International Journal of Agronomy The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Climate Change and Sugarcane Production: Potential Impact and Mitigation Strategies Thu, 22 Oct 2015 08:19:29 +0000 Sugarcane (Saccharum officinarum L.) is an important crop for sugar and bioenergy worldwide. The increasing greenhouse gas emission and global warming during climate change result in the increased frequency and intensity of extreme weather events. Climate change is expected to have important consequences for sugarcane production in the world, especially in the developing countries because of relatively low adaptive capacity, high vulnerability to natural hazards, and poor forecasting systems and mitigating strategies. Sugarcane production may have been negatively affected and will continue to be considerably affected by increases in the frequency and intensity of extreme environmental conditions due to climate change. The degree of climate change impact on sugarcane is associated with geographic location and adaptive capacity. In this paper, we briefly reviewed sugarcane response to climate change events, sugarcane production in several different countries, and challenges for sugarcane production in climate change in order for us to better understand effects of climate change on sugarcane production and to propose strategies for mitigating the negative impacts of climate change and improving sugarcane production sustainability and profitability. Duli Zhao and Yang-Rui Li Copyright © 2015 Duli Zhao and Yang-Rui Li. All rights reserved. Effects of Fungicides, Time of Application, and Application Method on Control of Sclerotinia Blight in Peanut Wed, 07 Oct 2015 08:50:17 +0000 Field studies were conducted from 2007 to 2010 to evaluate the response of peanut cultivars to different fungicides, application timings, and methods. Overall, fungicides reduced Sclerotinia blight incidence and increased pod yields when applied to susceptible and partially resistant cultivars. Disease suppression was greater when full fungicide rates were applied preventatively; however, yields between fungicide treated plots were similar. Lower levels of disease and higher yields were achieved with the partially resistant cultivar Tamrun OL07 compared to the susceptible cultivars Flavor Runner 458 and Tamrun OL 02. Despite possessing improved resistance Tamrun OL07 responded to all fungicide applications. While similar levels of disease control were achieved with broadcast or banded applications made during the day or at night, the yield response for the different application methods was inconsistent among years. A negative relationship (slope = −73.8; ; ) was observed between final disease incidence ratings and yield data from studies where a fungicide response was observed. These studies suggest that both boscalid and fluazinam are effective at controlling Sclerotinia blight in peanuts. Alternative management strategies such as nighttime and banded applications could allow for lower fungicide rates to be used; however, additional studies are warranted. Jason E. Woodward, Scott A. Russell, Michael R. Baring, John M. Cason, and Todd A. Baughman Copyright © 2015 Jason E. Woodward et al. All rights reserved. Growth, Development, and Mineral Nutrient Accumulation and Distribution in Tulip from Planting through Postanthesis Shoot Senescence Mon, 03 Aug 2015 06:09:24 +0000 Tulips were grown under field conditions from mid-November through early-June. Plants were harvested and dissected into eight organs on twenty-one dates. These parts were dried, weighed, and analyzed for N, P, K, Ca, and Mg. A transition (as determined by curve join points) from a linear to a steep negative cubic response occurred prior to shoot emergence for N (82 days after planting (DAP)), at shoot emergence for K (93 DAP) and Ca (94 DAP), and after shoot emergence for Mg (102 DAP) and dry matter (118 DAP). A transition from a linear to a steeper linear response occurred at shoot emergence for P (93 DAP). Growth, organ development, and nutrient accumulation occurred continuously from planting to maturity (188 DAP), except for K which did not accumulate during the initial linear phase. Since the increase in accumulation of all five nutrients preceded the dry matter accumulation, these nutrients could be used as predictors in growth models. Practical implications from this study include the importance of maintaining soil Ca levels through liming and applying the N, P, and Mg as split applications with smaller rates at planting and larger rates at emergence. The entire K application may be applied at emergence. Carl E. Niedziela Jr., Paul V. Nelson, and David A. Dickey Copyright © 2015 Carl E. Niedziela Jr. et al. All rights reserved. Seedling Performance Associated with Live or Herbicide Treated Tall Fescue Thu, 19 Feb 2015 17:30:04 +0000 Tall fescue is an important forage grass which can host systemic fungal endophytes. The association of host grass and endophyte is known to influence herbivore behavior and host plant competition for resources. Establishing legumes into existing tall fescue sods is a desirable means to acquire nitrogen and enhance the nutritive value of forage for livestock production. Competition from existing tall fescue typically must be controlled to ensure interseeding success. We used a soil-on-agar method to determine if soil from intact, living (L), or an herbicide killed (K) tall fescue sward influenced