Resumo em Inglês:

ABSTRACT The aim of the study was to evaluate the genetic diversity, agronomic traits and promising combinations of cowpea genotypes under conditions of low technological level in the region south of Piaui. The experiment was conducted in rainfed condition in the experimental area of the Federal Institute of Piauí, Uruçuí - PI, in DBC with four replications. We used 10 genotypes of commercial cultivars. The following variables were evaluated: Cycle; Number of pods /plants; Number of grains/pods; Weight of 100 grains and yield. The genetic divergence was obtained by Mahalanobis distance and clustering by UPGMA method. The genotypes BRS Tumucumaque, BRS Pajeú and BRS Guariba are promising for cultivation in the first crop under conditions of low technological level in the Cerrado region of Piauí. The combinations of genotypes BRS Tumucumaque and BRS Imponente, BRS Tumucumaque and BRS Aracê, BRS Guariba and BRS Imponente, BRS Guariba and BRS Aracê and BRS Pajeú and BRS Imponente have great potential for use in breeding programs to obtain promising segregating populations for grain yield and other attributes. The traits weight of 100 grains, cycle and number of grains per pod have the greatest contribution to the genetic diversity in the studied population.

Resumo em Inglês:

ABSTRACT Large amounts of nitrogen (N) fertilizers applied to maize cropping systems support high yields but cause adverse environmental impacts. The development of cultivars with higher N use efficiency is essential to maintain sustainable production. Thus, the present study aimed to select popcorn inbred lines efficient and responsive to N fertilization expressing high popping expansion. Fifty-one popcorn inbred lines from different origins were evaluated in the field under low and high N availability, arranged in a randomized complete block design with three replications. The two main traits of economic interest in the crop were evaluated: grain yield (GY) and popping expansion (PE). A joint analysis of variance was performed and a scatter plot was generated to classify the inbred lines regarding the response to the N use, focusing on GY. For PE, a Scott-Knott grouping of means was conducted. Within the panel of evaluated popcorn inbred lines, it was possible to identify sources of favorable alleles for nitrogen use efficiency and popcorn expansion, highlighting the inbred lines L205, L206, L217, and L395. These genotypes emerge as potential parents to be included in mating blocks for the development of hybrids and/or breeding populations with high nitrogen use efficiency and popping expansion.

Resumo em Inglês:

ABSTRACT Plant growth-promoting rhizobacteria (PGPR) can ensure the sustainability of agricultural growth. The objectives of this study were to characterize and determine the effects of Bacillus subtilis, isolate IMA Bs/170005, applied as co-inoculant in the soybean planting furrow. In all treatments, the seeds had been pre-inoculated with Bradyrhizobium japonicum. The experiments were carried out in a greenhouse, and in the field. Different doses of formulated (8.108 spores mL-1) product with B. subtilis (0; 0.2; 0.4; 0.8; 1.2; 1.6 and 2.0 L ha-1) were tested. The isolate proved efficient for in vitro auxin production. Under greenhouse conditions, the response to B. subtilis co-inoculation consisted of an increase of up to 26% in length of the root system. In the field, co-inoculation in the furrow proved beneficial for crop growth and yield and can be recommended. The best response rate was 0.4 L ha-1. At this dose, averaged over 20 and 40 days after sowing and compared to the control with Bradyrhizobium inoculation alone, increases of 5.3% were observed for plant height, 14.8% for shoot fresh weight, 14.1% for shoot dry weight, 8.5% for root dry weight and 6.5% for soybean yield, demonstrating the efficiency of this B. subtilis isolate as a PGPR.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the influence of the environment and the genetic factor on the the phenology of 16 advanced selections of peachtrees in the municipality of Urussanga, state of Santa Catarina. The experiment was conducted in two areas (360 m and 220 m above sea level) in 2017, 2018, and 2019 harvests. The selections are part of the EPAGRI fruit breeding program. The dates of beginning, full, and end of flowering and budding, percentage of flowering, budding and effective fructification were determined. The standard model (number of hours with temperatures below 7.2 °C) was not the most suitable. Full flowering was anticipated by five days, on average over three years, at the highest altitude due to the greater accumulation of cold. The 16 selections were classified into three groups: early (harvest in October), medium (harvest in November), and late (harvest in December). It is concluded that the environment and the genetic factor influence the phenology of advanced peach selections. Being the first, it influences the periods of flowering and budding and the percentages of flowering, budding and effective fruiting. The second with emphasis the maturation cycle and the harvest period.

