International Journal of Agronomy The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Weed Management in Spring Seeded Barley, Oats, and Wheat with Prosulfuron Mon, 07 Apr 2014 13:36:58 +0000 A limited number of preplant (PP) herbicides are available for spring seeded cereals in Ontario. Six field trials were conducted at the Huron Research Station, Exeter, Ontario, over a two-year period (Exeter, 2010 and 2011) to evaluate glyphosate, prosulfuron, and glyphosate plus prosulfuron applied PP for weed management in spring seeded no-till barley, oats, and wheat. There was no injury in barley, oats, and wheat with glyphosate, prosulfuron, and glyphosate plus prosulfuron applied preplant at the rates evaluated at 1, 2, and 4 weeks after crop emergence. Prosulfuron provided 49–99% control of AMBEL, 28% or less control of CONAR, 31–94% control of POLCO, 49–98% control of SINAR, and 46–79% control of SONAR. Prosulfuron in combination with glyphosate provided 73–98% control of AMBEL, less than 43% control of CONAR, 39–94% control of POLCO, 63–98% control of SINAR, and 60–85% control of SONAR. Prosulfuron reduced density of AMBEL 76% and SINAR 93% but had no significant effect on density of CONAR, POLCO, or SONAR. Prosulfuron in combination with glyphosate reduced biomass of AMBEL as much as 96% and SINAR 98% but had no significant effect on biomass of CONAR, POLCO, or SONAR. Yield of barley, oats, and wheat was not affected with glyphosate, prosulfuron, and glyphosate plus prosulfuron at the rates evaluated. Nader Soltani, Lynette R. Brown, Todd Cowan, and Peter H. Sikkema Copyright © 2014 Nader Soltani et al. All rights reserved. Effect of Preplant Irrigation, Nitrogen Fertilizer Application Timing, and Phosphorus and Potassium Fertilization on Winter Wheat Grain Yield and Water Use Efficiency Thu, 03 Apr 2014 11:48:31 +0000 Preplant irrigation can impact fertilizer management in winter wheat. The objective of this study was to evaluate the main and interactive effects of preplant irrigation, N fertilizer application timing, and different N, P, and K fertilizer treatments on grain yield and WUE. Several significant two-way interactions and main effects of all three factors evaluated were observed over four growing seasons for grain yield and WUE. These effects could be described by differences in rainfall and soil moisture content among years. Overall, grain yield and WUE were optimized, if irrigation or adequate soil moisture were available prior to planting. For rain-fed treatments, the timing of N fertilizer application was not as important and could be applied before planting or topdressed without much difference in yield. The application of P fertilizer proved to be beneficial on average years but was not needed in years where above average soil moisture was present. There was no added benefit to applying K fertilizer. In conclusion, N and P fertilizer management practices may need to be altered yearly based on changes in soil moisture from irrigation and/or rainfall. Jacob T. Bushong, D. Brian Arnall, and William R. Raun Copyright © 2014 Jacob T. Bushong et al. All rights reserved. Assessing the Spectral Separability of Flue Cured Tobacco Varieties Established on Different Planting Dates and under Varying Fertilizer Management Levels Wed, 26 Mar 2014 09:29:08 +0000 The NDVI was used to discriminate tobacco variety, assess fertilizer levels, and determine the impact of planting date on separating crops. A split plot design with four planting dates, September, October, November, and December, as main plots, variety as subplot, and fertilizer treatments as sub-subplots was used. Radiometric measurements were taken from 5 m × 5 m sampling plots, using a multispectral radiometer. The September, October, and November crops had significant variety x fertilizer treatment differences () from the age of 10 weeks. T 66 and KRK26 varieties had similar () NDVI values and these were greater () than those for K E1. The 100% and the 150% fertilizer treatments were similar () and both were greater () than the 50% fertilizer treatments. All of the fertilizer and variety treatments at the December planting dates had similar reflectance characteristics (), which were lower () than the September and October planting dates. The results showed that planting dates, varieties, and fertilizer levels could be distinguished using spectral data. Weeks 10-11 and 15 after the start of the experiment were optimal for separating the planting date effect. Ezekia Svotwa, Anxious J. Masuka, Barbara Maasdorp, and Amon Murwira Copyright © 2014 Ezekia Svotwa et al. All rights reserved. Estimating Rice Yield under Changing Weather Conditions in Kenya Using CERES Rice Model Wed, 26 Mar 2014 06:44:54 +0000 Effects of change in weather conditions on the yields of Basmati 370 and IR 2793-80-1 cultivated under System of Rice Intensification (SRI) in Mwea and Western Kenya irrigation schemes were assessed through sensitivity analysis using the Ceres rice model v 4.5 of the DSSAT modeling system. Genetic coefficients were determined using 2010 experimental data. The model was validated using rice growth and development data during the 2011 cropping season. Two SRI farmers were selected randomly from each irrigation scheme and their farms were used as research fields. Daily maximum and minimum temperatures and precipitation were collected from the weather station in each of the irrigation schemes while daily solar radiation was generated using weatherman in the DSSAT shell. The study revealed that increase in both maximum