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Yield Potential (yield + potential)
Selected AbstractsSoil greenhouse gas fluxes and global warming potential in four high-yielding maize systemsGLOBAL CHANGE BIOLOGY, Issue 9 2007M. A. A. ADVIENTO-BORBE Abstract Crop intensification is often thought to increase greenhouse gas (GHG) emissions, but studies in which crop management is optimized to exploit crop yield potential are rare. We conducted a field study in eastern Nebraska, USA to quantify GHG emissions, changes in soil organic carbon (SOC) and the net global warming potential (GWP) in four irrigated systems: continuous maize with recommended best management practices (CC-rec) or intensive management (CC-int) and maize,soybean rotation with recommended (CS-rec) or intensive management (CS-int). Grain yields of maize and soybean were generally within 80,100% of the estimated site yield potential. Large soil surface carbon dioxide (CO2) fluxes were mostly associated with rapid crop growth, high temperature and high soil water content. Within each crop rotation, soil CO2 efflux under intensive management was not consistently higher than with recommended management. Owing to differences in residue inputs, SOC increased in the two continuous maize systems, but decreased in CS-rec or remained unchanged in CS-int. N2O emission peaks were mainly associated with high temperature and high soil water content resulting from rainfall or irrigation events, but less clearly related to soil NO3 -N levels. N2O fluxes in intensively managed systems were only occasionally greater than those measured in the CC-rec and CS-rec systems. Fertilizer-induced N2O emissions ranged from 1.9% to 3.5% in 2003, from 0.8% to 1.5% in 2004 and from 0.4% to 0.5% in 2005, with no consistent differences among the four systems. All four cropping systems where net sources of GHG. However, due to increased soil C sequestration continuous maize systems had lower GWP than maize,soybean systems and intensive management did not cause a significant increase in GWP. Converting maize grain to ethanol in the two continuous maize systems resulted in a net reduction in life cycle GHG emissions of maize ethanol relative to petrol-based gasoline by 33,38%. Our study provided evidence that net GHG emissions from agricultural systems can be kept low when management is optimized toward better exploitation of the yield potential. Major components for this included (i) choosing the right combination of adopted varieties, planting date and plant population to maximize crop biomass productivity, (ii) tactical water and nitrogen (N) management decisions that contributed to high N use efficiency and avoided extreme N2O emissions, and (iii) a deep tillage and residue management approach that favored the build-up of soil organic matter from large amounts of crop residues returned. [source] Evaluation of Common Bean for Drought Tolerance in Juana Diaz, Puerto RicoJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2009T. G. Porch Abstract Drought tolerance is an increasingly important trait in common bean (Phaseolus vulgaris L.) due to the reduction in water resources, a shift in production areas and increasing input costs. The objective of this study was to evaluate 29 genotypes for drought tolerance under drought stress (DS) and reduced stress treatments in Juana Diaz, Puerto Rico. The use of DS and reduced stress treatments facilitated the identification of drought tolerant germplasm that also had good yield potential under more optimal conditions. Based on the results of seed yield under DS and reduced stress conditions, and DS indices, including the geometric mean (GM), stress tolerance index (STI) and percent yield reduction (YR), genotypes were identified with greater yield potential under the tested environment. Based on average GM over the 2 years, the superior common bean genotypes identified were SEA 5, G 21212, A 686, SEN 21 and SER 21. These genotypes performed well in both years and under both treatment conditions and thus may serve as parents for DS improvement and genetic analysis. [source] Spring Cereals for Forage and Grain Production in a Cool Maritime ClimateJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2003A. G. Todd Abstract Newfoundland's climate is marginal for agricultural production. The availability of locally grown cereal grain and high-quality forage are major limitations to successful animal agriculture in this region. Here, our overall objective was to compare several spring cereal species for both annual forage and grain production in Newfoundland's cool Maritime climate. Several varieties of barley (Hordeum vulgare L.), wheat (Triticum aesitivum L.), oats (Avena sativa L.) and pea (Pisum sativum L.),cereal mixtures for forage yield and quality, as well as grain yield and maturity, were compared in field trials on the east and west coasts in both 1999 and 2000. Barley headed earliest, yielded greatest forage dry matter, had lowest forage protein and acid detergent fibre (ADF) percentages, and had neutral detergent fibre (NDF) mean values greater than those of pea,cereal