bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic Tools from Nature and the Nature of Genetic Tools
Authors: Phillips Ronald L.
Published: September 2006

The opportunity to apply genetics to the improvement of crops is greater now than any time in history. Agricultural advancements will depend even more on genetics in the future as we try to produce more food, while being in harmony with the environment. The genetic tools available today and those to be developed will increase the precision of plant breeding and—at least in many instances—reduce the time required to respond to an ever‐changing environment, both natural and social. A brief synopsis of some of the major events in genetics that led to the formation of the Crop Science Society of America (CSSA) C‐7 Division is presented along with many of the questions in crop science yet to be answered.
A Top 10 List of Developments and Issues Impacting Crop Management and Ecology During the Past 50 Years
Authors: Crookston R. Kent
Published: September 2006

Colleagues from around the world contributed to this paper, all via e‐mail. This was in response to a solicitation I made of those who aligned themselves with the Crop Ecology, Management, and Quality division of Crop Science Society of America (CSSA Division C‐3). I asked for their nominations of the most important developments and/or issues impacting their profession during the past 50 yr. Their responses were used to develop a top 10 list. Ranking within the list was based on frequency of nominations (i.e., professional recognition). The list was: no. 10, alternative crops and alternative uses for crops (18 nominations); no. 9, improved water management (20 nominations); no. 8, improved mechanization (31); no. 7, precision technology (global positioning system, GPS, and geographical information system, GIS) (32); no. 6, a shift of the Land Grant purpose and domain to industry and the launching of big ag (35); no. 5, conservation tillage (CT) (40); no. 4, the environmental movement and sustainability (43); no. 3, government programs and policies (45); no. 2, substitution management or the replacement of crop rotations and animals with chemicals (96); and no. 1, improved crop genetics, whether via conventional plant breeding or bioengineered crops (112). In addition to the top 10, there were 10 other nomination categories that received a total of 72 bids; these are noted in the text.
Transgenic Expression of Onion Leaf Lectin Gene in Indian Mustard Offers Protection against Aphid Colonization
Authors: Hossain Munshi Azad , Maiti Mrinal K. , Basu Asitava , Sen Supriya , Ghosh Arnab K. , Sen Soumitra K.
Published: September 2006

Genes of three naturally occurring monocot mannose‐binding lectins from snowdrop (Galanthus nivalis L. agglutinin, GNA), garlic (Allium sativum L. leaf agglutinin, ASAL), and onion (Allium cepa L. agglutinin, ACA) and a recombinant fusion lectin between ASAL and ACA genes were expressed in a bacterial system. The pure and active form of the recombinant lectin peptides were utilized for estimation of their sensitivity potential against feeding nymphs of mustard aphid [Lipaphis erysimi (Kaltenbach)], a major sap‐sucking insect pest of Indian mustard [Brassica juncea (L.) Czern.], an oilseed crop. The artificial diet bioassay revealed that ACA and the fusion lectin contained higher toxicity potential than GNA and ASAL. Ectopic expression of these lectins in mustard plants confirmed their protective capacity on the development of the population of aphids on transgenic plants. Based on the strong possibilities that lectins originating from diverse sources would have differential insecticidal potential against different insects, deployment of the appropriate lectin gene figures as crucial in the transgenic approach to protect crop plants against sap‐sucking insect pests.
Influence of Irrigation on Mineral Concentrations in Three Old World Bluestem Species
Authors: Philipp D. , Brown C. P. , Allen V. G. , Wester D. B.
Published: September 2006

