Genotypic Variation in Sweetpotato Ipomoea Batatas (L.) Lam. Clones.

Arbitrarily-primed PCR-based assays established the presence of sweetpotato intra-clonal genetic variability. These DNA polymorphism assays provided benchmark information regarding cultivar genetic uniformity in sweetpotato foundation seed programs. Arbitrarily-primed markers were also used to compare the genetic uniformity among sweetpotato clones derived conventionally, i.e., through adventitious sprouts, and nodally-based propagation systems. Initially, 38 primers generated 110 scorable DNA fragments using two virus-indexed plants from each clone source. Twenty-one bands (18.6%) were scored as putative polymorphic markers based on the presence or absence of amplified products. A subset of 14 marker loci generated by four selected primers was used to further assay 10 sample plants per clone group. Polymorphism ranged from 7.1% to 35.7% in five of eight clone groups. Field studies show variation in nearly all yield grades measured. In three tests during the 1991 and 1992 seasons, yield differences ranged from 27% to 46% within the economically important U.S. No. 1 root grade. The results suggest the usefulness of arbitrarily-primed markers in detecting intra-clonal genomic variability in the crop. To determine the role of propagation method in sweetpotato genotypic uniformity, a single sprout each of \u27Jewel,\u27 \u27Sumor,\u27 and L87-95 served as source of clonal plants simultaneously propagated through conventional adventitious procedures and an in vitro-based nodal technique. Fifteen arbitrary primers generated 64 scorable amplified fragments, 29 of which were putatively polymorphic across n = 60 samples (10 each of nodal and adventitiously derived plants/genotype). Within adventitiously derived materials, putative polymorphisms ranged from 4.7% to 31.3% depending upon genotypic class. In contrast, putative polymorphisms ranged from 0.0% to 3.1% among nodally-derived samples. The marker loci differentiated the genotypes and putative marker phenotype variants as revealed through multidimensional scaling analysis. An \u27analysis of molecular variance\u27 shows that genotypic effects accounted for 88.7% of the total marker variability, while propagation effects (within genotypic groups) accounted for 11.3%. The results suggest variability associated with propagation, wherein clonal plants derived from pre-existing meristematic regions are more genetically uniform than plants propagated from adventitious origins

The Intellectual Capital Capability and the Income Generating Project of a Philippine University

Intellectual capital is a new concept for a new way of doing business. It involves looking at products, processes, and people in order to profit from the intelligence it contains. State universities in the Philippines has to adopt this concept through corporatization due to the impending cut down on government subsidy. Anchored on an integration of intellectual theories and models, this study sought to come up with an analysis of the level of intellectual capital capability in terms of its human capital; structural capital, and; relational capital of the Leyte Normal University. There is an average level of LNU’s intellectual capital capability in terms of human, structural and relational. A few people inside the organization are aware that they are equipped with intellectual capital. There were insufficient management strategies, management skills of the people running the income generating projects

School Climate and Teachers Performance in an Elementary School in a Resettlement Area

This study investigated the relationship between school climate and teachers’ performance in Palanog Resettlement Elementary School. Using the descriptive- correlational research design the study included all teachers of the school. The school climate was measured through the Organizational Climate Descriptive Questionnaire and the teachers’ performance through the Performance Appraisal System for Teachers. The data were analyzed using frequency count, percentages, means, Pearson-r product moment correlation and t-test correlation coefficient. The findings revealed that the supportive principal behavior and collegial teacher behavior dimension of school climate has significant relationship on teachers performance. Based on the findings, it was suggested that school head should continue the supportive climate on teachers but not to disregard the directive behavior as to ensure the implementation of the school policies.     &nbsp

Genetic variation among sweetpotatoes propagated through nodal and adventitious sprouts