mixtures, but less than those of oats and wheat. Forage harvested from pea,cereal mixtures was similar to that of barley for yield, ADF and NDF, while P and protein percentage were much greater. Barley matured 10,15 days earlier than both wheat and oats. In general terms, all three spring cereals exhibited similar grain yield potential. Oats tillered less, but compensated by producing more kernels spike,1. Days to maturity for cereal grains in western Newfoundland were roughly similar to those reported for the Maritime provinces of Canada. Yield and maturity results for both forage and grain production suggest that eastern Newfoundland is a unique agro-ecoregion in North America, and agronomic recommendations specific to other regions may not be applicable in this region. [source] Characterizing laboratory colonies of western corn rootworm (Coleoptera: Chrysomelidae) selected for survival on maize containing event DAS-59122-7JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2008S. A. Lefko Abstract Event DAS-59122-7 is a novel transgenic trait designed to protect the roots and yield potential of maize from the insect pest corn rootworm Diabrotica spp. (Col.: Chrysomelidae). The increased pest status of corn rootworm, exceptional efficacy of this trait, and anticipated increases in farm efficiency and grower and environmental safety will drive adoption of this trait. Strong grower acceptance of this trait highlights the importance of science-based and practical resistance management strategies. A non-diapause trait was introgressed into two laboratory colonies of Diabrotica virgifera virgifera collected from geographically distinct locations: Rochelle, IL and York, NE. Both colonies were divided and each reared on maize containing event DAS-59122-7 or its near isoline. Selected and unselected colonies were evaluated for phenotypic change in larval development, injury potential and survival to adulthood during 10 and 11 generations. The F1 generation of both selected colonies displayed increased larval development, survivorship and measurable, but economically insignificant increases in injury potential on DAS-59122-7 maize. Survival rates of 0.4 and 1.3% in F1 generations of both selected colonies corroborate field estimates of survival on DAS-59122-7 maize. Over later generations, total phenotypic variation declined gradually and irregularly. Despite the absence of random mating, the tolerance trait could not be fixed in either population after 10 or 11 generations of selection. An allele conferring major resistance to DAS-59122-7 was not identified in either selected colony. The assessment also concluded that major resistance gene(s) are rare in populations of D. v. virgifera in the United States, and that a minor trait(s) conferring a low level of survival on DAS-59122-7 maize was present. The tolerance trait identified in this study was considered minor with respect to its impact on DAS-59122-7 maize efficacy, and the role this trait may play in total effective refuge for major resistance genes with recessive inheritance is the basis of future work. [source] Quantitative Trait Loci for Panicle Layer Uniformity Identified in Doubled Haploid Lines of Rice in Two EnvironmentsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2009Liangyong Ma Abstract Uniformity of stem height in rice directly affects crop yield potential and appearance, and has become a vital index for rice improvement. In the present study, a doubled haploid (DH) population, derived from a cross between japonica rice Chunjiang 06 and indica rice TN1 was used to analyze the quantitative trait locus (QTL) for three related traits of panicle-layer-uniformity; that is, the tallest panicle height, the lowest panicle height and panicle layer disuniformity in two locations: Hangzhou (HZ) and Hainan (HN). A total of 16 QTLs for three traits distributed on eight chromosomes were detected in two different environments. Two QTLs, qTPH -4 and qTPH -8 were co-located with the QTLs for qLPH -4 and qLPH -8, which were only significant in the HZ environment, whereas the qTPH -6 and qLPH -6 located at the same interval were only significant in the HN environment. Two QTLs, qPLD -10-1 and qPLD -10-2, were closely linked to qTPH-10, and they might have been at the same locus. One QTL, qPLD -3, was detected in both environments, explaining more than 23% of the phenotypic variations. The CJ06 allele of qPLD -3 could increase the panicle layer disuniformity by 9.23 and 4.74 cm in the HZ and HN environments. Except for qPLD -3, almost all other QTLs for the same trait were detected only in one environment, indicating that these three traits were dramatically affected by environmental factors. The results may be useful for elucidation of the molecular mechanism of panicle-layer-uniformity and marker assisted breeding for super-rice. [source] Screening for Drought Resistance of Rice Recombinant Inbred Populations in the FieldJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 10 2007Gui-Hua Zou Abstract In a 2-year experiment, 187 genotypes were grown under well-watered and drought stress conditions, imposed at