Future outlook for Pinus patula in South Africa in the presence of the pitch canker fungus (Fusarium circinatum)

Approximately 50% of the area planted to softwood trees in South Africa has been established with Pinus patula, making it the most important pine species in the country. More effort has gone into developing this species for improved growth, tree form and wood properties than with any other species. This substantial investment has been threatened in the last 10 years by the pitch canker fungus, Fusarium circinatum. The fungus infects and contaminates nursery plants and, once transferred to the field, causes severe mortality of young trees in the first year after establishment. Although nurserymen have some control of the disease, it is recognised that the best long-term solution to mitigate damage because of F. circinatum infection is to identify tolerant species, clones and hybrids for deployment in plantations in the future. Research has shown that alternative species such as P. tecunumanii, P. maximinoi and P. elliottii are suitable for warm sites. Pine hybrids, particularly between P. patula and the high-elevation sources of P. tecunumanii, appear to be a suitable replacement on subtemperate and temperate sites. Although these alternative species and hybrids are more sensitive to subfreezing temperatures than P. patula, their planting range can be increased by including cold tolerance as a selection criterion. Future breeding efforts will most certainly focus on improving the tolerance of pure P. patula to F. circinatum, which can be achieved by identifying specific family crosses and tolerant clones. The commercial deployment of disease-tolerant control-pollinated P. patula and hybrid families will most likely be established as rooted cuttings, which requires more advanced propagation technology. In the long term, new seed orchards comprised of P. patula clones tolerant to F. circinatum could be used to produce seed for seedling production.     

Suppression of spinach wilt disease by biological soil disinfestation incorporated with Brassica juncea plants in association with changes in soil bacterial communities

Biological soil disinfestation (BSD) is a method of controlling soil-borne pests and diseases through anaerobic decomposition of plant biomass incorporated in field soil with temporary irrigation and covering with sheets. In this study, effects of BSD on suppression of spinach wilt disease were investigated in two different field experiments using mainly Brassica juncea plants as plant biomass. Soil bacterial community compositions were analyzed with clone library analysis based on 16S rRNA gene sequences to determine the relationship between the bacterial composition in the treated soil and suppression of the disease. For the BSD-treated soils, oxidation–reduction potential dropped, and acetate was usually detected at high concentrations. Although the control treatment (irrigation and polythene covering without biomass) decreased the wilt disease incidence in spinach plants cultivated in the treated plot as compared with those for the non-treated plot, BSD-treatments suppressed the disease more effectively. The clone library results showed that both non-treated and control soils contained diversified bacterial communities of various phylogenetic groups, while members of the Firmicutes mainly from the class Clostridia dominated in the BSD-treated soils. The clostridial groups detected were diverse and the major clone groups were closely related to strictly anaerobic fermentative bacteria such as Clostridium saccharobutylicum, Clostridium cylindrosporum, Clostridium sufflavum, and Clostridium xylanovorans. These clostridial groups were almost eliminated from the soil bacterial community when the BSD-treated soil was treated again with irrigation and covering without biomass before the next cropping, in which the wilt disease was hardly suppressed.     

Efficacy of slow-release albendazole capsules in controlling lungworms and gastro-intestinal nematodes in red deer (Cervus elaphus)

One hundred and fifteen young red deer (Cervus elaphus), heavily infected with lungworm (Dictyocaulus viviparus) and lightly infected with gastro-intestinal nematodes, were divided into three groups. One group of 50 animals was treated with one adult sheep dose of a slow-release albendazole capsule, another group of 50 was dosed orally five times with liquid albendazole and 15 were left as untreated controls. The capsule eliminated faecal lungworm larvae during the 103-day trial period There was a highly significant difference in faecal larval counts between the capsule-treated and control group. Over the trial period, the mean body weight gain of the untreated, liquid albendazole and capsule-treated animals was 0.1 kg, 4.5 kg and 7.8 kg respectively.     

Protection of chicks against salmonella infection induced by spray application of intestinal microflora in the hatchery

Summary

The efficacy of spray application of intestinal microflora of the adult bird in protection of broilers against salmonella infections was studied in 3 experiments under laboratory and field conditions.

