Robust transformation procedure for the production of transgenic farmer-preferred cassava landraces

ABSTRACT: Recent progress in cassava transformation has allowed the robust production of transgenic cassava even under suboptimal plant tissue culture conditions. The transformation protocol has so far been used mostly for the cassava model cultivar 60444 because of its good regeneration capacity of embryogenic tissues. However, for deployment and adoption of transgenic cassava in the field it is important to develop robust transformation methods for farmer- and industry-preferred landraces and cultivars. Because dynamics of multiplication and regeneration of embryogenic tissues differ between cassava genotypes, it was necessary to adapt the efficient cv. 60444 transformation protocol to genotypes that are more recalcitrant to transformation. Here we demonstrate that an improved cassava transformation protocol for cv. 60444 could be successfully modified for production of transgenic farmer-preferred cassava landraces. The modified transformation method reports on procedures for optimization and is likely transferable to other cassava genotypes reportedly recalcitrant to transformation provided production of high quality FEC. Because the three farmer-preferred cassava landraces selected in this study have been identified as resistant or tolerant to cassava mosaic disease (CMD), the adapted protocol will be essential to mobilize improved traits into cassava genotypes suitable for regions where CMD limits production.     

Effect of various injection times in ovulation stimulation in gilts following previous biotechnical puberty induction

A conclusion derived from the slaughter of 69 gilts was that no role was played by the time intervals tested between puberty induction, using 500 IU of PMS and 250 IU HCG, and subsequent action to stimulate ovulation. Very good follicle maturation and follicle formation as well as the usual uterus and ovary weights were observed, no matter whether 500 IU of HCG were injected to stimulate ovulation 54, 72 or 78 hours after puberty had been induced. Ovulation was very efficiently synchronised by 500 IU of HCG in all three groups in which the ovulation figures relative to follicle formation 120 hours from puberty induction were 92.6, 94.6 or 92.7 per cent.     

The course of ovulation in gilts after the use of two GnRH injections for ovulation stimulation

The status of ovulation and amount of ovulated follicles in 410 gilts which had received differentiated pretreatment produced evidence to the feasibility of substitution of HCG by Gn-RH vet. "Berlin-Chemie" to stimulate ovulation. Yet, 2 injections are necessary with an adequate interval between them and with appropriate dosage. The highest synchronisation effect in all experimental variants was obtained from 350 and 750 micrograms of Gn-RH with 50 minutes in between or 750 plus 750 micrograms of Gn-RH with an interval of 40 minutes. Ovulation was most reliably stimulated by 500 I.U. of HCG.     

Evaluating grain sorghum hybrids for tolerance to iron chlorosis

Grain sorghum production in calcareous soils is frequently affected by iron (Fe) chlorosis. Greenhouse experiments were conducted to screen sorghum hybrids for their tolerance to iron deficiency chlorosis (IDC) and evaluate the effectiveness of Fe chelate application in alleviating IDC. Treatments in Exp. 1 were a factorial combination of 14 sorghum hybrids and three Fe chelate application rates (0, 3.4 and 6.8?kg product ha^?1) applied in-furrow with the seed at the time of planting. Exp. 2 evaluated two sorghum hybrids (85Y40 and NK5418) and three Fe chelate rates (0 and 3.4?kg product ha^?1) at planting, and a split treatment of 3.4?kg ha^?1. Results showed iron chelate application suppressed IDC and increased leaf chlorophyll content and grain yield in susceptible hybrids. Split application of Fe chelate suppressed IDC and increased grain yield. Our results indicate sorghum hybrids G8G08, 86G32 and 87P06 showed promise for tolerance to IDC.     

