Resumo em Inglês:

ABSTRACT Currently, one of the most used practices in national coffee production is skeletal pruning, to preserve productive capacity, correct plant architecture, minimize the occurrence of diseases, among others. Also, it reduces the plants diameter, exposing the soil to climatic conditions, erosion, loss of moisture and nutrients, negatively affecting the development of coffee. The use of cover plants intercropped with coffee is presented as a technique to avoid and minimize these problems. Therefore, the objective of this research was to evaluate the effect of cover crops on the chemical and physical characteristics of the soil and the skeleton coffee tree. The experiment took place at Fazenda Boa Esperança, city of Serrania, South of Minas Gerais, from October/2017 to December/2018, in randomized blocks, composed of 8 treatments with and without cover crops. Three replicates per treatment were used, totaling 24 experimental plots, each with 14 plants, being the 10 central considered useful for evaluation. The cover crops contributed to the improvement of nutrient contents in the soil, maintained a better level of humidity and milder temperatures providing a greater development to the skeletonized coffee. They also positively influence weed control, but none could suppress all plants present in the research.

Resumo em Inglês:

ABSTRACT This work aimed to evaluate granulation incidence and severity and quality parameters of ‘Monte Parnaso’ navel orange in different harvest and collection dates. The 2018 and 2019 harvests were evaluated, and the collection dates of 0, 15, 30, and 45 days after commercial collection. The evaluated parameters were granulation incidence and severity, fruit weight, longitudinal and transversal diameters, peel thickness, juice content, soluble solids content, titratable acidity, SS/TA ratio, and ascorbic acid content. The results underwent chi-squared to evaluate granulation incidence and severity, and analysis of variance for the quality parameters; occurring statistical difference, the means were compared by Tukey’s multiple range test at 5 % probability. Granulation incidence and severity were not related to collection time. Only severity was related to the harvest. The quality parameters were influenced significantly only by the harvest factor, with exception of the parameters of titratable acidity, influenced only by the factor collection date, and ascorbic acid content, which presented interaction between factors. Granulation incidence and severity were higher in the larger and heavier fruits. The frequency of fruits in the categories of higher severity (> 50 %) was higher in the 2018 harvest than in the one of 2019.

Resumo em Inglês:

ABSTRACT The aim of this study was to evaluate the genotypes developed by the Peach Breeding Program at the Federal University of Viçosa, as regards to resistance to M. incognita. Six rootstocks genotypes propagated by cuttings (713-07, 713-13, 913-3, 913-6, 913-11 and 913-17) and two rootstocks propagated by seeds (‘Okinawa’ and hybrid between scion cultivars Aurora 2 x Aurora 1), were evaluated. The experimental design was randomized block design with five replicates and one plant per experimental units. After establishing the plants in pot, maintained in a greenhouse, this were inoculated with 11.000 juveniles + eggs of M. incognita. Evaluations were performed at 140 days after inoculation. The roots were evaluated and the number of galls and egg mass in the roots were determined. The eggs were extracted from each plant for quantification and determination of the Reproduction Factor (RF) of the nematode. The peach genotypes 913-3, 913-6, 913-11, 913-17 and 713-7 showed an immune reaction to M. incognita. Genotype 713-13 showed susceptible reaction to M. incognita. The hybrid between scion cultivars Aurora 2 x Aurora 1 confirmed susceptible.

Resumo em Inglês:

ABSTRACT The selection of common bean lines with intermediate cycle, upright plant architecture and high grain yield is an important goal of breeding programs. This study proposes to examine the genetic diversity of common bean genotypes for agronomic traits, select superior genotypes for traits that provide high agronomic performance and define promising crosses. Seventeen common bean genotypes were evaluated in two growing seasons in 2019. A total of 17 agronomic traits were determined, which comprised the cycle, 12 traits related to plant architecture and four traits related to production. All traits exhibited a significant genotype × environment interaction, except for lodging and insertion of the first pod. Tocher's and the unweighted pair group method with arithmetic mean (UPGMA) cluster analyses resulted in the formation of three groups of genotypes. Tocher and UPGMA analyses do not allow identifying differences between the superior genotypes of high agronomic performance. Cultivars Fepagro Triunfo and Fepagro Garapiá and lines SM 1510 and Linhagem 110, selected by the multiplicative index, stand out for different agronomic traits. The cross between cultivars Fepagro Triunfo and Fepagro Garapiá (superior agronomic traits) is recommended for the breeding program. Recombiants with high agronomic performance could be setected from the tested hybrid combinations.

