International Journal of Plant Production
Volume:6 Issue: 4, Oct 2012

The objective of this study was to determine the effect of Verticillium dahliae Kleb. on cotton yield and fiber technological properties, relationships among to disease and seed cotton yield, fiber yield and fiber technological properties and also determine susceptible and tolerant cotton varieties. The study was conducted in the Southeastern Anatolia Agricultural Research Institute’s experimental area during 2004-2006. The experiment was arranged as a randomized split block design with four replications. Main plot consisted of infected and non-infected area, sub-plot consisted of varieties. In this study 10 different commercial cotton varieties were grown to test the v erticillium wilt performance. The results indicated that there were significant differences among varieties for all of the investigated characteristics. Area differences were significant for all of the investigated traits except ginning percentage. The results of the non-infected area showed that there were decreasing with regard to foliar disease index (FDI), vascular disease index (VDI), vascular disease rate (VDR), first picking percentage, fiber fineness, micronaire and yellowness; while increasing with regard to seed cotton yield, fiber yield, fiber length, strength, elongation, uniformity, reflectance and spinning consistecy index. Only ginning percentage was unaffected from area differences. With planting cotton varieties in non-infected area there were 323.60 kg ha -1 increase for seed cotton yield and 114.50 kg ha -1 for lint yield. Disease led to a decrease (7.86%) in seed cotton yield and (6.73%) in fiber yield. The results of this study indicated that GW-Teks, GW-Golda and Carmen varieties were tolerant; while Maraş 92, Sayar 314 and Stoneville 453 were sensitive in terms of FDI, VDI and VDR and tolerant varieties can be used as parents in Verticillium breeding programs.

Cassava (Manihot esculenta Crantz) is currently the most important upland crop of Cambodia, but information on yield variations and causal factors which is important for efficiently targeting efforts to increase production is still lacking. The objectives of this study were to determine the yield variations and causal factors for cassava production in Kampong Cham province in Cambodia. Forty five households in four production zones were selected for the study. A farm survey employing semistructured interviews, combined with field visits, were used for the collection of information on farmers’ practices in cassava cultivation, while crop cutting was done to provide estimates of cassava yields. The data were analyzed for yield variations,yield gaps and causal factors. The results showed large variations in yield among farmers’ fields, ranging from 12.7 to 37.2 t ha -1 . The fields were divided into five yield categories, with the mean yields of the lower four categories ranging from 76.0 to 34.2% of the maximum yields, with corresponding yield gaps ranging from 8.9 to 24.4 t ha -1 . The main yield constraints identified were soil nutrient deficits, short crop duration and weed competition. The highest yielding fields had no production constraints, but the number and/or the level of constraints increased in fields with lower crop yields. However, for different fields with similar yield levels, the main production constraints sometimes differed. The results clearly indicated that there are opportunities for yield improvement and narrowing of yield gaps through the adoption of field specific improved technologies and management practices.

Conventional procedures are inadequate for optimizing the concentrations ofnutrients to increase the sugar yield. In this study, an artificial neural network(ANN) was used to optimize the Ca, Mg, N, K and Na content of the storage rootto increase sugar yield (Y) by increasing both sugar content (SC) and root yield(T). Data from three field experiments were used to produce a wide range ofvariation in nutrient content, SC and T. In the training phase of the ANN, R2 was0.91 and 0.94 for SC and T, respectively. The high R2 values obtaineddemonstrating the ability of the ANN to predict SC and T. The obtained optimumvalues were 0.37%, 0.35%, 0.97%, 4.67 (meq/100 g) and 0.33% for Ca, Mg, N, Kand Na, respectively. Optimization increased the potential Y by 17%.

Many soils are contaminated by heavy metals, with arsenic posing serious environmental threat. Enrichment of soil with phosphate is believed to reduce the arsenic toxicity. However, only a few attempts have already been conducted towards understanding the precise role of phosphate in controlling As toxicity. Moreover, there is no adequate information on the effect of phosphate on As-induced oxidative stress, a major contributor of As toxicity in plant system. Τ he present study aims to determine the effect of varying concentrations of phosphate on As-mediated oxidative stress in pearl millet ( Pennisetum typhoides ). Our study revealed that a concentration of 100 μM of phosphate was able to protect the test plant from As (100μM)-mediated oxidative stress, as evident from the data on growth and lipid peroxidation. This novel finding was further supported by the increased chlorophyll content of the test plant raised in phosphate supplemented media. Phosphatemediated improvement of antioxidant enzymes, such as SOD (superoxide dismutase), CAT (catalase), and APX (peroxidase), could be a crucial factor in regulating As-induced oxidative stress in pearl millet. The results of the present study suggest that availability of phosphate in the surrounding media has a clearly pivotal role in the generation of oxidative stress in P. typhoides exposed to As.