Testing the local reality: does the Willamette Valley growing region produce enough to meet the needs of the local population? A comparison of agriculture production and recommended dietary requirements

Eating locally continues to be promoted as an alternative to growing concerns related to industrialized, global, corporate agriculture. Buying from local famers and producers is seen as a way to promote a healthier diet, reduce environmental impacts, and sustain communities. The promotion of the local food movement presents the question: is it possible to feed a community primarily from the foods produced locally? We conducted a systematic analysis comparing the United States Department of Agriculture’s (USDA) recommended dietary requirements for the estimated 2008 population with annual local agricultural production for the years 2004–2008 within the counties of the Willamette Valley growing region. Our results indicate that current agricultural production in this highly fertile region does not meet the dietary needs of the local inhabitants for any of the USDA’s six food groups: grains, vegetables, fruits, dairy, meat and beans, and oils. In the most recent year of our analysis, 2008, Willamette Valley agriculture production met 67% of annual required grains, 10% of vegetable needs, 24% of fruits, 59% of dairy, 58% of meat and beans, and 0% of dietary oil requirements. Over the past 5 years there have been significant fluctuations in crop production, particularly in 2006 when grain yields dropped to 29% of needs met. Additionally, many of these commodities are exported as cash crops, thus not contributing to meeting local food needs. We discuss these results as well as areas of potential for increasing production of edible crops for local consumption in the region.     

X-ray and CT morphology of atlas variants in the dog

To investigate variations in atlas shape in dogs the image archives of the Department for Small Animals and Horses, University of Vienna, and The Royal Veterinary College, University of London were searched for radiographs and CT images of the canine atlas. 32 radiographic and 78 CT studies, including 51 toy and 54 large breed dogs, were retrieved and analysed. Five dogs had both radiographs and CT scans. Patients with pathologic alterations, such as fractures and incomplete ossification of the atlas, as well as oblique projections were excluded. Compared to large breed dogs (body weight more than 30 kg) the atlas of toy breed dogs (body weight less than 10 kg) had a reduced craniocaudal and an increased dorsoventral diameter. The vertebral longitudinal axis appeared to be dorsorotated, resulting in a steeper rise of the atlas wings and a more dorsally located lateral vertebral foramen. When comparing the atlas of toy and large breed dogs, the distribution of three morphologic parameters was statistically different: Ratio length to height (toy breeds > 1, large breeds < or = 1), shape of the vertebral chanal (toy breeds: vertically oval, large breeds: round resp. cross-oval, or vertically oval) and trabecular bone of the dorsal arch (toy breeds: absent, large breeds: present). There was no significant difference in the morphology of the ventral arch. Differences in atlas morphology could contribute to the predisposition of toy breed dogs to atlanto-axial instability; however, further studies are necessary to test this hypothesis.     

The analgesic effects of intrathecal xylazine and detomidine in sheep and their antagonism with systemic atipamezole

OBJECTIVE: To evaluate the analgesic and adverse side effects of intrathecal (IT) xylazine (XYL) and detomidine (DET) and the subsequent effects of two doses of intravenous (IV) atipamezole (ATI). STUDY DESIGN: Prospective, randomized, cross-over. ANIMALS: Five adult healthy female sheep with mean body mass of 55 +/- 2.3 kg. Material and methods Each sheep underwent four treatments: 1) 50 microg kg(-1) XYL IT and 5 microg kg(-1) ATI IV, 2) 50 microg kg(-1) XYL IT and 2.5 microg kg(-1) ATI IV, 3) 10 microg kg(-1) DET IT and 5 microg kg(-1) ATI IV, 4) 10 microg kg(-1) DET IT and 2.5 microg kg(-1) ATI IV. Pain threshold (TH) was tested by applying pulsed and stepwise incremental direct current to the skin overlying the pastern. The current at the point of foot lift was recorded as the TH. Heart rate (HR), mean arterial pressure, arterial oxygen (PO(2)) and carbon dioxide (PCO(2)) tensions were monitored. Outcomes were derived as differences between baseline assessment and measurements after treatment. Two-way anova was used to analyse drug effects, treatment differences between groups were examined with an F-test or Wilcoxon's rank sum test in case of non-parametric data distribution. p was set at 0.05. RESULTS: Both drugs increased the pain TH, caused small increases in PCO(2), and small decreases in HR, the latter was only significant for XYL recipients. Xylazine produced a significantly higher TH, more rapidly and for longer than DET. Atipamezole only significantly affected PaCO(2) in the XYL group 2. The pain TH was not affected in either group after IV ATI. CONCLUSIONS: At the doses used, IT XYL, and to a lesser extent DET, induced pastern analgesia. Atipamezole 5 microg kg(-1) IV antagonized some side effects without affecting analgesia. CLINICAL RELEVANCE: Intrathecal XYL may be useful as an analgesic in sheep. Its safety is increased because IV ATI antagonizes side effects, but not analgesia.     