Old world bluestems (Bothriochloaspp.) are grown widely in the Texas High Plains under both irrigated and dryland conditions, but little is known regarding their mineral characteristics.Bothriochloa bladhii(Retz),B. ischaemum(L.) Keng. var.ischaemum(Hack.), andB. caucasica(Trin.) were dryland managed and surface drip‐irrigated with low, medium, and high irrigation levels from 2001 to 2003. Water applied in the high treatment was 100% replacement of grass reference evapotranspiration minus precipitation. Medium and low treatments were 66 and 33% of the high treatment. Concentrations of P, Al, Fe, S, Cu, Zn, and Mn in plants were greater under dryland than with irrigation. Magnesium and Zn concentration increased while Fe decreased with increasing irrigation. Concentrations of P, Cu, and K were lower at medium irrigation than either high or low irrigation. Overall, effects of irrigation on most minerals were minor.Bothriochloa bladhiiwas higher in Mg (2.6 g kg−1), K (14.6 g kg−1), Ca (10.0 g kg−1), Al (649 mg kg−1), and Cu (5.2 mg kg−1) concentrations than the other two species. Manganese concentrations increased with increasing irrigation inB. caucasica(44–61 mg kg−1) andischaemum(57–83 mg kg−1), but not inB. bladhii(average 71 mg kg−1). In general,B. bladhiiwould provide greater mineral concentrations to grazing animals than eitherB. caucasicaorB. ischaemum, but P, S, Cu, Na, and Zn supplements are likely needed.
Seeds: The Delivery System for Crop Science
Authors: TeKrony Dennis M.
Published: September 2006

Seeds have always played a dominant role in agriculture, serving as the primary mechanism by which crop plants are propagated. During the past 50 yr, seed science has matured to gain recognition as a sub‐discipline of crop science, which was enhanced by the establishment of graduate training in seed biology at many land grant universities. These programs have provided leadership to the C‐4 Division, which led to nine special CSSA publications, two major reviews, and several excellent text books written by members of C‐4. The division sponsored more than 15 symposia covering seed production, seed health, synthetic seeds, and distance education. The efforts of seed scientists enhanced the quality control programs of the seed industry by contributing to the development and use of seed vigor tests, sophisticated genetic and herbicide trait tests, improved techniques for seed production and storage, and seed enhancements including film coating, priming, and pelleting. The major factors that have influenced seed science during the past five decades include: The Plant Variety Protection Act and the granting of utility patents, the influence of biotechnology, the use of seed enhancements, seed vigor testing, and the internet in teaching and training. Seeds will continue to provide a mechanism for the propagation of crop plants, however, in the future they may assume new roles as a delivery tool in high technology.
Differential Responses of the Cultivated and Wild Species of Soybean to Dehydration Stress
Authors: Chen Yanyun , Chen Pengyin , de los Reyes Benildo G.
Published: September 2006

The Dehydration Responsive Element‐Binding protein/C‐repeat Binding Factor (DREB/CBF) plays important roles in regulating physiological processes and downstream gene expression for drought stress in Arabidopsis thaliana, rice, and wheat. ‘Essex’ soybean [Glycine max (L.) Merr.] was identified as tolerant and a wild soybean PI 407155 (Glycine soja Sieb. & Zucc.) as more tolerant to dehydration stress in a greenhouse screen. In this study, we cloned and characterized the Glycine DREB1 (GlyDREB1) from the dehydration‐induced PI 407155 and Essex using a semi‐quantitative RT‐PCR, rapid amplification of cDNA ends (RACE), and northern blot. We also investigated the physiological characteristics including biomass accumulation, moisture content, and electrolyte leakage for both soybean genotypes under dehydration stress. Analysis of homologous GlyDREB1 genes from PI 407155 and Essex indicated differences in both the timing and strength of expression under dehydration stress. The GlyDREB1 in PI 407155 was rapidly induced in 1 h of dehydration shock and the transcription level was much higher than that in Essex. The root system of PI 407155 maintained higher moisture content and biomass accumulation than that of Essex on the 15 d without irrigation. The percentage electrolyte leakage in Essex was almost twice that in PI 407155 under 5 d no irrigation treatment. Both molecular and physiological studies indicated that PI 407155 had higher level of tolerance to dehydration stress than Essex, therefore providing a new potential soybean genome for developing dehydration stress cultivars.
Fifty Years of Splendor in the Grass
Authors: Shearman R. C.
Published: September 2006

