Journal of Agricultural Science and Technology
Volume:12 Issue: 2, Mar 2010

This study examined the nature and patterns of rice consumption in Nigeria, using Kwara State as a case study. The study methodology comprised a two stage sampling technique which was used to survey 110 rice consumer households across two villages and six towns in Kwara State. Analytical tools used in the study include descriptive statistics and the multinomial logit model. The major factors that significantly influence household preferences for either a combination of local and imported rice or the imported rice only to the local rice were the income of the head of household, household size and the educational status of the heads of household, the price per unit kilogramme of rice, however, was not a significant factor. This study therefore recommends that an effort should be made to increase rice production coupled with the provision of standard processing facilities. This will help to make the local rice sufficiently more competitive thereby increasing its demand.

The biology of Chrysocharis pentheus (Walker) (Hymenoptera: Eulophidae), the most abundant endoparasitoid of Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) in Ehime prefecture, Japan, was studied under laboratory and field conditions. The mean immature developmental time and adult longevity at different temperatures (22 to 31°C) under 50-70% RH decreased as the temperature increased, and females survived longer than males. The developmental threshold of male and female was 8.9°C and 11.9°C, respectively. The effective accumulative temperature (thermal constant) for males and females from egg to adult was 181.8 and 238.1 degree-days, respectively. C. pentheus appeared to be a synovigenic species. The offspring sex ratio from females provided with males was 73.8% males and 26.2% females. Presumably, mated females began oviposition 1-2 days after emergence and continued for up to 40 days. Females laid a mean of 118.2±10.10 eggs each, and their longevity reached 32.3±0.30 days at 27±1°C, 50-70% RH. The intrinsic rate of natural increase (rm) was 0.144. Host feeding or stinging without oviposition killed 65.7±8.65 P. citrella larvae per female. Oviposition in the field was highest (62.7%) on the third instar larva of P. citrella, with the rest on the prepupal stage (37.3%), showing a significant preference for third instars. The sex ratio (M:F) of C. pentheus reared from the third instar larvae of host and pupae was 3.3:1.0 and 1.0:3.0 respectively.

Study of the spatial distribution of a pest and its natural enemies provides better decision tool for integrated pest management. The spatial distribution and seasonal activity of Panonychus ulmi (Koch) and its predator Zetzellia mali (Ewing) were studied in an apple orchard in Khoramdareh (Zanjan Province, Iran) during 2007. The interaction (density dependence) between the prey and its predator was determined. For P. ulmi RV (relative variation) and reliable sample size were calculated with 25 percent variation from primary sampling at 18.8% and 59 leaves, respectively. The distribution pattern of both species was analyzed using nine statistical formulae: Taylor’s power law, Iwao’s patchiness regression, index of dispersion, Morisita’s coefficient of dispersion, Lloyd’s mean crowding, David and Moore''s index, Cole''s index of dispersion, Green''s index and coefficient of ''K'' (coefficient of aggregation). The results indicated that the highest population density of P. ulmi and Z. mali were on 11 August (23.92 per leaf) and 11 September (8.2 per leaf), respectively. The slopes of Taylor''s power law and Iwao''s patchiness regression methods were 1.82 and 2.18 for prey and 1.39 and 1.92 for predator, respectively. These slopes had significant difference from one, indicating aggregated spatial distribution in prey and predator. The index of dispersion (ID) showed that the spatial distribution of P. ulmi in apple orchards was aggregated but it showed random distribution for Z. mali. The Morisita’s coefficient, Lloyd’s mean crowding and Green''s index showed an aggregated distribution for both species. The regressions between population densities of P. ulmi and Z. mali indicated a density independent reaction of predator to the prey. The effect of temperature and humidity on the prey and predator populations was estimated. Spatial distribution parameters of the prey and predator can be used in integrated pest management programs.

Rice bran sterols have antioxidant activity as well as physiological and biological effects. Because of these benefits, the aim of this study is evaluating the quantity and quality of Iranian rice bran sterols. Three widespread Iranian rice cultivars (Khazar, Hashemi, and Alikazemi) were used for determination of their sterol contents. Two methods of sample preparation were compared and the better one was used in this work. Rice bran samples were saponified directly after acid hydrolysis. Unsaponified materials were extracted, purified by solid phase extraction, silylated, and their sterol fractions determined by GC-MS. The sterol composition (in mg kg-1 bran) of three cultivars (Khazar, Alikazemi, and Hashemi) were 1,330.69, 1,279.95, 1,313.17 β-sitosterol; 747.52, 696.05, 756.8 campesterol; 112.8, 115.36, 114.24 Δ-5-avenasterol, 38.912, 33.08, 38.24 Δ-7-avenasterol; 8.05, 7.07, 7.56c holesterol; 4.20, 3.99, 4.23 brassicasterol; and 2,722.016, 2,706.176, 2,717.68 total sterols, respectively. The results showed that there were no significant differences between the individual and total sterol contents of these three cultivars (P> 0.05), except campesterol, β-sitosterol, and Δ-7-avenasterol. The highest and lowest sterols were ß-sitosterol and campesterol.