and minimum temperatures affects Basmati 370 and IR 2793-80-1 grain yield under SRI. Increase in atmospheric CO2 concentration led to an increase in grain yield for both Basmati and IR 2793-80-1 under SRI and increase in solar radiation also had an increasing impact on both Basmati 370 and IR 2793-80-1 grain yield. The results of the study therefore show that weather conditions in Kenya affect rice yield under SRI and should be taken into consideration to improve food security. W. O. Nyang’au, B. M. Mati, K. Kalamwa, R. K. Wanjogu, and L. K. Kiplagat Copyright © 2014 W. O. Nyang’au et al. All rights reserved. Evaluation of Green Manure Amendments for the Management of Fusarium Basal Rot (Fusarium oxysporum f.sp. cepae) on Shallot Tue, 04 Mar 2014 09:04:46 +0000 Shallot (Allium cepa L. var. ascalonicum) is the most traditional vegetable crop in Ethiopia. Shallot is susceptible to a number of diseases that reduce yield and quality, among which fusarium basal rot (FBR) caused by Fusarium oxysporum f.sp. cepae (Foc) is one of the most important yield limiting factors in Ethiopia. The present study was designed to evaluate the effectiveness of Brassica crops for the management of shallot FBR on shallot. The experiments were carried out at Debre Zeit Agricultural Research Center using cabbage (Brassica oleracea), garden cress (Lepidium sativum), Ethiopia mustard (B. carinata), and rapeseed (B. napus). The evaluations were done under in vitro and greenhouse conditions. Under in vitro test condition it was confirmed that extracts of Ethiopian mustard and rapeseed showed higher inhibition on the growth of Foc pathogen compared to control. Data on seedling emergence, plant height, plant stand, disease incidence, severity, cull bulbs, and bulb weight were collected in greenhouse experiment. The green manure amendments of rapeseed and Ethiopian mustard significantly reduced disease incidence by 21% and 30% and disease severity by 23% and 29%, respectively. However the plant emergency was not significantly different among treatments in greenhouse test. These results indicated that Ethiopian mustard and rapeseed crops have potential as green manure for the management of FBR disease of shallot crop. Assefa Sintayehu, Seid Ahmed, Chemeda Fininsa, and P. K. Sakhuja Copyright © 2014 Assefa Sintayehu et al. All rights reserved. Effect of Osmopriming Duration on Germination, Emergence, and Early Growth of Cowpea (Vigna unguiculata (L.) Walp.) in the Sudan Savanna of Nigeria Thu, 27 Feb 2014 09:26:32 +0000 Seed osmopriming could be a sustainable method to increase crop establishment, uniform emergence, and growth of plant on the field. Laboratory and field studies were carried out in 2010 cropping season at Usmanu Danfodiyo University, Sokoto, to study the effect of seed osmopriming duration on the germination, emergence, and growth of cowpea seeds. Treatments consisted of three osmopriming duration (soaking in 1% KNO3 salt for 6, 8, and 10 hrs), one hydroprimed control (10 hr), and an unprimed control. These five treatments were laid out in a completely randomized design (CRD) replicated four times. The results showed that osmopriming with KNO3 for different durations was at par but was superior to unprimed treatments in terms of seed germination, emergence, plant height, and dry matter accumulation at 3 weeks after sowing. From this study, it can therefore be concluded that seeds of cowpea could be primed (both hydro and osmopriming) for increased performance. However, osmopriming with KNO3 salt (soaked in 1% KNO3 salt solution and dried before sowing) for 6 hours could result in greater seed germination and seedling height than hydropriming. Ajit Singh, Rabi Dahiru, Mukhtar Musa, and Bello Sani Haliru Copyright © 2014 Ajit Singh et al. All rights reserved. Growth Rate and Yield of Two Tomato Varieties (Lycopersicon esculentum Mill) under Green Manure and NPK Fertilizer Rate Samaru Northern Guinea Savanna Thu, 20 Feb 2014 07:05:48 +0000 Field experiments were conducted in 2010-2011 and 2011-2012 dry seasons at the Research farm of the Institute for Agricultural Research, Samaru northern guinea savanna agro ecological zone of Nigeria to study growth rate and yield of tomato under green manure and NPK fertilizer rates. Treatment consisted of two tomato varieties (Roma VF and UC82B), four rates of NPK 15-15-15 fertilizer (0, 150, 300, and 450 kg ha−1), and three rates of green manure (0, 5, and 10 t ha−1), laid in a split-plot design with three replications. The variety and fertilizer constituted the main plot while green manure was allocated in subplot. Both varieties responded linearly in growth stages of 5 and 7 weeks after transplanting (WAT) on plant height, relative growth rate, and crop growth rate (CGR). However, UC82B proves superior over Roma VF on growth indices CGR at 5–7 WAT, net assimilation rate (NAR) at 7–9 WAT, and total fruit yield with 10.6% higher. Application of NPK fertilizer significantly increased growth such as plant height, crop dry weight, crop growth rate, and yield. Application between 250 and 280 kg ha−1 NPK fertilizers was found efficient for total fruit yield. A. S. Isah, E. B. Amans, E. C. Odion, and A. A. Yusuf Copyright © 2014 A. S. Isah et al. All rights reserved. Distribution of Glyphosate- and Thifensulfuron-Resistant Palmer Amaranth (Amaranthus palmeri) in North Carolina Tue, 11 Feb 2014 15:48:20 +0000 Glyphosate resistance in Palmer amaranth was first confirmed in North Carolina in 2005. A survey that year indicated 17 and 18% of 290 populations sampled were