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Volume 2 Number 1 & 2 2008 
CONTENTS AND ABSTRACTS
Number 1
Andreza Viana Neri, Virginia Londe de Camargos (Brazil) Pedological Features and Fire Influence the Brazilian Cerrado (pp 1-4)
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ABSTRACT
Invited Mini-Review: The Cerrado covers 22% of the land surface of Brazil and is mainly located in the Central Region. This biome is considered the richest savanna and also has high endemism. The vegetation is very varied in form, ranging from dense grassland, usually with sparse covering of shrubs and small trees, to almost closed woodland. The presence of certain species and physiognomy is strongly related with the soil chemical and physical features. The Cerrado soil is considered acid, mainly, because of the high concentration of aluminum, but in this case, some species present different tolerance levels. Miconia albicans, considered an aluminum-accumulating species develops an abundant population in the Alic soil region. In the same way that tolerant species occur in high aluminum concentration, others occur only where it is lower and the fertility is greater, like Magonia pubescens. Besides pedological features, the physiognomic variation and the species distributions can be related with the fire frequency, too. Many species have morphological adaptations like xylopodium and thick cork bark that provide larger protection during the fire action. The relation Cerrado-fire is focused in many studies, because some species require high temperature to break dormancy, to germinate and to flower. In spite of the several environmental conditions influences, the pedological features and the fire frequency are decisive in the physiognomic diversity and in the species distribution.
Curtis L. VanderSchaaf, David B. South (USA) RCDlob: A Growth and Yield Model for Loblolly Pine that Incorporates Root-Collar Diameter at Time-of-Planting (pp 5-11)
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ABSTRACT
Original Research Paper: An individual tree model for loblolly pine (Pinus taeda L.) was developed to predict the response resulting from varying root-collar diameter (RCD) at time of planting. Data for this model were obtained from four plantations in the Lower Atlantic Coastal Plain of the United States. The study involved two levels of silvicultural intensity (1- standard; 2- intensive) and two bareroot seedling ideotypes (1 ? standard; 2 ? morphologically improved). Measurements were made up to age 12 years. The output from RCDlob was compared to two existing loblolly pine growth and yield model programs. Based on these analyses, a model system was developed that resulted in estimates of stand development for planting densities ranging from 988 to 1730 trees per hectare and stand ages up to 25 years. This model has been incorporated into a downloadable Windows-based Visual Basic program.
Number 2
Peter Hargreaves (Brazil) Phytosociology in Brazil (pp 12-20)
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ABSTRACT
Invited Mini-Review: A more or less random selection of the international journal literature on the subject of phytosociology in Brazil with publication dates from 1998 to 2007 is reviewed. The 90 papers are reviewed on the basis of three fundamental themes. First by their coverage of the various plant physiognomies that can be found in Brazil, and indeed throughout much of the Neotropics: phytoplankton, fungi, lichen, ferns, aroids, epiphytic orchids and bromeliads, Velloziaceae, palms, grasses, bamboo, succulents, stranglers, trees, shrubs and lianas. Then as representative of the Brazilian biomes: Amazon Biome, Cerrado Biome, Caatinga Biome, Pantanal Biome, Atlantic Forest Biome, and Coastal and Island Biome, there being none for the Pampa Biome. Finally, from a more critical viewpoint they are examined for their coverage of the environmental factors that help determine composition and structure of plant communities. The phytosociological methods for the predominantly woody plants and related multivariate data analysis are also briefly described. Many uses have been made of the results of phytosociological surveys, highlighting Brazil as a macrocosm of plant community ecology and vegetation science.
Maria Eugenia Ortiz Esobar, Teogenes Senna de Oliveira (Brazil) Substitution of Brazilian Native Plants for Agricultural Systems (pp 21-31)
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ABSTRACT
Invited Review: The substitution of natural ecosystems by agriculture is mostly due to the persistent food insecurity of a growing population. It produces a series of negative outcomes such as an increase in the greenhouse effect, a decrease of biodiversity, soil quality and water availability, as well as decreases in the rates of addition and decomposition of soil organic matter. Native vegetation is increasingly being replaced by agricultural crops and cultivated pastures in Brazil, especially by large land owners that produce cattle for export to developed countries, or also by small farmers that farm for subsistence. Agricultural systems can sometimes positively influence the environment, although they are the main factor responsible for imbalances in natural systems, and for losses of biodiversity. In this article, we focus on the effects of agricultural systems over four of the main native Brazilian vegetation types: Amazonia, Atlantic Forest, Caatinga and Cerrado.