Resumo em Inglês:

ABSTRACT This work was carried out in Antioquia, Colombia, in a collection of the Furcraea and Agave genera, important in the country for manufacturing strings, sacks, geotextiles, and handicrafts Currently, to enhance its use, applications have been developed in textiles, biodegradable materials and thermo-acoustic insulation, among others. The aim of this study was to characterize phenotypically and agronomically 94 accessions. The variables were weighted according to the degree of discrimination; a dissimilarity dendrogram was constructed using UPGMA based on Gower's distance, and the cophenetic correlation coefficient was determined. Six groups were identified; on the one hand, the accessions of the Agave genus formed groups A and B, with and without spines, respectively, showing the highest elongation values. On the other hand, the Furcraea accessions formed groups C to F, with the highest average values ​​of fiber per plant, allowing a first approach to identify promising clones for their use per se or utilized in plant breeding programs. This study represents an approach to knowing the morphological and agronomic variability of the collection and highlights the importance of maintaining the germplasm bank for ex situ conservation.

Resumo em Inglês:

ABSTRACT Peppers belongs to Capsicum genus and have a lot of different varieties. They can be different uses such as potted ornamental plants. Retail market for this type of pepper requires the development of a greater number of commercial cultivars with adequate ornamental characteristics as well as an extended shelf life (post-production). Ethylene exposure causes adverse effects in ornamental pepper post-production. Then, the goal of this study was to select ornamental pepper elite lines (Capsicum annuum L.) for ethylene-insensitive. The experiment was conducted at the Laboratory of Plant Biotechnology of the Center for Agricultural Sciences of the Federal University of Paraíba, Areia, PB. The experiment was arranged in a completely randomized design. Eight elite lineages and two control cultivars evaluated at three times 48, 72 and 96 hours after ethylene exposure were disposed in a split-plot arrangement. Each treatment was composed of ten repetitions. The data were submmited to analysis of variance, Scott-Knott criteria (5%), and regression analysis. The leaves demonstrated to be more sensitive to ethylene while fruits were more insensitive. It is recommended selection of UFPB lines: 56.8.24.1; 56.26.15.1 and 56.26.34.1 to participate in trials tests aiming at registration of new ethylene-insensitive cultivars.

Resumo em Inglês:

ABSTRACT Grafting has been increasingly used to overcome soilborne pathogens. The commercial rootstock hybrids AF-8253 (Sakata) and Fortaleza (Takii), as well as Embrapa’s new hybrid, BRS Acará, were evaluated as rootstocks for the bell pepper hybrids Margarita (Syngenta) and Pampa (Clause) as scions, under natural infestation of Ralstonia pseudosolanacearum, as well as upon artificial inoculation with a) ten Ralstonia isolates, b) one Phytophthora capsici isolate, c) Meloidogyne incognita race 1, and d) Meloidogyne enterolobii (only rootstocks for c and d). Grafted bell peppers consistently showcased a higher productivity than did non-grafted ones under natural R. pseudosolanacearum infestation, and the rootstock genotype affected fruit size distribution. Rootstocks presented higher resistance than did commercial bell pepper hybrids (scions) for 6 out of 10 Ralstonia isolates. AF-8253 and BRS Acará displayed an immune-like response to P. capsici, while Fortaleza was moderately resistant (25% symptomatic plants) and the bell pepper hybrids (scions) were susceptible (100% symptomatic plants). Rootstocks were immune to M. incognita race 1, but slightly (AF-8253 and BRS Acará) or moderately (Fortaleza) resistant to M. enterolobii. Grafting with BRS Acará, as well as with AF-8253 or Fortaleza, is recommended for managing bacterial wilt, Phytophthora blight, and root-knot nematodes.

Resumo em Inglês:

ABSTRACT In view of the increase in the infested areas and the difficulty in controlling Chamaesyce hirta (L.) Millsp (garden spurge) there is growing interest in identifying herbicides that can be applied in pre and post-emergence, helping to reduce infestation and to provide species control. The objective of this work was to evaluate efficient alternatives of herbicides applied in pre and post emergence aiming at the control of Chamaesyce hirta. Three experiments were carried out in a greenhouse in a completely randomized design with four replications. The first with the application of herbicides in pre-emergence, the second with the application of herbicides in post-emergence when the plants of C. hirta had two to four true leaves fully expanded, and the third experiment, also with the post-emergence application at the flowering and branching stage of the plants. For herbicides applied in pre-emergence, at 28 days after application (DAA), all herbicides evaluated were considered effective for the control of Chamaesyce hirta, showing results above 90%. Several herbicides were efficient in controlling the species with two to four leaves, however, in the flowering stage, there is greater difficulty in control, showing the importance of the plant stage at the time of application.