resistant to glyphosate and thifensulfuron, respectively. During the fall of 2010, 274 predetermined sites in North Carolina were surveyed to determine distribution of Palmer amaranth and to determine if and where resistance to fomesafen, glufosinate, glyphosate, and thifensulfuron occurred. Palmer amaranth was present at 134 sites. When mortality for each biotype was compared to a known susceptible biotype for each herbicide within a rate, 93 and 36% of biotypes were controlled less by glyphosate (840 g ae ha−1) and thifensulfuron (70 g ai ha−1), respectively. This approach may have underestimated resistance for segregating populations due to lack of homogeneity of the herbicide resistance trait and its contribution to error variance. When mortality and visible control were combined, 98% and 97% of the populations were resistant to glyphosate and the ALS inhibitor thifensulfuron, respectively, and 95% of the populations expressed multiple resistance to both herbicides. This study confirms that Palmer amaranth is commonly found across the major row crop production regions of North Carolina and that resistance to glyphosate and ALS-inhibiting herbicides is nearly universal. No resistance to fomesafen or glufosinate was observed. Amy H. Poirier, Alan C. York, David L. Jordan, Aman Chandi, Wesley J. Everman, and Jared R. Whitaker Copyright © 2014 Amy H. Poirier et al. All rights reserved. A Review on Recycling of Sunflower Residue for Sustaining Soil Health Tue, 04 Feb 2014 13:11:30 +0000 Modern agriculture is now at the crossroads ecologically, economically, technologically, and socially due to soil degradation. Critical analysis of available information shows that problems of degradation of soil health are caused due to imbalanced, inadequate and promacronutrient fertilizer use, inadequate use or no use of organic manures and crop residues, and less use of good quality biofertilizers. Although sizeable amount of crop residues and manure is produced in farms, it is becoming increasingly complex to recycle nutrients, even within agricultural systems. Therefore, there is a need to use all available sources of nutrients to maintain the productivity and fertility at a required level. Among the available organic sources of plant nutrients, crop residue is one of the most important sources for supplying nutrients to the crop and for improving soil health. Sunflower is a nontraditional oil seed crop produced in huge amount of crop residue. This much amount of crop residues is neither used as feed for livestock nor suitable for fuel due to low energy value per unit mass. However, its residue contains major plant nutrients in the range from 0.45 to 0.60% N, 0.15 to 0.22% P, and 1.80 to 1.94% K along with secondary and micronutrients, so recycling of its residue in the soil may be one of the best alternative practices for replenishing the depleted soil fertility and improving the physical, chemical, and biological properties of the soil in the present era of production. However, some researchers have reported allelopathic effects of sunflower residue on different crops. So, selection of suitable crops and management practices may play an important role to manage the sunflower residue at field level. Subhash Babu, D. S. Rana, G. S. Yadav, Raghavendra Singh, and S. K. Yadav Copyright © 2014 Subhash Babu et al. All rights reserved. Evaluation of Agronomic Management Practices on Farmers’ Fields under Rice-Wheat Cropping System in Northern India Thu, 30 Jan 2014 10:02:35 +0000 Rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori and Paol.) is the most important two crops a year intensive rice based cropping system of Asia. Agronomic management is the most important input for getting potential yield and high net returns in any crop or crop sequence. Most of the farmers used to grow old varieties of rice and wheat without any row arrangement. Fertilization is mainly limited to nitrogenous fertilizer only. Therefore, the present study was undertaken to find out the effect of different agronomic management practices on productivity and economics of rice-wheat system at farmers’ fields. Inclusion of improved variety in rice and wheat incurred additional cost of $52/ha and provided additional return of $101/ha, whereas sowing/transplanting of rice and wheat in lines incurred additional cost of $30/ha and resulted in additional returns of $146/ha. Balanced fertilization incurred additional cost of $38 over the imbalanced fertilization and provided additional returns of $180/ha. Recommended package of practices (improved variety, line sowing/transplanting and balanced fertilization) incurred additional cost of cultivation of $120/ha over the farmers’ practice and achieved additional net returns of $426/ha. Dinesh Kumar Singh, Purushottam Kumar, and A. K. Bhardwaj Copyright © 2014 Dinesh Kumar Singh et al. All rights reserved. Response of Dry Bean to Sulfentrazone Plus Imazethapyr Thu, 30 Jan 2014 09:37:51 +0000 Field studies were conducted in 2010 and 2011 at the Huron Research Station, Exeter, Ontario and from 2009 to 2011 at the University of Guelph Ridgetown Campus, Ridgetown, Ontario to evaluate the sensitivity of four market classes of dry bean to sulfentrazone applied preemergence at 105, 140, and 280 g ai/ha alone and in combination with imazethapyr at 37.5 g ai/ha. At 1 week after emergence (WAE), sulfentrazone alone or in combination with imazethapyr at all doses evaluated caused no significant visible injury in dry bean. At 2 WAE, sulfentrazone alone caused 1–11, 1–11, 1–5, and 3–19% visible