germination and seedling growth of three cultivars of tall fescue (E+, MaxQ, and E−) or legumes (alfalfa, red clover, and white clover). After 30 days, seedlings were larger and present in greater numbers when grown in L soil rather than K soil. Root growth of legumes (especially white clover) and tall fescue (especially MaxQ) were not as vigorous in K soil as L soil. While shoot biomass was similar for all cultivars of tall fescue in L soil, MaxQ produced less herbage when grown in K soil. Our data suggest establishing legumes or fescue cultivars may not be improved by first killing the existing fescue sod and seedling performance can exhibit significant interseasonal variation, related only to soil conditions. Jonathan J. Halvorson, David P. Belesky, and Harry W. Godwin Copyright © 2015 Jonathan J. Halvorson et al. All rights reserved. Productivity of Onions Using Subsurface Drip Irrigation versus Furrow Irrigation Systems with an Internet Based Irrigation Scheduling Program Sun, 08 Feb 2015 10:33:20 +0000 Selection of the proper irrigation method will be advantageous to manage limited water supplies and increase crop profitability. The overall objective of this study was to evaluate the effect of subsurface drip irrigation (SDI) and furrow irrigation on onion yield and irrigation use efficiency. This study was conducted in two locations, a commercial field and a field located at the Texas A&M AgriLife Research Center in Weslaco, TX. This study was conducted as a split-plot design for both sites with two treatments (SDI and furrow irrigation) and three replications per treatment. The total onion yield obtained with the SDI systems was more than 93% higher than the yield obtained with furrow irrigation systems. The large onion size was 181% higher for the SDI system than the furrow system in both sites. The colossal size yield was also higher. At one site colossal yield was 206% higher than furrow, while at another site furrow yielded no colossal onions and SDI had some production. It was concluded that drip irrigation systems more than double yields and increased onion size while using almost half of the water. This was due to SDI allowing for more frequent and smaller irrigation depths with higher irrigation efficiency than furrow irrigation systems. Juan Enciso, John Jifon, Juan Anciso, and Luis Ribera Copyright © 2015 Juan Enciso et al. All rights reserved. Sugarcane Yield Response to Furrow-Applied Organic Amendments on Sand Soils Mon, 02 Feb 2015 14:26:14 +0000 Organic amendments have been shown to increase sugarcane yield on sand soils in Florida. These soils have very low water and nutrient-holding capacities because of the low content of organic matter, silt, and clay. Because of high costs associated with broadcast application, this field study was conducted to determine sugarcane yield response to furrow application of two organic amendments on sand soils. One experiment compared broadcast application (226 m3 ha−1) of mill mud and yard waste compost, furrow application (14, 28, and 56 m3 ha−1) of these materials, and no amendment. Another experiment compared furrow applications (28 and 56 m3 ha−1) of mill mud and yard waste compost with no amendment. There were significant yield (t sucrose ha−1) responses to broadcast and furrow-applied mill mud but responses to furrow applications were not consistent across sites. There were no significant yield responses to yard waste compost suggesting that higher rates or repeated applications of this amendment will be required to achieve results comparable to mill mud. Results also suggest that enhancing water and nutrient availability in the entire volume of the root zone with broadcast incorporation of organic amendments is the more effective approach for low organic matter sands. J. Mabry McCray, Shangning Ji, and Leslie E. Baucum Copyright © 2015 J. Mabry McCray et al. All rights reserved. Winter Wheat Row Spacing and Alternative Crop Effects on Relay-Intercrop, Double-Crop, and Wheat Yields Mon, 19 Jan 2015 12:43:38 +0000 In Missouri as well as much of the Midwest, the most popular double-cropping system was winter wheat (Triticum aestivum L.) followed by soybean (Glycine max (L.) Merr). These two crops can also be used in an intercrop system, but optimal row spacing was important to increase crop productivity. Research was conducted to evaluate (1) winter wheat inter- and double-crop production systems, using a variety of alternative crops, and (2) the impact of different wheat row spacings on intercrop establishment and yields within the various cropping systems. Field research was conducted during droughts in 2012 and 2013. Spacing of wheat rows impacted wheat yields by 150 kg ha−1, as well as yields of the alternative crops. Narrower row spacings (150 kg ha−1) and the double-crop system (575 kg ha−1) increased yield due to the lack of interference for resources with wheat in 2013. Land equivalent ratio (LER) values determining productivity of intercrop systems of 19 and 38 cm row showed an advantage for alternative crops in 2013, but not 2012. This signified that farmers in Northeast Missouri could potentially boost yield potential for a given field and produce additional forage or green manure yields in a year with less severe drought. Leah Sandler, Kelly A. Nelson, and Christopher Dudenhoeffer Copyright © 2015 Leah Sandler et al. All rights reserved. Indirect Estimations of Lentil Leaf and Plant N by SPAD