ABSTRACT Vegetable intercropping systems use complementarity between species to increase agricultural profitability. This study evaluated the effects of intercropping chicory and arugula species with collard greens on crop yield and land use efficiency (LUE). Six treatments, consisting of species planted as monocultures or intercropped in various combinations, were evaluated in a randomized block design with four replicates. The cultivars ‘Top Bunch’ (collard greens), ‘Pão de Açúcar’ (chicory) and ‘Folha Larga’ (arugula) were used. The yield of collard greens in monoculture did not differ from those obtained when they were intercropped with chicory, arugula, or both species, whereas chicory and arugula yields were higher in monoculture. However, even with yield losses for chicory and arugula in intercropping, LUE indices were greater than 1.0 in all intercropping systems, indicating their viability. The highest LUE index (2.41) was obtained in the chicory-arugula-collard green intercropping system.

ABSTRACT Sorghum is a commonly grown plant in the Central-West region of Brazil as a second crop; however, it is grown almost exclusively as a second crop after maize in the state of Paraná (South region). The growth of sorghum crops is an option for areas or times in which the growth of maize crops can be risky. Thus, the objective of this work was to evaluate the agronomic characteristics of eight sorghum hybrids (ADV-123, ADV-114, 1G100, 50A10, 1G244, 50A40, 50A50, and 1G282) grown in three sowing times in two agricultural years: 2014 (February 20, March 02, and March 03) and 2015 (February 09, February 19, and March 01), and four maize hybrids in 2014 (DKB-330-Pro, P-3431-HX, Formula-TL, and AG-9010-Pro) and five maize hybrids in 2015 (DKB-330-Pro, P-3431-HX, Formula-TL, DKB-275-Pro, and DKB-290-Pro), in the same sowing times used for sorghum. A randomized complete block experimental design with a split-plot factorial arrangement was used, with the sowing times in the plots and the hybrids in the sub-plots. The variables evaluated were: number of days from sowing to flowering, leaf area index, 1,000-grain weight, grain yield, number of spikelets per panicle, for the sorghum crop; and number of rows per ear and number of grains per row, for the maize crop. The comparison between the two crops showed that the sorghum maintained higher production stability in the different sowing times.

ABSTRACT Seed treatment with fungi of the genus Trichoderma spp. provides several benefits, including plant growth promotion, stress tolerance, and pathogenic fungi control. Moreover, to avoid inadequate doses and unnecessary costs, these treatments must be applied in proper amounts. However, no study has evaluated their applicability in wheat seeds. This study aimed to determine the most efficient dose of Trichoderma-based products applied as a seed treatment for improving the physiological and sanitary quality of the wheat cultivars TBIO ‘Toruk’ and TBIO ‘Sossego’, besides comparing the performance of biological and chemical agents. Two biological treatments (Trichoderma asperellum SF 04 and Trichoderma harzianum IBLF006) were applied at 0 (control), 5 × 10 11 , 1 × 10 12 , 1.5 × 10 12 , and 2 × 10 12 colony-forming units (CFU) 100 kg–1 seed. Two chemical treatments (carboxin + thiram and pyraclostrobin + thiophanate-methyl + fipronil) were applied at the manufacturers’ recommended doses. Seed germination, shoot and root lengths, seedling dry matter, and sanitary quality were analyzed under laboratory conditions, while seedling emergence, shoot length, and shoot dry matter were analyzed under greenhouse conditions. The optimal dose for wheat seed treatment with T. asperellum SF 04 and T. harzianum IBLF006 was 2 × 10 12 CFU 100 kg–1 seed. When comparing biological and chemical products, our findings indicate that both options are adequate for managing wheat diseases and providing seedling growth via seed treatment.

ABSTRACT The use of green manure from spontaneous species has gained prominence for vegetable crops focused on environmental sustainability and is an alternative method for the Semiarid region in the Northeast of Brazil. Two experiments were conducted in two growing seasons (autumn and spring-summer), in Serra Talhada, PE, Brazil, to evaluate the effects of different amounts of biomass of Calotropis procera (roostertree) and incorporation times on the agro-economic performance of beet crops. A randomized block experimental design was used, with three replications, in a 4 × 4 factorial arrangement; the first factor consisted of amounts of C. procera biomass (5.4, 8.8, 12.2, and 15.6 Mg ha-1 on a dry basis) and the second factor consisted of times of incorporation into the soil (0, 10, 20, and 30 days before planting beet). Commercial root yield, production costs, and the following economic indicators were determined: gross income, net income, return rate, and profitability index. The use of 15.6 Mg ha-1 of C. procera biomass resulted in the highest gross and net incomes and the use of 5.4 and 12.2 Mg ha-1 resulted in the best return rates and profitability indexes in autumn and spring-summer seasons, respectively; the planting time was considered as ideal for the biomass incorporation. The spring-summer growing season resulted in a higher economic return than the autumn growing season. The use of C. procera as a green manure for beet production is economically viable, regardless of the factors evaluated.

