plant shoot showed the following decreasing order: Ca>N>K>Mg>P>S, in the fruits: K>N>P>Ca>Mg>S and in the whole plant: K>N>Ca>P>Mg>S. For micronutrients, the decreasing order of accumulation for the shoot and the entire plant were Fe>Mn>Zn>B>Cu, and for fruits were Fe>B>Zn>Mn>Cu.The expansion of crop productivity such as watermelon can be reached by providing adequate nutrition in quantity and when plants need it most. It is known that well-nourished plants better resist biotic and abiotic stresses, being determinants for more sustainable management. In this sense, the objective of the present study was to evaluate the plant growth, the rate of nutrient absorption, the proportion of absorption, and estimate the quantity of exported nutrients by watermelon fruits. The experiment was implemented in randomized block design with eight treatments (phenological phases) - 33 and 40 (growth), 47 and 54 (flowering), 61 and 68 (filling), 75 and 82 (maturation) days after planting (DAP). Each evaluation consisted of plant collection for dry mass, macro, and micronutrient analysis in the shoot (leaves and stems), fruits, and the entire plant. The period between 61 and 68 DAP was the one with the highest plant dry matter increment. The accumulation of macronutrients in the plant shoot showed the following decreasing order: Ca>N>K>Mg>P>S, in the fruits: K>N>P>Ca>Mg>S and in the whole plant: K>N>Ca>P>Mg>S. For micronutrients, the decreasing order of accumulation for the shoot and the entire plant were Fe>Mn>Zn>B>Cu, and for fruits were Fe>B>Zn>Mn>Cu.The expansion of crop productivity such as watermelon can be reached by providing adequate nutrition in quantity and when plants need it most. It is known that well-nourished plants better resist biotic and abiotic stresses, being determinants for more sustainable management. In this sense, the objective of the present study was to evaluate the plant growth, the rate of nutrient absorption, the proportion of absorption, and estimate the quantity of exported nutrients by watermelon fruits. The experiment was implemented in randomized block design with eight treatments (phenological phases) - 33 and 40 (growth), 47 and 54 (flowering), 61 and 68 (filling), 75 and 82 (maturation) days after planting (DAP). Each evaluation consisted of plant collection for dry mass, macro, and micronutrient analysis in the shoot (leaves and stems), fruits, and the entire plant. The period between 61 and 68 DAP was the one with the highest plant dry matter increment. The accumulation of macronutrients in the plant shoot showed the following decreasing order: Ca>N>K>Mg>P>S, in the fruits: K>N>P>Ca>Mg>S and in the whole plant: K>N>Ca>P>Mg>S. For micronutrients, the decreasing order of accumulation for the shoot and the entire plant were Fe>Mn>Zn>B>Cu, and for fruits were Fe>B>Zn>Mn>Cu

Calcium salts as an alternative to preserve minimally processed table grape quality

The effects of calcium lactate, propionate, chloride, ascorbate and propionate (5 g L−1), combined with heat treatment (60 °C, 2 min), on the quality parameter of minimally processed table grapes, stored for 21 days at 5 °C, were investigated. Berries sanitised with NaOCl (100 mg L−1) were used as control. The respiration rate of Ca-treated berries remained below that of the control up to 17 days. No differences were found on the atmosphere composition. Firmness was maintained on berries treated with Ca until 14 days of storage, especially on the propionate and ascorbate treatments. The bound, free and total Ca measured values, were higher on Ca-treated berries. The functional quality did not show differences among the treatments. The Ca treatment combined with heat treatment, especially with the addition of ascorbate and propionate, maintained the firmness of the berries but did not show major effects on the other quality parameters evaluated.&nbsp

Incubation period and fungi identification in seeds of Salvia hispânica L.

Seed sanitary quality is an essential factor in crop success, and through the evaluation of fungi contamination of seeds, measures can be adopted to control and avoid the transferability of this contamination to the plants. Equally important is the method used to verify the occurrence and identify the species, especially when it comes to crops that have not yet been studied, such as chia, which has a mucilaginous layer that may present some interference in the development of fungi. This study's objective was to identify the genera of fungi present in lots of saved chia seeds, define the best period for their evaluation and its transmissibility to the plantlet. Eight lots from saved seeds of chia were analyzed into two evaluations at seven and 14 days of incubation via the Blotter test method, in which fungi were identified by their reproductive structure using a stereomicroscope. Besides, the transmissibility rate from seed to plantlet of the most incident fungus was evaluated, through the direct isolation method. All estimated seed lots of chia showed fungi contamination, with emphasis on Fusarium sp., Phomopsis sp., Penicillium sp., and Aspergillus sp. The best evaluation period to Phomopsis sp. its at 14 days of incubation by the Blotter test method. The genus Fusarium sp. presents a high transmissibility rate from seed to plantlet.  A qualidade sanitária das sementes é fator primordial para o sucesso das lavouras, sendo que através da avaliação da contaminação fúngica das sementes pode-se adotar medidas para controlar e evitar a sua transmissibilidade para as plantas. Igualmente importante é o método utilizado para verificar a ocorrência e identificar as espécies, principalmente quando se trata de culturas ainda pouco estudadas, como o caso da chia que possui uma camada mucilaginosa que pode apresentar alguma interferência no desenvolvimento dos fungos. O presente estudo teve por objetivo identificar os gêneros de fungos presentes em lotes de sementes de chia, definir o melhor período de sua avaliação e a sua transmissibilidade para a plântula. Foram analisados oito lotes de sementes salvas de chia, realizando-se duas avaliações, aos sete e 14 dias de incubação pelo método do Blotter test, sendo os fungos identificados pelas suas estruturas reprodutivas, com o auxílio de microscópio estereoscópico. Também foi avaliada a taxa de transmissibilidade semente/plântula do fungo de maior incidência, através do método de isolamento direto. Todos os lotes de semente de chia avaliados apresentaram contaminação fúngica, sendo detectados dezesseis gêneros, com destaque para Fusarium sp., Phomopsis sp., Penicillium sp. e Aspergillus sp. O melhor período de avaliação para Phomopsis sp. é aos 14 dias de incubação pelo método Blotter test. O gênero Fusarium sp. apresenta alta taxa de transmissibilidade semente/plântula