conventional tillage with burned residue (CT 2), reduced tillage with heavy tandem disc-harrow (RT1 ), reduced tillage with rotary tiller (RT 2 ), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) and no tillage (NT). Disturbed and undisturbed soil samples were collected to determine saturated hydraulic conductivity (HC), bulk density (BD), mean weight diameter (MWD), available water content (AWC) and total porosity at 0-10, 10-20 and 20-30 cm depths. The highest HC values of 0-10 cm and 10-20 cm depths were obtained with CT 1 (9.70×10-6 m s-1, 8.74×10-6 m s-1) and CT2 (9.39×10-6 m s-1 , 8.58×10 -6 m s-1) applications. CT2 treatment destructed the soil aggregates and resulted in greater bulk density and low total porosity at 0-10 cm depth. The available water content at 0-10 cm depth was significantly reduced with the CT 1 (P 2 applications (Pcaused higher bulk density and low porosity, increase in MWD is an indication of soil and water conservation. Therefore, no till and reduced till applications should be adapted to the farmers’ conditions for sustainability in agriculture.

The effect of grafting and post-grafting temperature on the plant development of two watermelon cultivars at transplantation and on subsequent fruit quality wasstudied. Watermelon cv. Sugar Baby and Crimson Sweet were self-rooted or grafted onto rootstock RS 841 F 1 (Cucurbita maxima × C. moschata) or bottlegourd Lagenaria siceraria f. clavata] (year 1), plus L. siceraria f. pyrotheca (year 2). After grafting, plants were held at 8 oC or 16 o C (minimum) until transplantation (28-29 days), at which stage growth was compared with that of the self-rooted control held under the same conditions. Plants were planted in the field and fruit quality assessed at harvest. At the time of transplantation in year 1, plants at 16 oC were taller and had a higher total fresh weight than those at 8 o C. The grafted plants of both cultivars were taller and had a higher leaf area and fresh weight than the self-rooted plants, irrespective of rootstock. In year 2, the grafted plants of both cultivars had better development (height, leaf area, leaf number, fresh weight) than self-rooted plants. The plants of Crimson Sweet × L. siceraria f. pyrotheca were taller than those of the other two scion-rootstock combinations, irrespective of temperature. Mean fruit weight at harvest was higher in grafted plants than in self-rooted plants, and sugar content varied with scion-rootstock combination. Grafting of watermelon results in better plant growth by the time of transplantation, whereas the scion-rootstock combination affects fruit quality. A minimum temperature of 16 o C is indicated during the post-grafting stage.

Quantification of the Nitrogen (N)-supplying capacity of organic manures provides an important insight into more effective N management practices. The aims of this study were to determine the potential N mineralization of cow manure (CM), poultry manure (PM), urea fertilizer (UF) and the combined use of cow manure + urea fertilizer (CM + UF) for silage maize (Zea mays L.) in a calcareous soil under field conditions. Selected soil samples were collected after different N sources application, and mineral N (NO3 -N and NH 4+ -N) was determined for a total of 110 days of field incubation, using the buried bag technique. Poultry manure-treated soils had significantly higher total N mineralization (244 kg ha-1) than CM (109 kg ha-1 ), UF (138 kg ha -1) and CM + UF (141 kg ha-1) treated soils. However, N availability was greater in UF (69%) and PM (61%) treated soils than that of CM + UF (47%) and CM (28%) fertilized soils. Shoot dry matter of maize and N uptake were considerably higher in PM treated soil than in UF, CM and CM + UF soils. Nevertheless, maize N recovery was significantly higher in urea soils (60%) than in PM (42%) and CM + UF (37%) soils followed by CM soil (15%). In conclusion, our data indicated that PM and the CM + UF that released N slowly resulted in high maize silage production, N uptake and N recovery following their application in these calcareous soils with low SOM content and N availability.

Water use efficiency (WUE) reflects the coupling of the carbon and water cycles and is an effective integral trait for assessing the responses of vegetated ecosystems to climate change. In this study, field experiments were performed to examine leaf WUE (WUE leaf) in response to changes in CO2concentration and other environmental variables, including soil moisture and air temperature. We also used yield of maize and soybean, soil water content and precipitation data to calculate water use efficiency at the level of grain yield (WUE grain) in a manner that enabled us to analyze the effects of climatic factors on WUE grain. The results showed that theWUE leaf measurements of maize and soybean plants were negatively correlated withsoil moisture and air temperature. At a photosynthetically active radiation (PAR) of 1.600 μmol m-2s-1, increasing ambient CO2 concentrations (from 400 to 800 μ -1) improved WUEleaf by 52.0% and 75.8% for maize (a C4species) and soybean (a C 3 species), respectively. Increased annual precipitation stimulated maize WUE grain up to levels of approximately 500-550 mm, although maize WUE grain decreased when annual precipitation exceeded 550 mm. It appears that 400-450 mm is an economical evaportranspiration (ET) for spring maize in Chaoyang area of northeast China. For soybean, more water often reduces WUE grain, and there is a linear relationship between changes in WUE grain and changes in annual temperature. The different responses of WUE grain and WUEleaf to climate change suggest that caution should be taken when attempting to up-scale WUE from leaf to grain or biomass levels.