Journal of Agricultural Science and Technology
Volume:13 Issue: 1, Jan 2011

Results of an evaluation of the impact of agricultural science and technology (AS and T) policy system institutions on efficiency and technical change in Kenyan and Ugandan agriculture are presented here. Data envelopment analysis was used to derive efficiency and technical change and logistic regression applied to delineate AS and T institutions that induced efficiency and technical progress. Technical progress was positively influenced by transboundary technology transfer, decentralization of extension services, thematic agricultural research and the literacy rate of the agricultural labour force. The intellectual property rights regulatory system negatively impacted on technical progress. On the other hand, efficiency progress was supported by the enactment of a regulatory framework for intellectual property rights system, but negatively influenced by transboundary technology transfer and decentralization of extension services.

Reproduction parameters for Helicoverpa armigera (Hübner) were determined and compared on 13 soybean varieties (DPX, L17, BP, Clark, JK, 356, M4, M7, M9, Gorgan3, Sahar, Zane and Williams) at 25±1ºC, 65±5% RH over a photoperiod of 16:8 (L:D) hours. Reproduction parameters were estimated for individual newly emerged moths, which had spent their immature stages on different soybean varieties. The highest rate of gross fecundity was on M4 (2,238 eggs female-1), whereas the lowest value of this parameter was on Gorgan3 (467 eggs female-1). The gross fertility rate was the highest on M7 (782 eggs female-1) and lowest on Gorgan3 (149 eggs female-1). The net fecundity rate varied from 192 (BP) to 1,275 eggs (M7). The net fertility rate was the highest on M7 (586 eggs female-1) and lowest on Sahar (56 eggs female-1). The daily number of eggs laid per female ranged from 50 to 282 eggs, the minimum on Gorgan3 and the maximum on M4. Our results demonstrated that M9, Williams, Clark, L17, M7, M4 and Zane varieties were more suitable host plants for reproduction of the studied population of H. armigera. The other varieties examined showed less suitability as host plants for H. armigera reproduction.

In vitro and greenhouse studies were conducted to investigate the possibility of an interaction between two systemic insecticides of: Thiodicarb (Larvin DF 80) and Imidacloprid (Guacho SW 70), and seedling disease organisms of: Rhizoctonia solani, Fusarium moniliforme and Pythium ultimum. When in vitro concentrations of Imidacloprid and Thiodicarb were applied, a fungistatic activity occurred. These insecticides inhibited mycelial growth of R. solani and F. moniliforme by 6.6-14.1 % and 15.2-70.8 %, respectively. F. moniliforme was more seriously affected by the insecticides while no significant effect was observed on P. ultimum. The pot experiments confirmed in vitro results so that, Thiodicarb provided excellent protection against pre- and post-emergence damping-off of the plant by 54.2% and 90.6 %, respectively.

Chemical insecticides have been widely employed for the control of storage grain pests. This has caused such problems as insecticide resistance along with contamination of foodstuffs with chemical residues. Thus, there is a growing interest in using pathogenic control agents as alternative. In this study, the potential of Beauveria bassiana (BbWeevil™, a commercial product containing 2×109 conidia g-1) was evaluated against adults of Tribolium castaneum, Sitophilus granarius and Oryzaephilus surinamensis. The experiments were carried out at the rates of 0, 250, 500, 750 and 1,000 mg kg-1 and exposure intervals of 5, 10 and 15 days, in 24±2°C and 50±5% r.h. Fifteen 1 kg lots of grain (one lot for each exposure time-rate) were prepared and treated with the appropriate predetermined doses. Four 50 g samples of each were taken as replications and placed in glass vials. Thirty 1-7 day old adults were introduced into each glass vial. Following mortality count in each exposure time, the adults (dead and alive) were removed and the vials left in the same conditions for a further 45 days to have the progeny production assessed. Means were separated by employing Tukey´s Test (P= 0.05). All main effects (dose, exposure time and insect species) as well as associated interactions were significant (P< 0.01), with the exception of exposure time×insect, which was not significant. In all the experiments, mortality increased with increase in dose rates and exposure time with the highest mortality being observed after 15 days of exposure to 1,000 mg kg-1 concentration. These amounts were recorded 88.33±3.96, 78.31±2.15 and 64.99±4.4% for S. granarius, O. surinamensis and T. castaneum, respectively. S. granarius was more susceptible than the others, because the highest mortalities in each of the three exposure times and for all dose rates were observed in this species. The lowest LC50 value within the exposure times was determined 452.855 mg kg-1 after 15 days for S. granarius. Results achieved from progeny indicate significant differences only between rates and insect species. For all species, the highest progeny production was observed in rate 0 mg kg-1. The results obtained in this research recommend that BbWeevil™ could be used to control different grain storage pests but to find longer exposure intervals and higher rates are subject to further future research.