Resumo em Inglês:

ABSTRACT The use of auxin mimics herbicides in agriculture is widespread in a great diversity of crops. The indiscriminate use of herbicides can cause adverse effects in the plants. Among the plant species that stand out for being highly competitive and resistant to biotic and abiotic stresses, it is the brazilian peppertree (Schinus terebinthifolius Raddi.). The objective of this work was to evaluate the phytotoxic and photosynthetic alteration effects of different rates simulating the drift of the herbicides 2,4-D and Dicamba in brazilian peppertree seedlings. The experiment was carried out in a completely randomized design with four replications. The treatments were arranged in 2 x 8 factorial design (herbicide x doses). The factor herbicide consisted the herbicides 2,4-D and Dicamba, and, the factor doses eight percentages of the herbicide applied. Phytotoxicity and alteration of photosynthetic and fluorescence of chlorophyll a parameters were evaluated. Increased rate of the 2,4-D and Dicamba cause phytotoxicity to the plants, whose Dicamba promotes greater injuries. Dicamba was the herbicide that caused the greatest damage to the photosynthetic apparatus on brazilian peppertree plants, while for 2,4-D the plants showed higher recovery potential after herbicidal exposure.

Resumo em Inglês:

ABSTRACT Italian ryegrass (Lolium multiflorum) is one of the main weeds in the wheat crop, and the application of synthetic auxin herbicides has the potential to reduce seed viability, therefore, restricting the input into the seed bank. The objective was to evaluate the effects of synthetic auxin herbicides applied at different growth stages on germination, emergence and initial growth of Italian ryegrass. The herbicides treatments were 2,4-D, 2,4-D+picloram and dicamba applied at four different growth stages of Italian ryegrass in field and seeds quality evaluated in laboratory and greenhouse studies. In both studies, the herbicides did not reduce Italian ryegrass seed germination or emergence regardless of application growth stages. Under laboratory conditions, the application of synthetic auxin herbicides increased vigor and germination speed by up to 64 and 47%, respectively, applied in growth stages. The greenhouse test evidenced an increase in vigor by the herbicides application, but only 2,4-D increased the emergence speed and plant dry matter when applied in early plant stage. The synthetic auxin herbicides do not alter germination or emergence. Progenies treated with herbicides had greater seed vigor.

Resumo em Inglês:

ABSTRACT Soil attributes can provide indicators for the management and conservation of natural and agrarian ecosystems. This study was carried out before the rupture of the Córrego do Feijão dam and aimed to evaluate and quantify the stocks of carbon, nitrogen and the C/N ratio in soils around the Paraopeba-MG river basin in five regions corresponding to the high, middle, and low river course, considering three usage factors: forest, pasture, and Shrubbery forest, correlating them with the chemical and physical properties of the soil, aiming at the interpretation of past use, to obtain management and conservation strategies for ecosystems. The results indicate a significant variation in carbon and nitrogen stocks with an increase in the 20-40 cm layer. Concerning the type of use, the forest system was the most efficient in accumulating carbon. About to site, the regions of Brumadinho and Fortuna de Minas showed similarities in the incorporation of carbon in the soil, differing from the regions of Jeceaba, Florestal, and Três Marias. There was a close correlation between stocks and the chemical and physical properties of the soil, making it possible to assess the quality of the soils in the study regions in terms of structure and fertility.

Resumo em Inglês:

ABSTRACT The objective of this work was to identify and describe the morphological aspects of the pyrene and the different stages of developing embryos of Ilex paraguariensis. The pyrenes were collected in the year 2016 and 2017, of ripe fruits. The pyrenes, a total of 400 per site and year of collection, remained for 24 h immersed in water for the section and internal observation. The pyrenes, with the visualized embryo, were used for the anatomical description and fixed for the histological evaluation. They were fixed in paraformaldehyde solution and included in Leica™ historesin. The samples were sectioned in Leica microtome with a thickness of 7 μm, and the sections were stained with Toluidine Blue. The pyrenes are formed by endocarp, integument, endosperm, and embryo. The embryos were classified in the globular, heart (occupying approximately 10% of the length of the seed), post heart (15% of length), torpedo (20% of length), and mature (40% of length) stages; and were located below the micropyle, aligned to the external point. The region surrounding the embryo, called the cavity, consists of a lignified layer.