ABSTRACT In Brazil, acerola trees infested by Meloidogyne enterolobii present lower yield and fruit quality. The use of rootstocks resistant to this pathogen is one of the alternatives to overcome this problem. This study aimed to assess the reaction of 22 acerola accessions to M. enterolobii, aiming to identify at least one resistant rootstock. The experiment was carried out in a randomized block design with 10 replications and each plot consisting of 10 plants. Each plant was inoculated with 350 eggs and second-stage juveniles of M. enterolobii, with the gall index (GI) and reproduction factor (RF) being determined after 90 days. The variables were analyzed using the mixed model methodology (REML/BLUP). The accessions ACO-13, ACO-14, ACO-18, and BRS Apodi stood out with four to six plants showing resistance reaction to the root-knot nematode, but the assessment of accessions should be performed under a higher density inoculum and longer time.

ABSTRACT This study aimed to determine how crop residue placement and composition would affect soil water content and temperature during the dry season in the central region of Espírito Santo state, Brazil. A 19-week field study was conducted from April to August 2017. A 2 x 4 factorial study with four replications was implemented using a randomized complete block design. Factors were soil management [conventional tillage (CT) and no soil disturbance (ND)] and residue amendment [maize (Zea mays L.), sunn hemp (Crotalaria juncea L.), a maize-sunn hemp mixture, and a no amendment control]. Soil water content and temperature were measured weekly at predetermined soil depth intervals. Soil water content was higher in ND plots amended with surface residues than under all other treatments in the 0 to 0.05 m depth range. All residue amendments in this range were equally effective in conserving soil water. Surface residues reduced soil temperature by up to 8.4 °C relative to the control in ND plots. Incorporating residue amendments by CT cancelled all temperature-moderating benefits provided by surface residues. These results indicate that surface residues from cereals, legumes, or cereal/legume mixtures are equally effective in conserving soil water and moderating soil temperature during the dry season. Additional research is needed to determine how improved soil environmental conditions, generated by surface residues, would affect nutrient acquisition and crop performance.

ABSTRACT Due to the predictions of climate change, there is a need to identify forage plants that can keep their productivity and nutritive value under hydric stress. The objective of this study was to evaluate the biomass and chemical responses of three Desmanthus spp. accessions under two water deprivation regimens (7 and 21-day). The experimental design used was randomized blocks in a 3 × 2 factorial arrangement (access and water deprivation) with four replications. There were reductions in the biomasses of leaf and stem fractions of 64% and 51%, respectively. The 43F accession showed greater leaf (1.86 g.plant-1) and stem (1.97 g.plant-1) biomasses under a total water restriction of 21 days, compared to the 89F and AusT accessions. In accessions 43F and 89F, there were carbohydrate accumulations in the leaves of 28% and 51%, respectively, under the 21-day water restriction, while AusT decreased 38% within a 7-day interval. Water deprivation affected the chemical characteristics of the accessions. Free proline was similar among accessions and accumulated 463% more in the leaves of plants submitted to 21-day water deprivation (90.22 mg.kg-1) compared to those subjected to water deprivation for 7 days (16.03 mg.kg-1). Proline and total soluble carbohydrate accumulation in 43F and 89F were insufficient to regulate crude protein, C content, and C:N ratios. These results demonstrate the variability in drought tolerance among accessions. Accessions 43F and 89F were more susceptible to 21-day water deprivation, while AusT showed greater drought tolerance.

ABSTRACT Fusarium wilt, caused by soil-borne Fusarium oxysporum f. sp. tracheiphilum (Fot), can reduce cowpea bean yield. Considering that genetic control through resistant genotypes is pivotal for Fusarium wilt control, the aim of the present study was to identify cowpea genotypes that are resistant to Fot from the Germplasm Bank of the Pernambuco Agronomic Institute, Embrapa Middle North, and other producing areas in the North and Northeast regions of Brazil. The cultivar BR-17 Gurguéia was used as a susceptible control and MNC01-649F-2-1 was used as a resistant control. Two experiments were carried out in a completely randomized design in the greenhouse of the Department of Agronomy of the University Federal Rural of Pernambuco. Plants with the first pair of expanded leaves were inoculated with a conidial suspension (106 conidia/mL) using the conidia root-immersion methodology. Fusarium wilt severity in plants was assessed 21 d after inoculation, with the aid of a descriptive scale. In the first experiment, we evaluated the resistance of 38 cowpea genotypes, of which 19 (5 moderately resistant and 14 resistant) were selected for the second experiment. In the first experiment, four genotypes (Canapu PE, Miranda IPA 207, Esperança, and BRS Pujante) did not show any symptoms of Fusarium wilt. In the second, 15 genotypes showed high resistance to Fot, including Canapu PE and Miranda IPA 207, which again had no symptoms of Fusarium wilt. In conclusion, this study identified that the genotypes, Canapu PE, Miranda IPA 207, Esperança, and BRS Pujante have greater resistance to Fusarium wilt.

