Agronomic Variables Research Articles

Implementación de huerto vertical sostenible en un área urbana residencial de Poza Rica de Hidalgo, Veracruz

El experimento se desarrolló Poza Rica de Hidalgo, Veracruz sobre estructuras construidas con madera reciclada de tarimas, los recipientes utilizados fueron botellas de PET de cuatro litros y protectores de polipropileno de ocho pulgadas de diámetro. El objetivo fue implementar el HVS en un área urbana y conocer la respuesta de los cultivos sembrados en suelo testigo y suelo más composta. Las variables evaluadas fueron: días de germinación, número de tallos, ancho de hoja, largo de hoja y diámetro de raíz. La influencia de la composta como mejorador del sustrato tuvo un efecto positivo en las variables agronómicas evaluadas en todos los cultivos, así como en la retención de agua en el sustrato. La tendencia en los días de germinación no tuvo diferencias entre el suelo testigo y suelo más composta. En todos los cultivos la Hi2 comprueba que la variable agronómica estudiada en suelo testigo es diferente al del suelo más composta. Para las variables hojas verdaderas, ancho y largo de hoja, número de individuos en y diámetro de raíz exclusivamente en rábano el suelo más composta mostraron un crecimiento sobresaliente en comparación con el tratamiento de suelo testigo en sus cuatro repeticiones.

A potato model intercomparison across varying climates and productivity levels.

A potato crop multimodel assessment was conducted to quantify variation among models and evaluate responses to climate change. Nine modeling groups simulated agronomic and climatic responses at low-input (Chinoli, Bolivia and Gisozi, Burundi)- and high-input (Jyndevad, Denmark and Washington, United States) management sites. Two calibration stages were explored, partial (P1), where experimental dry matter data were not provided, and full (P2). The median model ensemble response outperformed any single model in terms of replicating observed yield across all locations. Uncertainty in simulated yield decreased from 38% to 20% between P1 and P2. Model uncertainty increased with interannual variability, and predictions for all agronomic variables were significantly different from one model to another (P<0.001). Uncertainty averaged 15% higher for low- vs. high-input sites, with larger differences observed for evapotranspiration (ET), nitrogen uptake, and water use efficiency as compared to dry matter. A minimum of five partial, or three full, calibrated models was required for an ensemble approach to keep variability below that of common field variation. Model variation was not influenced by change in carbon dioxide (C), but increased as much as 41% and 23% for yield and ET, respectively, as temperature (T) or rainfall (W) moved away from historical levels. Increases in T accounted for the highest amount of uncertainty, suggesting that methods and parameters for T sensitivity represent a considerable unknown among models. Using median model ensemble values, yield increased on average 6% per 100-ppm C, declined 4.6% per °C, and declined 2% for every 10% decrease in rainfall (for nonirrigated sites). Differences in predictions due to model representation of light utilization were significant (P<0.01). These are the first reported results quantifying uncertainty for tuber/root crops and suggest modeling assessments of climate change impact on potato may be improved using an ensemble approach.

Association between Grain Yield, Grain Quality and Morpho-physiological Traits along Ten Cycles of Recurrent Selection in Bread Wheat (Triticum aestivum L.)

The objective of the present investigation was to examine the relationships between agronomical behavior and grain quality along ten cycles of a recurrent selection program performed under rainfed condition. Twenty-four lines, four for each one of the 0, 2, 4, 6, 8 and 10 cycles of recurrent selection, were evaluated for two consecutive years (2011 and 2012). The experimental lines were evaluated under conventional (CT) and no tillage (NT) systems. Grain yield and grain weight were determined and harvest index and grain number estimated. Flour protein content, sodium dodecyl sulphate sedimentation (IS-SDS) and lactic acid SRC (LASRC) were considered as end-use quality predictive tests. The Spearman correlation coefficient was used to measure the relationships among yield, its components and grain quality parameters. Within the context of CT, flour protein content was negatively associated with all the agronomic variables. The IS-SDS has a negative association with the grain weight; meanwhile, LASRC associated positively with all the agronomic variables. When wheat was grown in NT, the relationship between IS-SDS and harvest index, like LASRC with all agronomic traits, was positive. Confining the discussion to the CT results, after ten cycles of recurrent selection the highest grain yield achieved was accompanied by a decrease in protein percentage. However, the decrease in the percentage of protein in more advanced selection cycles was offset by an improvement of its quality.