Emerson Alves da Silva, Paulo Mazzafera (Brazil) Influence of Temperature and Water on Coffee Culture (pp 32-41)
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ABSTRACT
Invited Review: Although originating in the understory of the Ethiopian tropical rainforest, coffee is nowadays cultivated under full sunlight in most of the producing countries. Such a transition from shade to light influenced growth and productivity stimulating several physiological studies about the effects of air temperature and water availability on coffee. In this review we summarize the main effects of water and air temperature on vegetative and reproductive growth of coffee plants, primarily focusing on Brazilian conditions. The use of modern technologies such as irrigation and increased plant density per area, as well as the influence of water management and controlled water deficits on flowering synchronization are also addressed.
John E. Erpelding (USA) Sorghum Germplasm Resistance to Anthracnose (pp 42-46)
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ABSTRACT
Invited Mini-Review: Anthracnose is one of the most damaging diseases for sorghum production. The disease can be successfully managed through the use of resistant cultivars, but the development of resistant cultivars is hindered by extensive variation in virulence within the pathogen population. Additional sources of resistance are needed to more effectively manage the disease and sorghum germplasm collections are important sources of genetic variation for anthracnose resistance. A disease inoculation procedure was developed to enhance the evaluation of anthracnose resistance for the sorghum collection maintained by the USDA-ARS National Plant Germplasm System. Germplasm evaluations have suggested that sources of anthracnose resistance could be associated with country of origin. For example, resistant germplasm was more frequently observed for the sorghum collections from Ethiopia, Mali, and Sudan. The anthracnose evaluation of the Mali germplasm collection indicated that resistance was also associated with weather patterns within Mali. Resistant germplasm was more frequently observed in regions associated with higher annual rainfall compared to drier regions. This association of resistance with rainfall patterns has been observed for collections from other African nations. For collections from wetter regions, such as Rwanda and Mozambique, the majority of the accessions were resistant. In comparison, nearly all the accessions in the collections from dry regions, such as Somalia and Algeria, were susceptible to anthracnose. The genetics of host plant resistance is presently being evaluated to determine if the greater frequency of resistance observed in these regions is associated with genetic variation for resistance.
Ítalo H.L. Cavalcante, Inez V.M. Oliveira, Márkilla Z. Beckmann-Cavalcante, Antonio B.G. Martins (Brazil) Substrate for Seedling Emergence of White Sapote in Brazil (pp 47-50)
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ABSTRACT
Original Research Paper: Aiming to evaluate seedling emergence of white sapote (Casimiroa edulis - Rutaceae) an experiment was developed with seeds from mature fruits originating from the Active Germplasm Bank of the São Paulo State University, Jaboticabal, Brazil. A completely randomized design was adopted and four treatments (substrates) were performed, with five repetitions of 50 seeds each, reaching 250 seeds in total. Substrates studied were: Plantmaxâ (processed and enriched barks + expanded vermiculite + processed and enriched peat); Coconut fiber; Washed sand and soil mixture commonly used for seedling formation [soil (red Oxisol) + sieved sand + bovine manure (3:3:1)]. The percentage seedling emergence and emergence rate were calculated at the end of the experiment, i.e., at 40 days after sowing. Seedling emergence and the speed of this process were not influenced by the substrate and all substrates studied could be used for seedling establishment of white sapote.
Haroon Rashid (Pakistan), Muhammad Azim Khan (Canada), Anees Amin, Khalid Nawab, Nazim Hussain (Pakistan), Pankaj K. Bhowmik (Canada) Effect of Parthenium hysterophorus L. Root Extracts on Seed Germination and Growth of Maize and Barley (pp 51-55)
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ABSTRACT
Original Research Paper: We studied the allelopathic effect of Parthenium hysterophorus on the germination and shoot growth of maize (Zea mays) and barley (Hordeum vulgare) in the laboratory. Both cereal species were negatively affected by the aqueous root extracts of parthenium. As the concentration of parthenium weed root extracts increased, so the germination, shoot length and root length of maize and barley decreased. Experiments, which were conducted under two different temperature regimes, indicated that both species reacted differently to the same concentrations as a direct influence of temperature. These preliminary findings indicate that a more extensive study is required to fully explore the allelopathic potential of parthenium weed extracts under various factors so that these may be used effectively against different weeds.
