Gustavo Alves Pereira

Guava (Psidium guajava L.) is known for its wide adaptation to different soil and climate conditions. However, the climatic seasonality of the growing regions exposes the plants to different environmental conditions, capable of influencing their phenology and production. Therefore, determining the behavior of cultivars at different fruiting pruning times is an important tool for crop planning. Thus, the present study aims to evaluate the phenological and productive behavior of guava cultivars, propagated vegetatively at different fruiting pruning times in the semiarid region. The experiment was conducted in randomized blocks, during the period from 2022 to 2023, in a 3 x 6 double factorial arrangement, the factors corresponded to: i) pruning season (rainy-dry, dry-rainy and dry) and, ii) cultivar + propagation method ('Paluma' grafted, 'Paluma' cutting, 'Tailandesa Vermelha' grafted, 'Tailandesa Vermelha' cutting, 'Tailandesa Branca' grafted and 'Tailandesa Branca' cutting). The phenological cycle and productive attributes were evaluated. The results revealed that the propagation methods do not alter the phenological cycle of the cultivars, which was 184 to 196 days. The grafting method provided better productive indices (number of fruits, production, average fruit weight) in the 'Paluma' and 'Tailandesa Branca' cultivars, in the 3 pruning seasons. The cultivars showed a reduced cycle between pruning and harvesting in the dry season. The productive potential of guava is greater in the dry-rainy season. The cultivar 'Tailandesa Branca' propagated by grafting with pruning in the dry-rainy season proved to be more promising in the semiarid region.

Bacillus subtilis has been recognized as an efficient biological controller against Meloidogyne spp. in roots of annual crops, but its efficiency in fruit tree roots remains poorly known. This study assessed the effect of the new B. subtilis strain (PRBS-1) on the suppression of Meloidogyne spp. in the soil and roots of banana, guava, and fig in field conditions naturally infested with the nematode. Thus, B. subtilis suspension was inoculated directly to the soil surface around the stem of these fruit trees at the dose of 1 L·ha^-1 (100 L of water), while plants not treated were used as control. The number of Meloidogyne spp. in the soil and roots was assessed before and after (three months) the application. The samples were collected from the central plants of the plot, at 20 cm from the stem and 5–30 cm soil layer of depth. B. subtilis promoted a decrease in the population of Meloidogyne spp. in soil and roots of fruit trees after three months of application, being more effective in decreasing Meloidogyne spp. in roots than soil. The decrease in Meloidogyne spp. in roots with the application of B. subtilis ranged from 70.1 to 86.3% in the roots of guava and fig, respectively. In the soil, the application B. subtilis decreased from 29.8 to 73.4% of the population of Meloidogyne spp. Therefore, this study showed that B. subtilis has potential as a biological control agent against Meloidogyne spp., in banana, guava, and fig roots.

Brazil is considered the world's largest producer of red guavas. This study aimed to evaluate the dynamics of the productive aspects of the guava cv. Paluma under the influence of different pruning and thinning intensities in two growing seasons in the region of Currais, Piauí, Brazil. The research was carried out in a commercial orchard at the Rancho Vale das Serras Farm, municipality of Currais, Piauí. The experiment was arranged in a randomized block design, in a factorial arrangement (3x3) composed of three pruning intensities (short, medium, and long) and three thinning intensities (0%, 10%, and 20%), during two growing seasons. The variables analyzed were plant height, canopy diameter, stem diameter, number of emerged shoots, number of vegetative branches, number of productive branches, number of open leaves, number of total fruits, longitudinal fruit diameter, transverse fruit diameter, chlorophyll a, b, and total, mean fruit weight, production, and yield. As for canopy diameter in the first season, the plants that underwent long and medium pruning showed greater vegetative growth due to the non-abrupt decrease in the CN ratio and because there was a greater amount of leaf area, resulting in greater growth. For the number of fruits, the results obtained showed that there was a smaller physiological drop in the subsequent medium and short pruning due to the smaller amount of plant tissues, turning the plant's energy towards fructification instead of growth. There was a significant effect of the pruning and thinning interaction on the mean fruit weight, production, and yield.