FACTORS INFLUENCING THE AGRONOMIC PERFORMANCE OF THE ADAPTED YAM MINISETT TECHNIQUE IN NIGERIA – PLANTING DATE AND GENDER OF THE FARMER

SUMMARYThis paper describes the results of 3 year's data from farmers using the Adaptive Yam Minisett Technique (AYMT) to produce seed yams in Nigeria. A total of 30 sites were established each year between 2013 and 2015 in the Idah area (Kogi State) of Nigeria and 58 plots in the Amoke area (Benue State) in 2015. Each site had yam setts (80 to 100 g) untreated and treated with a pesticide ‘dip’ prior to planting and farmers (male and female) were free to select the variety and manage the sites as they wished. In line with previous research, the results suggest that treatment does increase the weight of tubers produced by a sett but not necessarily the number of tubers. Varietal differences were also observed. For the first time, the results suggest that the time of planting does have a significant impact on seed tuber weight, with later planting leading to small tubers. Also, the gender of the farmer had an impact on some of the agronomic variables, with male owners of the site generally producing more and larger tubers per sett planted and sprouted than female owners. Various mechanisms for the latter are discussed in the paper.

Retention of Moisture in Soil With Organic Amendments Cultivated with Amaranthus Hypochondriacus

A field experiment was conducted to investigate the effect of different organic amendments (corn stubble and amaranth stubble, goat manure, compost, and green fertilizer (Medicago sativa)), alone and in combination with a hydrogel, into the moisture retention of the soil, deposited over the soil surface and mixed with surface soil, making a total of 14 treatments. To test their effects, the amaranth plants (Amaranthus hypochondriacus L.), were subjected to different periods of drought. Considered as tolerant to the drought and estimating their vegetative development for leaf production, the treatments were proven under random arrays with 10 repetitions. The agronomic variables considered were, height and survival of the plants as well as their stem diameter. The amendments do not present significant effects on the retention of moisture at 5 cm soil depth. In relation to the vegetative parameters, the hydrogel application demonstrates significant statistical differences for the survey of the plants (p&gt;0.05). The amendments evaluated under the organic padding conditions with corn stubble, in conjunction with the green Medicago sativa fertilizer and the corn stubble mixed with soil, were the treatments which present the best results, in both stem diameter and plant height (Tukey`s test, α=0.05). All the variables show significant statistical differences according to the drought periods of between 0 and 15 days, applied to the different essays.

Agronomic aspects of soybean plants subjected to deficit irrigation

ABSTRACT This study aimed to evaluate the behavior of soybean plants subjected to irrigation management with controlled water deficits in different phenological stages. The research was conducted in an experimental area of the Federal University of Tocantins (UFT), in Palmas-TO, Brazil. The experimental design was randomized blocks with four replicates, and treatments arranged in a split-plot scheme. The plots consisted of irrigation levels that induced plants to water deficit in the vegetative stage, reproductive stage and throughout the entire cycle, based on potential crop evapotranspiration (ETpc). The subplots corresponded to two soybean cultivars (M9144RR and TMG1288RR). The following agronomic variables were evaluated: days until flowering, days until maturation, plant height, first pod height, number of pods per plant, stem diameter, leaf area and yield. Irrigation management with moderate water deficit, 50% of ETpc, in the vegetative stage, promoted the best agronomic characteristics and contributed to increase the yield of the evaluated soybean cultivars, especially M9144RR.