Pollen grains as well as whole plants of four olive (Olea europaea L.) cultivars were screened for NaCl salinity stress. Different vegetative and physiological indexes of the cultivars were analyzed. Leaf and root Na/K ratio as well as stomatal resistance of plants exposed to salinity proved to be appropriate indexes of whole plant response to salt stress. Whereas, in vitro pollen germination percentage served as a reliable index of pollen tolerance to salinity, pollen tube growth did not. A close correlation between pollen (gametophyte) and whole plant (sporophyte) responses to salinity was observed. These parallel responses imply that selection exerted at the gametophytic level could overcome breeding problems encountered at sporophytic level when dealing with adult olive plants.

Iran is one of the main date (Phoenix dactylifera) producing countries in the world. however, little information is available on the pollen viability and favorable storage conditions of Iranian male date cultivars. This study was conducted to estimate the best in vitro pollen germination of three male date palm cultivars, `Ghanami’, `Samsmavi’ and `Gheibani’ using various doses of boric acid (0, 50, 100 and 200 mg L-1), calcium nitrate (0, 200 and 300 mg L-1) and sucrose (15% and 25% (w/v)) in a Modified Brebaker and Kwack (MBK) medium. The results showed that the best germination was achieved with 50 mg L-1 boric acid, 200 mg L-1 calcium nitrate and 15% (w/v) sucrose. Once the optimal in vitro germination medium had been established, pollen viability (% germination) of these three cultivars stored for up to 200 days at room temperature (dark and light), in a refrigerator (4˚C), freezer (-20˚C) and in liquid nitrogen (-196˚C) was compared. For all the tested cultivars, germination declined as storage temperature increased and, by 200 days, the highest survival rate was obtained with cryostored pollen. Long-term storage of date pollen using an ultra-low temperature (-196˚C) can be used without any deteriorating effect on pollen viability, while room temperature storage significantly reduced pollen germination.

Regional impact studies of the future climate change effects are necessary because projected changes in meteorological variables differ from one region to another, and different climate systems can react in varied ways to the same changes. In this study, the effects of climate change on bioclimatic deficiency were compared in two cultivation methods (irrigated and rainfed) in a semi-arid region, Ahar (East Azarbaijan, IRAN). The agricultural land uses selected for evaluation were wheat (Triticum aestivum), alfalfa (Medicago sativa), sugar beet (Beta vulgaris), potato (Solanum tuberosum), and maize (Zea mays). In this way, Terraza model included in the land evaluation decision support system, called MicroLEIS DSS, was used. Terraza gives a quantitative prediction of a site bioclimatic deficiency. Soil morphological and analytical data were obtained from 44 sampling points based on a grid survey. Agro-climatic data, referred to temperature and precipitation, were collected from weather stations located in Ahar region, which benefits from more than 20 consecutive years of weather data. A future scenario of climate change was calculated according to the Intergovernmental Panel on Climate Change (IPCC) on regions of Asia under scenario A1FI (highest future emission) for 2080s. Although, increasing of precipitation being available by climate change in the future scenario, humidity index will be reduced because of high temperature. The results showed that climate change is likely to cause severe water stress in irrigated cultivation of alfalfa, sugar beet, potato, and maize, the use of irrigation methods being essential to maintain agricultural productivity. Although irrigation is indicated as very important in this regime of semi-arid agriculture, cultivation of rainfed wheat can be possible instead of the irrigated one. Also, it is revealed that climate perturbation effects on rainfed conditions are more serious than those on the irrigated conditions in the area.

Geometry of the chute blocks in stilling basins plays a significant role in size and type of these structures. One of the most influencing factors in the design of the blocks is the fluctuating pressure which may cause fatigue on the blocks. Despite investigations conducted by many researchers, there is not enough information about the pressure fluctuation around chute blocks in compacted stilling basins such as Saint Anthony Falls (SAF) basins. In this paper, the results of a naval experimental work and measurement of pressure fluctuations around chute blocks of SAF stilling basins are reported. The results show that the pressure fluctuations around the chute blocks cannot be overlooked in designing such structures. The variation of pressure fluctuation with Froude number of incoming supercritical flow at various faces of the chute block is reported, which shows an increasing trend of pressure fluctuation. It is also observed that the submergence of hydraulic jump will decreasingly affect the pressure fluctuations. The trend of variations will follow different patterns at the different faces of the block.