The pruning time for Vitis vinifera sp. is determined by environmental factors that affect the level of hormones in the plant and, consequently, control metabolic changes. Inducing meristematic activity and altering the phenology of the vine. However, a drastic reduction in the yield of excessively pruned vines has been observed with potential effects not only for the current season but also for subsequent seasons, due to the decrease in the plant's reserves. Thus, this review provides a comprehensive discussion on how pruning time affects the phenology of vines grown in a semi-arid climate, highlighting how environmental factors regulate vine growth in regions with a semi-arid climate, and which strategies can be used for cultivation in this region. Estimating the best pruning time encourages better practices and timely actions to improve vine productivity and grape quality. Therefore, this study provides important information for planning grapevine cultivation at different pruning times.

The objective of this study was to evaluate the performance of acerola genotypes regarding the postharvest quality of fruits of the genotypes BRS 366 Jaburu, Clone 09, Clone 13, Clone 14, Junko, and Sertaneja, cultivated in southwestern Piauiense, northeastern Brazil. A randomized block design (BCT) was used, with treatments consisting of six genotypes, three repetitions, and three plants per plot. Productivity, fruit mass, fruit length, fruit diameter, color, juice yield, anthocyanins and flavonoids, carotenoids, pH, titratable acidity, and ascorbic acid were evaluated. The results show a high productive potential of Clone 13. However, the genotype BRS 366 Jaburu stands out regarding the physical characteristics of the fruit, providing a better balance in the titratable acidity, good contents of total polyphenols, and high amount of vitamin C allied to the juice yield, which is required for acerola fruits. Thus, BRS 366 Jaburu shows promise for cultivation in the edaphoclimatic conditions of the Sudoeste Piauiense region.

Plant and fruit quality is a reflection of several factors, one of which is the way the seedlings were produced. The aim of this study was to analyse the phytotechnical and nutritional characteristics of fig tree seedlings (Ficus carica L.) produced in a substrate comprising decomposed stems of the buriti palm (Mauritia flexuosa L.). A randomised block design was used, with treatments distributed in a 5x6 factorial scheme with one additional treatment, arranged in five blocks. The substrates included the following levels of decomposed buriti stems: 20%, 40%, 60%, 80% and 100%, with a different decomposition time (0; 15; 30; 45; 60 and 75 days) for each treatment. There was one additional treatment comprising 100% soil. The following variables were evaluated to determine the effects of the treatments: number of leaves (NL), number of branches (NB), leaf chlorophyll index, diameter of the largest shoot (DLS), length of the largest shoot (LLS), leaf area (LA), root length (RL), root volume (RV), shoot fresh matter (SFM), root fresh matter (RFM), shoot dry matter (SDM) and root dry matter (RDM), with a chemical analysis of the shoots and soil before and after setting up the experiment. The proportion of decomposed buriti palm stem in the substrate yielded significant results for the morphological variables, including the number of leaves, shoot fresh matter, root fresh matter and root volume. For the nutritional variables relating to the aerial part of the seedlings, the proportion of substrate yielded significant results for the levels of calcium, magnesium, iron and zinc. There were no significant results from the decomposition time; however, multivariate analysis showed that by the end of the experiment the nutrient concentration in the soil was higher than before the experiment.

It is important to determine optimal experimental plot size in order to ensure accurate results and correct decision making. There are no studies of this nature for lima bean cultivation. As such, the aim of this study was to determine the optimal plot size to estimate lima bean yield in family farming and experimental areas, combining the number of treatments, repetitions, and accuracy levels. Experiments were conducted in two 12[ ]m × 16[ ]m plots, each subdivided into 192 basic units (BUs) measuring 1[ ]m ² . Bean weight was assessed in each of the units (g). Smith’s index of soil heterogeneity and optimal plot size were estimated using the Modified Maximum Curvature Method and Hatheway’s Method. The index of soil heterogeneity was higher than 0.7 for all the variables analyzed. Plot size between 10[ ]m ² and 15[ ]m ² is considered efficient in estimating lima bean weight. These first estimated optimal plot sizes will allow researchers and farmers who work with the crop to obtain more robust yield estimates.