ABSTRACT Previous investigations showed that diverse varieties of melon may have different attractiveness for bees. Therefore, the objective of this study was to evaluate the composition, frequency and behavior of flower visitors of some melon (Cucumis melo) cultivars (Amarelo, Pele de Sapo, Cantaloupe, Gália) in different conditions (conventional and organic farming, dry and rainy seasons, with and without mulching and introduction or not of honey bee hives) in the main production poles in the Brazilian Northeast (Petrolina-PE/Juazeiro-BA, Pacajus-CE and Mossoro-RN). Observations and collections of flower visitors occurred from 5p.m. to 6p.m, in non-consecutive days. We recorded 12 species of insects, mostly bees. The most frequent was Apis mellifera (99.68%), but other species appeared sporadically (less than 0.5%): Xylocopa grisescens, Trigona spinipes, Plebeia sp., Melipona mandacaia, Frieseomelitta doedereleini, Halicitidae. Apis mellifera was present in all studied cultivars and sites. Xylocopa grisescens appeared in two poles, but not in Pacajus-CE, Amarelo cultivar. In addition, Trigona spinipes, although present in the three poles, was not recorded on Pele de Sapo. The Amarelo cultivar, under organic farming, without the use of mulching, and presence of honey bee hives, in the Petrolina-PE/Juazeiro-BA pole, in the dry season, was the combination of factors showing the largest number of Apis mellifera as the main visitor of melon flowers.

Lisianthus is an important ornamental species, whose cultivation in pot still requires studies, mainly regarding the use of alternative management. Thus, the aim of this work was to evaluate the influence of resistance elicitors on the production and post-production quality of potted lisianthus.  Plants grown in pots were treated with two  elicitors: (E1)  phosphorylated mannano-oligosaccharide and (E2) citric bioflavonoids and phytoalexins, in the doses (D) of 1 and 2μL.L-1 (E1D1 1μL.L-1, E1D2 2μL.L-1, E2D1 1μL.L-1, E2D2 2μL.L-1 and control), with 5 replications, in  a completely randomized  design.  After opening the first flower buds, the plants remained in the greenhouse for 15 days, until they reached at least 3 open flowers, when were transferred to the room conditions (24 ± 2 oC and 72 ± 2%) for another 15 days. The application of elicitors did not influence the culture cycle or the size of the stem. There was an increase, however, in the number of viable buds and open flowers, in addition to an increase in flower’s useful life paralleled to the reduction of senescent flowers, in relation to the control. The dose of 2μL.L-1 of the E2 kept the percentage of viable open flowers in relation to the control for at least another 5 days, reducing the percentage of senescent flowers. Together, with the application of the E2 elicitor in potted lisianthus, the viability of the flowers can be prolonged, maintaining quality and delaying senescence, and, in this way, increasing the market period. | O lisianthus é uma importante espécie ornamental, cujo cultivo em vaso ainda requer estudos, principalmente quanto ao emprego de manejo alternativo. Assim, o objetivo deste trabalho foi avaliar a influência de elicitores de resistência na produção e na qualidade pós-produção de lisianthus em vaso. Plantas de lisianthus cultivadas em vaso foram tratadas com dois elicitores: (E1) manano-oligossacarideo fosforilado e  (E2) bioflavonóides  e fitoalexinas cítricas, nas doses (D) de 1 e 2μL.L-1 (E1D1 1 μL.L-1, E1D2 2 μL.L-1, E2D1 1 μL.L-1, E2D2 2 μL.L-1 e controle), com 5 repetições, em  delineamento  inteiramente casualizado. Após a abertura dos primeiros botões florais, as plantas permaneceram na estufa durante 15 dias, até atingirem  pelo menos 3 flores abertas, quando foram transferidas para a condição ambiente (24 ±2 oC e 72 ±2%)  durante mais 15 dias  A aplicação dos elicitores não influenciou o ciclo da cultura nem o tamanho da haste. Entretanto, observou-se  aumento nos números de botões e de flores abertas viáveis, além de aumento dos dias de vida útil, paralelo à redução de flores senescentes em relação ao controle. A dose de 2μL.L-1 de E2 manteve em, pelo menos, mais 5 dias o percentual de flores abertas viáveis com relação ao controle, reduzindo o percentual de flores senescentes. Em conjunto, com a aplicação do elicitor E2 em lisianthus em vaso pode-se prolongar a viabilidade das flores, por manter a qualidade e retardar a senescência e,  assim sendo, aumentar o período de comercialização.