APLIKASI MODEL REGRESI STEP WISE DALAM PENENTUAN HASIL JAGUNG PUTIH

White corn is a source of functional food, particularly in dry land and dry climate environments. Indonesian Agency for Agricultural Research and Development (IAARD) has released six white corn varieties with various characteristics with wide adaptation area. Breeding programs for developing high yielding white maize varieties is conducted by a series of steps including evaluation of agronomic characteristics of lines/varieties. The objective of the research was to test the applicability of step wise regression model to determine/select agronomic variables that significantly contributed to the yield of white corn. Research was conducted in rainy season 2012 at Muneng experimental station, East Java Province. Maize parental plants used were the result of crossing CML140 x CML264Q lines namely Bima Putih. A total of 14 variables were tested for their significances to maize yield. SPSS and Microstat software were used to calculate the best variables that contributed to the yield significantly. The results showed that among 14 variables involved in the calculation, there were five variables that contributed to the yield, namely: weight of cob at harvest (x5), ratio of the weight of dry grain to the total cob weight (x9), the seed moisture content (x6), and number of ears (x4). Regression models generated from step wise screening was y=-4,33+0,763x5+0,1009x11+0,104x9-1,22x6+0,016x4. The coefficient of determination (R2 ) of the model was 0.99, indicating the ability of the regression model to fit the data. This showed that the five independent variables included in the model were the main variables in determining the outcome of hybrid seed Bima Putih-1. This result could be further used as reference to conduct parameter screening to produce high yielding white maize

Agronomic characteristics associated with the normalized difference vegetation index (NDVI) in the peanut crop

Advances in agricultural technology have led to the development of active remote sensing equipment that can potentially estimate components of crop production; however, this assessment is still in its early stages for the peanut crop. The objective of this study was to evaluate the normalized difference vegetation index (NDVI) generated by a terrestrial sensor and its relationship with agronomic variables of peanut crops grown at different densities. The parameters evaluated were the NDVI, pod yield, mass of 100 grains, green and dry mass and vegetation cover. The study was conducted in an experimental field and used a randomized block design with plots consisting of four plant populations (86,111, 103,520, 127,603 and 141,144 plants ha -1 ) with six replicates per treatment. The two densest populations of peanut plants showed similar behavior among the variables analyzed, whereas the variables of vegetation cover, yield and plant population strongly correlated with the NDVI obtained by the terrestrial sensor. For the seeding rates, the higher densities (14 and 18 seeds m -1 ) are the most recommended because showed the highest values of productivity and vegetation cover. The results indicated that the NDVI obtained through the GreenSeeker sensor can be used to estimate productivity, vegetation cover and plant population on peanut crop. This may provide an additional tool for farmers to evaluate the potential of their culture; enabling even that agronomic measures can take effect so that this potential is improved.

Global synthesis of drought effects on cereal, legume, tuber and root crops production: A review

As a result of climate change, drought is predicted to pose greater pressure on food production system than in the past. At the same time, crop yield co-varies with both environmental (e.g., water, temperature, aridity) and agronomic variables (i.e., crop species, soil texture, phenological phase). To improve our quantitative understanding on the effects of these co-varying factors on agricultural productivity, we synthesized previous meta-analysis studies summarizing the results of numerous independent field experiments on drought and its effect on the production of cereal, legume, root and/or tuber (root/tuber) crops. We also included new crops species that were not covered in previous meta-analyses and the effects of heat stress. Our results indicated that cereals tended to be more drought resistant than legumes and root/tubers. Most crops were more sensitive to drought during their reproductive (i.e., grains filling, tuber initiation) than during their vegetative phase, except for wheat, which was also sensitive during vegetative phase. Recovery from drought impact at reproductive phase was either: (i) unfeasible for crops experiencing damage to their reproductive organs (e.g., maize, rice) or (ii) limited for root/tuber crops, provided that water was abundant during the subsequent root/tuber bulking period. Across soil texture, the variability of yield reduction for cereals was also lower in comparison to legume or root/tuber crops, probably due to the extensive and deep rooting system of cereal crops. As crop species, plant phenology, and soil texture were important co-varying factors in determining drought-induced crop yield reduction, no single approach would be sufficient to improve crop performance during drought. Consequently, a combination of approaches, particularly site-specific management practices that consider soil conditions (i.e., intercropping, mulching, and crop rotation) and selection of crop varieties adjusted to the local climate should be adopted in order to improve the sustainability of agricultural production in a changing climate.