panicle initiation stage. The relationship of genotypic variation in yield under drought conditions to potential yield, heading date and flowering delay, reduction in plant height, and to a drought response index (DRI) was detected. Grain yield under drought stress conditions was associated with yield under well-watered conditions (r = 0.47**, and r = 0.61** during 2 years of tests). The delay of heading date ranged from ,1 (no delay) to 24 days, and was negatively associated with grain yield (r = ,0.40*), spikelet fertility percentage (r = ,0.40**), harvest index (r = ,0.58**), but positively associated with yield reduction percentage (r = 0.60**). The reduction in plant height was negatively associated with grain yield (r = ,0.24**, and r = ,0.29**), spikelet fertility percentage (r = ,0.23**, and r = ,0.21*), harvest index (r = ,0.37**, and r = ,0.54**), and positively associated with yield reduction percentage (r = 0.58**, and r = 0.58**) in 2003 and 2004, respectively. The DRI of genotypes was strongly associated with grain yield (r = 0.87**, and r = 0.77**), fertility percentage (r = 0.66** and r = 0.54**), harvest index (r = 0.67** and r = 0.61**), and negatively associated with grain reduction percentage (r = ,0.70**, and r = ,0.73**) under drought stress. The results indicate that genotypes with drought resistance can be identified by measuring yield potential, delay in flowering, reduction in plant height, or DRI under test environments of well-watered and drought stress. [source] Effects of Brown Streak Virus Disease on Yield and Quality of Cassava in TanzaniaJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2001R. J. Hillocks Abstract Brown streak virus disease is the most important biotic constraint to cassava production in the coastal areas of southern Tanzania. Symptoms include foliar chlorosis and sometimes stem lesions. The disease also affects the tuberous roots which develop a yellow/brown, dry, corky necrosis within the starch-bearing tissues, sometimes accompanied by pitting and distortion, that is visible externally. The foliar symptoms of the disease often do not greatly affect plant growth, although the most sensitive cultivars may be stunted and defoliated. The main impact of the disease on the crop is by causing root necrosis. Field experiments were conducted at two sites in Tanzania to determine the effect of the disease on yield and quality of the roots. Cassava brown streak disease (CBSD) decreased root weight and patches of root necrosis made roots unmarketable, although the unaffected parts might still have been suitable for home consumption. The disease therefore has two effects, one on total root yield and one on root quality, which affects marketability. The field trials showed that CBSD can decrease root weight in the most sensitive cultivars by up to 70%. The length of time between the appearance of foliar symptoms and the development of root necrosis is a varietal characteristic. In the most susceptible cultivars, root necrosis may appear within 6 months of planting cuttings derived from symptomatic mother plants. A local cultivar known as cv. Nachinyaya exhibited a form of tolerance to CBSD in which foliar symptoms appeared but the development of root necrosis was delayed allowing the full yield potential to be realized. [source] Breeding of Pleurotus florida (oyster mushroom) for phenotypic pigmentation and high yield potentialJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2008Jatinder Kaur Abstract BACKGROUND: Cross-hybridisation is a technique for exchange of genetic material between two compatible nuclei to develop a recombinant genome with a probable expression for a desirable trait. This technique as an example of classical genetics has been applied in a heterothallic bifactorial/tetrapolar fungus Pleurotus florida. It has worked successfully during this study in a small number of experiments. RESULTS: Fruit bodies from the Pleurotus florida PAU-5 were allowed to shed their basidiospores on filter paper under aseptic conditions. Forty-nine monokaryons were isolated from three spore prints, namely Ja, Jb and K. Three hundred and fifty-six crosses were laid to result in five compatible reactions (PFJ4, PFJ9, PFJ11, PFJ13 and PFJ14). The fruit bodies of the hybrid dikaryon PFJ4 were found to show grey pigmentation. The hybrid dikaryons PFJ11 and PFJ14 grew faster in wheat straw substrate to take 39 and 41 days, respectively, for complete mycelial impregnation as compared to the parent, PAU-5 (48 days). The dikaryon PFJ11 out-yielded the parent by giving 34.2% biological efficiency compared to 29.8% for the parent. CONCLUSION: Through cross-hybridisation various changes at the genetic level are possible, showing altered phenotypic expression of the characters, such as change in fruiting efficiency and variability in fruit body characteristics (e.g., pileus shape and pigmentation). This technique can also be applied to other crops to improve their yield potential and bring about desirable phenotypic changes. Copyright © 2008 Society of Chemical Industry [source] Site-independently integrated transgenes in the