The aim of this study was to perform a morphological and morphoagronomic analysis of wild Manihot species from a Brazilian semiarid region for inclusion in the collection at the Center for Agricultural Sciences, Federal University of Paraíba. To characterize the 55 accessions, 12 quantitative and 18 qualitative descriptors were used. A dissimilarity matrix was generated by Mahalanobis generalized distance (D²), and clusters were identified by the UPGMA method. It was possible to verify the formation of 8 dissimilar groups based on morphological characters and 5 groups based on morphometric characters, indicating the presence of genetic diversity among accessions. The evaluated morphometric variable with the greatest relative contribution was the length between the central lobe. Based on the dissimilarity matrix, the accessions 16 x 48 were the most genetically distant accessions, followed by 47 x 49. The accessions 4 Monteiro, 16 Soledad, 38 Boa Vista, 3 Pedra Lavrada, 7 Junco, 10 Barra de Santa Rosa, 21 Monteiro, and 39 Junco are the most promising and can be used as parents in breeding programs for this forage species.

The use of plant growth-promoting bacteria (PGPB), which aims to replace chemical fertilizers and biological control, is a goal for achieving agriculture sustainability. In this scenario, our goal was to identify and evaluate the potential of bacteria isolated from maize roots to promote plant growth and be used as inoculants. We evaluated 173 bacterial strains isolated from the maize (Zea mays L.) rhizosphere for the properties of their PGPB in vitro. Twelve strains were positive for siderophores, indole acetic acid (IAA) production, biological nitrogen fixation (BNF), and phosphate solubilization. Sequence analysis of 16S rRNA identified these strains as belonging to the genera Cellulosimicrobium, Stenotrophomonas, Enterobacter, and Bacillus. The elite strains were evaluated under greenhouse conditions upon the inoculation of two maize hybrids, ATL100 and KWX628. The ability of the isolates to promote plant growth was dependent on the maize genotype; Enterobacter sp. LGMB208 showed the best ability to promote growth of hybrid ATL100, while Enterobacter sp. strains LGMB125, LGMB225, and LGMB274 and Cellulosimicrobium sp. strain LGMB239 showed the best ability to promote growth of hybrid KWX628. The results highlight the potential of bacterial genera little explored as maize PGPB but indicate the need to investigate their interactions with different plant genotypes.

The objective of this study was to evaluate gene expression related to water deficit tolerance in maize lines. For this, lines previously classified as tolerant (91-T and 32-T) and non-tolerant (24-NT and 57-NT) to water deficit were used. The seeds of the four lines were evaluated for emergence and emergence speed index, and the seedlings were evaluated for root and shoot length under two conditions of water availability (70 and 10% substrate water retention capacity). In transcript analysis, the expression of several genes associated with water deficit tolerance, ZmDBP3, ZmALDH9, ZmAN13, and ZmDREB2A, was evaluated by qRT-PCR for the 91-T and 57-NT lines. It can be concluded that soil water deficiency did not reduce root development. However, the shoot length was significantly lower under dry conditions. Through transcript analysis, the genes ZmDBP3 and ZmAN13 were identified as potential markers for the early selection of maize lines tolerant to water deficit.

Environment and storage time influence stored seed quality, especially for oilseeds such as castor beans because they have a high lipid content and are more prone to deterioration. This study evaluated the physiological quality of seeds from three castor bean genotypes stored at 10 and 20°C for 300 days. The experimental design was completely randomized, with 4 replications, in a 2 x 6 (2 temperatures x 6 storage periods) split-plot design. The seeds were placed in low-density polypropylene bags and stored in climatic chambers at 10 and 20°C, in which the temperature and relative humidity were registered. Physiological quality (germination, germination rate index, emergence, rate of emergence, electrical conductivity and accelerated aging) were evaluated at baseline and after 60, 120, 180, 240, and 300 days of storage. Castor seeds of genotype EVF 106 showed better physiological quality when stored at 10°C. Castor seeds of genotype EVF 701 could be stored at 10 and 20°C for 300 days. Castor seeds of genotype EVF 712 presented reduced physiological quality during their 300 days in storage, regardless of temperature.

Varronia curassavica (Jacq.) is a shrub and perennial plant native to Brazil that has therapeutic, anti-inflammatory and cicatrizing properties. The objective of this work was to study the chemical diversity of the native populations of this species maintained in the in vivo germplasm bank from Montes Claros, Minas Gerais, Brazil. The essential oils of 10 accessions analyzed in triplicate were obtained by hydrodistillation. Fifty-five compounds were detected, 46 of which were identified by GC-MS analysis. Essential oil yield ranged from 0.1 (VC-9) to 1.22% (VC-3) among the studied accessions. Three groups were formed by cluster analysis. Group A presented lower relative abundance of the compounds α-humulene (1.4%) and β-caryophyllene (8.5%). Conversely, in Group B, the most abundant compound was α-humulene (31.6%). Group C, with the greatest number of accessions, presented values of up to 6.1 and 41.2% for α-humulene and β-caryophyllene, respectively. Only two accessions (VC-1 and VC-5) presented α-humulene content lower than that recommended for phytotherapeutic production. These results, along with consolidating breeding programs, contribute to the conservation of the species.