Fifty years ago there were only a few states with turfgrass research programs. Today, most states have turfgrass research and education programs at their land grant institutions. In 1955, 15 research papers were presented at the annual meeting and in 2004 there were 215. Division C‐5 (Turfgrass Science) has grown to more than 500 members. This manuscript addresses some of the important historical developments of Division C‐5, and discusses some of the accomplishments and contributions of its members to turfgrass science. During the last 50 yr, turfgrass science has experienced a number of important milestones in turfgrass breeding, genetics, and evaluation, physiology, soil physics, soil cultivation, and environmental impacts. These milestones are discussed here. The importance and availability of turfgrass information and funding resources are discussed. The 10 most influential contributors to turfgrass science during the past 50 yr as recognized by their peers are also identified. Like our sister divisions in the Crop Science Society of America (CSSA), Division C‐5 can take pride in its past contributions, and can look forward to a bright and challenging future.
Identification of New Sources of Resistance to Tan Spot, Stagonospora Nodorum Blotch, and Septoria Tritici Blotch of Wheat
Authors: Singh P. K. , Mergoum M. , Ali S. , Adhikari T. B. , Elias E. M. , Hughes G. R.
Published: September 2006

Leaf spot of wheat (Triticum aestivum L.) in North America consists of a group of diseases involving tan spot [Pyrenophora tritici‐repentis (Died.) Drechs.], Stagonospora nodorum blotch [Phaeosphaeria nodorum (E.Müller) Hedjarroude], and Septoria tritici blotch [Mycosphaerella graminicola (Fückl) J. Schröt. in Cohn]. A complex of these diseases occurs in nature hence managing leaf spots is difficult. Use of resistant cultivars is the most effective and economical means of controlling leaf spot; however, none of the widely grown wheat cultivars in North America show high levels of resistance to these diseases. Hence, this study aimed to identify new sources of resistance to leaf spotting diseases. To achieve this objective, 975 accessions of wheat and its relatives were evaluated for P. tritici‐repentis, race 1, resistance under controlled environments. Of these 975 accessions, 40 selected accessions were further screened against six virulent races (1, 2, 3, 5, 10, and 11) of P.tritici‐repentis and to foliar pathogens P. nodorum and M. graminicola. New sources of resistance effective against the three leaf spotting disease were identified in accessions of T.monococcum L., T. turgidum L., T. dicoccum Schrank ex Schübler, T. dicoccoides (Körn. ex Asch and Graebner) Schweinf., T. timopheevii (Zhuk.) Zhuk., T. spelta L., and T. aestivum L. including synthetic wheat. Resistance was observed in all three ploidy levels of the wheat genome and presently efforts are being made to transfer the leaf spot resistance into adapted wheat and durum cultivars.
Stem Morphological and Cell Wall Traits Associated with Divergent In Vitro Neutral Detergent Fiber Digestibility in Alfalfa Clones
Authors: Jung H. G. , Lamb J. F. S.
Published: September 2006

Poor cell wall digestibility of alfalfa (Medicago sativa L.) stems limits available energy to ruminants. This study compared alfalfa clones identified as either low or high rapid (16 h), or low or high potential (96 h) stem in vitro neutral detergent fiber digestibility (IVNDFD) for stem detergent fiber, cell wall, and morphology traits. Clones were established in replicated field plots at two sites in Minnesota during 2001 and harvested twice (primary spring growth and first summer regrowth) in the two following years. Presence of flowers, stem length, internode number, mean internode length, and number of elongating internodes was determined on 10 stems from each plot at every harvest. Herbage was dried and the stem fraction was analyzed for 16‐ and 96‐h IVNDFD, detergent fiber components, and cell wall concentration and composition (Klason lignin, individual neutral sugars, and total uronic acids). Stem neutral detergent fiber (NDF) and cell wall concentration were lower for the high rapid than low rapid IVNDFD clones, but the high and low potential IVNDFD clonal groups did not differ. Lignin and pectin concentrations of the cell wall were lower and higher, respectively, for both high IVNDFD groups than their corresponding low groups. The low rapid and high potential IVNDFD groups had longer stem and internode lengths than their corresponding groups.
Pasture and Cattle Responses in Rotationally Stocked Grazing Systems Sown with Differing Levels of Species Richness
Authors: Tracy Benjamin F. , Faulkner Dan B.
Published: September 2006