Resumo em Inglês:

ABSTRACT Several studies have used edible packaging for food preservation due to its composition of biodegradable polymers and natural additives. In the present work, bioactive extracts obtained from the fermented and unfermented flour of tamarind residues were incorporated into formulations of edible coatings for the conservation of grapes of the cultivar ‘Italia’. The flours extracts were obtained with 80% aqueous ethanol solution. Edible coating formulations containing 10 g L-1 cassava starch and 5 g L-1 chitosan without extract or containing 10 g L-1 unfermented or fermented flour extract were prepared and applied to grapes stored at 25 °C for 15 days. The physical-chemical characteristics of the coated and uncoated fruits were similar during storage. The addition of fermented and unfermented flour extracts to the edible coatings improved the in vitro antioxidant activity of the grapes, especially that determined by the ferric reducing antioxidant power method, on the last day of storage, with emphasis on grapes coated with a formulation containing fermented residue extract. Extracts of tamarind residues incorporated in edible coatings promoted the acquisition of bioactive coatings with the potential to improve the antioxidant activity of grapes during 15 days of storage at 25 °C.

Resumo em Inglês:

ABSTRACT The curing before storing the tubers is necessary for the formation of damage periderm, promoting greater post-harvest conservation. In which, the rate curing and the maintenance of the quality of the tubers depends on the temperature. This way, the search aimed to determine the effect of the curing temperature on the regeneration of the damage periderm and on the carbohydrate metabolism of cultivar Markies and Challenger potatoes tubers destined for industry. For this, the curing was carried out for 14 days on tubers with excoriation injury and tubers without excoriation (control) at temperatures of 8, 14 and 20 °C (RH ± 90%). The fresh mass loss rate (FMLR) daily was higher in the excoriation tubers. The excoriation injury and the temperature of 8 °C increased the total soluble sugar (TSS), reducing sugars (RS) and non-reducing sugars (NRS) of the tubers of ‘Markies’ and TSS of ‘Challenger’. The excoriation injury tuber the process of cell division was induced in the periclinal plane, forming phellogen, with few layers of collapsed cortical cells. In both cultivars, at 14 °C the new phellogen became more evident and at 20 °C some layers of a new cork were formed. In ‘Markies’ the development of new periderm was earlier than in ‘Challenger’, even at 8 °C. It is concluded that the temperature of 14 ºC provided better curing and regeneration of the excoriation periderm tubers maintain post-fry quality of potatoes destination by industry processing.

Resumo em Inglês:

ABSTRACT Papaya (Carica papaya L.) is one of the most cultivated fruits in Brazil. Thus, increasing efforts to improve the crop efficiency have been carried out, being the study of quality seedling production of fundamental importance. Arbuscular mycorrhizal fungi, in symbiosis with the root system of plants, can bring great improvements to the morphophysiological aspects of the papaya tree. The aim of this study was to evaluate the interaction of papaya seeds treated with AMF, in order to support management works on the crop. The experiment was installed in an agricultural greenhouse in a completely randomized design with three treatments: T0 – control (no inoculation); T1 - inoculation of seeds with Gigaspora rosea + Gigaspora margarita; and T2 - inoculation of seeds with Rhizophagus clarus, with 40 replicates, with each sowing cell being considered a replicate. Mycorrhizal colonization, seedling emergence and biometric indices at 60 days after sowing were evaluated. High symbiosis rate was observed between papaya seedlings with Rhizophagus clarus and Gigaspora rosea + Gigaspora margarita. Increase in the percentage and speed emergence and decrease in emergence time in relation to control was observed, in addition to increase in biometric characteristics of seedlings, evidencing its beneficial use for higher production.