Ravindra B. Malabadi (Canada/India), Jaime A. Teixeira da Silva (Japan), K. Nataraja (India) A New Approach Involving Salicyclic Acid and Thin Cell Layers for Cloning Mature Trees of Pinus roxburghii (Chir Pine) (pp 56-59)
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ABSTRACT
Original Research Paper: The cloning of mature conifers by somatic embryogenesis is potentially a low-cost method and is capable of producing unlimited numbers of normal individuals. This paper highlights for the first time the role of salicyclic acid (SA) on induction of embryogenic cultures using thin cell layers of vegetative shoot apices of mature trees of P. roxburghii. Embryogenic cultures were successfully initiated at a high percentage (12 to 31%) in 10 different genotypes following the addition of 1.0 mg l-1 SA to DCR basal medium. On the other hand, DCR basal medium lacking SA (control) showed a lower percentage (0 to 13%) of somatic embryogenesis in these 10 genotypes. SA improved the initiation of embryogenic cultures and also resulted in the formation and development of more pro-embryos on maintenance medium than in our previous protocols of somatic embryogenesis which lacked SA. Higher concentrations (2.0 and 5.0 mg-1) of SA resulted in the browning of cultures, and thus had an inhibitory effect. These results indicate a positive role of SA as a growth regulator in conifer somatic embryogenesis.
Evangelos D. Gonias, Derrick M. Oosterhuis, Androniki C. Bibi (USA) Cotton Growth and Yield Enhancement by the Insecticide TrimaxTM (pp 60-62)
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ABSTRACT
Short Communication: TrimaxTM, a formulation of the active ingredient imidacloprid, is an insecticide registered for use in cotton (Gossypium hirsutum L.) to control the major sucking/piercing insects. There have been anecdotal reports of crop growth and yield enhancement after foliar applications of Trimax in the absence of insects, but no research has been conducted to support such reports. To study the effect of Trimax on the growth and yield of cotton, field trials were conducted for two years. Treatments consisted of an untreated control and Trimax at 109.5 mL/ha applied three times at weekly intervals starting at the pinhead square growth stage. Measurements were made of lint yield and yield components, fiber quality, as well as crop growth, dry matter partitioning and crop maturity. Increased lint yield due to applications of Trimax was recorded for both years of the study. Furthermore, increased dry matter production and number of fruit was observed after Trimax application indicating a positive effect on crop growth. The crop monitoring program COTMAN revealed an effect of Trimax on crop maturity, with the treated plants reaching the physiological maturity stage 3 to 5 days earlier than the untreated control. This is the first research documentation of the yield and growth promoting properties of Trimax in cotton in the absence of insects.
L. Milenka Arévalo Soliz, Derrick M. Oosterhuis, Dennis L. Coker, Robert S. Brown (USA) Physiological Response of Cotton to High Night Temperatures (pp 63-68)
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ABSTRACT
Original Research Paper: Variable yields of cotton (Gossypium hirsutum L.) have been mostly attributed to high day temperatures. However, high night temperatures seem to play a major role due to their effect on respiration by affecting the carbohydrate supply for plant growth and yield. Little is known about the effect of night temperatures on the metabolism of field-grown cotton. This study evaluated the effect of different periods (weeks) of high night temperatures on leaf respiration and photosynthesis, leaf carbohydrate concentration, and fiber yield as determined by the fiber weight per seed. Night temperatures were elevated daily for 4 hours during flowering and boll development and their effect compared with ambient conditions. Results showed that short periods of one week of high night temperatures in the field in 2002 and 2003 had little effect on respiration, whereas the longer period of 4 weeks in 2004 caused a significant increase in respiration. There was also no effect of high night temperatures on respiration of plants cultivated under growth room conditions. Photosynthesis and the leaf carbohydrate content were not affected by the night temperature regimes in either environment. There was a significant increase in boll abscission by the second week of high night temperature treatment under growth room conditions followed by compensation. The only component of yield affected by high night temperature was fiber per seed which would suggest less available carbohydrate. Overall, the high night temperatures had some small effect on respiration, no effect on photosynthesis, and resulted in a decrease in fiber weight.