Increasing species richness of temperate pastures beyond one or two forage species could improve grazing system productivity. An experiment in western Illinois, USA, was initiated in August 2001 to test this idea. The main study objective was to determine how pastures sown with increasing levels of species richness would affect herbage yield and cow‐calf performance. Three seed mixtures that contained three, five, or eight forage species were sown into 3‐ to 6‐ha pastures. Mixtures were replicated three times and rotationally stocked with beef cow–calf groups. Herbage mass and accumulation were estimated by a rising plate meter method and weight gain evaluated cow–calf performance. We also evaluated forage nutritive value indices and changes in forage species composition. After pasture establishment in 2001, herbage mass was marginally higher (P= 0.15) in eight‐species mixtures (98 g m−2) compared with three‐species mixes (43 g m−2). Once grazing started, pasture mix had no effect on herbage responses or stocking rate (P> 0.05). Cow–calf performance was also unaffected by pasture mix, although average daily gain (ADG) was higher in 2003 (P< 0.05). Cow and calf ADG averaged 0.33 and 1.17 kg d−1, respectively, in 2003 compared with 0.05 and 1.01 kg d−1in other years. Overall, species richness in pastures had minimal effects on forage yield and cattle performance. Grazing management (e.g., stocking rate) and climatic conditions more strongly influence grazing system productivity.
Stability of Fatty Acid Profile in Soybean Genotypes with Modified Seed Oil Composition
Authors: Oliva M. L. , Shannon J. G. , Sleper D. A. , Ellersieck M. R. , Cardinal A. J. , Paris R. L. , Lee J. D.
Published: September 2006

Genetic effects and temperature during the reproductive period for unsaturated fatty acids in soybean [Glycine max (L.) Merr.] seed oil affect oil composition. Increasing oleic and reducing linolenic acids are desirable to improve oil for food and other uses. The objective of this study was to access the environmental effect on fatty acids of seed oil for seventeen soybean genotypes with normal and modified fatty acid profiles. Stability coefficients (b values) were calculated from the regression of fatty acid level on average temperature over the final 30 d of the reproductive period across 10 environments. Mid‐oleic acid genotypes were generally less stable for oleic acid content than genotypes with reduced oleic acid. Significant differences, however, were found for oleic acid stability among mid‐oleic acid genotypes. Mid‐oleic acid lines N98–4445A and N97–3363–4 were the most unstable among the 17 genotypes with stability coefficients of 3.28 and 2.53, respectively. However, the higher oleic acid line M23 was relatively stable in oleic acid with a stability coefficient of 0.13 over environments. IA 3017 at 10 g kg−1 was the most stable in linolenic acid content across environments while progressively higher linolenic acid genotypes were less stable. Soybean lines similar to M23 and IA 3017 will be essential to develop increased oleic acid and reduced linolenic acid cultivars to ensure consistent production of soybean oil with the desired fatty acid levels.
Plant Density Modifications of Cotton Within‐Boll Yield Components
Authors: Bednarz Craig W. , Nichols Robert L. , Brown Steve M.
Published: September 2006

One approach to improving cotton (Gossypium hirsutum L.) yield and quality is to identify crop management practices that may exploit the most basic (i.e., within‐boll) yield components. One of the parameters that may influence within‐boll yield components is plant density. Thus, the objectives of this investigation were to determine how yield components in cotton are altered through plant density management. Two cotton cultivars were overseeded and hand thinned to 3.6, 9.0, 12.6, and 21.5 plants m−2 in 2001 and 2002. Before machine harvest, plants from 6 m of one row were removed from each plot and hand harvested by fruiting position. After hand harvest, seed cotton from each fruiting position was ginned separately. Boll number, lint mass, seed number, seed mass, seed surface area, and fiber properties were determined for each fruiting position. These data were then used for yield component calculations. Lint mass boll−1, individual seed mass, and seed number boll−1 decreased as plant density increased while total seed surface area m−2 of land area increased, which resulted in increased lint yield m−2 of land area. Lint mass cm−2 of seed surface area and fiber number seed−1 did not consistently respond to plant density. These results indicate that plant density management may influence total seed surface area per unit land area. Most within‐boll yield components, however, appear to be controlled more by cultivar than crop management.
Using Independent Culling to Screen Plant Introductions for Combined Resistance to Soybean Cyst Nematode and Sudden Death Syndrome
Authors: Gelin J. R. , Arelli P. R. , Rojas‐Cifuentes G. A.
Published: September 2006