A two year field experiment was carried out to evaluate the competitive effects of wild mustard densities growing with rapeseed (cultivar Talaye) under different nitrogen rates. Treatments were wild mustard densities (0, 10, 20, 30, and 40 plant m-2) and nitrogen (N) rates (0, 50, 100, 150, and 200 kg N ha-1). The factorial set of treatments was arranged into a randomized complete block design with four replications. Rapeseed yield and the yield components decreased as wild mustard density increased. At 0 and 10 wild mustard plants m-2, grain yield increased with increasing N fertilizer up to 150 kg ha-1. At higher wild mustard densities, grain yield decreased above 100 kg N ha-1. These results indicate that increases in nitrogen application only increased the competitiveness of the weed versus the crop.

This study was performed to determine the effect of injecting selenium into pregnant heifers at the last stage of gestation on the serum Se, Cu, Zn and Fe status of the heifers and their calves. Fifty Holstein heifers were randomly assigned to one of five treatments. Four and two weeks before the expected time of calving, the heifers were injected intramuscularly 10 ml (T1), 20 ml (T2), 30 ml (T3), 40 ml (T4) of selenium and vitamin E, respectively. The control (C) group received no supplement. Each ml of the supplement© (Vet. Anim. Health BV) contained 0.5 mg Se as sodium selenite and 40 IU of D-L alpha-tocopheryl acetate. Blood samples were collected from heifers two weeks before the expected time of calving and on calving day. Blood samples of newborn calves also were taken from the jugular vein at birth and 7 days of age to measure the Se, Cu, Zn and Fe concentrations. The results indicated that the serum concentrations of Se increased in treated heifers compared with the controls. The selenium concentrations were significantly increased in the colostrum of treated heifers (P< 0.05). Zn concentration of both serum and colostrum decreased in the treated group compared with controls but it was not significantly different. Serum Se, Cu concentrations of calves of treated heifers increased during the first week of age but the serum concentration of Zn decreased in newborn calves at 7 days of age (P< 0.05). It seems that a high Se injection (T4) in pregnant heifers could increase the Cu and decrease the Zn concentrations and, thus, might disturb the Zn:Cu ratio which, in turn, leads to zinc reduction in heifers and their newborn calves. It can be concluded that a higher amount of Zn should be supplemented when more than 40 ml Se supplements are administered to pregnant heifers.

The changes of total calcium content of Persian sturgeon, Acipenser persicus follicles were investigated during different stages of germinal vesicle migration. Total calcium content increased during maturation and ripening of the oocytes i.e. migration of nucleus toward the animal pole. According to data, the total calcium of follicles with Polarization Index (PI: the ratio of the distance of the germinal vesicle from the animal pole over the animal-vegetal oocyte diameter×100) less than 5.2 (group I) were significantly higher than those in groups with 5.7< PI< 8.1 (group II) and PI> 9.4 (group III). Also, there were no significant differences observed in total calcium content of follicles with PI> 9.4 (group III) and follicles retained for 20 days in body cavity with PI> 10.5 (group IV). As well, there was a significant negative relationship observed between PI values and total calcium content of follicles. It is concluded that calcium is accumulated during the final oocyte maturation in Persian sturgeon.

