Quality of black bean seeds harvested with different moisture contents and submitted to two different storage systems

Bean (Phaseolus vulgaris L.) is one of the main foods of the Brazilian diet. However, to achieve high yields, one of the determining factors is seed quality, which can be influenced by harvesting time and storage. The objective of this work was to evaluate the physical quality and physiological performance of black bean seeds as function of the moisture content at harvest and storage method. For that, black bean seeds, cultivar BRS Campeiro, were used. The harvest was performed when the seeds reached moisture contents of 26.2; 16.6 and 13.5%. The storage was carried out in hermetic (PET bottles) and conventional (paper bags) systems for 240 days. There was a reduction in the physical quality and the physiological performance of the bean seeds according to the storage time and the harvest delay. However, the seeds stored in a sealed system showed less reduction in physical quality and physiological performance over time, regardless of the harvest moisture content. The harvest of black bean seeds, cultivar BRS Campeiro, with moisture contents between 16.6 and 26.2% and stored in hermetic system present better physical quality and physiological performance

Weed Management in Sprinkler-Irrigated Rice: Experiences from Southern Brazil

Sprinkler rice saves water compared to paddy rice. However, in paddy fields, the water table is efficient for weed suppression. In sprinkler rice, there is no water table on soil; thus, weed management used in paddy rice may not be suitable for sprinkler rice, since herbicides and water table are expected to interact. Weed pressure in sprinkler rice is higher than in paddy rice; annual grasses are the main weeds in both paddy and sprinkler rice. Barnyardgrass, goosegrass, crabgrass and Alexandergrass show vigorous growth in sprinkler rice. A 3-year study shows that weeds in sprinkler rice reduce grain yield between 11 and 95%. Herbicides used in conventional and Clearfield® rice (clomazone, imazethapyr + imazapic, imazapyr + imazapic, pendimethalin and penoxsulam) were tested, contrasting paddy and sprinkler rice. Additionally, the technique locally called “needle-point” (glyphosate applied over the first-day emerging rice) was combined with pre- and postemergence herbicides. When using only pre- or postemergence, weeds reduced rice grain yield; a combination of products was the best option for sprinkler-irrigated rice. The Clearfield technology was efficient in controlling most weeds. However, using it combined to the needle-point promoted the best results. The main approaches for weed management in sprinkler-irrigated rice were summarized

EVALUATION AND GROUPING OF SUGARCANE GENOTYPES IN AGREEMENT WITH THEIR PHYSIOLOGIC CHARACTERISTICSOTYPES

AbstractThe objective of this work was to evaluate physiological characteristics of sugar cane genotypes, as well as characterize them in groups according to their similarity, checking the ability of ecological adaptability of these genotypes. The work was performed in field conditions, being assessed ten sugarcane genotypes (RB855113, RB835486, RB867515, SP80-1816, RB72454, RB925345, RB855156, RB937570, RB947520 and RB925211) in a randomized block design with three repetitions. It were evaluated the stomatal gas flow rate (U - μ mol s-1), the concentration of under-stomatal CO2 (Ci - μmol mol-1), the photosynthetic rate (A - μmol m-2 s-1), the CO2 consumed (Δ C - μmol mol-1), the stomatal conductance (Gs - mol m-1 s-1), the temperature gradient between leaf and air (Δ T), and the transpiration rate  (E - mol H2O m-2 s-1), being also calculated the water use efficiency (WUE - mol CO2 mol H2O-1) from the values of the amount of CO2 fixed by photosynthesis and amount of water transpirated. Both univariate and multivariate data analysis were made. The genotype SP80-1816 showed better water use efficiency, combined with low stomatal conductance and transpiratory rate. The cultivar RB855113 stood out by having high photosynthetic rate, and high consumption of CO2. The cultivar RB867515, in addition to showing high water use efficiency, also showed high photosynthetic rate. With respect to the multivariate analysis, the biotypes RB925345, RB925211, RB855156 and RB855113 are situated in different groups when compared to the others as to the physiological characteristics with respect to other genotypes with isolation in separate groups.Keywords: Saccharum spp. photosynthesis. Transpiration. Cultivars

CARACTERÍSTICAS FISIOLÓGICAS E DE DESENVOLVIMENTO DE Cyperus difformis L. RESISTENTE E SUSCETÍVEL AO HERBICIDA PYRAZOSULFURON-ETHYL