Chlorophyll Meter Mon, 12 Jan 2015 06:09:29 +0000 A Soil Plant Analysis Development (SPAD) chlorophyll meter can be used to screen for leaf nitrogen (N) concentration in breeding programs. Lentil (Lens culinaris L.) cultivars were grown under varied N regimes, SPAD chlorophyll meter readings (SCMR) were recorded from the cultivars leaves, and leaf N concentration was measured by combustion. Linear regression and the nonlinear Radial Basis Functions (RBF) neural networks models were employed to estimate leaf N concentration (LNC) based on the SCMR values. The closest estimates of LNC were obtained from the multivariate models in which the combination of plant age, leaf thickness, and SCMR was employed as the independent variable. In comparison, SCMR as the single independent variable in both models estimated less than 50% of LNC variations. The results showed significant effects of soil moisture and plant age on the association of LNC –SCMR as well as the relationship of LNC with plant N, grain yield, and days to maturity. However, the effect of cultivar on the measured variables was negligible. Although lentil N can be diagnosed by comparing SCMR values of the crop with those from a well-fertilized (N fixing) plot, the results did not support using SPAD chlorophyll meter for screening lentil LNC. Hossein Zakeri, Jeff Schoenau, Albert Vandenberg, Mohammadreza Tayfeh Aligodarz, and Rosalind A. Bueckert Copyright © 2015 Hossein Zakeri et al. All rights reserved. Ear Leaf Photosynthesis and Related Parameters of Transgenic and Non-GMO Maize Hybrids Thu, 08 Jan 2015 08:46:54 +0000 Hybrid maize (Zea mays L.) through transgenics now includes δ-endotoxins for insect control and tolerance to the herbicides glyphosate and glufosinate. Some hybrids have multiple transgenic traits as part of their genotype (stacked gene). Limited information is available on how these traits alone affect (net assimilation rate; µmol CO2 m−2 s−1) and related physiological parameters. A two-year, two-location, irrigated experiment comparing four stacked gene, four glyphosate tolerant, and two non-GMO hybrids for ear leaf , (stomatal conductance; mol H2O m−2 s−1), Em (transpiration; mol H2O m−2 s−1), IWUE (intrinsic water use efficiency; ), and Ci (intercellular [CO2] µmol CO2 mol air−1) was completed at Stoneville, MS, in 2012. Data were collected at growth stages R1 (anthesis) and R2 (early kernel filling) using a Li-Cor LI-6400XT set at 355 μmol mol−1 CO2 with a flow rate of 500 μmol s−1 and a 6400-02 light source set at 87.5% full sunlight. Measurements were made between 08:30 h and 11:30 h CST, within 48 h of 25 ha mm irrigation and ≥33.0% cloud cover. Transgenic traits did not influence the physiological parameters of , , Em, IWUE, or Ci during the critical growth stages of R1 or R2. H. Arnold Bruns Copyright © 2015 H. Arnold Bruns. All rights reserved. Effect of Irrigation and Preplant Nitrogen Fertilizer Source on Maize in the Southern Great Plains Wed, 17 Dec 2014 00:10:21 +0000 With the demand for maize increasing, production has spread into more water limited, semiarid regions. Couple this with the increasing nitrogen (N) fertilizer costs and environmental concerns and the need for proper management practices has increased. A trial was established to evaluate the effects of different preplant N fertilizer sources on maize cultivated under deficit irrigation or rain-fed conditions on grain yield, N use efficiency (NUE), and water use efficiency (WUE). Two fertilizer sources, ammonium sulfate (AS) and urea ammonium nitrate (UAN), applied at two rates, 90 and 180 kg N ha−1, were evaluated across four site-years. Deficit irrigation improved grain yield, WUE, and NUE compared to rain-fed conditions. The preplant application of a pure ammoniacal source of N fertilizer, such as AS, had a tendency to increase grain yields and NUE for rain-fed treatments. Under irrigated conditions, the use of UAN as a preplant N fertilizer source performed just as well or better at improving grain yield compared to AS, as long as the potential N loss mechanisms were minimized. Producers applying N preplant as a single application should adjust rates based on a reasonable yield goal and production practice. Jacob T. Bushong, Eric C. Miller, Jeremiah L. Mullock, D. Brian Arnall, and William R. Raun Copyright © 2014 Jacob T. Bushong et al. All rights reserved. Effect of Seed Distribution and Population on Maize (Zea mays L.) Grain Yield Tue, 09 Dec 2014 06:31:22 +0000 Maize planting is normally accomplished by hand in the developing world where two or more seeds are placed per hill with a heterogeneous plant spacing and density. To understand the interaction between seed distribution and distance between hills, experiments were established in 2012 and 2013 at Lake Carl Blackwell (LCB) and Efaw Agronomy Research Stations, near Stillwater, OK. A randomized complete block design was used with three replications and 9 treatments and a factorial treatment structure of 1, 2, and 3 seeds per hill using interrow spacing of 0.16, 0.32, and 0.48 m. Data for normalized difference vegetation index (NDVI), intercepted photosynthetically active radiation (IPAR), grain yield, and grain N uptake were collected. Results showed that, on average, NDVI and IPAR increased with number of seeds per hill and decreased with increasing plant spacing. In three of four site-years, planting 1 or 2 seeds per hill, 0.16 m apart, increased grain yield and