Samuel P. Stacey (Australia), Derrick M. Oosterhuis (USA), Mike J. McLaughlin (Australia) The Effect of Chelating Agents on the Foliar Sorption of Zinc Fertilizers (pp 69-73)
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Original Research Paper: This study investigated the sorption of chelated zinc (Zn) fertilizers applied to plant foliage. n-Octanol water partition coefficients showed that rhamnolipid formed lipophilic complexes with Zn. It was hypothesized that the lipophilic complex would be better absorbed by leaves than ZnSO4 because leaf cuticles are primarily hydrophobic. Cuticle/water partition coefficients, which were measured using enzymatically isolated Valencia orange (Citrus sinensis) cuticles, showed that a chelating polymer called polyethylenimine and rhamnolipid increased Zn sorption to adaxial cuticle surfaces by 2-fold and 5-fold, respectively. The chelate EDTA reduced cuticle sorption of Zn to 17% of the ZnSO4 control. The rate of Zn diffusion across isolated adaxial cuticles was measured by dialysis. In addition, Zn sorption by cotton (Gossypium hirsutum L.) foliage was measured by spraying chelated Zn solutions on the foliage before washing the leaves with a rainfall simulator at set intervals. The results showed that the rate of Zn diffusion across C. sinensis cuticles was not related to the cuticle/water partition coefficients of the chelate solution. Nor did the formation of lipophilic Zn-rhamnolipid complexes increase Zn diffusion across the primarily hydrophobic cuticle. Six hours after application to G. hirsutum leaves, rhamnolipid, EDTA and polyethylenimine had reduced the rate of Zn sorption by 71, 74 and 81% of the ZnSO4 control, respectively, which suggested that these chelates may increase the risk of Zn-fertilizer runoff during rainfall events. The reduction in Zn sorption with chelate application was probably due to the size selectivity of aqueous pores that are present within leaf cuticles and the efficiency with which aqueous pores transport ionic Zn2+.
Sanjib Nandy, Qin Chen (Canada), Shan Cheng Sun (China), Faiz Ahmad, Robert Graf, Gerald Kereliuk (Canada) Nutritional Analyses and Their Inheritance Properties in Colored Wheat Seed lines from Different Origins Using Near-Infrared Spectroscopy (pp 74-79)
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Original Research Paper: Black, purple and blue wheat could provide a potential replacement of synthetic color with a nutritional ingredient for the cereal industry. Near Infrared reflectance spectroscopy (NIRS) has been widely used for the analysis of seed color and quality traits of intact seeds from cereals and oilseeds plants. The objective of this work was to study nutritional properties and their inheritance in winter and spring colored wheat from different origins by NIRS. Hybrid seeds from ‘Black wheat76’ crossed with ‘Purendo 38’, ‘Konini’ and ‘Lo2147-3-4’ were all black in color. The gene(s) responsible for Chinese winter wheat seed color was shown to have a dominant effect in nature as the reflectance spectra of the hybrid seed was found to be same as Chinese parental lines. Black colored wheat contained higher protein levels than the blue and purple colored wheat lines from both Canadian and Chinese origins. Highest protein percentage was observed in the hybrid between ‘Black wheat76’ and ‘Purendo 38’, whereas purple colored seed ‘Konini’ and black colored seed ‘Lo2147-3-4’ showed a high level of starch content. A strong positive correlation was found between protein and crude fibre percentage, while a high negative correlation was found between protein and moisture content, as well as protein and starch content. All hybrid plants had high protein content, high crude fibre and high minerals content but lower starch and moisture content than their respective parental lines. Further quantification of individual anthocyanins in black, purple and blue color wheat with high nutrient content would facilitate the use of these grains as natural colorants and functional food ingredients in the future.
Appanna Vikram (Canada), Ajjanna R. Alagawadi (India), Habiballah Hamzehzarghani (Iran), P. U. Krishnaraj (India) Efficacy of Phosphate Solubilizing Bacteria on the Yield and Phosphorus Uptake of Green Gram (Vigna radiata (L.) Wilczek) (pp 80-84)
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Original Research Paper: The efficacy of phosphate solubilizing bacteria (PSB) on the yield and phosphorus uptake of green gram (Vigna radiata L.) was studied in a field experiment at the Main Research Station, University of Agricultural Sciences, Dharwad, India. All the strains of PSB used, except for strain PSBV-7, significantly increased the grain and straw yield of green gram as compared to rock phosphate control. The highest grain and straw yield was recorded by strain PSBV-13 which differed significantly over single super phosphate control and other strains of PSB. The phosphorus content in shoot, root and grain increased by 29-45, 17-30 and 12-17%, respectively, due to inoculation of PSB over the rock phosphate control. In most treatments there were significant increases in the rhizosphere population of the PSB suggesting their successful establishment. The results suggest the possible use of efficient strains of PSB as a biofertilizer to enhance crop production.