Resumo em Inglês:

ABSTRACT Despite the great economic importance of yerba mate (Ilex paraguariensis A. St.-Hil.), information about clonal plantations and planting conditions of this tree is still scarce. Thus, we evaluated initial field establishment of five clonal yerba mate cultivars, planted at three seasons of the year (summer, autumn, and spring) in a shaded environment, and in the autumn, we also established blocks in a full sunlight environment, to compare both cultivation environments. We evaluated plants at 3, 6, 9, and 12 months after planting, counting the surviving plants, shoots number, and measuring height and canopy diameter. At 12 months we also analyzed the caffeoylquinic acids (CQA) contents in mature leaves from different environments. Plant survival and growth were not affected by planting seasons. Cultivars Aupaba and BRS 409 had the highest survival rates in all seasons evaluated. The shaded environment provided greater survival and growth than full sunlight, also showing higher CQA levels in the leaves. Clonal cultivars Aupaba, BRS 408, and BRS 409 presented higher growth in both environments. The severe drought in the first year may have affected survival; however, growth was considered satisfactory and plants’ initial establishment was better in the shaded environment.

Resumo em Inglês:

ABSTRACT Nitrogen (N) fertilization effectiveness in onion depends on N source, as well as on soil type and management system. The aim of the study is to investigate the effect of N sources and doses applied as top-dressing on bulb yield, leaf N contents and on the postharvest conservation of onion bulbs grown under no-tillage (NTS) and conventional tillage (CTS) systems. Three experiments were carried out: two in Lebon Régis County-SC, under NTS; and one in Caçador County-SC, under CTS. The herein tested N sources comprised urea, ammonium nitrate, calcium nitrate and ammonium sulfate, in combination to N doses applied as top-dressing (70, 140, 210, 280 and 350 kg N ha-1) in addition to the control, without N. The N sources did not affect yield parameters, leaf N content and post-harvest onion losses. The maximum technical efficiency in bulb yield was observed at N doses of 195.8 and 258.4 kg ha-1 in the no-tillage system (NTS) and at 270.7 kg N ha-1 in the CTS. The NTS enabled maximum yield at N dose 47% lower than the officially recommended one. Maximum relative commercial yield was associated with 31.1 g kg-1 of leaf N.

Resumo em Inglês:

ABSTRACT The objective of this work was to evaluate the agronomic performance of a second crop maize grown under different methods of inoculation with Azospirillum brasilense. The experiment was conducted in a randomized block design with 6 treatments and four replications. The treatments used were: no inoculation (T1); inoculation with A. brasilense via seed (T2); inoculation with A. brasilense via sowing furrow (T3); inoculation with A. brasilense via leaf (T4); two inoculations with A. brasilense via leaf (T5); and combination of inoculations via seed, sowing furrow, and leaf (T6). Physiological, morphological, production, and yield components of the second crop maize were evaluated. The data were subjected to analysis of variance at 0.05 probability level and when significant, the means were subjected to the Scott-Knott test at 0.05 probability level, using the R-bio statistical program. Inoculation via seed results in higher nitrate reductase enzyme activity. The inoculation with A. brasilense does not result in gains in grain yield for second crop maize; however, it improves the maize quality by increasing its gross protein contents.

Resumo em Inglês:

ABSTRACT The objective of the work was to evaluate the response of growth and production, the interception efficiency of photosynthetically active radiation, the extinction coefficient, and the productivity components of sunflower in with the use of cover nitrogen doses in subtropical environments. The experiment was conducted at Santa Maria-RS, Brazil, where they were evaluated the leaf area index (LAI), interception efficiency (εi), and extinction coefficient (k) of photosynthetically active radiation (PAR), plant height (PH), chapter diameter (CPD), stem diameter (SD), the mass of one thousand achenes (MTA), and grain productivity (PROD) were evaluated. Nitrogen doses influenced the LAI only at 52 and 65 DAE, while the canopy interception efficiency (CIE) was influenced at 36, 42, 52, and 86 DAE. Therefore , for growth and production doses of cover N positively influence stem diameter and grain productivity. The application of cover nitrogen fertilizer linearly and positively affects the sunflower crop, and 160 kg ha-1 N. Interception efficiency of photosynthetically active radiation by the canopy and the leaf area index are positively influenced by the doses of nitrogen in the canopy. The extinction coefficient of the photosynthetically active radiation in sunflower decreases with the increasing dose of cover N.