Eighteen wheat breeding lines were evaluated along with two check cultivars across nine locations of temperate zone of Iran during two crop seasons (2003-2004 and 2004-2005). Field records were taken for some important traits especially grain yield. Combined ANOVA for nine locations in the first season and for seven locations in both seasons was undertaken. In each case, additive main effects and multiplicative interaction analysis (AMMI) was employed and the biplot of the Interaction Principal Components (IPC) were evaluated for stability and adaptation relationships among genotypes and locations. IPC1, IPC2 and IPC3 accumulatively defining 78.4% of genotype×environment (G×E) interaction variation were found out as significant in the first crop season. Biplot of first two IPCs identified at least two sub-regions among the locations. Some genotypes (M-82-7 and M-82-17) showed specific adaptation toward one of the drought-prone sub-regions. For the combined data of both seasons, only IPC1 was significant defining 41.5% of G×E interaction variation. Thus, plot of IPC1 along with grain yield means were employed for an interpretation of adaptation relationships. Entries M-82-8, M-82-9, M-82-11 and M-82-15 showed specific adaptation to Mashhad station which was interactive and particular in behavior. The results indicated that AMMI is an informative method of stability and adaptation analysis to be employed in practical plant breeding and subsequent variety recommendations.

Quantitative valuations of observed heterosis for 11 traits of 15 F1 hybrids generated by half diallel crosses of six diverse rice cultivars (Domsefid, Hashemi and Binam, three Iranian local cultivars; Dorfak, Kadous and IR30, three improved cultivars), were made in this study. Fifteen F1 hybrids and their parents were evaluated in a randomized complete block design with three replications at the Research Farm of the University of Guilan at Rasht, (Iran) in 2006. The studied traits were growth period, reproductive period, flag leaf area, plant height, panicle length, number of panicles per plant, number of grains per panicle, 1000-grain weight, grain yield, brown grain length and brown grain width. The significance of specific combining ability (SCA) and general combining ability (GCA) for all studied traits revealed that both additive and non-additive gene effects contributed to the inheritance of the traits. Assessment of standard heterosis based on check variety Dorfak showed that there was significant heterosis for all the traits studied in the 15 hybrids. For grain yield, the Dorfak×Domsefid cross had the highest heterosis. This hybrid had good heterosis values for many traits such as growth period, reproductive period and 1000-grain weight and was recommended as the most promising combination for developing high yielding hybrid rice varieties.

Deoxynivalenol contamination was determined in corn produced in Golestan and Ardabil (Moqan) Provinces, Iran, in 2004-2005. Samples were collected from different stages of production, including before harvest, at harvest, post harvest as well as after drying. Ground sub samples were extracted with water; each extracted sample was cleaned up through an immunoaffinity column. Deoxynivalenol was estimated through reversed-phase High Performance Liquid Chromatography (HPLC). The linearity of standard curve for 50 -10,000 ng ml-1 of standard solutions was proved (R2= 0.9999). Detection limit was 10 ng g-1. Recovery of the method for 1,000 and 500 ng g-1 spiked samples was 73.5% and 93.5% (n= 5). Deoxynivalenol contamination was found in 76.7% of samples in the range of 54.4-518.4 ng g-1. The mean of contamination was 116.25 ng g-1. This is the first report of natural DON contamination of corn from Iran.

The soil erodibility factor varies spatially according to variations of some soil properties on the surface. This study was carried out to compare spatial variability of the soil erodibility factor as estimated and measured using the USLE. The study was conducted in an agricultural zone with an area of in 900 km2 in Hashtrood, northwestern Iran. In the study area, 36 square grids with a dimension of 5 km were considered. In each grid, three unit plots were installed on the southern aspect with a slope of 9%. The soil erodibility factor was estimated using the USLE nomograph and measured as mean rate of soil loss from the unit plots per unit rainfall erosivity factor on an annual basis. The results indicated that the difference between the measured and estimated soil erodibility factor was significant (P 0.001) and correlation between the two was very poor with r2= 0.21. The spherical simulations were the best models to explain spatial variations of both the estimated and measured erodibility factors. The effective range of the spatial variations of the measured soil erodibility factor (2.43 km) was smaller than that in the estimated value (11.51 km). There was a considerable difference in the effective range (P 0.001) of spatial variations between the estimated and measured soil erodibility factor on the study area. The map of the proportion of the estimated values to measured values of the soil erodibility factor was nearly uniform (between 7.4 and 9.6) on the study area. The study indicated that use of the USLE nomograph would considerably lead to over-estimation of the soil erodibility in the entire the study area.