VitiCanopy: A Free Computer App to Estimate Canopy Vigor and Porosity for Grapevine.

Leaf area index (LAI) and plant area index (PAI) are common and important biophysical parameters used to estimate agronomical variables such as canopy growth, light interception and water requirements of plants and trees. LAI can be either measured directly using destructive methods or indirectly using dedicated and expensive instrumentation, both of which require a high level of know-how to operate equipment, handle data and interpret results. Recently, a novel smartphone and tablet PC application, VitiCanopy, has been developed by a group of researchers from the University of Adelaide and the University of Melbourne, to estimate grapevine canopy size (LAI and PAI), canopy porosity, canopy cover and clumping index. VitiCanopy uses the front in-built camera and GPS capabilities of smartphones and tablet PCs to automatically implement image analysis algorithms on upward-looking digital images of canopies and calculates relevant canopy architecture parameters. Results from the use of VitiCanopy on grapevines correlated well with traditional methods to measure/estimate LAI and PAI. Like other indirect methods, VitiCanopy does not distinguish between leaf and non-leaf material but it was demonstrated that the non-leaf material could be extracted from the results, if needed, to increase accuracy. VitiCanopy is an accurate, user-friendly and free alternative to current techniques used by scientists and viticultural practitioners to assess the dynamics of LAI, PAI and canopy architecture in vineyards, and has the potential to be adapted for use on other plants.

Interest of carbon isotope ratio (δ13C) as a modelling tool of grapevine yield, berry size and sugar content at within-field, winegrowing domain and regional scale

Carbon isotope ratio (δ13C) has been increasingly used in the study of grapevine water relations, and the main challenge for physiologists and agronomists is now to harness the information δ13C provides. One of the fields where δ13C can be more useful is modelling, as in this discipline, measuring plant water status with a sufficient frequency is not usually feasible. The aim of this work is to evaluate the interest of including δ13C data on modelling of three relevant agronomical variables such as yield, berry weight and sugar concentration (TSS) at three scales: within-vineyard, at domain and at regional scale. The models calculated showed that δ13C is a useful tool for modelling variations in yield and berry weight at the three scales, but this ability was not observed for modelling sugar concentration. The fact δ13C had a relevant role in berry weight modelling at the three scales needs to be highlighted, and underlines the great relevance water availability has in Mediterranean viticulture.

Soybean cultivars agronomic performance and yield according to doses of Azospirillum brasilense applied to leaves

Alternative methods of inoculation such as the application of the bacteria Azospirillum brasilense via spray in an advanced stage of the crop can increase the soybean performance. The aim of this study was to evaluate the agronomic traits and grain yield in soybean crops through Azospirillum brasilense doses applied by spray coverage. The experiment was conducted in randomized blocks in a 4 × 6 factorial, with four cultivars (Anta 82 RR ® , BRS Favorita RR ® , BRS 780 RR ® , BRS 820 RR ® ) and six doses of Azospirillum brasilense (0, 300, 400, 500, 600, 700 mL ha -1 ) with three replications in two crop years. The characters such as plant height, shoot dry mass, chlorophyll content, leaf nitrogen content at flowering were evaluated. At harvest, the evaluated characters were plant height, height of the first pod insertion, number of pods per plant, number of grains per pod, thousand grain mass, grain yield and grain harvest index. For the conditions that this study was carried out and according to the results, the spray with different Azospirillum brasilense doses did not affect the agronomic variables studied and the grain yield in RR ® soybean cultivars.