elite restorer rice line Minghui 63 allow removal of a selectable marker from the gene of interest by self-segregationPLANT BIOTECHNOLOGY JOURNAL, Issue 3 2003Jumin Tu Summary In this study, we have demonstrated that two independent loci are involved in the integration of the insecticidal protein gene cryIAb/cryIAc and selectable marker gene hph in the recipient genome of the elite Chinese CMS restorer line Minghui 63. We have also documented the structural organization of these transgenes in each locus by restriction enzyme digestion and Southern blot analysis. The independent locus integration of different transgenes allowed us to remove the selectable marker gene hph from the gene of interest simply by self-segregation. Not having the selectable marker gene will enhance the commercial value of our transgenic line TT51-1, which showed a consistently high level of resistance against repeated infestations of yellow stem borers and natural outbreaks of leaf-folders, without a reduction in yield potential. [source] Mapping quantitative trait loci influencing panicle-related traits from Chinese common wild rice (Oryza rufipogon) using introgression linesPLANT BREEDING, Issue 6 2009X. Luo Abstract Panicle-related traits are important agronomic traits which directly associated with grain yield. In this study, we investigated quantitative trait loci (QTLs) associated with panicle-related traits using a set of 265 introgression lines (ILs) of common wild rice (Oryza rufipogon Griff.) in the background of Indica high-yielding cultivar Guichao 2 (O. sativa L.). A total of 39 QTLs associated with panicle-related traits including panicle length (PL), primary branch number (PBN), secondary branch number (SBN), spikelet number per panicle (SPP) and spikelet density (SD), were detected in the ILs with single-point analysis. The alleles of 20 QTLs derived from wild rice showed positive effects, and some QTLs, such as, QPl1b for PL, QPbn8 for PBN, QSd4 and QSd11b for SD and QSpp4 for SPP showed larger positive effects, providing good candidates and useful information for marker-aided improvement of yield potential of rice. Most of the QTLs controlling SPP, SBN and SD were located in cluster or closely linked on chromosomes, and the directions of their additive effects were consistent, which explained the genetic basis of significant correlations between their phenotypic characters. [source] Oxygen isotope enrichment (,18O) reflects yield potential and drought resistance in maizePLANT CELL & ENVIRONMENT, Issue 11 2009LLORENÇ CABRERA-BOSQUET ABSTRACT Measurement of stable isotopes in plant dry matter is a useful phenotypic tool for speeding up breeding advance in C3 crops exposed to different water regimes. However, the situation in C4 crops is far from resolved, since their photosynthetic metabolism precludes (at least in maize) the use of carbon isotope discrimination. This paper investigates the use of oxygen isotope enrichment (,18O) as a new secondary trait for yield potential and drought resistance in maize (Zea mays L). A set of tropical maize hybrids developed by the International Maize and Wheat Improvement Center was grown under three contrasting water regimes in field conditions. Water regimes clearly affected plant growth and yield. In accordance with the current theory, a decrease in water input was translated into large decreases in stomatal conductance and increases in leaf temperature together with concomitant 18O enrichment of plant matter (leaves and kernels). In addition, kernel ,18O correlated negatively with grain yield under well-watered and intermediate water stress conditions, while it correlated positively under severe water stress conditions. Therefore, genotypes showing lower kernel ,18O under well-watered and intermediate water stress had higher yields in these environments, while the opposite trend was found under severe water stress conditions. This illustrates the usefulness of ,18O for selecting the genotypes best suited to differing water conditions. [source] The effect of drought and heat stress on reproductive processes in cerealsPLANT CELL & ENVIRONMENT, Issue 1 2008BEÁTA BARNABÁS ABSTRACT As the result of intensive research and breeding efforts over the last 20 years, the yield potential and yield quality of cereals have been greatly improved. Nowadays, yield safety has gained more importance because of the forecasted climatic changes. Drought and high temperature are especially considered as key stress factors with high potential impact on crop yield. Yield safety can only be improved if future breeding attempts will be based on the valuable new knowledge acquired on the processes determining plant development and its responses to stress. Plant stress responses are very complex. Interactions between plant structure, function and the environment need to be investigated at various phases of plant development at the organismal, cellular as well as molecular levels in order to obtain a full picture. The results achieved so far in this field indicate that various plant organs, in a definite hierarchy and in interaction with each other, are involved