Two infectious diseases that cause most yield losses in soybean [Glycine max (L.) Merr.] are soybean cyst nematode (SCN), caused by Heterodera glycines Ichinohe, and sudden death syndrome (SDS), caused by Fusarium solani (Mart.) Sacc. f. sp. glycines (Fsg). Because SCN and SDS have a synergistic effect on yield when they occur jointly in the field, breeders are attempting to develop varieties with dual resistance to these two diseases. Using independent culling as a selection strategy, we screened a set of 31 new soybean plant introductions (PI) that were field evaluated in 1995 at two locations in Southern Illinois. We identified 11 elite PIs that were resistant to SCN race 3, had yellow seed coat, a relatively good field response to SDS, and a moderate seed yield. These superior genotypes can be used as potential parents in soybean breeding programs.
Accuracy and Reliability of High‐Throughput Microsatellite Genotyping for Cacao Clone Identification
Authors: Zhang Dapeng , Mischke Sue , Goenaga Ricardo , Hemeida Alaa A. , Saunders James A.
Published: September 2006

Microsatellite‐based DNA fingerprinting has been increasingly applied to cacao (Theobroma cacaoL.) genotype identification. However, the accuracy and reliability of using high throughput microsatellite analysis for cacao clone identification have not yet been rigorously assessed. Despite the use of highly robust fingerprinting protocols, cacao genotype identification has been affected by genotyping errors, which potentially mislead the result of clone identification. In this paper, we calculated the probability of identity for 15 selected microsatellite loci. We then quantified the genotyping error rate through repeated genotyping and simulated the impact of the genotyping error on cacao clone identification. Allelic dropout (ADO), or failure to amplify one allele for a heterozygous locus, and false allele (FA), or an amplicon size error by the polymerase, accounted for 48 and 52% of the genotyping inconsistencies, respectively. The result of simulation showed that 99% of the consensus genotype can be generated for the ambiguous loci through a minimum of three polymerase chain reaction (PCR) repetitions. On the basis of the error rate and probability of identity (PID), we designed a genotyping scheme and applied it to the cacao germplasm held in the USDA cacao collection at Mayaguez, Puerto Rico. Out of the 141 samples, we unambiguously identified nine duplicated groups consisting of 34 cacao accessions. This genotyping scheme is being implemented in large scale fingerprinting of cacao germplasm.
Genotypic Variation for Stem Reserves and Mobilization in Wheat: II. Postanthesis Changes in Internode Water‐Soluble Carbohydrates
Authors: Ehdaie B. , Alloush G. A. , Madore M. A. , Waines J. G.
Published: September 2006

Grain filling in wheat crops grown in semiarid regions may depend more on stored water‐soluble carbohydrates (WSC) than on current photosynthesis. We evaluated the hypothesis that internode WSC content, specific content (WSC content/internode length), and concentration (WSC content/internode weight) of genotypes affect accumulation and mobilization of stem WSC. Genotypic variation for internode WSC‐related traits was measured on the main stem at 10‐d intervals in 11 diverse wheats grown under well‐watered and droughted field conditions across 2 yr. Relationships among internode WSC‐related traits were determined. Date of harvest was the most important factor affecting internode WSC‐related traits followed by genotype, irrigation, and year. Genotype × date of harvest was the most important interaction. Drought reduced WSC content, specific content, and concentration in different internodes, except WSC concentration in peduncles. Mobilized WSC from peduncle, penultimate, and lower internodes ranged from 70 to 244 mg, from 95 to 227 mg, and from 175 to 450 mg, respectively. The lower internodes provided 51% of the stem mobilized WSC. Mobilized WSC was higher in well‐watered than in droughted conditions for penultimate (164 vs. 135 mg) and lower internodes (274 vs. 244 mg). Drought improved mobilization efficiency in the peduncle, penultimate, and lower internodes by 33, 17, and 11%, respectively. Postanthesis maximum WSC content was highly correlated (r = 0.89 to 0.99) with the amount of WSC mobilized in different internodes, and could be used as a selection criterion to stabilize grain yield under stressful environments.
Development of a Screening Method for Drought Tolerance in Cotton Seedlings
Authors: Longenberger P. S. , Smith C. W. , Thaxton P. S. , McMichael B. L.
Published: September 2006