injury, and sulfentrazone + imazethapyr caused 3–11, 2–10, 2–5, and 4–20% visible injury in black, cranberry, kidney, and white bean, respectively. At 4 WAE, sulfentrazone alone caused 1–7, 1–7, 0–4, and 1–16% visible injury and sulfentrazone + imazethapyr caused 1–8, 1–5, 1–3, and 2–14% visible injury in black, cranberry, kidney, and white bean, respectively. Sulfentrazone PRE caused slightly greater injury in black and white bean compared to cranberry and kidney bean. Generally, crop injury with sulfentrazone at rates up to 140 g ai/ha alone and in combination with imazethapyr at 37.5 g ai/ha was minimal with no adverse effect on plant height, shoot dry weight, seed moisture content, and yield. Based on these results, there is potential for preemergence application of sulfentrazone at rates up to 140 g ai/ha alone or in combination with imazethapyr at 37.5 g ai/ha in black, cranberry, kidney and white bean. Nader Soltani, Christy Shropshire, and Peter H. Sikkema Copyright © 2014 Nader Soltani et al. All rights reserved. Development of an Effective Nonchemical Method against Plasmodiophora brassicae on Chinese Cabbage Wed, 29 Jan 2014 00:00:00 +0000 Clubroot disease, caused by Plasmodiophora brassicae, is a serious soil-borne disease of crucifer worldwide, and it can significantly reduce yield and quality. Although some agrochemicals have been used to manage clubroot and can provide effective control, increasing use of chemical inputs causes several negative effects. In this study, using Chinese cabbage (Brassica rapa L. subsp. chinensis) as the test crop, we developed an effective nonchemical method that would protect the roots against P. brassicae infection by using a combination heat treatment and a cocktail of biocontrol agents. The data showed that this method could cause 91.7% inhibition of P. brassicae infection. The average height of plants (13.5 cm) using this method was about twice higher than that in control group (6.7 cm), and the average plant weight (3.19 g) was about three times increased compared to that in control set (1.23 g). Yu Gao and Guanghui Xu Copyright © 2014 Yu Gao and Guanghui Xu. All rights reserved. Potential of Cowpea Variety Mixtures to Increase Yield Stability in Subsistence Agriculture: Preliminary Results Thu, 23 Jan 2014 16:24:46 +0000 Cowpea Vigna unguiculata (L.) Walp. is an important leafy vegetable and grain legume in Uganda. Unlike in commercial agriculture, where variety mixtures are known to give higher and more stable yields, the performance of cowpea variety mixtures in subsistence agriculture is little known. Mixtures containing up to four cowpea varieties were subjected to all possible 2-way, 3-way, and 4-way combinations. These cowpea varieties and mixtures were grown at three locations in Soroti and Kumi districts in order to assess the relative mixture effect, defined as: Mixture effect (%) = (mixture yield − pure line component average)/pure line component average × 100. Yield data was subjected to one-way ANOVA using the GLM procedure of SYSTAT. PLABSTAT was used to generate ecovalence () values as a measure of stability with low ecovalence values indicating higher stability. The total cowpea dry matter (DM) yield was in the range of  3.7–6.7 g/m2 (leaf) and 12.1–36.7 g/m2 (grain), respectively. Mixture effects were between  −9.3–14.0% (leaf) and −30.3–21.9% (grain). Yield stability spanned   = 0.06–5.30 (leaf) and = 4.45–894.84 (grain). The results suggested that yields of cowpea variety mixtures grown in marginal environments were more stable than of single varieties but not all mixtures yielded more than single varieties. Joshua S. Okonya and Brigitte L. Maass Copyright © 2014 Joshua S. Okonya and Brigitte L. Maass. All rights reserved. Irrigated Soybean Leaf Photosynthesis in the Humid Subtropical Midsouth Thu, 23 Jan 2014 08:52:32 +0000 Photosynthesis (CER (μmol CO2 s−1)), stomatal conductance (), and intercellular [CO2] () of soybean (Glycine max L. Merr.) grown using the early soybean production system (ESPS) of the midsouth were determined. Three irrigated cultivars were grown using ESPS on Bosket (Mollic Hapludalfs) and Dundee (Typic Endoaqualf) soils in 2011 and 2012 at Stoneville, MS. Single leaf CER, , and were determined at growth stages R3, R4, and R5 using decreasing photosynthetic photon flux densities (PPFD, μmol m−2 s−1) beginning at 2000 PPFD and decreasing by 250 PPFD increments to 250 PPFD. Photosynthesis changes fit a quadratic polynomial for all fixed variables and range from ~6.0 and 9.0 CER at 250 PPFD and ~22.0 to 28.0 CER at 2000 PPFD. No cultivar differences in CER, , or were noted at any growth stage or site either year. In 2012, CER, , and were lower when measured at R5 than the two previous growth stages, which was not observed in 2011. The R5 sampling in 2012 had accumulated 39 to 70 more growing degree units at 10°C base temperature (GDU 10’s) than in 2011 and were likely more mature. Increased soybean yields from ESPS appear not to result from higher leaf CER. H. Arnold Bruns Copyright © 2014 H. Arnold Bruns. All rights reserved. Moisture and Salinity Stress Induced Changes in Biochemical Constituents and Water Relations of Different Grape Rootstock Cultivars Mon, 20 Jan 2014 11:20:26 +0000 Ten grape rootstocks were subjected to moisture and salinity stress in two separate experiments. The influence of these stresses on gas exchange, water relation, and biochemical parameters was monitored at various stages of stress cycle. Both stresses indicated significant changes in the physiological