Resumo em Inglês:

ABSTRACT The production of strawberry seedlings in a soilless cultivation system can be an alternative for the production of seedlings of high physiological and sanitary quality. The objective of this study was to evaluate the influence of the use of different nutrient solutions in mother plants on the production and quality of strawberry seedlings of the Aromas and Camarosa cultivars. The experiment was carried out in two crop cycles: the first cycle in 2016/2017, where four different nutrient solutions (1; 2; 3 and 4) were used for the nutrition of the parent plants of the cultivars under study and the second in 2017/2018, when the most productive solutions (nutrient solution 3 and 4) based on the results of the first cycle were used, together with the two cultivars. The propagules produced were collected, evaluated and rooted in substrate-filled trays, forming plant plugs, which were evaluated for quality. Nutritional solutions influence the propagative potential of the parent plants more than the physiological quality of the plug plant seedlings produced, when they are formed on substrates that provide nutrients. The nutrient solution 4 is the most recommended for the production of strawberry seedlings of the cultivars Aromas and Camarosa, in a soilless system.

Resumo em Inglês:

ABSTRACT This study aimed to determine the main causes of low germination of Zanthoxylum rhoifolium Lam. (Rutaceae) seeds. Initially, the physical and physiological qualities were evaluated in seeds from four areas (lots) (Step I). Then, tests were performed (Step II) to determine physical dormancy (imbibition in water and methylene blue), physiological (germination test with scarification) and morphological (analysis of the embryo), in addition to histochemical analysis and (Step III) bioassay in aqueous and hydroalcoholic extracts. In Step I, a low germination was observed in all evaluated lots (≤ 1.0%); however, in the tetrazolium test, a high viability was verified for the Dois Vizinhos lot (88%). The lots showed differences in their physical aspects, with the predominance of seeds with damage. In Stage II, developed embryos were verified and there has no germination without the tegument. The methylene blue and histochemical test indicated the presence of an impermeable and thick tegmen. The bioessays with hydroalcoholic extracts indicated the presence of germination inhibitor(s). The main causes associated with low germination of Z. rhoifolium seeds are attributed to the combined dormancy due to an impermeable tegmen and some non-specific physiological dormancy, as well as the presence of damaged seeds. The seeds also contain germination inhibitors.

Resumo em Inglês:

ABSTRACT The quest for resistance sources against Meloidogyne incognita as a control measure is essential in tomato. Thus, this study aimed to evaluate the reaction of six species of wild solanaceae to M. incognita. The species of wild solanaceae studied were Solanum capsicoides, S. asperolanatum, S. americanum, S. viarum, S. palinacanthum and Nicandra physaloides. Seedlings of wild solanaceae species were transplanted and inoculated with M. incognita. The experiment was performed in a completely randomized design with eight replicates. The analyzed variables were: height of the aerial portion, fresh weight of the aerial portion, fresh weight and length of the root system, gall index, number of galls/g of root, number of egg masses/g of root, number of eggs/g of root and the nematode reproduction factor. Based on gall index and reproduction factor criteria the species S. capsicoides, S. americanum, S. palinacanthum and N. physaloides were classified as resistant against M. incognita. These species also showed a significant increase in height and fresh weight of the aerial portion, length of the root system and fresh weight of the root system. Therefore, these species of wild solanaceae may contribute to the management of M. incognita in future applications.

Resumo em Inglês:

ABSTRACT Amaranthus hybridus is a C4 broadleaf species widely spread across Brazilian agricultural territory. Recently, several herbicide resistance reports have been documented in southern Brazil, including the reports for enolpyruvilshikymate-3-phosphate (EPSPS)- and acetolactate-synthase (ALS)- inhibitors. The objective of this study was to confirm the existence of an ALS resistant (R) A. hybridus population from Paraná state. Dose-response experiments were conducted with R and a known susceptible (S) population with herbicides from three different chemical groups of ALS inhibitors. Biomass relative to untreated control was quantified and GR50 (dose for 50% of biomass reduction), GR90 (dose for 90% of biomass reduction) and resistant index (RI) were calculated based on non-linear regression analysis. The R population was 6.9-fold resistant to chlorimuron-ethyl and 6.5-fold resistant to metsulfuron-ethyl (sulfonylureas - SUL). Additionally, the recommended rates from each herbicide was not sufficient to reach 90% control to R based on GR90 parameter estimation. There was no resistance to imazethapyr (imidazolinone - IMI) and cloransulan-methyl (triazolopyrimidine - TRI) due to the low doses of GR90 and non-significant RIs. The R A. hybridus population investigated was resistant to ALS inhibitors chlorimuron-ethyl and metsulfuron-ethyl (SUL), but susceptible to IMI and TRI herbicides.