Effect of calf age and dam breed on intake,energy expenditure,and excretion of nitrogen,phosphorus, and methane of beef cows with calves

The effects of calf age and dam breeds of different milk yield potential on turnover of energy and nutrients were followed in 16 Simmental and 16 Angus beef cows with Angus-sired calves. Calf ages investigated were 1, 4, 7, and 10 mo. The forage offered for ad libitum access consisted of hay for the calves and of a constant mixture of grass silage, meadow hay, and straw (1:0.7:0.3 on a DM basis) for the cows. Calves of 10 mo of age received an additional 2.6 kg DM/d of crushed barley. The animals were kept in groups of four cows and four calves except in the respiration chambers, where only one cow (tethered) and her calf (loose) were grouped together. Indicator techniques were applied to obtain individual data on feces and urine volumes during group housing. In the Simmental cows, heavier on average by 22 kg, voluntary DMI was higher than in the Angus cows (14.0 vs 12.3 kg/d). In calves, DMI from supplementary feeds was 1.6, 3.9, and 6.3 kg/d, on average, at 4, 7, and 10 mo of age, respectively. Dam breed had no significant effect on DMI and ADG of calves and on BW changes of cows. System retention of energy, N, and P showed a curvilinear development with calf age. System energy expenditure, which linearly increased with calf age, was higher with Simmental than with Angus dams (11%), even when adjusted for metabolic BW (8%). Energy loss through methane linearly increased with NDF intake and, consequently, with calf age from 18 to 30 MJ/d (446 to 751 L/d) for cows and calves together. Similarly, fecal and urinary N excretion and fecal P excretion steadily increased with calf age. In calves, the easily volatile N percentage of manure N rapidly decreased from very high levels in young calves. The resulting changes in inclination to gaseous N loss during manure storage for 8 wk were more than compensated by alterations in N intake of the calves, resulting in an increased total system N loss with progressing lactation. Overall, the present results indicate a difference between Angus and Simmental in efficiency of nutrient and energy utilization that might be explained by the difference in amount of delivery of nutrients to the calves via milk vs forage. Suggestions are made as to how the emissions of N, P, and methane, which were excessive in relation to productivity, could be reduced by nutritional means.     

Grazing methods and stocking rates for direct-seeded alfalfa pastures: III. Economics of alternative stocking rates for alfalfa pastures

A framework that permits estimation of economically optimal stocking rates for alternative economic parameters and alfalfa forage allowance was developed and applied to a controlled grazing experiment conducted with Holstein steers (243 kg) placed on direct-seeded alfalfa pastures in central Michigan. Responses of ADG to alternative levels of forage allowance (FA) were summarized by a quadratic function and the associated gains/hectare were calculated. The standard stocking rate (SSR; standard livestock units/ha) that maximized gain/hectare increased with FA and was greater than that which maximized ADG. Net returns to fixed resources(NRFR)/hectare were calculated for alternative SSR and economically optimal SSR were identified under various levels of herbage mass (kg/d). The SSR that maximized NRFR were between the SSR that maximized ADG and gain/hectare. Magnitude of the sale price discount for heavier calves, the slide, influenced the optimal SSR and the sensitivity of net return to SSR. The economically optimal SSR increased as the slide increased because animals stocked under higher SSR weighed less off pasture and therefore received a lower price discount.