Genetic uniformity was assessed among sweetpotato (Ipomoea batatas ) clones propagated through adventitious and nodal procedures. A single sprout each of \u27Jewel.\u27 \u27Sumor,\u27 and L87-95 was used as source of clonal plants that were simultaneously propagated through conventional adventitious procedures and a tissue culture-based nodal culture technique. A sample of 15 decamer primers generated 64 scorable amplified fragments in a PCR-based assay. 29 of which were putatively polymorphic across n = 60 samples ( 10 each of nodal and adventitiously derived plants/genotype). Within adventitiously derived materials, putative polymorphisms ranged from 4.7 \u3c7r to\u3e3U\u3c£ depending on the genotypic class. In contrast, putative polymorphisms ranged from 0.0\u3c£ to 3.1 **• among nodally derived samples. Marker loci differen-tiated genotypes as well as putative marker phenotype variants through a multidimensional scaling analysis of the genetic similarity matrix. An \u27analysts of molecular variance\u27 shows that genotypic effects accounted for 88.7°«• of the total molecular marker variability, w hue propagation effects ( within genotypic groups I accounted for 1U4T. Results confirm that clonal plants derived from preexisting meristematic regions arc more genetically uniform than plants propagated from adventitious origins

Using growing degree days, agrometeorological variables, linear regression, and data mining methods to help improve prediction of sweetpotato harvest date in louisiana

Predictive models of optimum sweetpotato (Ipomoea batatas) harvest in relation to growing degree days (GDD) will benefit producers and researchers by ensuring maximum yields and high quality. A GDD system has not been previously characterized for sweetpotato grown in Louisiana. We used a data set of 116 planting dates and used a combination of minimum CV, linear regression (LR), and several algorithms in a data mining (DM) mode to identify candidate methods of estimating relationships between GDD and harvest dates. These DM algorithms included neural networks, support vector machine, multivariate adaptive regression splines, regression trees, and generalized linear models. We then used candidate GDD methods along with agrometeorological variables to model US#1 yield using LR and DM methodology. A multivariable LR model with the best adjusted r2 was based on GDD calculated using this method: maximum daily temperature (Tmax) - base temperature (B), where if Tmax \u3e ceiling temperature [C (90°F)], then Tmax = C, and where GDD = 0 if minimum daily temperature \u3c60°F. The following climate-related variables contributed to the improvement of adjusted r2 of the LR model: mean relative humidity 20 days after transplanting (DAT), maximum air temperature 20 DAT, and maximum soil temperature 10 DAT (log 10 transformed). In the DM mode, this GDD method and the LR model also demonstrated high predictive accuracy as quantified using mean square error. Using this model, we propose to schedule test harvests at GDD = 2600. The harvest date can further be optimized by predicting US#1 yield using GDD in combination with climate-based predictor variables measured within 20 DAT

Ceratocystis fimbriata alters root system architecture and causes symptom development only in detached storage roots in Bayou Belle and Beauregard sweet potato

Little is known about how the sweet potato (Ipomoea batatas) root system responds to Ceratocystis fimbriata in the growth substrate. Understanding whether the fungus affects the root system before harvest of storage roots (SR) could guide timing of management efforts. Cuttings of cultivars Bayou Belle and Beauregard, both previously considered susceptible to black rot, were in unamended or infested sand. At the onset of SR formation, effects on first- and second-order lateral root (LR) length and number among and within treatments, cultivars and replicate experiments were recorded. First-order LR length in inoculated Bayou Belle plants was 31% greater than in inoculated plants of cultivar Beauregard in Expt 1, but there were no differences in Expt 2. Second-order LR length varied among, and within, cultivars, inoculum treatments and experiments in Expts 1 and 2. At 49 days after planting in Expt 1, only inoculated plants had necrotic lesions on stems in both cultivars, with more than twice as many recorded on Bayou Belle than Beauregard. SR had no lesions at harvest. Detached SR originating from inoculated treatments and stored in sampling bags for 25 days developed black rot lesions at either end of the SR (45% and 31% of total in Expt 1 and Expt 2, respectively) or elsewhere, including those centred on LR emergence sites or lenticels (55% and 69%, respectively). Exposing developing plants to inoculation may reveal differences in SR susceptibility not found when harvested SR are wounded and inoculated