In chicks treated soon after hatching (in the hatchers at approximately 30 per cent hatch or in the chick delivery boxes in the hatchery) with crop‐caecum homogenate or a mixture of aerobically and strict anaerobically cultured intestinal flora, very good results were achieved.

A very obvious protective effect against a high infection dose (3 × 10 c.f.u. S. infantis bacteria per chick) and complete protection against natural infection with different salmonella types was induced.

A significant improvement of growth rate was observed in broilers treated by spray in the hatchery and reared for 7 weeks under field conditions in an environment heavily contaminated with different salmonella types.     

Predicting early lactation energy balance in primiparous Red Dairy Cattle using milk and body traits

Abstract

The relationship of milk fat–protein ratio (FP), body condition score (BCS), body weight (BW) and their changes (ΔBCS, ΔBW) to energy balance (EB) in early lactation, and usefulness of the traits for predicting of EB of primiparous Finnish Red Dairy Cattle were studied. BW on the first test-day after calving correlated negatively (r=?0.30; P<0.02) with EB, suggesting large loss of body reserves for heavier cows. FP correlated significantly (r=?0.37) with EB on the first but not on the other test-days. Thus, when a single measure of FP is used to predict EB, records on the first test-day after calving seem to be the most appropriate. Milk FP was a better predictor of EB than BCS, BW or their changes. The accuracies of predictions were moderate; the best prediction explained 39.4% of EB variation. The low accuracy was suggested to be caused by imprecision in estimation of the EB.     

Effects of Various Phytohormones On Haploid Wheat Production in Wheat x Maize Crosses

Abstract

The Effects of Phytohormones On The Production of Haploid Wheat Were Examined in The intergeneric Crosses Between Japanese Wheat Cultivar (Triticum Aestivum Cv. Zenkojikomugi) and Maize (ZEA MAYS Cv. Pioneer P80 Lisa). The Detached Wheat Spikes Pollinated With Maize Were Cultured in A Solution Containing Sucrose and Sulfurous Acid Supplemented With 2,4―Dichlorophenoxyacetic Acid (2,4―D), indole-Acetic Acid, Naphthalene Acetic Acid, Kinetin Or 6-Benzylaminopurine At 0, 0.1, 1, 10, 100 Or 1000 Mg L-¹. Haploid Embryos Obtained Were Cultured On Agarose-Solidified B5 Medium. The Frequency of Plant Regeneration Was Significantly Affected Only By The Treatment With 100 Mg L-¹ 2,4―D. Thus, The Detached Spikes Were Cultured in The Medium Containing 2,4―D At 0, 25, 50, 75, 100, 125, 150, 175, 200 Or 400 Mg L-¹. The Treatments With 50 Mg L-¹ 2,4―D increased The Embryo Size, But The Treatments With Above 75 Mg L-¹ 2,4―D inhibited The Development of The Embryo. The Percentage of Florets Developing into Haploid Plants Was increased By The Treatment With 100 Mg L-¹ 2,4―D. Therefore, The Concentration of 2,4―D in THe Spikes Treated With 2,4―D At 50, 100 and 150 Mg L-¹ WERe Measured By Gas Chromatography. The Concentration of 2,4―D in THE Seed Was increased To 9.24 Ppm By The Treatment With 100 Mg L-¹ 2,4―D, A Further increase of 2,4―D Concentration in The Medium Having No Effect. On The Other Hand, The Concentration of 2,4―D in The Glumes and Rachis increased Up To 12.72 and 41.55 Ppm By The TreatmenT With 100 and 150 Mg L-¹ 2,4―D, Respectively. The Treatments With 2,4―D At A Concentration Higher Than 100 Mg L-¹ inhibited Embryo Development. The Present Results Suggested That 2,4―D At The Concentrations From 50 To 100 Mg L-¹ Would Be Optimum For Haploid Wheat Production Using Maize.     