in determining crop yield under stress. Here we attempt to summarize the currently available information on cereal reproduction under drought and heat stress and to give an outlook towards potential strategies to improve yield safety in cereals. [source] Managing grapevines to optimise fruit development in a challenging environment: a climate change primer for viticulturistsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2010M. KELLER Abstract Grapevine reproductive development extends over two seasons, and the genotypic expression of yield potential and fruit composition is subject to environmental impacts, which include viticultural manipulations, throughout this period. This paper reviews current knowledge on yield formation and fruit composition and attempts to identify challenges, opportunities and priorities for research and practice. The present analysis of published information gives a critical appraisal of recent advances concerning variables, especially as they relate to global climate change, that influence yield formation and fruit composition at harvest. Exciting discoveries in fundamental research on the one hand and an increasing focus on outcomes and knowledge transfer on the other are enabling the development and implementation of practical recommendations that will impact grape production in the future. Future research should aim to minimise seasonal variation and optimise the profitable and sustainable production of high-quality fruit for specific uses in the face of climate change, water and labour shortages, shifting consumer preferences and global competition. Better control of product quantity and quality, and differentiation to meet consumer demands and market preferences will enhance the competitiveness and sustainability of the global grape and wine industries. [source] Bioengineering nitrogen acquisition in rice: can novel initiatives in rice genomics and physiology contribute to global food security?BIOESSAYS, Issue 6 2004Dev T. Britto Rice is the most important crop species on earth, providing staple food for 70% of the world's human population. Over the past four decades, successes in classical breeding, fertilization, pest control, irrigation and expansion of arable land have massively increased global rice production, enabling crop scientists and farmers to stave off anticipated famines. If current projections for human population growth are correct, however, present rice yields will be insufficient within a few years. Rice yields will have to increase by an estimated 60% in the next 30 years, or global food security will be in danger. The classical methods of previous green revolutions alone will probably not be able to meet this challenge, without being coupled to recombinant DNA technology. Here, we focus on the promise of these modern technologies in the area of nitrogen acquisition in rice, recognizing that nitrogen deficiency compromises the realization of rice yield potential in the field more than any other single factor. We summarize rice-specific advances in four key areas of research: (1) nitrogen fixation, (2) primary nitrogen acquisition, (3) manipulations of internal nitrogen metabolism, and (4) interactions between nitrogen and photosynthesis. We develop a model for future plant breeding possibilities, pointing out the importance of coming to terms with the complex interactions among the physiological components under manipulation, in the context of ensuring proper targeting of intellectual and financial resources in this crucial area of research. BioEssays 26:683,692, 2004. © 2004 Wiley Periodicals, Inc. [source] A web-based decision support system for integrated management of weeds in cereals and sugarbeet,EPPO BULLETIN, Issue 3 2003P. Rydahl A Danish decision support system (DSS) named Crop Protection Online (CPO) for integrated management of weeds in cereals and beet has been developed during the past 20 years. CPO is based on a model that runs in three main steps: model step 1 quantifies the level of weed control needed on a field level, model step 2 selects candidate herbicides and calculates dose rates to meet the need, and model step 3 calculates tank mixtures of herbicides with two to four mixing components, if advantageous. CPO has been developed in cereals and beet, and various prototype versions have been validated in 1679 field tests. CPO secured yield potentials, and the level of residual weeds was not increased when compared with reference treatments. The potential of CPO to reduce herbicide use has been observed in all model crops, but the potential was greatest in cereals. In spring cereal field trials highly infested with weeds, the present version of CPO suggested 35% of one full herbicide dose on average and in winter cereals CPO suggested 44% on average of one full dose. The results from validation trials demonstrate that CPO is capable of suggesting robust treatment options with a low input of herbicides. The system architecture of CPO has been exported to Poland and the Baltic countries, and the system is expected to be suitable for export to other countries too. [source] | |||||||||||||