and biochemical parameters studied. Some biochemical constituents increased by several folds in few rootstock cultivars which also recorded increased osmotic potential suggesting their role in osmotic adjustment. Some of the rootstock cultivars such as 110R, 1103P, 99R, Dogridge, and B2/56 recorded increased phenolic compounds under stressed conditions. The same rootstock also recorded increased water use efficiency. The increased accumulation of phenolic compounds in these cultivars may indicate the possible role of phenolic compounds as antioxidants for scavenging the reactive oxygen species generated during abiotic stresses thus maintaining normal physiological and biochemical process in leaves of resistant cultivars. Satisha Jogaiah, Sahadeo D. Ramteke, Jagdev Sharma, and Ajay Kumar Upadhyay Copyright © 2014 Satisha Jogaiah et al. All rights reserved. Influence of Priming Duration on the Performance of Amaranths (Amaranthus cruentus L.) in Sokoto Semiarid Zone of Nigeria Sun, 19 Jan 2014 08:18:23 +0000 Two field trials were conducted during the 2012 cropping season at the Fruits and Vegetable Teaching and Research Farm of the Department of Crop Science, Usman Danfodiyo University, Sokoto (located on latitude N-N and longitude -), to evaluate the effect of priming duration on the growth and yield of amaranth. Treatments consisted of four priming durations (2, 4, 6, and 8 hours) and control (where no priming was applied). The treatments were laid out in a completely randomized design (CRD) replicated three times for the germination test and randomized complete block design (RCBD) for the field trial. Data were collected on days to 50% germination, percentage germination, days to 50% emergence, and percentage emergence. Results revealed significant effect of priming duration on days to 50% germination, percentage germination, and days to 50% emergence. Soaking seeds for 2 hours reduced the number of days to 50% germination and emergence and also recorded higher germination. Thus, from the findings of this study, it could be concluded that priming amaranth seeds for 2 hours could be applied to enhance amaranth production. Mukhtar Musa, Ajit Singh, and Aminu Aliyu Lawal Copyright © 2014 Mukhtar Musa et al. All rights reserved. Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils Thu, 16 Jan 2014 14:34:44 +0000 Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+ were carried out on three surface (0–30 cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27 cmolc kg−1) but relatively high base saturations (≫50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. The values obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions. Tope O. Bolanle-Ojo, Abiodun D. Joshua, Opeyemi A. Agbo-Adediran, Ademola S. Ogundana, Kayode A. Aiyeyika, Adebisi P. Ojo, and Olubunmi O. Ayodele Copyright © 2014 Tope O. Bolanle-Ojo et al. All rights reserved. Row Spacing, Landscape Position, and Maize Grain Yield Tue, 14 Jan 2014 09:56:36 +0000 The use of narrow row spacing for the different landscape positions of a field could punish maize (Zea mays L.) grain yield. Two experiments were conducted (2006/07 and 2007/08) at different landscape positions in the Inland Pampas of Argentina. Hybrid DK190MG was grown at the commonest plant density used at each landscape position (approximately 5.1 plants/m2 at the summit, 6.5 plants/m2 at shoulder-slope position, and 7.6 plants/m2 at foot-slope position) with three row spacings (0.38 m, 0.52 m, and 0.38 m in a skip-row pattern). At the silking stage of maize crops, soil water content (0–200 cm depth) and maximum light capture differed () among landscape positions but were similar among row spacings. Differences in grain yield among landscape positions (mean 806, 893, and 1104 g/m2 at the summit, shoulder-slope position, and foot-slope position, resp.) were related to kernel number/m2 (), which was closely related () to light capture around silking. Grain yield reductions (6 to 20%) were recorded when crops were cultivated in rows 0.38 m apart. The skip-row pattern did not improve grain yield. Maize grain yield was optimized in rows 0.52 m apart along the sandy landscape positions of the fields. Gustavo Ángel Maddonni and Joaquín Martínez-Bercovich Copyright © 2014 Gustavo Ángel Maddonni and Joaquín Martínez-Bercovich. All rights reserved. Amendment of Tephrosia Improved Fallows with Inorganic Fertilizers Improves Soil Chemical Properties, N Uptake, and Maize Yield in Malawi Mon, 06 Jan 2014 16:29:52 +0000 Maize production in Malawi is limited mainly by low soil N and P. Improved fallows of N-fixing legumes such as Tephrosia and Sesbania offer options for improving soil fertility particularly N supply. The interactions of Tephrosia fallows and inorganic fertilizers on soil properties, N uptake, and maize yields were evaluated at Chitedze Research Station in Malawi. The results indicated that the level of organic matter and pH increased in all the treatments except for the control. Total N remained almost unchanged while available P decreased in all plots amended with T. vogelii but increased in T. candida plots where inorganic P was applied. Exchangeable K increased in all the plots irrespective of the type of amendment. The interaction of N and P fertilizers with T. vogelii fallows significantly increased the grain yield. The treatment that received 45 kg N ha−1 and 20 kg P ha−1 produced significantly higher grain yields (6.8 t ha−1) than all the other treatments except where 68 kg N ha−1 and 30 kg P ha−1 were applied which gave 6.5 t ha−1 of