Inheritance of C3―C4 Intermediate Photosynthesis in Reciprocal Hybrids Between Moricandia Arvensis (C3―C4) and Brassica Oleracea (C3) That Differ in Their Genome Constitution

Abstract

To Elucidate The Genetic Mechanisms Underlying C₃―C₄ intermediate Photosynthesis, We investigated The Structural and Photosynthetic Characteristics of Leaves of Reciprocal Hybrids Between The C₃―C₄ intermediate Species Moricandia Arvensis (L.) Dc. (Mama) and The C₃ Species Brassica Oleracea L. (Cabbage; Cc), Which Differ in Genome Constitution. Moricandia Arvensis Bundle Sheath (Bs) Cells included Many Centripetally Located Chloroplasts and Mitochondria, Whereas Those of Cabbage Had Few Organelles. Hybrid Leaves Were Structurally intermediate Between Those of The Parents and Showed Stronger intermediate C₃―C₄ Features As The Proportion of The Ma Genome increased. The P-Protein of Glycine Decarboxylase (Gdc) Was Confined Mainly To Bs Mitochondria in M. Arvensis, But Accumulated More in The Mesophyll (M) of Cabbage. in The Hybrids, The Accumulation of Gdc in Bs Cells increased With An increasing Ma:C Ratio. Hybrids Exhibited Gradients in Structural and Biochemical Features, Even in Reciprocal Crosses. The Co₂ Compensation Point of Reciprocal Hybrids With High Ma:C Ratios Was Lower Than That of Cabbage But Higher Than That of M. Arvensis. Thus, The Structural and Biochemical Features in Hybrid Leaves Reduced Photorespiration. Moricandia Arvensis Had A Higher Photosynthetic Rate Than Cabbage, But The Photosynthetic Rates of Hybrids Were intermediate Between Those of The Parents Or Comparable To That of M. Arvensis. Our Results Demonstrate That The C₃―C₄ intermediate Characteristics Are inherited Based On The Ratio of The Parent Genomes, and That There Is No Evidence of Cytoplasmic inheritance in These Characteristics.     

A description of the postlarva of Cygnodraco mawsoni Waite, 1916 (Pisces,Bathydraconidae), from the Southern Ocean

Eight postlarvae of Cygnodraco mawsoni Waite, 1916, were collected off the Australian Antarctic Mawson Station in the South Indian Ocean, during the South African SIBEX II expedition. These postlarvae are distinctive by having a long and slender body, projecting lower jaw and bicoloured caudal fin. Their morphology and pigmentation are unlike any known bathydraconid early life history stages.     

Sampling plans for aphids and their parasitoids in blueberry fields in Argentina

Densities of aphids (Aphis gossypii and A. spiraecola) and mummified aphids at different phenological stages of a blueberry crop were estimated for the purpose of developing sampling plans. Our data set comprised 99 samples taken during the period 2006–2008 in four fields in Buenos Aires Province, Argentina. Estimation of population density based on the proportion of sample units infested by individuals was investigated. We also calculated the minimum number of sample units to estimate the density of individuals on buds and buds + flowers using enumerative sampling. The relative precision of both methods was compared. Moreover, an enumerative sequential sampling protocol was developed. The presence–absence sampling plan gave density estimates with large variances (as measured by confidence intervals and large standard errors). The aggregation of mummies was similar on buds and buds + flowers, so the required number of sample units for density estimates was the same. Relative precision of estimates was much lower for the presence–absence sampling than the enumerative sampling, even at intermediate densities. An enumerative sequential plan would be the most appropriate and useful method in management plans for aphids and mummified aphids in blueberries.     

Relative Efficiency of Zinc Sulfate and Zinc Oxide–Coated Urea in Rice–Wheat Cropping System

Abstract

Rice–wheat cropping system covers about 24 million hectares in China, India, Pakistan, Nepal, and Bangladesh, and zinc deficiency is widespread in rice–wheat belts of all these five countries. The current practice of applying zinc sulfate heptahydrate (ZnSO₄ · 7H₂O) to soil is problematic because of the poor quality of the nutrients available in the market to the farmers. Zinc (Zn)–coated urea is therefore being manufactured to guarantee a good‐quality Zn source. This article reports the results from a field study conducted to study the relative efficiency of zinc sulfate and zinc oxide (ZnO)–coated ureas in rice–wheat cropping system. The highest grain yield of rice–wheat cropping system was obtained with 2.0% coating of urea. Zinc sulfate was also a better coating material than ZnO. Partial factor productivity, agronomic efficiency, apparent recovery, and physiological efficiency of applied Zn decreased as the level of Zn coating was increased.