N uptake. Over sites, planting 1 seed, every 0.16 m, increased yields by an average of 1.15 Mg ha−1 (range: 0.33 to 2.46 Mg ha−1) when compared to the farmer practice of placing 2 to 3 seeds per hill, every 0.48 m. Bee Khim Chim, Peter Omara, Natasha Macnack, Jeremiah Mullock, Sulochana Dhital, and William Raun Copyright © 2014 Bee Khim Chim et al. All rights reserved. Erratum to “Apple Pollination Biology for Stable and Novel Fruit Production: Search System for Apple Cultivar Combination Showing Incompatibility, Semicompatibility, and Full-Compatibility Based on the S-RNase Allele Database” Thu, 06 Nov 2014 07:10:51 +0000 Shogo Matsumoto Copyright © 2014 Shogo Matsumoto. All rights reserved. Modelling the Effects of Soil Conditions on Olive Productivity in Mediterranean Hilly Areas Sun, 19 Oct 2014 07:51:29 +0000 The majority of olive (Olea europaea L.) production in Mediterranean environments is characterized by low external inputs and is practiced in hilly areas with shallow soils. This study aimed to study the yield and nutritional status for olive (cv. “Zeiti”) trees in northwestern Syria and establish correlations between yield, on the one hand, and soil/land factors and tree nutrition, on the other hand, to determine the most yield-affecting factors. Land and soil fertility parameters (field slope, soil depth, and soil nutrients) and concentrations of leaf minerals were determined. As olive roots can go deep in the soil profile to extract nutrients, the total available nutrients per tree (over the whole profile) were estimated. Multiple regression analyses were performed to determine the model that best accounts for yield variability. Total available soil potassium amount (), soil total N amount (), and soil depth () had the highest correlations with olive fruit yields. Available soil potassium amount and soil depth explained together 77% of the yield variability observed. In addition to these two factors, adding leaf B and Fe concentrations to the model increased the variability explained to 83%. Ashraf Tubeileh, Francis Turkelboom, Anwar Al-Ibrahem, Richard Thomas, and Kholoud Sultan-Tubeileh Copyright © 2014 Ashraf Tubeileh et al. All rights reserved. Physical and Aerodynamic Properties of Lavender in relation to Harvest Mechanisation Tue, 07 Oct 2014 10:06:01 +0000 A laboratory study evaluated the physical and aerodynamic properties of lavender cultivars in relation to the design of an improved lavender harvester that allows removal of flowers from the stem using the stripping method. The identification of the flower head adhesion, stem breakage, and aerodynamic drag forces were conducted using an Instron 1122 instrument. Measurements on five lavender cultivars at harvest moisture content showed that the overall mean flower detachment force from the stem was 11.2 N, the mean stem tensile strength was 36.7 N, and the calculated mean ultimate tensile stress of the stem was 17.3 MPa. The aerodynamic measurements showed that the drag force is related with the flower surface area. Increasing the surface area of the flower head by 93% of the “Hidcote” cultivar produced an increase in drag force of between 24.8% and 50.6% for airflow rates of 24 and 65 m s−1, respectively. The terminal velocities of the flower heads of the cultivar ranged between 4.5 and 5.9 m s−1, which results in a mean drag coefficient of 0.44. The values of drag coefficients were compatible with well-established values for the appropriate Reynolds numbers. Christos I. Dimitriadis, James L. Brighton, Mike J. O’Dogherty, Maria I. Kokkora, and Anastasios I. Darras Copyright © 2014 Christos I. Dimitriadis et al. All rights reserved. Phosphorus Placement Effects on Phosphorous Recovery Efficiency and Grain Yield of Wheat under No-Tillage in the Humid Pampas of Argentina Tue, 23 Sep 2014 12:57:35 +0000 No-till (NT) affects dynamics of phosphorus (P) applied. Wheat response to P fertilization can be affected by available soil P, grain yield, placement, rate, and timing of fertilization. Furthermore, mycorrhizal associations could contribute to improving plant P uptake. Three experiments were used to evaluate P rate (0, 25, and 50 kg P ha−1) and fertilizer placement (broadcasted or deep-banded) effects in NT wheat on P recovery efficiency (PRE) yield and arbuscular mycorrhizal colonization (AMC) which was assessed in one experiment. Fertilization increased dry matter (DM) and accumulated P. Broadcasted P produced lower P accumulation than deep-banded P only at tillering. Phosphorus rate decreased PRE, and placement method did not affect it. Grain yield response was increased by P rate (857 and 1805 kg ha−1 for 25 and 50 kg P ha−1, resp.) and was not affected by placement method (4774 and 5333 kg ha−1 for broadcasted and deep-banded, resp.). Deep-banded P depressed root AMC compared with broadcast applications. Highest AMC in P broadcasted treatments could help to explain the lack of differences between placement methods. These results indicate that Mollisol have low P retention capacity. Therefore, broadcasted P could be used as an alternative of fertilizer management for NT wheat. Pablo Andrés Barbieri, Hernán René Sainz Rozas, Fernanda Covacevich, and Hernán Eduardo Echeverría Copyright © 2014 Pablo Andrés Barbieri et al. All rights reserved. Effect of Cultivars and Planting Date on Yield, Oil Content, and Fatty Acid Profile of Flax Varieties (Linum usitatissimum L.) Mon, 15 Sep 2014 00:00:00 +0000 In