Grapevine is a fruit species of great agronomic interest since both fresh fruit and wine are highly marketable products. Therefore, there is growing interest in this crop among researchers in the pursuit of increased yields and better cultivation conditions. Asexual propagation is the most commonly used method for propagating grapevine seedlings, with cuttings used for rootstock formation and subsequent grafting of materials to form the canopy. The rootstock is responsible for support, water, and nutrient uptake, thus determining the vigor of the plant; therefore, it is essential to understand the suitable conditions in which roots can thrive and thereby enhance plant growth. The type of cutting, type of substrate, and application of exogenous auxins are among the factors that interfere with the rooting of grapevine rootstocks, and determining and implementing the best combination of these factors could provide for more vigorous plants. Reviewing high-quality published scientific research from diverse countries is a method of identifying data, grouping information, and obtaining reliable answers. Furthermore, it can allow for the detection and grouping of the main factors affecting the rooting of grapevine cuttings, thus enabling a clearer recommendation and better understanding of the issue.

Yacon is a perennial herbaceous plant that naturally occurs in South America at altitudes ranging from 2,000 m to 3,100 m above sea level. The yacon culture has recently grown in popularity as it has high productive potential in mild climates and multiple benefits to human health. This study aimed to determine the lower and upper base temperatures, cycle duration, and thermal constant for the yacon culture, based on phenological data from field experiments that were carried out during three growing seasons (fall, winter, and spring) in 2013. The experiments were conducted in the municipality of Ibatiba in the state of Espírito Santo, Brazil, in a randomized block design with four replicates. The lower base temperature was determined using methods of the lowest standard deviation in days and degree-days, relative development, and variation coefficient in degree-days for two subperiods: emergence to maturation, and onset of tuberization to maturation. The upper base temperature was determined by the standard deviation and coefficient of variation methods, both in degrees-days. The relationship between meteorological elements and the onset of tuberization was also investigated. The lower base temperature values determined for yacon were 12.5ºC in the two subperiods studied with a base temperature above 34.0ºC. The productivity of these tuberous roots was higher in the fall because of the longer cycle, lower temperature, and lower photoperiod. In turn, a higher thermal sum was needed to initiate tuberization with the delay of planting.

Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), which is a gram-positive bacterium that causes wilting in several cultivated plants, is one of the main disease-causing bacteria in beans (Phaseolus vulgaris L.). Different techniques are employed to detect pathogens in bean plants; however, only a few slow and inefficient methodologies can be used to detect Cff. Hence, there is a need for rapid and efficient techniques to detect Cff for disease management. The objective of our study was to develop a technique to effectively detect Cff in the leaves of infected bean plants by optimizing a previously developed method. We modified the extraction method by reducing the amount of water used, replacing seeds with leaf tissues (obtained from the veins and petioles) and using CffFOR2 and CffREV4 primers specific for Cff. Our optimized method exploits a concentration gradient generated in the plant tissue through osmosis to disrupt the plant cell wall and efficiently isolate bacterial cells. DNA extracted from the isolated bacterial cells was amplified by polymerase chain reaction. This method allowed efficient detection of Cff in leaf tissues.

. The objective was to study the habitat complexity of mite populations on Caryocar brasiliense trees under natural and cultivated field conditions. The study was performed in the municipality of Montes Claros, in the state of Minas Gerais, Brazil, over 3 years. Three types of areas were studied: 1) Cerrado, 2) pasture, and 3) a university Campus. Several chlorotic spots were detected on leaves with larger populations of Tetranychus sp. and Eutetranychus sp. (Tetranychidae). The greatest numbers of Agistemus sp. (Stigmaeidae) on leaves and Histiostoma sp. (Histiostomidae) and Proctolaelaps sp. (Ascidae) on fruits were observed in the pasture, and that of Histiostoma sp. on leaves in the pasture and on the university Campus. In general, the herbivorous mites (e.g., Tetranychus sp.) found on C. brasiliense plants were correlated with more clayey soils with a higher cationic exchange capacity; larger populations of mites (e.g., Agistemus sp. and Histiostoma sp.) were found on the C. brasiliense trees with the largest crown sizes; and associations between predator mites (e.g., Agistemus sp.) and phytophagous mites (e.g., Tetranychus sp.1) were observed. Greater habitat diversity and more complex plant architectures favored the mite populations. The positive effect of loamier soil on herbivorous mites indicates that these species are adapted to Cerrado conditions. Some recorded species of herbivorous mites can be pests in commercial plantations of C. brasiliense.

In agriculture with 4.0 technologies, developing a decision model with a 0.0 cost is attractive to small farmers. In water management, if this approach could be used to promote sustainability and optimization, it could become a pathway to reach the sustainable development goal in 2030. The core of this work is the development of a 4.0 mathematical model (based on fuzzy concepts) to verify the benefits of the production of lettuce irrigated with magnetically treated water at different replacement rates. This approach is achieved using computational 4.0 software and manual methods. The aim of mathematical modeling is to understand or explain a natural phenomenon associated with a given area of knowledge, and fuzzy-rule-based systems have been widely used in different types of in-depth research.