The key to an efficient screening method is the ability to screen large amounts of plant material in the shortest time possible. Due to the complexity of drought tolerance, a quick and effective screen for this trait has yet to be established. The research reported herein was designed to evaluate a screening method for drought tolerance in cotton (Gossypium hirsutum L.) seedlings. Twenty‐one converted race stocks (CRS) and two cultivars were evaluated for seedling drought tolerance (SDT) on an individual plant basis. Genotypes were evaluated October–November 2004 and February–March 2005 under greenhouse conditions. Seedlings were subjected to three sequential cycles of drought at 15 d after planting (DAP). Drought cycles consisted of withholding water until the moisture content of indicator ‘Deltapine 491’ (DP 491) plants had an average volumetric water content of 0.07. Plants then were watered to saturation and allowed to drain to field capacity and percent survival recorded after 48 h. Genotypes differed in their percent survival following three consecutive drought cycles. Drought cycles 2 and 3 did not contribute to the separation of genotypes. DP 491 was the most tolerant genotype evaluated. The drought tolerance of the CRS was similar to that of ‘Acala 1517–99’. CRS M‐9044–0165 was the most stable genotype, according to an analysis of the difference in percentage of survival for each genotype across the two experiments.
Selection for Drought Resistance in Dry Bean Landraces and Cultivars
Authors: Muñoz‐Perea Carlos German , Terán Henry , Allen Richard G. , Wright James L. , Westermann Dale T. , Singh Shree P.
Published: September 2006

Drought is a worldwide constraint to dry bean (Phaseolus vulgaris L.) production. The objective of this research was to determine the response of three dry bean landraces and 13 cultivars evaluated under non‐stressed (NS) and intermittent drought‐stressed (DS) environments at Kimberly, Idaho in 2003 and 2004. The NS received seven irrigations in 2003 and five in 2004, and DS only four in 2003 and two in 2004. Most water use occurred within the top 0.5 m soil in both the NS and DS. Drought reduced biomass and seed yield, harvest index, and seed weight. Maturity was delayed in severe drought, but was similar or shortened by 1 to 6 d under moderate drought. Mean seed yield was reduced by 62% in 2003 and by 27% in 2004. Common Red Mexican and CO 46348 had high seed yield in both NS and DS environments, whereas ‘Matterhorn’ and ‘Othello’ yielded comparatively high under DS but moderately in NS environment. Drought resistance was inadvertently reduced from Common Red Mexican landrace to intermediate levels in ‘NW‐63’ and ‘UI 239’ released in 1979 and 1993, respectively, and more recently released ‘LeBaron’ (1999) and ‘UI 259’ (1996) were susceptible. Conversely, drought resistance was increased in newer pinto (Othello 1986; CO 46348) and great northern (Matterhorn 1998) releases compared to the landraces and older cultivars tested for those market classes. Seed yield in NS and DS was positively correlated. Seed yield was also correlated with harvest index in DS and NS. All early maturing cultivars except Othello (e.g., UI 59, US 1140, Common Pinto, Topaz, UI 320, and LeBaron) were susceptible. Common Red Mexican did not have any reduction in seed weight due to drought stress. Drought resistant genotypes should be used for determining irrigation frequency, amount of water to be applied, and mechanisms of resistance and for identifying, mapping, and pyramiding favorable genes for dryland and irrigation‐assisted sustainable production systems.
Predicting Oleic and Linoleic Acid Content of Single Peanut Seeds using Near‐Infrared Reflectance Spectroscopy
Authors: Tillman Barry L. , Gorbet Daniel W. , Person George
Published: September 2006