order to determine the effect of cultivars and planting date on flax fatty acid profile, seed yield, and oil content, an assay with seven cultivars (Baikal, Prointa Lucero, Prointa Ceibal, Panambí INTA, Curundú INTA, Carapé INTA, and Tape INTA) was carried out at Parana Agricultural Experimental Station, Argentina. Significant differences among cultivars were found for content of palmitic (5–7 g/100 g), stearic (5–8 g/100 g), linoleic (13–19 g/100 g), saturated (11–15 g/100 g), and unsaturated acids (92–96 g/100 g) within the seven cultivars. The best seed yields were observed in Prointa Lucero and Carapé INTA varieties (2091.50 kg·ha−1 and 2183.34 kg·ha−1, respectively) in the first planting date and in Carapé INTA and Prointa Lucero (1667 kg·ha−1 and 1886 kg·ha−1, respectively) in the second planting date. A delayed planting date had a negative effect on seed yield (1950 kg·ha−1 and 1516 kg·ha−1) and oil content (845 kg·ha−1 and 644 kg·ha−1) but did not affect oil composition. Maricel Andrea Gallardo, Héctor José Milisich, Silvina Rosa Drago, and Rolando José González Copyright © 2014 Maricel Andrea Gallardo et al. All rights reserved. Root Distribution and Nitrogen Fixation Activity of Tropical Forage Legume American Jointvetch (Aeschynomene americana L.) cv. Glenn under Waterlogging Conditions Mon, 08 Sep 2014 08:33:16 +0000 We investigated the root distribution and nitrogen fixation activity of American jointvetch (Aeschynomene americana L.) cv. Glenn, under waterlogging treatment. The plants were grown in pots under three different treatments: no waterlogging (control), 30 days of waterlogging (experiment 1), and 40 days of waterlogging (experiment 2). The plants were subjected to the treatments on day 14 after germination. Root dry matter (DM) weight distribution of waterlogged plants was shallower than controls after day 20 of waterlogging. Throughout the study period, the total root DM weight in waterlogged plants was similar to that in the controls. Enhanced rooting (adventitious roots) and nodule formation at the stem base were observed in waterlogged plants after day 20 of waterlogging. The average DM weight of individual nodules on the region of the stem between the soil surface and water surface of waterlogged plants was similar to that of individual taproot nodules in the controls. Waterlogged plants had slightly greater plant DM weight than the controls after 40 days of treatment. The total nitrogenase activity (TNA) of nodules and nodule DM weight were higher in waterlogged plants than in the controls. Waterlogged American jointvetch had roots with nodules both around the soil surface and in the area between the soil surface and water surface after 20 days of waterlogging, and they maintained high nitrogenase activity and net assimilation rate that resulted in an increased growth rate. Manabu Tobisa, Masataka Shimojo, and Yasuhisa Masuda Copyright © 2014 Manabu Tobisa et al. All rights reserved. Management of Vegetation by Alternative Practices in Fields and Roadsides Sun, 24 Aug 2014 07:25:11 +0000 In attempts to reduce the amounts of conventional herbicides used, alternative practices are sought in the management of roadside vegetation. In this investigation, alternative herbicides (citric-acetic acids, clove oil, corn gluten meal, limonene, and pelargonic acid), flaming, and mulching were assessed in management of annual and perennial, herbaceous vegetation in field and roadside plots. Several formulations of alternative herbicides applied singly or repeatedly during the growing season were evaluated and compared with conventional herbicides (glyphosate and glufosinate ammonium) or with flaming or mulching. Citric-acetic acid formulations, clove oil, limonene, or pelargonic acid applied as foliar sprays immediately desiccated foliage, but the efficacy lasted for no longer than five weeks. Repeated applications were better than single applications of these herbicides in suppressing plant vegetative growth. Corn gluten meal imparted little or no early control and stimulated late-season growth of vegetation. A single flaming of vegetation gave no better control than the alternative herbicides, but repeated flaming strongly restricted growth. Mulching with wood chips or bark gave season-long suppression of vegetation. Glyphosate gave season-long inhibition of vegetation, but the efficacy of glufosinate ammonium waned as the growing season progressed. For season-long suppression of vegetation with alternative herbicides or flaming repeated applications will be required. Allen V. Barker and Randall G. Prostak Copyright © 2014 Allen V. Barker and Randall G. Prostak. All rights reserved. Response of Soybean to Early-Season Planting Dates along the Upper Texas Gulf Coast Thu, 14 Aug 2014 09:22:51 +0000 Soybeans (Glycine max L.) can be planted along the upper Texas Gulf Coast from mid-March through May to take advantage of early season rains and to complete harvest before hurricane season and fall rains become a problem. However, in the Calhoun County area (28.5° north latitude), these planting dates have resulted in below average yields and reasons for these yield reductions are not clear. To determine if earlier planting dates could be an option to eliminate the low yields, field studies were conducted from 2005 through 2010 in Calhoun County, Texas, to determine soybean cultivar response to planting dates which ranged from mid-February through the last of