Os biótipos de plantas daninhas resistentes a herbicidas podem apresentar diferenças fisiológicas e de desenvolvimento quando comparado a biótipos suscetíveis. O objetivo deste trabalho foi comparar características fisiológicas e de desenvolvimento de biótipos Cyperus difformis resistente e suscetível ao herbicida pyrazosulfuron-ethyl. Foram conduzidos dois experimentos em casa de vegetação, um na Universidade Federal de Pelotas (Exp. I) e outro na Universidade Federal de Viçosa (Exp. II), em delineamento experimental completamente casualizado, com quatro repetições. No primeiro experimento (Exp. I) os tratamentos constaram de biótipos de C. difformis resistente (CYPDI 9) e suscetível (CYPDI 8) ao herbicida pyrazosulfuron-ethyl e de seis épocas de coletas (14, 28, 42, 56, 70 e 84 dias após a emergência) e no segundo (Exp. II) os biótipos de C. difformis resistente e suscetível foram avaliados com e sem a aplicação do herbicida pyrazosulfuronethyl, na dose de 20g ha-1. As variáveis avaliadas no Exp. I foram área foliar (AF), massa da parte aérea seca (MPAS), taxa de crescimento absoluto e a relação AF e MPAS; no Exp. II, CO2 consumido, taxa de fluxo de gases, concentração de CO2 subestomático, taxa transpiratória, condutância estomática de vapores de água, taxa fotossintética e eficiência do uso da água. Observou-se que os biótipos de C. difformis resistente e suscetível ao herbicida pyrazosulfuron-ethyl apresentam características fisiológicas e de desenvolvimento semelhantes. ABSTRACT The resistance of weed to herbicides can cause alterations in physiologic characteristics and development of the resistant biotype. The objectives of this work went to compare physiologic characteristics and development from biotypes of resistant and susceptible C. difformis to ALS inhibiting herbicides. For that, two Studies were driven at green house of UFPel (Study I) and of UFV (Study II) in completely randomized design, with four replicates. In Study I the treatments consisted of resistant biotype (CYPDI 9) and susceptible (CYPDI 8) of C. difformis to herbicide pyrazosulfuron-ethyl and six times of collections (14, 28, 42, 56, 70 and 84 days after the emergency) and in Study II the same biotypes (resistant and susceptible) added of the application of pyrazosulfuron-ethyl in the rate of 20g ha-1. The variable availed were leaf area, aerial dry mass, rate growth and the relation leaf area and aerial dry mass, in Study I and consumed CO2, rate of flow of gases for the stomata, concentration of CO2 sub-stomatal, transpiration rate, stomatic conductance of steams of water, photosynthetic rate and efficiency of the water use in Study II. Before the results, it can be observed that the resistant and susceptible biotypes of C. difformis to pyrazosulfuron-ethyl herbicide, present physiologic characteristics and development similar

Weed flora in rice areas under distinct cropping systems, herbicide and irrigation managements

We aimed to evaluate the incidence of weeds in the pre-planting of the summer crop as a function of planting system, herbicide use and irrigation management. The experiment was installed in field conditions, in RBD and 3 x 2 factorial scheme with eight replications. Treatments consisted in submitting rice to three management factors: water management – continuously flooded or intermittend irrigation (Factor A), coupled to the application (traditional control) or not (semi-ecological system) of herbicides (Factor B), and planting system – conventional soil tillage, minimum tillage and no till systems (Factor C). One year after rice cultivation, preceding the planting of the next cropping season, phytosociological evaluations of the weed communities were carried out. We assessed the overall infestation and weed species composition, which were classified by their respective density, frequency and dominance. We also estimated the diversity coefficients of Simpson and Shannon Weiner, and the sustainability coefficient of Shannon; treatments were also grouped by similarity in weed composition. In flood-irrigated rice, no till provides the lowest levels of weed infestation and, together with the conventional cropping system, results in values closer to the ecological sustainability; The application of herbicides in flooded rice crops reduces weed infestation, increases diversity and equalizes the ecological sustainability, compared to areas without the application of weed management methods. However, chemical control leads to the selection of resistant or tolerant species to herbicides, such as Polypogon sp.; Both continuous and intermittent water management systems did not cause changes in the level of infestation, composition or diversity coefficients

Habilidade competitiva de cultivares de soja com Ipomoea indivisa

Among the weeds that infest soybeans, the morning glory (Ipomoea indivisa) stands out for competing with water, light, nutrients and also interfering in the crop harvesting process. The aim of this study was to test the competitive ability of soybean cultivars in the presence of I. indivisa, in substitutive experiments. The experiments were carried out in a completely randomized design, with four replicates, using the soybean cultivars M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445, and NS 6601. A constant final yield for soybean and I. indivisa was observed with 24 plants per pot. Relative and total productivities were analyzed using diagrams applied to substitutive experiments with soybean and I. indivisa plants proportions of 24:0, 18:6, 12:12, 6:18, and 0:24 plants pot-1 (crop:weed). On 35 days after the emergence of the culture and the I. indivisa, the morphophysiological characteristics of the plants were assessed and the relative competitiveness indices were calculated considering the 50:50 plant ratio (12:12 plants pot-1). Morning glory affected the morphophysiological characteristics of soybean cultivars, demonstrating superior competitive ability for environmental resources. There was a competition between soybean cultivars and I. indivisa, which caused reductions in the shoot dry matter for both species. In this study, interspecific competition was more harmful than intraspecific competition.Dentre as plantas daninhas que infestam a soja, a corda-de-viola (Ipomoea indivisa) se destaca por competir por água, luz, nutrientes e também interferir no processo de colheita da cultura. O objetivo deste trabalho foi testar a habilidade competitiva de cultivares de soja na presença de I. indivisa, em experimentos substitutivos. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com quatro repetições, utilizando as cultivares de soja M 5838, DM 53i54, DM 57i52, DM 66i68, NS 5445 e NS 6601. Observou-se produtividade final constante para soja e I. indivisa com 24 plantas por vaso. As produtividades relativa e total foram analisadas por meio de diagramas aplicados a experimentos substitutivos com plantas de soja e I. indivisa nas proporções de 24:0, 18:6, 12:12, 6:18 e 0:24 plantas vaso-1 (cultivar:planta daninha) . Aos 35 dias após a emergência da cultura e da I. indivisa, foram avaliadas as características morfofisiológicas das plantas e calculados os índices de competitividade relativa considerando a proporção de plantas de 50:50 (12:12 plantas vaso-1). A corda-de-viola afetou as características morfofisiológicas das cultivares de soja, demonstrando superior capacidade competitiva por recursos ambientais. Houve competição entre as cultivares de soja e I. indivisa, o que ocasionou reduções na matéria seca da parte aérea para ambas as espécies. Neste estudo, a competição interespecífica foi mais prejudicial do que a competição intraespecífica