maize grain. T. candida fallows alone or in combination with N and P fertilizers did not significantly affect grain yield. However, T. candida fallows alone can raise maize grain yield by 300% over the no-input control. Based on these results we conclude that high quality residues such as T. candida and T. vogelii can be used as sources of nutrients to improve crop yields and soil fertility in N-limited soils. However, inorganic P fertilizer is needed due to the low soil available P levels. Maggie G. Munthali, Charles K. K. Gachene, Gudeta W. Sileshi, and Nancy K. Karanja Copyright © 2014 Maggie G. Munthali et al. All rights reserved. Covariance Structures in Conventional and Organic Cropping Systems Tue, 31 Dec 2013 17:49:45 +0000 Guidelines are needed to develop proper statistical analyses procedures and select appropriate models of covariance structures in response to expected temporal variation in long-term experiments. Cumulative yield, its temporal variance, and coefficient of variation were used in estimating and describing covariance structures in conventional and organic cropping systems of a long-term field experiment in a randomized complete block design. An 8-year database on 16 treatments (conventional and organic cropping systems, crop rotations, and tillage) was subjected to geostatistical, covariance structure, variance components, and repeated measures multivariate analyses using six covariance models under restricted maximum likelihood. Differential buildup of the cumulative effects due to crop rotations being repeated over time was demonstrated by decreasing structured and unstructured variances and increasing range estimates in the geostatistical analyses. The magnitude and direction of relationships between cumulative yield and its temporal variance, and coefficient of variation shaped the covariance structures of both cropping systems, crop rotations, and phases within crop rotations and resulted in significant deviations of organic management practices from their conventional counterparts. The unstructured covariance model was the best to fit most factor-variable combinations; it was the most flexible, but most costly in terms of computation time and number of estimated parameters. Abdullah A. Jaradat Copyright © 2013 Abdullah A. Jaradat. All rights reserved. Comparison of Two Inoculation Methods for Evaluating Maize for Resistance to Aspergillus flavus Infection and Aflatoxin Accumulation Thu, 28 Nov 2013 15:41:44 +0000 Aflatoxin, the most potent carcinogen found in nature, is produced by the fungus Aspergillus flavus and occurs naturally in maize, Zea mays L. Growing maize hybrids with genetic resistance to aflatoxin contamination are generally considered a highly desirable way to reduce losses to aflatoxin. Developing resistant hybrids requires reliable inoculation methods for screening maize germplasm for resistance to A. flavus infection and aflatoxin accumulation. The side-needle technique is a widely used inoculation technique: an A. flavus conidial suspension is injected underneath the husks into the side of the ear. This wounds the ear and limits expression of resistance associated with husk coverage, pericarp thickness, and seed coat integrity. In this investigation, the side-needle technique was compared with a second inoculation method that involved dispensing wheat kernels infected with A. flavus into plant whorls at 35 and 49 days after planting. Results showed that although the side-needle technique produced higher levels of aflatoxin accumulation, differences in A. flavus biomass produced by the two inoculation techniques were not significant. Both inoculation techniques were effective in differentiating resistant and susceptible single cross hybrids irrespective of the use of A. flavus infection or aflatoxin accumulation as a basis to define resistance. W. Paul Williams, Michael N. Alpe, Gary L. Windham, Seval Ozkan, and J. Erik Mylroie Copyright © 2013 W. Paul Williams et al. All rights reserved. Factors Affecting Isoflavone Content in Soybean Seeds Grown in Thailand Tue, 05 Nov 2013 15:54:58 +0000 Soybeans are the most common source of isoflavones in human foods. The objectives of this study were to determine the effects of Thai soybean variety, planting date, physical seed quality, storage condition, planting location, and crop year on isoflavone content, as well as to analyze the relationship between seed viability and isoflavone content in soybean seeds grown in Thailand. Isoflavone content in Thai soybeans varied considerably depending on such factors as variety, physical seed quality, crop year, planting date (even in the same crop year), and planting location. Most varieties (except for Nakhon Sawan 1 and Sukhothai 1) had significantly higher isoflavone content when planted in early rather than in late dry season. Additionally, seed viability as well as long-term storage at or at ambient condition seemed unlikely to affect isoflavone content in Thai soybean varieties. Isoflavone content in soybean seeds grown in Thailand depends on multiple genetic and environmental factors. Some varieties (Nakhon Sawan 1 and Sukhothai 1) exhibited moderately high isoflavone content regardless of sowing date. Soybeans with decreased seed viability still retained their isoflavone content. Supanimit Teekachunhatean, Nutthiya Hanprasertpong, and Thawatchai Teekachunhatean Copyright © 2013 Supanimit Teekachunhatean et al. All rights reserved. Grape Preservation Using Chitosan Combined with β-Cyclodextrin Sat, 02 Nov 2013 14:29:49 +0000 The effect of 