Information on the thermophysical properties of the Iranian ultrafiltrated (UF) white cheese is very limited. In this research, those thermal properties determined experimentally were thermal conductivity, specific heat, density and water activity. The thermal conductivity and specific heat of Iranian ultrafiltrated white cheese (IUFWC) ranged from 0.447 to 0.480 W m-1 °C-1 and from 3.871 to 4.005 kJ kg-1 °C-1 for temperatures varying from 1°C to 23°C and from 1°C to 40°C, respectively. Both thermal conductivity and specific heat increased with moisture content and temperature. A three-step model predicting thermal conductivity as a function of cheese composition and temperature was developed based on the parallel and Maxwell models. The effective thermal conductivity predicted by the model developed was in good agreement with the experimental data. The modeling of density and water activity using non-linear regression concepts showed that density was highly affected by salt concentration and temperature; water activity was also strongly dependent on salt concentration and moisture content.

The present study explores the chemical constitution and antioxidant activity of the essential oils of the aerial parts of Artemisia dracunculus L. and the flower heads of Matricaria chamomilla L. GC-MS analysis revealed the presence of (Z)-anethole (51.72%), (Z)-β-ocimene (8.32%), methyleugenol (8.06%), limonene (4.94%) and linalool (4.41%) in Artemisia dracunculus and (E)-β-farnesene (24.19%), guaiazulene (10.57%), α-bisabolol oxide A (10.21%), α-farnesene (8.7%) and α-bisabolol (7.27%) in M. chamomilla L.. The antioxidant activity (AOA) of the essential oils was investigated using DPPH• (2, 2′-diphenyl 1-picrylhydrazyl) free radical scavenging and β-carotene/linoleic acid methods. The essential oil EC50 values were determined as 3.19±0.13 and 5.63±0.20 mg ml-1 for A. dracunculus and M. chamomilla, respectively. Further, the A. dracunculus L. essential oil (ADEO) and M. chamomilla L. essential oil (MCEO) were able to reduce the oxidation rate of soybean oil under accelerated conditions at 60 °C (oven test).

Effects of sodium salt solutions on physicochemical and sensory characteristics of refrigerated Persian sturgeon (Acipenser persicus) fillets during 12 days of storage were investigated. Fillets were dipped in solutions (2.5% w/v) of sodium acetate (SA), sodium lactate (SL), sodium citrate (SC) and distilled water (as control) for 10 minutes and then packaged. An assessment of TBARS, FFA, pH, heme iron and sensory attributes (flavor, color and odor) was carried out on 0,3,6,9 and 12 days past the storage time. Results indicated that TBARS values of each sample increased with the storage time (P< 0.05). Control showed the highest values of TBARS while sodium acetate sample had the significantly (P< 0.05) lowest figures among the treatments (1.04 for SA versus 2.34 for control). Lipid hydrolysis assessment revealed that the sodium salt treated samples, especially sodium acetate, acquired the lower FFA amounts (P< 0.05) as compared with control. No significant differences (P> 0.05) were observed among the pH values of the treatments. Heme iron assessment showed that the samples treated with sodium acetate contained more heme iron as compared with control. Sensory assessment revealed more desirable scores for the sodium acetate treated group as compared with others samples. The order for the sodium salt treated effects was: SA> SC> SL. As a consequence, sodium salts, in particular sodium acetate, might be considered as effective tools in preventing the quality degradation of the fillets, resulting in an extension of their shelf life.

In order to determinate appropriate stability parameters, six statistics were studied for flower yield stability of 35 Rosa damascena landraces in 8 locations over two years (2007-8) in Iran, using a randomized complete blocks design with 3 replications. A positive correlation between environmental variance (S2) and flower yield suggested that only low yield landraces develop a similar phenotype over a range of environments. The stable and adaptable landraces using the environmental coefficient of variation (CV) produced a flower yield about average for landraces or higher. Although all of the stable landraces by S2 produced very low yield, some of adaptable ones by CV (e.g. YZ2) showed high flower yield and stability simultaneously. A negative correlation was observed between CV and flower yield. The regression coefficient of yield over environments (b) was positively correlated with flower yield; the regression coefficients of all studied landraces were statistically different from zero therefore were not stable with static stability concept (b equal to zero). The stable and adaptable landraces according to dynamic stability concept (b equal to unity and Sd2 or variance due to deviation from regression equal to zero) produced a flower yield higher than average for landraces or near it. The superiority index (P) determined some of the highest flower yield as adaptable landraces. The stable landraces with the least variance of years within places (MSY/P) produced the least flower yield; because of a mixing of effects (year with plant age), MSY/P isn’t a favourable parameter for flower yield in perennial plants. Some high flower yield landraces were found (e.g. YZ2 and IS5) showing stability and adaptability with varying statistics such as CV, b, Sd2 and P. It could be concluded that a genotype can demonstrate both static and dynamic stability with high flower yield. In addition, the coefficient of variation (CV), dynamic view statistics (b equal to unity and Sd2 equal to zero) and superiority index (P) are proposed as desirable parameters for evaluation of flower yield stability with different concepts in Damask rose genotypes.

