International Journal of Plant Production
Volume:9 Issue: 1, Jan 2015

One of the major field constraints to seed production in safflower has proven to be soil born pathogens, Phytophthora drechsleri and Pythium ultimum. In order to evaluate the efficiency of a field-laboratory selection method to improve resistance of safflower against soil born pathogens, Ph. drechsleri and P. ultimum, a two-year investigation was conducted. The results showed that selection is an efficient method for increasing resistance to seed and seedling death caused by Phytophthora and Pythium in safflower. Selection could have improved germination percent, days to 50% germination, percent of undamaged seedlings and index of disease percent when genotypes were faced with both pathogens. Regarding kind of damages, Pythium caused more seed rot and Phytophthora induced more seedling death. It could be concluded that selection for resistance to Pythium, could also increase resistance to Phytophthora. Safflower was, however, more susceptible to Phytophthora than Pythium. Also, genes for resistance to seed rot are different than those controlling resistance to seedling death, so preemergence damping off should be considered a completely independent trait from post-emergence damping off in safflower. It was concluded that used fieldlaboratory selection method could well improve resistance of safflower to pathogens Phytophthora and Pythium and hence seed yield.

The purpose of the present study was to investigate the limits of irrigation water salinity and soil water content for growth inhibition of vetiver. Moreover, different models were studied to describe the root water uptake and plant top growth under salinity and water stresses in a pot experiment. Irrigation treatments consisted of three irrigation intervals (3, 6 and 9-day). The salinity levels of the irrigation water were 0. 8 (tap water), 10, 20 and 30 dS m-1. It is concluded that by enforcing salinity and increasing its level up to 30 dS m-1, no significant decline in the top dry matter (TDM) has been observed. However, in the salinity level of 30 dS m-1 increasing of soil water stress caused TDM to decrease. The maximum amount of leaf area index (LAI) was observed at water salinity level of 0. 8 dS m-1 and as the salinity increased, it decreased. However, at different water salinity levels, the reduction of LAI was not significant. Moreover, the results showed that the water stress did not have significant effects on reduction of LAI separately, while the water salinity did. The thresholds of water salinity and irrigation intervals for affecting vetiver''s root were between 20 and 30 dS m-1 and 6 days (80% soil available water depletion), respectively. Moreover, the threshold values of soil salinity were 13. 8 dS m-1 for top and 19. 4 dS m-1 for root growth. Then, it can be concluded that the top growth is more sensitive to thewater salinity, than the root one. Therefore, in terms of economic, if using root is more substantial, root production would be more beneficial. The growth reduction per unit increase in soil salinity for top growth and root growth are 2% and 3% per dS m-1, respectively. Therefore, top and root growth affected similarly by increasing the soil salinity. Relative yield response factor to water stress was 0. 472 that showed the vetiver resistance to soil water stress. It is «> indicated that the root water uptake coefficient (α) was predicted accurately after considering the results and comparing different models. Furthermore, the estimated values of α predicted the shoot dry weight accurately. However, Homaee and Feddes method is preferred for estimation of TDM

Sowing crops following cover crops on forage may cause injuries and productivity reduction, due reasons as allelopathy or glyphosate residues. The objective of this study was to evaluate the influence of differing periods between cover crop (Urochloa ruziziensis) desiccation with glyphosate and sunflower (Aguará 4) sowing in a no-tillage system on crop development and productivity. Two assays were performed in two seasons, one in pots and the other in a field. Treatments in field assay consisted on 5 desiccation times of U. ruziziensis (with an application of glyphosate at 1.08 kg ae ha-1) preceding the sowing of no-till sunflower (0, 3, 7, 10 and 30 days). At the pot assays, 6 times were studied: 0, 3, 7, 10, 15 and 20 days between cover crop desiccation and sunflower sowing. A control without cover crop was also included in this assay. Biometric evaluations were performed at the vegetative stage and at harvest. As the period between U. ruziziensis desiccation and sunflower sowing was shortened, achene production in sunflower was exponentially reduced. Glyphosate application at 3 or 0 days pre sowing diminished sunflower development and achene production by approximately 30% compared to desiccation periods greater than 7 days.

Maize (Zea mays L.) is an important crop among Brazilian smallholder farmers, who are also responsible for 40% of the poultry and egg production in the country. Although poultry litter is considered a potential pollutant, if properly stabilized and distributed in the field it can be used as a source of nitrogen for maize production.In this study, the response of maize to mineral fertilizer and poultry litter as source of nitrogen was evaluated and the results were then used to parameterize a processbased model. For both sources of nitrogen used in the second trial the average observed yield was higher than the average yield obtained by farmers during the preceding years, indicating that there is a potential for improvement of maize yield in the region. A rate of 195 kg ha-1 of nitrogen as poultry litter provided a slightly higher yield than a rate of 145 kg ha-1 of nitrogen as mineral fertilizer. After adjustments in the CSM-CERES-Maize cultivar-specific coefficients the model satisfactorily simulated maize anthesis, physiological maturity and yield. Poultry litter has the potential to be an alternative source of nitrogen for maize production in smallholder farms. The CSM-CERES-Maize model properly simulated maize growth, development and yield for both, mineral fertilizer and poultry litter sources of nitrogen.