1% chitosan combined with 2% β-cyclodextrin to the preservation of fresh grapes under ambient temperature was investigated. The results indicated that the hydrogen bond formed between the hydroxyl group of β-cyclodextrin and the amidogen or hydroxyl group of chitosan and the crystal form of chitosan was also changed when cyclodextrin was doped into chitosan coating. The compound coating could prolong the shelf life of grapes, maintain lower respiration rate and higher activities of superoxide dismutase, peroxidase, and catalase during storage time, and restrain weight loss and malonaldehyde content increase. Coating grapes with chitosan + β-cyclodextrin was a good method in postharvested grape preservation. Yu Youwei and Ren Yinzhe Copyright © 2013 Yu Youwei and Ren Yinzhe. All rights reserved. Transgene Pyramiding of the HVA1 and mtlD in T3 Maize (Zea mays L.) Plants Confers Drought and Salt Tolerance, along with an Increase in Crop Biomass Thu, 31 Oct 2013 15:27:38 +0000 The pBY520 containing the Hordeum vulgare  HVA1 regulated by the rice actin promoter (Act1 5′) or the JS101 containing the bacterial mannitol-1-phosphate dehydrogenase (mtlD) also regulated by rice Act1 5′ and a combination of these two plasmids were transferred into the maize genome, and their stable expressions were confirmed through fourth generations. Plants transcribing a combination of the HVA1+mtlD showed higher leaf relative water content (RWC) and greater plant survival as compared with their single transgene transgenic plants and with their control plants under drought stress. When exposed to various salt concentrations, plants transcribing the HVA1+mtlD showed higher fresh and dry shoot and dry root matter as compared with single transgene transgenic plants and with their control plants. Furthermore, the leaves of plants expressing the mtlD accumulated higher levels of mannitol. Plants expressing the HVA1+mtlD improved plant survival rate under drought stress and enhanced shoot and root biomass under salt stress when compared with single transgene transgenic plants and with their wild-type control plants. The research presented here shows the effectiveness of coexpressing of two heterologous abiotic stress tolerance genes in the maize genome. Future field tests are needed to assure the application of this research. Thang Xuan Nguyen, Truong Nguyen, Hussien Alameldin, Benjamin Goheen, Wayne Loescher, and Mariam Sticklen Copyright © 2013 Thang Xuan Nguyen et al. All rights reserved. Estimation of Blast Severity on Rye and Triticale Spikes by Digital Image Analysis Thu, 31 Oct 2013 14:22:31 +0000 In Brazil, more efficient methods are a necessity for evaluating blast severity on spikes in the breeding programs of rye, triticale, wheat, and barley. The objective of this work was to determine the feasibility of assessing blast severity based on the analysis of digital images of symptomatic rye and triticale spikes. Triticale and rye genotypes were grown to anthesis in pots and were then inoculated with a mixture of Magnaporthe oryzae isolates. Blast severity on the spikes was evaluated visually and after that the spikes were detached and photographed. Blast severity was determined using the program ImageJ to analyze the obtained images. Two methods of image analysis were used: selection of symptomatic areas using a mouse cursor (SCU) and selection of symptomatic areas using image segmentation (SIS). The SCU method was considered the standard reference method for determining the true value of blast severity on spikes. An analysis of variance did not determine any difference among the evaluation methods. The coefficient of determination (R2) obtained from a linear regression analysis between the variables SIS and SCU was 0.615. The obtained data indicate that the evaluation of blast severity on spikes based on image segmentation is feasible and reliable. João Leodato Nunes Maciel, Alfredo do Nascimento Junior, and Cristina Boaretto Copyright © 2013 João Leodato Nunes Maciel et al. All rights reserved. Effect of Early Foliar Disease Control on Wheat Scab Severity (Fusarium graminearum) in Argentina Mon, 28 Oct 2013 14:59:30 +0000 Wheat scab is common in Argentina mainly durum wheat and some bread varieties. The epidemics occur every 5 to 7 years. During the 2007, 2008, and 2009 growing seasons, three trials were conducted at the INTA Balcarce Experimental Station. Each plot had six rows of 5 m long, spaced 0.15 m apart and was set up in a randomized complete block design with four replications. Trifloxystrobin plus cyproconazole was sprayed at Z3.1 stage. Treatments were sprayed at Z6.1 stage with tebuconazole, prochloraz, and metconazole to improve scab control. Artificial inoculations were made in Z6.1. Severity of Septoria leaf bloth and leaf rust was assessed in boot stage (Z3.9). Scab severity was rated at early dough stage (Z8.3). Yields were recorded each year. Fungicide only applied at Z3.1 stage did not reduce field scab severity but reduced the seeds infection and increased the yields. Early fungicide spray produced yield increase at about 22% and a decrease in seed infection of up to 40%. Yields increased in a 55.3% and in a 19.6% when compared with the inoculated and not inoculated check, respectively. The purpose of this study was to evaluate the effect of foliar disease control on scab, crop yield, and seed health. Jorge David Mantecón Copyright © 2013 Jorge David Mantecón. All rights reserved. Identification and Characterization of Wheat Streak Mosaic Virus Isolates in Wheat-Growing Areas in