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.

The phenological adaptability and growth of the fig tree (Ficus carica L.) was observed periodically in the Brazilian semi-arid, State of Piauí, Brazil. The study was done using in 46 plants of the fig tree cv “Roxo de Valinhos”, in Bom Jesus, Piauí in the period from April to August of 2018. The meteorological elements associated with phenology were: air temperature, relative humidity, precipitation, and photoperiod. The results revealed significant relations between the phenology, growth, and climatic conditions showing promising answers for the cultivation of the fig tree cv “Roxo de Valinhos”, in the semi-arid region of Piauí.

The objective of this research was to evaluate the vegetative growth of papaya seedlings, propagated by seeds, regarding the use and application rates of two biostimulants in two types of soil. The experiment was carried out at the State University of Piauí (UESPI)/Campus de Corrente, with papaya (Carica papaya L.) as a research culture, on a screen at 50% brightness. The completely randomized design consisted of four treatments arranged according to the following application doses (0, 4, 8, 12, and 16 ml) using the biostimulant Solofull® and Stimulate® via soil, with six replicates per treatment, totaling 24 experimental units. The soil used came from two situations, soil 1 (area in process of degradation, Gilbués—PI) and soil 2 (pasture area, Corrente, PI). At 65 days after sowing, height, stem diameter, number of true leaves, leaf area, height ratio of plants, and stem diameter and root length were evaluated. The data were submitted to analysis of variance. The degraded area soil provided the best growth of the aerial part. The types of biostimulants and application doses used in this study did not provide significant differences between treatments.

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.

This study aimed to investigate the impacts of the growing season on the physiological performance, phenological cycle, and yield of grapevines grown in a semiarid climate. Thus, we established a field experiment in two growing seasons using cultivars with intermediate cycles (BRS Magna and BRS Núbia), and early cycles (BRS Violeta) in Bom Jesus, Piauí, Brazil. Our results suggest that vines cultivated during the second season (September-December) anticipated the phenology from sprouting to berry maturation (BBCH01-BBCH89) of all studied cultivars. The vines cultivated in the 2nd season had an average duration of 109 days after pruning. The growing season within each cultivar level showed that the 2nd season was the best for all studied cultivars. In all cases, plants from the second growing season showed higher rates of CO2 assimilation, transpiration, stomatal conductance, leaf temperature, and the relationship between internal, and external CO₂ concentrations (Ci/Ca ratio). BRS Magna had the highest production (3563.5 kg/plant), the highest number of berries per bunch (34.5), longitudinal diameter (35.1 mm), and transverse diameter, universal of the berry (15.3 mm), fruit mass (61.83 g), berries (2.4 g), and total soluble solids (14.9 °Brix). Principal component analysis (PCA) showed that the studied cultivars differed from each other, highlighting alterations in the analyzed variables as affected by growing season. Our findings provide relevant information for the growing season, and behavior of vine cultivars to be used as a basis for viticulture cultivation in semiarid environments.

Esse estudo avaliou o emprego de ferramentas de gestão de risco de carteiras de ativos em mercados de capitais em cenários simulados de monocultivo e rotação de soja e milho. O estudo foi realizado na região do Sudoeste Piauiense-BR. A metodologia de simulação foi a Monte Carlo. Foram seis cenários de produção, com Monocultura de Soja (S1), Monocultura do milho (S2), (S3) 50% soja + 50% milho, (S4) 75% soja + 25% milho, (S5) 25% soja + 75% milho e (S6) 66,6% soja + 33,3% milho, de 1998 a 2017. As variáveis de entrada foram custo de produção, produtividade e preço da commodity. A avaliação dos resultados foi feita com base nos valores VaR, PaR, MV. O sistema 4 (S4) obteve a melhor relação retorno-risco com lucro médio estimado de R$ 695,99 e risco de R$ 1005,20 enquanto, o sistema S2 apresentou a menor relação com lucro médio esperado de R$ - 167,64 e risco R$ 1.540,85. Ainda, constatou-se que as ferramentas de gestão de risco podem ser eficientes para auxiliar a gestão de empresas agrícolas.