This work aimed to characterize the biochar produced from residues of coconut fruit and to evaluate how it might beneficially alter the retention capacity of water and nutrients in soils with a sandy texture. The biochar was produced in a retort furnace and later analyzed to determine its chemical and physical characteristics. Experiments to analyze the retention potential of the biochar for water and nutrients were performed in PVC columns filled to a 400 mm depth, with the upper 300 mm receiving treatments that consisted of 0, 1, 2, 3, 4, and 5% (p p-1) biochar mixed with soil. For the nutrient retention experiment, in addition to the biochar concentrations, the treatments received the same NPK fertilization. The experiments were performed in a completely randomized design with four replications. The water retention in the upper 300 mm, as well as the pH, effective cation exchange capacity (ECEC) of the substrate, base saturation, and concentrations of P and K, increased with increasing biochar concentration. Coconut biochar demonstrated potential for increasing water retention and improving nutrient retention in sandy soils.

The objective of this study was to evaluate the the ability of foliar application of potassium nitrate (KNO3) to induce water deficit tolerance in sorghum plants (Sorghum bicolor cv. P898012) subjected to water deficit at pre-flowering. The experiment was conducted under greenhouse conditions with 4 treatments: field capacity (FC), water deficit (WD), field capacity + KNO3 (FC + KNO3), and water deficit + KNO3 (WD + KNO3). Two foliar applications of 3% (m/v) KNO3 were made, the first on day zero of stress and the second on the fifth day. All analyses were performed after 12 days of stress (end of stress). Foliar application of KNO3 to irrigated plants led to increases in relative chlorophyll content, photosynthetic rate, stomatal conductance, transpiration, and carboxylation efficiency. It also induced increases in leaf concentrations of P, Mg, S, Cu, and Fe, in addition to height growth. Under water deficit conditions, plants treated with KNO3 presented higher relative chlorophyll content, leaf area, photosynthetic rate, stomatal conductance, transpiration, carboxylation efficiency, and higher levels of P, K, Mg, S, Cu, and Fe than those not treated with KNO3. The morphometry of the root system was not altered by the treatments. In addition, plants treated with KNO3 under water deficit conditions showed higher growth and a grain yield 32.2% higher than those that did not receive KNO3. These results demonstrated that KNO3 applied to the leaves induced water deficit tolerance in sorghum plants subjected to severe water stress at pre-flowering.

Phytophagous mites can cause economic losses in many crops, including grapevines. The changes in their population levels may be associated with changes in the predator-prey relationship. Knowledge of the distribution of mites in plants is important for planning sampling strategies and facilitating control decisions. The aims of this study were to (i) evaluate the abundances of Tetranychus urticae (Tetranychidae) and Neoseiulus californicus (Phytoseiidae), and the correlations between them and environmental factors; (ii) determine their distribution on the top, middle, or base strata of the evaluated grapevines (Vitis vinifera, Chardonnay cultivar) and, additionally, report the first occurrence of damage caused by T. urticae in grapevine leaves in the state of Rio Grande do Sul, Southern Brazil. Sixteen samplings were conducted, divided between the 2018 and 2019 seasons. In each sampling, three leaves from the three strata of the plant (top, middle, and base) were collected from 20 plants, totaling 60 leaves per sampling. The predator-prey relationship and their association with environmental variables were evaluated with multivariate correlation, whereas the number of mites per plant leaf strata was compared using a generalized linear mixed model in R software. It was possible to observe the symptoms of damage caused by T. urticae attacks on grapevines in Southern Brazil, characterized by the presence of yellow spots and general yellowing of the vineyard. Our findings indicate that T. urticae and N. californicus individuals are strongly associated with each other regardless of the environmental variables, and such relationship occurs mainly on the lower strata (middle and base leaves) of grapevines. Thus, by taking into account the damage on the leaves of grapevines and the occurrence of T. urticae and N. californicus majorities on specific strata of these vineyards, we suggest that the lower strata of grapevines should be the priority targets for management strategies to control such mites.

In regions with high temperatures, carrot cultivation is impracticable, as high temperatures tend to reduce yield and quality of the product. However, with the advent of summer cultivars, carrot cultivation in these regions has become viable. The aim of this work was to evaluate the performance of ten carrot cultivars in different planting seasons. The experiments were carried out at the Rafael Fernandes Experimental Farm of the Federal Rural Semiarid University (UFERSA). The experiments were carried out in May, June, July and August of 2017. The experimental design was a randomized block with ten treatments and four repetitions. The characteristics that were evaluated were the root classification (long, average and short roots); commercial, non-commercial and total yield; dry plant weight and root fresh weight. Both the planting season and the cultivar played important roles in agronomic performance throughout the experimental period. In May and June, the highest average yields and plant growth were obtained (43 and 45 t ha-1 yield, respectively). Hybrid cultivars showed better performance than open-pollinated cultivars in terms of yield. The Brasília, BRS Planalto, and Kuronan varieties showed poor performance in all the evaluated characteristics.

Grain size is an essential trait in common bean breeding as it determines the acceptance of a new cultivar by producers, consumers, and the industry. The objectives of this study were to identify the ideal traits for selecting common bean lines in the F3 generation to obtain an adequate sieve yield and to identify the best lines for sieve yield by applying early generation selection. Two trials were conducted in two locations during the 2016/2017 crop season. These trials were composed of 300 F3 populations and two parents (used as checks). The experimental design used was an augmented block design without repetition for the treatments (lineages). After harvest, the grain yield, yield components, and sieve yield (SY) were evaluated. In conclusion, selection in the F3 generation can be performed for sieve yield, considering the traits SY12+13, SY14, and relative grain yield, as they present the highest values of heritability and greatest correlation between genotype and performance in the evaluated environments. Additionally, the lines selected to continue in the breeding program are composed of the 15 best lineages for traits SY12+13, SY14, and relative grain yield. Preference should be given to lines that excel in more than one of these traits.