Brazil Thu, 24 Oct 2013 08:17:47 +0000 Wheat streak mosaic virus (WSMV—Potyviridae, Tritimovirus), transmitted by the eriophyid mite Aceria tosichella Keifer (Acari: Eriophyidae), was considered a quarantine pest in South America. Since the first report of virus in Argentina, the vector has been found in Argentina, Uruguay and Brazil. The objective of this work was to determine the occurrence of WSMV in Brazil and characterize isolates from wheat-growing areas. Between 2009 and 2011, a total of 40 samples collected in wheat (Triticum aestivum) growing areas, where the presence of the mite was previously related, were tested by RT-PCR for virus detection. Six isolates of WSMV were obtained and characterized by sequencing. Two of them had their host range determined. The Brazilian WSMV isolates clustered in clade D are closely related to the Argentine isolate Arg2 (FJ348359). As expected, isolates were unable to infect dicotyledons plants. They caused mosaic in Triticum aestivum, Hordeum vulgare, Secale cereale, ×Triticosecale, and Zea mays, and they were also able to infect Avena sativa. The presence of WSMV in wheat-growing areas of the Brazilian state Rio Grande do Sul was confirmed, possibly having been introduced from a common source and/or direct vector bearing virus migration from Argentina. Talita Bernardon Mar, Douglas Lau, Jurema Schons, Paulo Roberto Valle da Silva Pereira, and Alan Johnny Carminatti Copyright © 2013 Talita Bernardon Mar et al. All rights reserved. Effect of Rhizobium and Phosphate Solubilizing Bacterial Inoculants on Symbiotic Traits, Nodule Leghemoglobin, and Yield of Chickpea Genotypes Mon, 21 Oct 2013 14:48:35 +0000 A field experiment was carried out during the rabi season of 2004-05 to find out the effect of Rhizobium and phosphate solubilizing bacterial (PSB) inoculants on symbiotic traits, nodule leghemoglobin, and yield of five elite genotypes of chickpea. Among the chickpea genotypes, IG-593 performed better in respect of symbiotic parameters including nodule number, nodule fresh weight, nodule dry weight, shoot dry weight, yield attributes and yield. Leghemoglobin content (2.55 mg g−1 of fresh nodule) was also higher under IG-593. Among microbial inoculants, the Rhizobium + PSB was found most effective in terms of nodule number (27.66 nodules plant−1), nodule fresh weight (144.90 mg plant−1), nodule dry weight (74.30 mg plant−1), shoot dry weight (11.76 g plant−1), and leghemoglobin content (2.29 mg g−1 of fresh nodule) and also showed its positive effect in enhancing all the yield attributing parameters, grain and straw yields. G. S. Tagore, S. L. Namdeo, S. K. Sharma, and Narendra Kumar Copyright © 2013 G. S. Tagore et al. All rights reserved. Analysis of Essential Elements for Plants Growth Using Instrumental Neutron Activation Analysis Sun, 22 Sep 2013 15:00:03 +0000 In this study, a total of ten essential elements for plants growth in the Guinea savanna region of Niger State in Northern Nigeria have been identified in the soils using instrumental neutron activation analysis. The experimental results show good agreement with certified or literature values within the agreed percentage range of ±2.35% to ±8.69%. However, the concentration distributions of the ten identified elements in the soil samples within the studied area for plants growth revealed the following: Fe (123.4 ppm), Mn (2100.7 ppm), K (5544.3 ppm), Al (54752.4 ppm), Ti (3082.9 ppm), Ca (4635 ppm), V (54.3 ppm), Na (857.5 ppm), Mg (13924.1 ppm), and Dy (12.1 ppm). A further analysis of the two fundamental soil physical parameters for healthy growth of some common crops like egusimelon, groundnut, rice, yams, soybeans, cassava, and potato analyzed in this work revealed a pH range of 4.0 pH–8.0 pH and a temperature range of 28.0°C to 29.3°C, which are optimal for plant nutrients availability in the soils within the study area. R. L. Njinga, M. N. Moyo, and S. Y. Abdulmaliq Copyright © 2013 R. L. Njinga et al. All rights reserved. Diallel Anaysis of Oil Production Components in Peanut (Arachis hypogaea L.) Thu, 12 Sep 2013 12:17:14 +0000 Peanut (Arachis hypogaea L.) has the potential to become a major source of biodiesel, but for market viability, peanut oil yields must increase. Oil yield in peanut is influenced by many different components, including oil concentration, seed mass, and mean oil produced per seed. All of these traits can potentially be improved through selection as long as there is sufficient genetic variation. To assess the variation for these traits, a diallel mating design was used to estimate general combining ability, specific combining ability, and heritability. General combining ability estimates were significant for oil concentration, weight of 50 sound mature kernels (50 SMK), and mean milligrams oil produced per SMK (OPS). Specific combining ability was significant for oil concentration. Reciprocal effects were detected for OPS. Narrow-sense heritability estimates were very high for oil concentration and 50 SMK and low for OPS. The low OPS heritability estimate was caused by the negative correlation between oil concentration and seed size. Consequently, oil concentration and seed mass alone can be improved through early generation selection, but large segregating populations from high oil crosses will be needed to identify progeny with elevated oil concentrations that maintain acceptable seed sizes. Jeffrey N. Wilson, Michael R. Baring, Mark D. Burow, William L. Rooney, and Charles E. Simpson Copyright © 2013 Jeffrey N. Wilson et al. All rights reserved.