April. Typically, soil temperatures in this area are above 18°C in mid-February and depending on weather patterns may not fall much lower during any time in the early portion of the growing season. The greatest yield was obtained with the mid-February and mid-March planting dates compared with early- or late-April planting dates. Typically, as planting date was delayed, the interval between planting and harvest decreased. W. James Grichar and Stephen P. Biles Copyright © 2014 W. James Grichar and Stephen P. Biles. All rights reserved. Effect of Cow Urine on the Growth Characteristics of Fusarium lateritium, an Important Coffee Fungus in Zimbabwe Wed, 23 Jul 2014 06:34:18 +0000 An in vitro assay was carried out to establish if cow urine at different concentrations (500 µL/mL, 300 µL/mL, 200 µL/mL, and 100 µL/mL) can be used to control the growth of F. lateritium, the fungal agent causing Fusarium bark disease in coffee. The growth characteristics selected were conidial germination, germ tube length, mycelial growth rate, and sporulation. Copper oxychloride 50% W.P. was the standard, distilled water was the negative control, and undiluted cow urine was the positive control. The undiluted cow urine was most effective in inhibiting fungal growth with the rest of the cow urine concentrations showing dose dependent efficacy compared to the negative control (P < 0.01). Copper oxychloride had the highest efficacy of all treatments with the exception of the inhibition of mycelial growth where undiluted cow urine had higher efficacy and sporulation where efficacy was comparable to undiluted cow urine. There is potential for the use of cow urine as a means of controlling Fusarium bark disease with other advantages being availability, low cost, and limited environmental damage. Timothy Gotora, Lawrence Masaka, and Marvelous Sungirai Copyright © 2014 Timothy Gotora et al. All rights reserved. Determining Critical Soil pH for Sunflower Production Sun, 06 Jul 2014 00:00:00 +0000 Soil acidity has become a major yield-limiting factor in cropping systems of the Southern Great Plains, in which winter wheat (Triticum aestivum L.) is the predominant crop. Sunflower (Helianthus annuus L.) is a strong rotational crop with winter wheat due to its draught and heat tolerance. However, the effects of low soil pH on sunflower productivity have not been explored. The objective of this study was to determine the critical soil pH and aluminum concentration () for sunflower. Sunflower was grown in a randomized complete block design with three replications of a pH gradient ranging from 4.0 to 7.0 at three locations with varying soil types. Soil pH was altered using aluminum sulfate (Al2(SO4)3) and hydrated lime (Ca(OH)2). Plant height, vigor, and survivability were all negatively affected by soil acidity. Sunflower yield was reduced by 10% at or below soil pH 4.7 to 5.3 dependent upon location and soil type. Levels of above 6.35 mg kg−1 reduced seed yield by 10% or greater. We concluded that sunflower may serve as a better rotational crop with winter wheat under acidic conditions when compared to other adaptable crops. Apurba Sutradhar, Romulo P. Lollato, Katy Butchee, and Daryl B. Arnall Copyright © 2014 Apurba Sutradhar et al. All rights reserved. FAO-56 Penman-Monteith Daily from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data Mon, 02 Jun 2014 06:13:19 +0000 Hargreaves equation (HG), which lacks a wind speed () term, was modified, through a linear regression calibration method, into LHGu which has terms. LHGu is effectively a simplified method for approximating FAO-56 Penman-Monteith equation (FPM) daily reference evapotranspiration () in tropics with only temperature data. In LHGu, the “0.0023” constant term in HG was calibrated as a shifted power function of , and the calibration constant was parametrized as a quadratic function of . LHGu was developed using simulated constant data and historical temperature data for four sites in West Africa: Abidjan, Accra, Daloa, and Lome. LHGu matched FPM better than HG over a wide range of : for Accra, for range 0.5–6.0 m/s, the modified coefficient of efficiency, , varied narrowly (0.83–0.98) for LHGu but widely (0.14–0.95) for HG optimized for  m/s; the corresponding MBE ranges were −0.05–0.01 mm/d for LHGu and 0.02–0.63 mm/d for HG which cannot respond to varying daily . LHGu is useful for quickly computing practically accurate estimates of FPM for varying daily where only temperature data are available. Eric Kra Copyright © 2014 Eric Kra. All rights reserved. Effect of Methyl Jasmonate on Phytoalexins Biosynthesis and Induced Disease Resistance to Fusarium oxysporum f. sp. Vasinfectum in Cotton (Gossypium hirsutum L.) Wed, 28 May 2014 11:23:12 +0000 The effect of methyl jasmonate (MeJA) sprayed on cotton healthy leaves was evaluated in terms of inherent bioactive chemicals induction. The total phenolic content significantly increased after MeJA 5.0 mM treatments compared to the other tested concentrations (0; 2.5; 10; 15; 20 mM). Among the eleven phenolic compounds which were found except for ferulic acid, gossypetin, gossypol, 3-p-coumaroylquinic acid, and piceatannol were identified as major phenolic constituents of cotton. Their content also significantly increased after the MeJA treatment. In addition, gossypol increased 64 times compared to the control, in the 5.0 mM MeJA treatment. Furthermore, cichoric acid, chlorogenic acid, and pterostilbene