Maize improvement for high temperature tolerance requires the reliable assessment of parental inbred lines and their combinations. Fifteen maize inbred lines were evaluated during 2007 and 2008 in Shushtar city (Khuzestan Province). The inbred lines were planted at two dates: 6 July, to coincide heat stress with pollination time; and 27 July, as normal planting to avoid high temperature during pollination and grain filling period. In addition, 28 hybrids from a combination of eight selected lines, were evaluated under the same conditions in 2008. Five stress tolerance indices, including mean productivity (MP), stress tolerance (TOL), stress susceptibility (SSI), stress tolerance index (STI) and geometric mean productivity (GMP) were used in this study. Data analysis revealed that the SSI, STI and GMP indices were the more accurate criteria for selection of heat tolerant and high yielding genotypes. The positive and significant correlation of GMP and grain yield under both conditions revealed that this index is more applicable and efficient for selection of parental inbred lines in producing hybrids to be tolerant to high temperatures and high yielding under both conditions. Based on two years’ data and using the STI, GMP and MP indices, K166B, K166A and K18×K166B proved to be the most heat tolerant lines and hybrid. Biplot analysis allowed us to distinguish groups of tolerant and sensitive inbred lines and hybrids. Based on the results of this study, the hybrid K18×K166B can be recommended for the Khuzestan region.

The selection of a growing medium is one of the most important decisions in the culture of hydroponic crops. In order to select a suitable medium for hydroponic cucumber (Cucumis sativus L. cv. Negin), an experiment was carried out on growing media containing different particle sizes of perlite and organic substrates in a run-to-waste system in a greenhouse experiment. The growing media tested were: very course perlite (VC-P, 70% by volume in the range of 2-3 mm), course perlite (C-P, 70% by volume in the range of 1-2 mm), medium perlite (M-P, 70% by volume in the range of 1 mm), fine perlite (F-P, 70% by volume in the range of 0.5-1 mm), very fine perlite (VF-P, 70% by volume < 0.5 mm), sawdust (Sd) (100%), one mixture of VC-P and Sd (50:50, v/v), one mixture of VC-P and poplar chip (Ch) (50:50, v/v) and one mixture of VC-P and wheat straw (St) (50:50, v/v). The eight treatments were arranged in a randomized complete block design with four replications. The results showed that there were significantly differences in the mean fruit weight, plant height, and leaf area of cucumber with respect to media containing very course (VC)-grade perlite (horticulture-grade perlite) and its incorporation with organic substrates, and media containing different grades of perlite (from very course to very fine-grade perlite). The incorporation of wheat straw (50:50) into VC-grade perlite brought decreases of about 35% in the mean fruit weight of cucumber, respectively. Media containing fine grade-perlite led to a significant increase in mean fruit weight (50%), plant height (25%), and leaf area (70%) of cucumber as compared with media consisting of very course-grade perlite. It was concluded that the medium containing fine-grade perlite had the best performance for cucumber plant growth.

The physico-chemical parameters, nutrient status and heavy metal ions of Huluka and Alaltu Rivers of Ambo, Ethiopia were studied. Temperature, pH, electrical conductivity, CO2 content, total dissolved solids, hardness, dissolved oxygen, Ca2+, Mg2+, Cl-, nitrate, phosphate and sulphate have been determined along with selected heavy metals to assess the various water quality profiles along the rivers due to addition of various waste materials through anthropogenic activities. The majority of the parameters show an increasing trend progressing downstream and the declining quality of the rivers. The downstream samples have shown almost a three times increase in most of the measured physico-chemical parameters but fell within the recommended limits for drinking water except for dissolved oxygen and phosphate. Along the river course, most of the heavy metals fulfill the maximum permissible limit for drinking water according to the international standards except Cd and Mn.