Effect of drought on storage root development and gene expression profile of sweetpotato under greenhouse and field conditions

Greenhouse and field culture systems were used to study the effect of drought conditions on the storage root (SR) formation in \u27Beauregard\u27 sweetpotato (Ipomoea batatas). In the greenhouse culture system, drought was simulated by withholding water for 5 and 10 days after transplanting (DAT) cuttings in dry sand. Control plants received water at planting and every 3 days thereafter. In the field studies, natural drought conditions and selective irrigation were used to impose water deprivation during the critical SR formation period. Greenhouse drought for 5 and 10 DAT reduced the number of SRs by 42% and 66%, respectively, compared with the controls. Field drought resulted in a 49% reduction in U.S. #1 SR yield compared with the irrigated condition. Quantitative real-time polymerase chain reaction (PCR) analysis showed differential expression of a set of sweetpotato transcription factors and protein kinases among greenhouse-grown plants subjected to well-watered conditions and water deficit during 5 DAT. A significant enhancement of expression was observed for known drought stress-associated genes such as an abscisic acid-responsive elements-binding factor, dehydration-responsive element-binding factor, and homeodomain- zip proteins. Members of calcium-binding proteins showed differential expression under drought stress. For the first time it is reported that knotted1-like homeobox and BEL1-like genes showed altered expression in response to drought stress under a greenhouse condition. In summary, the results suggest that water deprivation during the SR formation period influences root development and expression patterns of stress-responsive genes and those previously found associated with SR formation in sweetpotato

Challenges and opportunities for quantifying roots and rhizosphere interactions through imaging and image analysis

The morphology of roots and root systems influences the efficiency by which plants acquire nutrients and water, anchor themselves and provide stability to the surrounding soil. Plant genotype and the biotic and abiotic environment significantly influence root morphology, growth and ultimately crop yield. The challenge for researchers interested in phenotyping root systems is, therefore, not just to measure roots and link their phenotype to the plant genotype, but also to understand how the growth of roots is influenced by their environment. This review discusses progress in quantifying root system parameters (e.g. in terms of size, shape and dynamics) using imaging and image analysis technologies and also discusses their potential for providing a better understanding of root:soil interactions. Significant progress has been made in image acquisition techniques, however trade-offs exist between sample throughput, sample size, image resolution and information gained. All of these factors impact on downstream image analysis processes. While there have been significant advances in computation power, limitations still exist in statistical processes involved in image analysis. Utilizing and combining different imaging systems, integrating measurements and image analysis where possible, and amalgamating data will allow researchers to gain a better understanding of root:soil interactions

Root Branching and Nutrient Efficiency: Status and Way Forward in Root and Tuber Crops

Plants are immobile organisms that require roots to efficiently and cost-effectively exploit their habitat for water and nutrients. Plant root systems are dynamic structures capable of altering root branching, root angle, and root growth rates determining overall architecture. This plasticity involves belowground plant-root mediated synergies coupled through a continuum of environmental interactions and endogenous developmental processes facilitating plants to adapt to favorable or adverse soil conditions. Plant root branching is paramount to ensure adequate access to soil water and nutrients. Although substantial resources have been devoted toward this goal, significant knowledge gaps exist. In well-studied systems such as rice and maize, it has become evident that root branching plays a significant role in the acquisition of nutrients and other soil-based resources. In these crop species, specific root branching traits that confer enhanced nutrient acquisition are well-characterized and are already being incorporated into breeding populations. In contrast, the understanding of root branching in root and tuber crop productivity has lagged behind. In this review article, we highlight what is known about root branching in root and tuber crops (RTCs) and mark new research directions, such as the use novel phenotyping methods, examining the changes in root morphology and anatomy under nutrient stress, and germplasm screening with enhanced root architecture for more efficient nutrient capture. These directions will permit a better understanding of the interaction between root branching and nutrient acquisition in these globally important crop species