Maize (Zea mays L.) production requires large amounts of nitrogen (N) that directly affect production cost. Poultry litter can be used as an alternative source of N. To optimize its use, poultry litter requires technical and economic feasibility analyses. Crop simulation models have proven to be efficient tools to support this type of research. The objectives of this study were to determine yield and net return of maize production fertilized with both mineral fertilizer and poultry litter. High inter-annual variation was observed in simulated yield for all fertilization strategies evaluated. The higher the mineral N rate, the higher the yield. Among the treatments fertilized with poultry litter the highest yield was obtained with a rate equivalent to 240 kg ha-1 of N. The trend of the economic net return for the different rates of mineral fertilizers was in the opposite direction of the trend in yield, i.e., the higher the rate of mineral fertilizer, the lower the economic return. Among the poultry litter fertilization strategies, the average economic net return increased up to a rate equivalent to 210 kg ha-1 of N, decreasing for higher rates. Poultry litter rates equivalent to 120 to 300 kg ha-1 of N, economically exceeded all the mineral fertilization strategies that were evaluated. Among all sources and rates, the highest net return was obtained for a rate of 210 kg ha-1 of N as poultry litter. Higher rates provided a lower net return and increased the likelihood of nitrate leaching.

ewline«> Castor (Ricinus communis L.) is an oilseed species, which in southern Italy is cultivated as annual during the spring-summer period under irrigation, but in most temperate areas such as those of eastern coast of Sicily, it could be grown as semiperennial with no irrigation, by the adoption of autumnal sowings. A field experiment was conducted in southeastern Sicily with the aim of assessing plant surviving, seed yield and oil quality of four castor genotypes originating from different geographical areas (two Sicilian, one Tunisian and one Brazilian). The favorable climatic conditions allowed the plant to survive during the fall-winter period. Seed yield reached 3. 45 t ha-1 on average of the two years and seed oil content ranged from 45% (Tunisian cultivar) to 48% (‘Local RG 2’ Sicilian genotype). Oil yield reflected the variation in seed yield. Genetic diversity for fatty acid composition and saponification number, iodine value and cetane number was evidenced. When ricinoleic acid is not taken into account, the oil of all genotypes satisfied the EU standards for biodiesel. The ricinoleic acid was the lowest (79%) in the Sicilian ‘Local RG 2’ and the highest (89%) in the Tunisian one, revealing a greater suitability of oil of the first genotype for biodiesel. In turn, the oil of Tunisian genotype could be exploited in other bio-based industrial sectors. The study also demonstrated that in the southeastern coast of Sicily autumnal sowings might be advantageous for castor grown as semi-perennial crop, mainly since they allow saving irrigation water.

«> The present study described the diversity of wheat and barley varieties and landraces available in farmer’s fields in Syria using different indicators. Analysis of spatial and temporal diversity and coefficient of parentage along with measurements of agronomic and morphological traits were employed to explain the diversity of wheat and barley varieties or landraces grown by farmers in Syria. Farm level surveys showed low spatial diversity of wheat and barley where only a few dominant varieties occupied a large proportion of wheat and barley areas. The five top wheat varieties (ACSAD 65, Cham 1, Cham3, Lahan and Cham 6) occupied 81% of the wheat area and were grown by 78% of the sample farmers. In case of barley one single landrace was grown in almost the entire survey area in north eastern Syria. The weighted average age of wheat varieties was highest with an average of 10. 8 years showing low temporal diversity by farmers. In Syria bread wheat showed lower average diversity and weighted diversity than durum wheat. Variance component analysis showed significant variations for desirable agronomic characters such as plant height, grain yield and yield components (kernels per spike-1, seed weight) among wheat and barley varieties and landraces. The principal component analysis explained the variations that existed among modern varieties and landraces. Cluster analysis based on agronomic and morphological traits grouped the modern varieties and landraces into separate clusters. The variation that existed among the landraces showed broad opportunities for using in plant breeding programs to develop varieties suitable for different agro-ecological zones. To date large areas previously grown to traditional varieties and landraces are now increasingly replaced by contiguous expanse of land planted to uniform modern bread and durum wheat varieties and are grown by large number of farmers. Apart from the landraces, the wild relatives and progenitors of both wheat and barley are being threatened by extinction in the center of origin.

India is the second largest producer of potato in the world. The Indo-Gangetic plains (IGP) is the main potato growing region accounting for almost 85% of the 1.8 Mha under the crop in India where it is grown as an irrigated crop during the winter season. Since IGP is in sub-tropical plains, duration of the thermally suitable window is the main determinant limiting yields. Hence the impact of climate change on potato in the IGP was assessed using MIROC HI.3.2 A1b and B1, PRECIS A1b, A2, B2 scenarios and estimated the potential adaptation gains. The potato crop duration in the IGP is projected to decrease due to climate change. The evapotranspiration (ET) is projected to increase while the water use efficiency (WUE) for potato yield is projected to decline in future climates as a consequence of low threshold temperatures for decline in WUE and yield than the ET. Results indicate that the upper threshold for ET decrease is ~23 oC while that for WUE is 15 oC. The optimal temperatures for tuber yield is ~17 oC and thus the reduction in WUE in future climates is discernable. Climate change is projected to reduce potato yields by ~2.5, ~6 and ~11% in the IGP region in 2020 (2010-2039), 2050 (2040-2069) and 2080 (2070-2099) time periods. Change in planting time is the single most important adaptation option which may lead to yield gains by ~6% in 2020 and its combination with improved variety or additional nitrogen may be required to adapt to climate change leading to positive gains by ~8% in 2020 and by ~5% even in 2050. However, in 2080 adoption of all the three adaptation strategies may be needed for positive gains. Intra-regional differences in the impact of climate change and adaptation gains are projected; positive impact in northwestern IGP, gains in Central IGP with adaptation and yield loss in eastern IGP even with adaptation.