Gas exchanges and water-use efficiency of Nopalea cochenillifera intercropped under edaphic practices

The Nopalea forage cactus (Nopalea cochenillifera) is the main xerophilic species cultivated in Brazil, highlighted as a compatible biological element with the semiarid environment. However, studies on its physiological aspects are still scarce. In this context, an experiment was performed in the Pendência Experimental Station, belonging to the State Company of Agricultural Research of Paraíba (EMEPA-PB), municipality of Soledade, state of Paraíba, Brazil, aiming to evaluate the gas exchanges and the water-use efficiency of intercropped Nopalea Cochenillifera plants in the soil under different edaphic managements. The treatments were distributed in randomized blocks, with three replications in a 2 × 5 factorial scheme, corresponding to the soil without and with mulch and five types of cultivation of Nopalea forage cactus, in monoculture and intercropped with forage watermelon, millet, sorghum, and buffelgrass. The analyzed variables were: stomatal conductance, transpiration rate, net photosynthesis rate, and internal CO2 concentration, besides the instantaneous water-use efficiency, intrinsic water-use efficiency, and instantaneous carboxylation efficiency. The use of soil mulch satisfactorily increased the photosynthetic rate of the forage cactus; this type of practice can aid in the productive development of the crop in semiarid zones, whereas the intercropping with buffelgrass and forage watermelon stimulated photosynthesis and the water-use efficiency.The Nopalea forage cactus (Nopalea cochenillifera) is the main xerophilic species cultivated in Brazil, highlighted as a compatible biological element with the semiarid environment. However, studies on its physiological aspects are still scarce. In this context, an experiment was performed in the Pendência Experimental Station, belonging to the State Company of Agricultural Research of Paraíba (EMEPA-PB), municipality of Soledade, state of Paraíba, Brazil, aiming to evaluate the gas exchanges and the water-use efficiency of intercropped Nopalea Cochenillifera plants in the soil under different edaphic managements. The treatments were distributed in randomized blocks, with three replications in a 2 × 5 factorial scheme, corresponding to the soil without and with mulch and five types of cultivation of Nopalea forage cactus, in monoculture and intercropped with forage watermelon, millet, sorghum, and buffelgrass. The analyzed variables were: stomatal conductance, transpiration rate, net photosynthesis rate, and internal CO2 concentration, besides the instantaneous water-use efficiency, intrinsic water-use efficiency, and instantaneous carboxylation efficiency. The use of soil mulch satisfactorily increased the photosynthetic rate of the forage cactus; this type of practice can aid in the productive development of the crop in semiarid zones, whereas the intercropping with buffelgrass and forage watermelon stimulated photosynthesis and the water-use efficiency

Production of blueberries in subtropical climate of altitude

Phenology and production potential studies are important to choose the cultivars more adapted to the climatic conditions of a region. The objective of this work was to evaluate the phenology, productivity and fruit quality of blueberry cultivars in subtropical climate of altitude, in three production cycles (2012/2013, 2013/2014 and 2014/2015). Eight cultivars from rabbiteye (Aliceblue, Bluebelle, Bluegem, Briteblue, Climax, Delite, Powderblue and Woodard) and two from highbush (Georgiagem and O'Neal) groups was evaluated. The experimental design was in randomized blocks with four replications and six plants per plot, with four useful plants. The beginning and the end of flowering, beginning and end of harvest, production, berry weight, berry size, pH, soluble solids, titratable acidity, ratio and skin color of blueberries were evaluated. The cultivars had flowering period from July to September, and concentrated harvest in November and December. ‘Bluegem’ presented the highest yields in the three evaluated cycles, reaching the production of 1215 g plant-1 in the third cycle. This cultivar also showed low acidity and high ratio. Berry size, pH and soluble solids contents were very close with some variations among the cultivars, in the three cycles evaluated. Coloring of the fruit presented few variations over the years of assessment. The most productive blueberry cultivar is the Bluegem, followed by cultivars Climax, Delite and Powderblue, of rabbiteye group, demonstrating better fit for cultivation in subtropical climate of altitude