J. Armando Muñoz-Sanchez, S. M. Teresa Hernández-Sotomayor (Mexico) Biotechnology in Coffee Research (pp 85-95)
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Invited Review: Coffee is the second most important commodity traded worldwide and its cultivation and processing constitutes a major economic and social activity in many countries. The main limitation in coffee breeding is the very narrow genetic base of the species Coffea arabica. Most C. arabica cultivars exhibit homogeneous agronomic behaviour combined with high pest and disease susceptibility. Enlarging the genetic diversity of Arabica varieties and improving their resistance to pathogens or environmental factors are high priorities in the effort to make coffee production economically and socially sustainable. Conventional coffee breeding methods require time. Selections are made in wild populations, hybridised and the progeny evaluated with back-crossing. The resulting seed production and distribution are insufficient to meet coffee grower needs. Developing reliable, rapid tools for improving selection methods is urgent. Major biotechnological advances in coffee research include successful in vitro manipulation and multiplication of coffee, development of gene transfer protocols, generation of transgenic coffee plants with specific traits (high yield and good quality) and description of the metabolic pathways involved in the response mechanism to environmental factors. These advances have opened new perspectives and generated a steady flow of coffee biotechnology data focused on improving agronomic and processing qualities. Genome research in coffee promises to add new dimensions to coffee research. This review focuses on the basic and applied aspects of biotechnology in coffee research and how it will advance genetic improvement of coffee.
Adalberto Di Benedetto, Jorge Rattin (Argentina) Transplant in Sweet Maize: A Tool for Improving Productivity (pp 96-108)
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Invited Review: An understanding of the response of sweet maize to particular short- and long-term stresses is limited even further by interactions with other stresses in the crop such as the root restriction imposed by small plug cell trays when a transplant routine is used. It is possible to obtain higher yield from sweet maize plants using a transplant method rather than direct seeding under optimal environments. Decreased shoot growth observed in transplanted maize seedlings is related to root restriction caused by the size of the previous container but does not affect mechanical impedance to any extreme level. Inadequate temperature, which is common following seeding in short-season areas, and which reduces both seedling emergence and leaf appearance rates and makes seeds and seedlings susceptible to disease organisms, leads to reduction in seedling vigor. According to the our experiments conducted in a marginal maize production area, transplanting sown sweet maize hybrids showed changes in dry weight accumulation, increased light interception, harvest index, radiation use efficiency and yield. We have been able to optimize plant density to almost 12 plants m-2 although daily maximum and minimum temperatures during the first stages of vegetative growth must be controlled. The economic feasibility for Argentina of transplant when such high density was used showed that the added cost of transplant is often possible.
Casey R. Meek, Derrick M. Oosterhuis, James M. Stewart (USA) Physiological and Molecular Responses of Common Cotton Cultivars under Water-Deficient Conditions (pp 109-116)
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Original Research Paper: Water-deficit stress is a major limiting factor in cotton (Gossypium hirsutum L.) production, but understanding of the level of drought tolerance among current cultivars is still lacking. To obtain an estimate of the diversity in drought tolerance in commercial cotton, seven cultivars representative of most of the major cotton areas were chosen for evaluation. These included ‘Maxxa’ (west), ‘Sphinx’ (southwest), ‘Fibermax’ (midsouth), ‘Deltapine Nu33B’, ‘Stoneville 747, ‘Sure-Grow 474’ (Mississippi Delta), and ‘Paymaster 1218’ (east). An Australian cultivar, ‘Siokra L-23’, was included for its known level of drought tolerance. Physiological characterization under water-deficit stressed conditions was performed in the field and growth chamber. Osmotic adjustment was measured 12 hours after re-watering. One week after rehydration, leaf epicuticular wax content and carbon isotope discrimination were measured. Photosynthesis was measured at 16 hours, three and seven days after re-watering. Significant differences in osmotic adjustment and carbon isotope discrimination were encountered among cultivars. Stressed plants discriminated less than control plants. Generally, cultivars with high levels of osmotic adjustment exhibited smaller differences in carbon discrimination between water treatments. Several cultivars showed significantly greater photosynthetic rate at three days after stress cessation compared to control plants, especially ‘Siokra L-23’ and ‘Sphinx’. Leaf epicuticular wax content was significantly higher in stressed plants. ‘Siokra L-23’ was screened via northern analysis for gene expression related to the compatible solutes, proline and trehalose which are reported to accumulate during drought stress. Slight up-regulation was observed in Δ1-pyrroline-5-carboxylate reductase (P5CR) and Δ1-pyrroline-5-carboxylate synthetase (P5CS), while proline dehydrogenase (PDH) was down-regulated. Trehalose-related genes [trehalose-6-phosphate phosphatase (TPP), trehalose-6-phosphate synthase (TPS), and trehalase] were up-regulated in response to water deficit stress. The overall results did not indicate major differences in water-deficit stress tolerance between commercial cultivars, whereas differences in proline and trehalose-related gene expression were observed between water treatments. |