The objective of this study was to verify the activity of invertases in Estilosantes under the influence of cultivation systems and nitrogen fertilization in two seasons. The experiment was conducted in the Xaraés area, where Estilosantes was planted according to a 2 x 2 factorial scheme with two cultivation systems (monoculture and mixed pasture) in the absence or presence of fertilization (75 kg of N ha-1). A randomized block design with four replications was used. The neutral cytosol (Inv-N), vacuole acid (Inv-V) and cell wall acid (Inv-CW) invertase activity and reducing sugar contents in the leaves and stems were evaluated and analyzed by a 5% probability F-test. The interaction between cultivation systems and nitrogen fertilization was significant for Inv-N in the leaves in the summer, such that greater activity occurred in response to the mixed pasture system and nitrogen fertilization. Nitrogen increased the activity of the Inv-N in the stem in both periods, increased the activity of Inv-V in the leaf in the summer, and decreased the activity of Inv-CW in the fall. This cultivation system influenced the activity of Inv-N regardless of the period of the year and did not interfere with the activities of the acid invertases. The invertases did not show regular changes in relation to nitrogen fertilization.

Germination metabolism of recalcitrant seeds of Araucaria angustifolia is activated in storage, which complicates the seeds conservation and utilization. This study aimed to identify the changes in the reserve metabolites of A. angustifolia seeds throughout storage in order to understand the processes of hydrolysis caused by germination metabolism. Mature seeds were harvested in southern Brazil and stored in an ambient environment and cold chamber conditions. Biochemical analyses were performed for embryos and megagametophytes from seeds stored for 0, 15, 30, 45, and 90 days. Due to seeds being in advanced germination in storage, they were evaluated at 90 days in different early developmental categories: I – seeds with mature embryos, II – seeds with embryos showing apparent elongation along the embryonic axis, and III – seeds with root protrusion. Higher contents of carbohydrate, protein, and amino acids were observed in embryos compared to megagametophytes, and these metabolites were decreased after onset of germination, especially in the embryo tissue. Mobilization of metabolites in megagametophytes would probably increase in later stages of germination. It is suggested that such alterations are not due to deterioration of reserve components, but instead are based on seed metabolism, which remains active after harvest with hydrolysis of metabolites providing energy for germination.

The leaf area index (LAI) is relevant in studies of phenomena at different scales, such as for the leaf to canopy scale and the calculation of the extinction coefficient of photosynthetically active radiation (kPAR), providing input for the parameterization of physiological basis models. The objective of this work was to verify the variation of the LAI and the coffee kPAR subjected to different drip irrigation levels (130, 100, 70, and 40%) and to compare the data obtained from radiation bar linear sensors (SunScan) in the plants that received full irrigation with the values found by other LAI estimation methodologies. The study was conducted in Piracicaba, São Paulo State, Brazil, using the species Coffea arabica cv. Red Catuaí IAC 144; a drip irrigation system was adopted, with the irrigation controlled by tensiometry. The mean LAI values were higher in the L130 (irrigation level of 130%) and L100 (irrigation level of 100%) treatments than those with deficit irrigation depths. The mean kPAR values were lower for the L130 and L100 treatments than the values found in the deficit irrigation depth treatments. When comparing SunScan to other methodologies, the mean error (ME) and absolute mean error (AME) were high.

The current scenario of increased water scarcity is due to climate change and directly affects food production. It is thus necessary to develop strategies to mitigate the impacts of low water availability. Therefore, the goal of the present study is to evaluate the physiological behaviour of melon cultivars under water stress. The experiment was conducted in a protected environment in the experimental Submedium region of the São Francisco River Valley in the period ranging from October to December. In this study, we used the melon cultivars 'Amarelo' and 'Piel de Sapo'. The experiment was conducted in a randomized block design with three replicates that were subdivided into plots, where the plots were comprised of four irrigation rates (50, 75, 100, and 125% of crop evapotranspiration – CET), subplots were comprised of the two melon cultivars, and sub-subplots were comprised of samplings for physiological analyses (15, 30, and 45 days after transplanting). The parameters evaluated were stomatal conductance, transpiration, net photosynthesis, relationship CI/CA, and accumulated dry matter. Water stress reduced the stomatal conductance, transpiration, net photosynthesis, CI/CA, and accumulated dry matter. 'Piel de Sapo' showed a higher photosynthetic adjustment than 'Amarelo' melon due to the gas exchange behaviour of the former, and it was, therefore, more tolerant to water stress.

Waterlogging stress is one of the abiotic factors which causes damage to crops affecting yield components and grain quality of wheat and barley. On the other hand, Fusarium poae is one of the most common Fusarium species isolated from wheat and barley. The aim of this study was to evaluate the effects of waterlogging and F. poae on disease parameters, yield components and grain quality of durum and bread wheat and barley. The experiment was carried out using pots under greenhouse conditions. Four treatments were applied: control/control (W0F0), control/F. poae (W0F1), waterlogging/control (W1F0) and waterlogging/F. poae (W1F1). The results showed that incidence, severity and FHB index of F. poae were higher in W0F1 compared to W1F1 suggesting that waterlogging treatment would be generating no favorable conditions for fungal growth. Therefore, yield components and grain composition and quality were significantly affected by the Fusarium presence and waterlogging treatment which could induce changes in parameters mainly related to the industrial quality of wheat and barley. These results highlight the behavior of wheat and barley under the combination of abiotic and biotic stress.