One objective of peanut breeders is to develop cultivars with elevated oleic acid content (>740 g kg−1). Testing single seeds for oleic acid content is possible using gas chromatography (GC), but it is time‐consuming and requires cutting a portion of the seed which could reduce germination. Using single, intact peanut seeds, we developed a near‐infrared reflectance spectroscopy (NIR) calibration equation relating oleic acid measured with GC to oleic acid predicted by NIR. The slope of the regression line of oleic acid measured with GC on oleic acid predicted by NIR was 1.01 g kg−1 (P > t < .0001) and the intercept was not different from zero. An independent set of 95 peanut seeds was used to validate the NIR calibration. The slope of the regression line was 1.01 g kg−1 (P > t < .0001) and the intercept was not different from zero. By selecting seeds with at least 700 g kg−1 NIR predicted oleic acid content, only four of the 43 seeds (validation set) with elevated oleic acid content were misclassified by NIR, and none with normal oleic acid content were misidentified. Results were similar for linoleic acid content. This research shows that NIR prediction of oleic acid and linoleic acid using intact peanut seeds is accurate and rapid and should be especially useful for early generation screening.
Development of a Mini Core Subset for Enhanced and Diversified Utilization of Pigeonpea Germplasm Resources
Authors: Upadhyaya Hari D. , Reddy L. J. , Gowda C. L. L. , Reddy K. N. , Singh Sube
Published: September 2006

Pigeonpea [Cajanus cajan (L.) Millsp.], endowed with rich dietary protein in its seed, provides the much needed protein requirements of predominantly vegetarian population. Pigeonpea plays an important role in providing food, shelter, medicine and other livelihood opportunities among the rural poor. The purpose of a core collection is to provide information necessary to improve the use of genetic resources in crop improvement programs. In many crops the number of germplasm accessions in the genebanks are in several thousands. Even a core collection (consisting of 10% of total accessions) is large and becomes unwieldy to evaluate and characterize the accessions for economic traits. Hence, a mini core collection of pigeonpea, comprising 146 accessions was constituted by evaluating a core collection of 1290 accessions. Examination of data for various morphological and agronomic traits indicated that almost the entire genetic variation and a majority of coadapted gene complexes present in the core subset are preserved in the mini core subset. Due to its greatly reduced size, the mini core subset will provide a more economical starting point for proper exploitation of pigeonpea genetic resources for crop improvement for food, feed, fuel, and other agricultural and medicinal purposes.
Crop Physiology: Significant Discoveries and Our Changing Perspective on Research
Authors: Boote K. J. , Sinclair T. R.
Published: September 2006

Division C‐2 (Crop Physiology and Metabolism) has been a major component of the Crop Science Society of America (CSSA) since its inception. In this paper, we reflect on the accomplishments of those involved with crop physiology since the founding of CSSA, on the present status of our discipline, and on the future opportunities for the discipline. Obviously, we cannot review all of the many advances that have been made in the past 50 yr, so this paper makes no attempt to be an exhaustive literature review. We apologize in advance to those whose important contributions are not mentioned. Since we have both been active in crop physiology for our whole careers, we will take the liberty of personal experience and observation, although the hope is that we are not too self‐indulgent! The three themes in this paper are, first, to highlight critical historical events impacting or reflecting crop physiological research during the past 50 yr; second, to highlight significant discoveries during this time period; and third, to discuss the need to consider crop physiology in a holistic and integrated way.
Empirical Modeling of Genetically Modified Maize Grain Production Practices to Achieve European Union Labeling Thresholds
Authors: Gustafson D. I. , Brants I. O. , Horak M. J. , Remund K. M. , Rosenbaum E. W. , Soteres J. K.
Published: September 2006

An empirical approach is given for specifying coexistence requirements for genetically modified (GM) maize (Zea mays L.) production, to ensure compliance with the 0.9% labeling threshold for food and feed in the European Union. Field data were considered in which pollen‐mediated gene flow (PMGF) was measured within maize receptor fields at a series of distances from source fields having a marker. An empirical model is presented that fits the observed decrease of gene flow with distance. The model was parameterized to provide both reasonable worst case and expected case predictions of gene flow for various combinations of isolation distance, use of non‐GM border rows in the GM field and/or separately harvested border rows in the receptor field. Based on the data assessed, the model is used to show that the effect of scale is minimal for source fields of surface area 4 ha and greater. Combinations of isolation distance and border rows of 20 m or more are predicted to result in gene flow of less than 0.9%, as a blended average for receptor fields 1 ha or larger. Lesser requirements are necessary when the source field is much smaller than the receptor, and an extension to the model is provided to estimate such effects.
Yield and Nutritive Value of Autumn‐Seeded Winter‐Hardy and Winter‐Sensitive Annual Forages
Authors: McCormick John S. , Sulc R. Mark , Barker David J. , Beuerlein James E.
Published: September 2006