Plant selection conducted in commercial orchards is mainly based on plant features. This study characterizes and selects acerola tree genotypes with promising features for cultivation in the Gurguéia Valley region, Piauí. Twenty-five genotypes were used, consisting of 15 clones (CL 03, CL 08, CL 09, CL 12, CL 13, CL 14, CL 20, CL 23, CL 26, CL 27, CL 30, CL 31, CL 33, CL 36, and CL 38) and 10 cultivars (BRS 235, BRS 236, BRS 237, BRS 238, BRS 366, Sertaneja, Costa Rita, Morena, Tropicana, and Junko). The experiment was set up in a randomized block design with three blocks and three plants per experimental unit in 4 m x 3 m spacing. A total of 40% of the genotypes evaluated showed an umbrella shape, 36% showed a semi-open shape, and 24% showed an open shape. Clones 09, 14, and 12 presented the highest cultivation potential in the region, with monthly production of 5.01, 4.30, and 3.70 kg plant-¹ per year and productivity of 4.16, 3.59, and 3. 08-ton ha-¹, respectively. Clone 27, cultivars BRS 236 and BRS 235, and clone 14 were the earliest genotypes, requiring 1,503.3, 1,535.6, 1,686.6, and 1,686.6 DD; respectively, to complete their cycle. Clones 09 and 14 stood out from the others and are potentially promising for cultivation in the Gurgueia Valley region.

Maintaining the plant architecture of Psidium guajava L. (guava tree) is essential for enhancing capture and distribution in the plant, directly affecting the fruit quality. The lifespan of the harvest period can be extended by proper pruning. Both timeliness and proper pruning play crucial roles in achieving high-quality fruit production and in maintaining a consistent fruit size while stimulating ascorbic acid levels, sugar content, total soluble solids (TSS), and titratable acidity. From this perspective, this study aimed to characterize the influence of different intensities of fruit pruning and thinning on guava trees grown under a seasonal tropical climate in two growing seasons in Currais, Piauí, Brazil. The experiment was set up in a randomized block design with a 3 × 3 × 2 factorial arrangement corresponding to short, medium, and long pruning intensities and 0%, 10%, and 20% thinning intensities during the two growth seasons, respectively. An analysis was performed to discriminate the treatment groups according to the physicochemical variables of the guava tree cv. Paluma and canonical discriminant analysis. There was significant variation in the SS, titratable acidity, ascorbic acid, and pH contents. Cluster analysis of all treatments allowed division into five different groups for the two pruning times. Canonical discriminant analysis showed that the first two canonical variables explained 91% of the total variance. The fruits of the second harvest exhibited a lower level of acidity, higher levels of soluble solids, and higher levels of ascorbic acid contents. In addition, these fruits also obtained better nutrient contents. Short pruning with up to 20% thinning, medium pruning with up to 10%, and long pruning without thinning favored better levels of macronutrients and micronutrients and, consequently, better fruit quality. Medium or long pruning with up to 20% thinning resulted in higher average fruit weights and nutrient contents (especially of Fe and Cu), lower acidity, and higher ascorbic acid contents. Thus, in general, the importance of production pruning in guava plants is evidenced and thinning of 20% is recommended to improve the fruit quality.

In guava plants, production pruning can be performed twice a year, and the return of growth is dependent on the physiological responses that are altered by the different cultivation environments and adopted management. From this perspective, this study aimed to characterize the photosynthetic dynamics of guava plants influenced by different pruning and fruit thinning intensities during two growing seasons in the region of Currais, Piauí, Brazil. The plants were distributed in a randomized block design with a factorial arrangement (3 × 3 × 2) consisting of three pruning intensities (short, medium, and long) and three fruit thinning intensities (0, 10, and 20%) during two growing seasons. The data were subjected to a cluster analysis and canonical discriminant analysis to discriminate treatment groups based on the variables. Through a cluster analysis for the evaluated treatments, it was possible to split the two pruning seasons into five different groups clustered for the first pruning season and the second pruning season. The highest assimilation values were observed in the first pruning season and especially in plants that received short pruning with 0% fruit thinning, medium pruning with 10% and 20% fruit thinning, and long pruning with 10% fruit thinning. Through the graphic representation of the canonical discriminant analysis, the first two variables explained 93.40% of the total variance contained in the nine original variables. The highest means of ambient PAR, transpiration, leaf temperature, internal carbon, and ambient temperature were observed in the second pruning season and in plants that received short pruning with 10% and 20% fruit thinning, medium pruning with 0% and 20% fruit thinning, and long pruning with 0%, 10%, and 20% fruit thinning favors a higher photosynthetic accumulation in guava plants. We observed a multiplicity of responses; however, short pruning with 10% thinning should be considered for both seasons.