Relation between Early Season–Measured Agronomic Variables and Sugar Yield Responses to Nitrogen

Several studies have demonstrated the use of early‐season plant response to N as a basis for determining N fertilizer requirements in cereal crops. In sugarcane (Saccharum spp. hybrids) production, the relationship of early‐season growth and responses to N fertilization to sugar yield at harvest has not been pursued. The objective of this study was to evaluate and relate the early‐season response to N fertilization (RI) of select agronomic variables to RI of measured sugar yield at harvest of three sugarcane varieties (HoCP 96‐540, L 01‐283, and L 99‐226). A variety × N (0, 45, 90, and 135 kg N ha−1) trial was established at two LSU AgCenter research stations: the Sugar Research Station in St. Gabriel and the Iberia Research Station, Jeanerette, LA, from 2010 to 2012. The positive correlations between RIs of agronomic variables collected at 4 and 5 wk after nitrogen application (WKN) and RIs at harvest were considered notable with RIbiomass at 5 WKN obtaining the highest r value (RIsugar = 0.69 and RIcane = 0.68). Sugar and stalk yield increases due to N were also correlated to RIN% and RINuptake at 4 to 6 WKN. The findings of the present study demonstrated that RIs of agronomic variables measured early in the season were related with RI at harvest, suggesting the potential use of response to N early in the season as a basis for in‐season determination of sugarcane N rate requirements.Core Ideas Determining seasonal N requirement in sugarcane is essential. High spatial and temporal variability in sugar and stalk yield to applied N were observed. Agronomic variable at early season can be used to predict N response of sugar yield.

Effectivity of Humic Substance Extracted from Palm Oil Compost as Liquid Fertilizer and Heavy Metal Bioremediation

Abstract Humic substances extracted from compost materials were proven able to chelate heavy metals. While the waste from Palm oil as the source material of compost is increasing, consequently the humic substances production from palm oil waste is promising. On the other hand, agricultural lands that were treated with high input which caused heavy metal accumulation (pollutant) up to hazardous level also increasing. The aim of this research was to evaluate the effectiveness of humic substance extracted from Palm Oil compost as liquid fertilizer and bioremediation of copper (Cu). The experiment was designed to discover a product which effectively improved the characteristics of acid soils, bioremediation of heavy metals, and plants production. The results of the experiment revealed that the content of pure humic substance extracted from compost of Palm Oil empty bunches waste was very low, 2.01%. It also contained very low in N, P, and K, which were 0.01%, 0.02%, and 0,11% of N, P 2 O 5 , and K 2 O respectively. The treatment of metal Cu as much as 300 mg Cu(OH) 2 .kg -1 into the media added with humic substance enriched with NPK (4.38; 8.24; and 9.24) showed non significant differences on some cucumber plant variables. NPK enrichments to humic substance showed significant differences on some agronomic variables than that of control. The length of plant treated with 3/3 NPK enrichment revealed the longest average of 564.2 cm, or increased by 38%. The highest fresh weight was obtained by 4/3 treatment followed by 2/3 rate of NPK enrichment. Whie the longest cucumber fruit was obtained by 3/3 rate. Total soil N was very low, consequently the NPK sorption by cucumber was very low. While soil P availability was high, however the NPK enrichment lowered the fresh cucumber fruit P content instead. The ratio of NPK nutrients in plant and in soil was higher if treated with Cu addition compared to that of control.

Considerations Regarding the Agronomical Variables Associated to the Performances of SWAT Model Simulations in the Romanian eco-climatic Conditions