are synthesized de novo in leaves of MeJA-treated plant. Treatment of cotton leaves with MeJA 5.0 mM followed 72 h of incubation hampered the expression of Fusarium wilt caused by Fusarium oxysporium f. sp. vasinfectum (FOV). MeJA efficiency was concentration and incubation time dependent. Disease severity on MeJA-treated leaves was significantly lower as compared to the control. Therefore, the high content of gossypetin, gossypol, 3-p-coumaroylquinic acid, ferulic acid, and piceatannol and the presence of cichoric acid, chlorogenic acid, and pterostilbene in plants treated with MeJA, contrary to the control, are essential to equip the cotton compounds with defences or phytoalexins against FOV. Yao Kouakou François Konan, Kan Modeste Kouassi, Kouakou Laurent Kouakou, Edmond Koffi, Koffi Nazaire Kouassi, Diabaté Sekou, Mongomaké Kone, and Tanoh Hilaire Kouakou Copyright © 2014 Yao Kouakou François Konan et al. All rights reserved. Temperature Effect on Yield and Yield Components of Different Rice Cultivars in Flowering Stage Sun, 18 May 2014 05:56:24 +0000 In order to study the effect of cold stress in flowering stage on yield and yield components of different rice cultivars, an experiment was performed as split plot factorial based on completely randomized design (CRD) in greenhouse of deputy of rice research institute of Iran (Amol) in 2010, in three repetitions. Treatment included 5 varieties as main factors that included cultivars of shirudi, fajr, local tarom, hybrid, and line 843. Two levels of temperatures (13°C, stress temperature) and (32°C, normal temperature, control) along with flowering stage were selected as two subfactors. Three seedlings were planted in each plot. The cold stress was done in flowering stage with holding pots at 13°C for 15 days. Results showed that low temperature had significant effect in level of 1 percent on all characters, such as the number of panicles, the length of panicle, and the number of full, empty, and total grains; as a result, yield had caused significant reduction. Interaction between temperature and varieties showed that most tolerant variety in relation to temperature stress along with least percentage yield (19%) is shirudi variety and the most sensitive one with most percentage of yield decrease (29%) was local tarom variety. R. Ghadirnezhad and A. Fallah Copyright © 2014 R. Ghadirnezhad and A. Fallah. All rights reserved. Control of Echinochloa sp. in the Irrigated Rice Crop Wed, 14 May 2014 12:02:00 +0000 The species of Echinochloa (barnyardgrass) stand out among major weeds infesting rice cropping and damages are variable depending on the weed population, rice cultivar, and management practices adopted by rice farmers. The objective of this work was to measure the control of barnyardgrass in rice cropping, cultivar Qualimax 1, due to the early times of flood irrigation, application times, and doses of penoxsulam. The experiment was conducted in the field, where the experimental design used a randomized block design with a split plot design with four replications. The treatments consisted of two application periods (early and late) of penoxsulam three times of irrigation start (1, 15 and 30 days after treatment application—(DAT)) and herbicide doses (0, 24, 36, 48 and 60 g ha−1). The herbicide penoxsulam revealed that combined with irrigation starting 15 days after herbicide application promoted efficient control of barnyardgrass. Luís Eduardo Panozzo, Dirceu Agostinetto, Pedro Valério Dutra de Moraes, Deivid Araújo Magano, Adilson Harter, and Luciana Barros Pinto Copyright © 2014 Luís Eduardo Panozzo et al. All rights reserved. Response of Winter Wheat Grain Yield and Phosphorus Uptake to Foliar Phosphite Fertilization Thu, 08 May 2014 11:18:34 +0000 One of the major problems that potentially hinders the use of foliar fertilization as a tool to improve nutrient use efficiency is the lack of effective formulations. A phosphite based product, Nutri-phite (3% N, 8.7% P, and 5.8% K) was used as model phosphite formulation for foliar application in winter wheat (Triticum aestivum L). Five field trials were established in the fall of 2009 and 2010 at Perkins, Perry, and Morrison, OK. Treatments encompassed the application of nitrogen (N) at 100 or 75% of crop need and phosphorus at 100 (P 100%) and 80% (P 80%) sufficiency with and without Nutri-phite. Nutri-phite was applied at one and/or two stages of wheat; GS 13 to 14 and GS 49 to 53 at the rate of 433 and 148 g ha−1 P and N, respectively. Grain yield was increased by Nutri-phite treatments, especially at Morrison. Grain P concentration of plots treated with two applications of Nutri-phite ranged from 13 to 55% more than the nontreated and standard NP received plots at Perkins in 2009/10 and Perry in 2010/11. Grain P uptake was increased due to application of Nutri-phite at Perkins in 2009/10 and Morrison and Perry in 2010/11. Combined over three year-locations, Nutri-phite increased grain P concentration by 11.6%. The higher grain P concentration of plots treated with Nutri-phite compared to the other treatments clearly demonstrates its potential in improving P status of wheat grain. Muaid S. Ali, Apurba Sutradhar, Ma Lourdes Edano, Jeffrey T. Edwards, and Kefyalew Girma Copyright © 2014 Muaid S. Ali et al. All rights reserved. Research Progress and Perspectives of Nitrogen Fixing Bacterium, Gluconacetobacter diazotrophicus, in Monocot Plants Wed, 07 May 2014 06:38:45 +0000 Gluconacetobacter diazotrophicus is a nitrogen fixing bacterium originally found in monocotyledon sugarcane plants in which the bacterium actively fixes atmosphere nitrogen and provides significant amounts of nitrogen to plants. This bacterium mainly colonizes intercellular spaces within the roots and stems of plants and does not require the formation of the complex root organ like nodule. The bacterium is less plant/crop specific and indeed G. diazotrophicus has been found in a number of unrelated plant species. Importantly, as the bacterium was of monocot plant origin, there exists a possibility that the nitrogen fixation feature of the bacterium may be used in many other monocot crops. This paper reviews and updates the research progress of G. diazotrophicus for the past 25 years but focuses on the recent research development. N. Eskin, K. Vessey, and L. Tian Copyright © 2014 N. Eskin et al. All rights reserved. Promoting Agricultural Research and Development to Strengthen Food Security in South Asia Tue, 06 May 2014 06:44:24 +0000 This study aims to highlight the status of agricultural R&D in South Asia and contends that creating an effective agricultural research and innovation systems is a vital element to ensure food security in this region. South Asia is home to around one-fourth of mankind and houses the largest proportion of undernourished people in the world. Despite a period of marked economic growth averaging 6% a year over the past two decades, it remains the world's second poorest region contributing a mere 2.2% in global annual GDP. Agriculture is the mainstay of South Asian economy employing around 60% of the total workforce and generating around 20% of total GDP. South Asia has the recognition of being the second most food-insecure region next only to sub-Saharan Africa. Though there is growing evidence that technological innovation has a key role to play in increasing agricultural production and strengthening food security, agricultural research and development (R&D) sector has failed to garner sufficient attention till now. This study also depicts the current situation of food security in South Asia and illustrates how agricultural education and innovation hold the master key to solve the food security issues for the world's most densely populated region. Ghose Bishwajit Copyright © 2014 Ghose Bishwajit. All rights reserved. Apple Pollination Biology for Stable and Novel Fruit Production: Search System for Apple Cultivar Combination Showing Incompatibility, Semicompatibility, and Full-Compatibility Based on the S-RNase Allele Database Wed, 30 Apr 2014 07:05:33 +0000 Breeding and cultivation of new apple cultivars are among the most attractive and important issues for apple researchers. As almost all apple cultivars exhibit gametophytic self-incompatibility (GSI), cross-pollination between genetically different cultivars and species is essential not only for stable fruit production, but also for breeding of new cultivars. For cross-pollination by insect or hand pollination, pollen viability and pistil fertility are key factors, but also the mechanism of GSI has to be taken into account. This paper reviews the germination rate of pollen after storage in different conditions, at different periods of flowering, and in combination with pistil fertility and cross-compatibility among wild-, crab-, and cultivated apples. Furthermore, suitable cultivar combinations for new attractive apple cultivars based on GSI are explored. Especially, details about S-genotypes of apple cultivars, which are present in recent cultivar catalogues, are introduced together with a newly established on-line searchable database of S-genotypes of cultivars, wild apples and crab apples that shows incompatibility, semicompatibility, and full-compatibility. Shogo Matsumoto Copyright © 2014 Shogo Matsumoto. All rights reserved. Rice Breeding for High Grain Yield under Drought: A Strategic Solution to a Complex Problem Mon, 28 Apr 2014 09:06:44 +0000 Drought is one of the major abiotic stresses that affect rice production in rainfed areas. Recent trends in climate change have predicted a further increase in drought intensity, making the development of new drought-tolerant rice cultivars critical to sustain rice production in this ecosystem. The use of grain yield as a selection criterion at the International Rice Research Institute (IRRI), through proper population development and precise phenotyping techniques, has allowed the development of several high-yielding rice cultivars that have been released in major rainfed rice-growing areas. This strategy has also allowed the identification of several major quantitative trait loci (QTLs) that show large effects under drought across environments and genetic backgrounds. These QTLs are being pyramided together to develop drought-tolerant versions of popular drought-susceptible varieties. The near-isogenic lines (NILs) developed can replace the popular, high-yielding but drought-susceptible varieties in rainfed areas prone to drought. Additionally, these NILs serve as suitable genetic material for the study of molecular and physiological mechanisms underlying these QTLs. This may provide a better understanding of plant functions responsible for high grain yield under drought and lead to the identification of new traits and genes. Shalabh Dixit, Anshuman Singh, and Arvind Kumar Copyright © 2014 Shalabh Dixit et al. All rights reserved.