Abstract The main objective of the study is to optimize the agronomical variables for prediction of water quality at river basin scale for various time intervals using the numerical modeling of the cumulative impact of agricultural operations due to the use of chemical inputs and specific tillage. SWAT (Soil & Water Assessment Tool) model was developed to determine with reasonable accuracy the effect of potential management decisions regarding the water use, sediment transport, and chemical transformations of substances discharged into surface waters in rural ungauged basins. The information flow must start with the adaptation of the inputs required by the SWAT model for the accurate definition of Hydrological Response Units that include unique combinations between slope, soil type, and land use/land cover. All thematic layers must be related to the same coordinate system using the 1970 stereographic projection and Dealul Piscului 1970 geographic coordinate system that are in force in Romania. The meteorological inputs used in SWAT include rainfall, maximum and minimum temperature, solar radiation, relative humidity and wind speed. The prediction of SWAT model considering the diffuse sources of pollution (land areas with intensive agriculture) were analyzed considering the cropping technologies used in various Romanian hydrographical basins, i.e. Ialomita River, Calmatui River, Teleajen River, and Mostistea River. The main constraints observed in the use of SWAT model for efficient predictions in various control sections can be adjusted by the careful selection/adaptation of inputs, the optimal calibration/sensitivity analysis of the model, and the updating of information regarding the land use/land cover in a specific river basin.

Assessment of the agricultural land under steep slope in Lithuania

The aim of this research was to evaluate and describe agricultural land handicapped by steep slope and to assess agricultural expertsf attitude towards impact of terrain factor on the generic farming activity. This paper analyses differences and similarities between Lithuanian rural elderships affected by steep slope constraint (i.e. ≥ 7° (15%) slope gradient) with the subsequent evaluation in selected agronomical variables. In total 514 rural elderships were classified into five groups by percentage of agricultural land with steep slope. The assessment of agricultural variables by steep slope groups revealed that the best developed are elderships (60.12%) falling into Group I, where mean value of area under steep slope was 0.32%. Very unfavourable conditions, especially for intensive farming, were identified in Group V (7.59% elderships), where the topographical character has a dominantly hilly terrain. Agricultural expertsf (scientists) for survey was used assessing the respondents attitude (6-point Likert Scale) towards terrain impact on the items related to generic farming sector, i.e., Agricultural development, Farming systems use, Land utilization possibilities and Soil erosion. The surveyed experts considered that terrain is a factor influencing land-use decisions and the item Land utilization possibilities has assumed the highest mean score (3.77). Therefore it should be a good overview of agricultural land with steep slope, as one of the most important natural agri-environmental constraint affecting generic farming possibilities in Lithuania.

Chlorophyll Concentration and Morphological Diversity in Corn Lines at Different Vegetative Stages

The objective of this study was to assess the chlorophyll content of corn lines at different vegetative stages and the diversity between them. The study was conducted in the experimental field of the Roque Institute of Technology (ITR) located in Roque, Celaya, Guanajuato, Mexico. We used 32 corn lines from CIMMYT and four lines from the breeding program of the ITR. The evaluation was conducted in the spring-summer cycle of 2014 at two planting dates. We used a completely randomized block design with three replications. The experimental unit consisted of two rows of five linear meters with a distance of 0.75 meters between rows. Chlorophyll was measured at six different stages: V6, VT, R3, R4, R5 and MF. The agronomic variables recorded were: PH, CH, LAC, LBC, FF, MF, PM, CC, CL, DC, RC, KR and GY. The results of the analysis of variance showed significant differences between lines, dates and their interaction. On average, 18 lines were found with chlorophyll concentrations above 51 SPAD units in the two environments. This indicated that these materials had a high potential for field performance. Using cluster analysis UPGMA method, we identified seven groups for chlorophyll and eight groups for agronomic characteristics for a breeding program. The groups were associated to the homogeneous characteristics of each variable.

Design and characterization of spatial units for monitoring global impacts of environmental factors on major crops and food security

AbstractThis paper describes the design and characterization of a limited number of areas to be used as spatial monitoring and reporting units (MRU) by CropWatch, the global crop monitoring system ( http://www.cropwatch.com.cn/) hosted by the Chinese Academy of Sciences. The MRUs are modified and adapted from an existing standard vegetation zoning map. They are designed to be areas of uniform vulnerability as assessed by three sets of variables: environmental (such as climate and NDVI), seasonality (such as intra‐annual climate variations and interannual NDVI variability) and agronomy (such as presence/absence of major crops and their yield). The paper pays due attention to within‐zone spatial variability for each of the three groups of variables: in general, the variability measured as the average of the spatial coefficient of variation inside MRUs, is much larger for agronomic variables (330%) than for environmental variables (38%) and seasonality (55%). The MRUs provide a rather coherent picture of the variations of global agriculture, for instance, the links between the distribution of crops, agricultural production potential, and environmental variability (over space and time). They closely delineate the distribution of the major nonsugar food crops (barley, cassava, maize, potatoes, rice, soybean, and wheat). The discussion focuses on the relations between the size of the MRUs and the within‐MRU variability (spatial heterogeneity) of cropping, and environmental conditions including seasonality. The conclusion stresses that spatial variability in agriculture is bound to be larger than the variability in the environmental variables used to define the units, regardless of the units’ size. The size of the spatial units (and therefore their number) is not a very critical constraint for operational impact reporting, especially if impact indicators focus on agricultural areas inside MRUs.

English

This study aimed to evaluate the effect of fungicide trifloxystrobin (200 g/L 20% m/v) + tebuconazole (100 g/L 10% m/v) at different phenological stages in controlling southern rust and Cercospora leaf spot in the maize crop and on its productivity. This work was carried out in 2013, Ertel farm, located in the city of Toledo &ndash; PR of Brasil. The experimental design was a randomized complete block in a factorial (2x4+1) with four replications. The treatments consisted of evaluating two diseases, Southern Rust and Cercospora leaf spot, and four phenological stages of fungicide application (V8, V10, VT and R1 of maize) with the presence of a control. The authors evaluated the disease incidence and severity, the Area Under Disease Progress Curve (AUDPC) and the fungicide control efficiency for foliar diseases were observed. In addition to this, some agronomic variables were also evaluated: plant height, ear insertion height, stem diameter, average diameter of ear, ear length, number of rows per ear, number of grains per row, number of grains per ear, thousand grain weight and productivity. The results showed no significant statistical difference for the variables evaluated, except for plant height. Based on these results, it can be concluded that the mixture of triazole with estrobirulina is feasible to control the severity of these diseases in maize, though it was not observed any statistical difference in the different treatments in relation to the average productivity. It is worth mentioning that the use of fungicide tends to provide greater sanity to plants and consequently it improves production rates. In general, the application of the fungicide in the pre-anthesis stage (VT) tends to exhibit better responses. &nbsp; Key words: Zea mays L., Puccinia polysora, Cercospora zeae-maydis.

Association of Phenotypic Traits with Ploidy and Genome Size in Annual Ryegrass

ABSTRACTAnnual ryegrass (Lolium multiflorum Lamarck) is planted annually on more than 1 million ha of pastures in the southeastern United States. The exact ploidy level and genome size of the annual ryegrass germplasm collection (USDA–ARS, Germplasm Resources Information Network, GRIN) are unknown and the future use of this germplasm relies on their determination. The study was conducted to (i) estimate the ploidy level and determine the DNA content of 139 accessions from the GRIN collection, 15 experimental lines, and 13 commercial cultivars through flow cytometry; and (ii) identify morphological and agronomic characteristics that could be used to differentiate diploid from tetraploid annual ryegrass. A total of 140 diploid and 27 tetraploid lines were successfully identified through flow cytometry. The average 2C DNA content was 6.13 ± 0.36 pg for the diploid lines and 12.30 ± 0.83 pg for the tetraploids. Diploid and tetraploid annual ryegrass showed significant differences for morphological and agronomic variables such as seed size, leaf width and length, guard cell size, plant height, tiller size, plant biomass, and seed head length, and all variables were significantly correlated with DNA content. The use of morphological and agronomic variables may guide the determination of ploidy when flow cytometry is not available. Ploidy level and genome size information will benefit those that request accessions from the GRIN system for specific studies at the diploid or tetraploid level in the species.