Winter‐hardy small grains produce abundant forage in the spring, but have low forage yield in autumn in the U.S. Midwest. Our objective was to evaluate the effectiveness of mixing annual forages with winter‐hardy small grains to improve forage supplies in late autumn without compromising yield the following spring. Field studies were established in mid‐September 2001 and 2002 at two locations in Ohio to compare autumn and spring forage yield and nutritive value of the winter‐hardy species (WHS) rye (Secale cereale L.), winter wheat (Triticum aestivum L.), and winter triticale (Triticum × Secale) seeded alone and in binary mixtures with the winter‐sensitive species (WSS) oat (Avena sativa L.), spring triticale (Triticum × Secale), annual ryegrass (Lolium multiflorum L.), and rape (Brassica napus L.). The WHS + WSS mixtures had greater forage yield in autumn than the corresponding WHS monocultures in 29 of 44 comparisons. Oat and spring triticale mixtures with WHS usually had the greatest autumn yield, greater than the yield of corresponding WHS monocultures in 91% of all comparisons. Forage yield of mixtures was usually similar to that of WHS monocultures in the spring. Forage nutritive value was high for all treatments. Oat, spring triticale, and rape were productive species to include with WHS for optimizing autumn and spring forage yield, but oat and rape had low seed cost ha−1, and thus were the most economical options.
Dehydrin‐Like Proteins in Soybean Seeds in Response to Drought Stress during Seed Filling
Authors: Samarah N. H. , Mullen R. E. , Cianzio S. R. , Scott P.
Published: September 2006

There is no information on accumulation of dehydrin proteins during seed development and maturation of soybean [Glycine max (L.) Merr.] in response to drought stress. Our objective was to study accumulation of dehydrin‐like proteins in developing soybean seeds in response to drought stress. A greenhouse experiment and a field experiment were conducted. In the greenhouse experiment, three treatments were imposed on soybean plants after beginning of linear seed filling (R5): well‐watered (WW), gradual stress (GS) imposed before severe stress, and sudden severe stress (SS). In the field treatments were irrigation (I) and nonirrigation (NI) (rainfed) conditions imposed from R5 to R8 (mature seeds). Greenhouse results indicated dehydrin‐like proteins (28 and 32 kDa) were detected 18 d after R5 (R5.8) in developing seeds from drought‐stressed plants but not in seeds from the well‐watered plants. In the mature seeds, dehydrin‐like proteins (28, 32, and 34 kDa) were detected in seeds from drought‐stressed plants as well as the well‐watered plants. In the field, dehydrin‐like proteins accumulated similarly under irrigation and nonirrigation conditions, with the first detection for dehydrins (28 and 32 kDa) at 22 d after R5 (R6). Accumulation of dehydrin‐like proteins was maximal in seeds harvested at 43 d after R5 (seed physiological maturity).
Effects of Xenia on Aspergillus flavus Infection and Aflatoxin Accumulation in Maize Inbreds
Authors: Gardner Hilarie D. , Williams W. Paul , Windham Gary L.
Published: September 2006

Aspergillus flavus Link:Fries infection and aflatoxin contamination pose an economic threat to maize (Zea mays L.) producers of the United States. Efforts to identify germplasm resistant to A. flavus infection and aflatoxin accumulation have raised questions regarding the role of xenia, the pollen effect on the embryo and endosperm, in resistance of maize grain to the pathogen. The objective of this study was to evaluate the importance of xenia on A. flavus infection and aflatoxin accumulation in seed of eight inbred lines with different levels of resistance to A. flavus infection and aflatoxin contamination. Resistant and susceptible maize lines were hand‐pollinated following a diallel mating design to produce seed for trials. The ears were inoculated 14 d after pollination with A. flavus spores. Grain was plated on agar to determine the extent of A. flavus infection and analyzed to measure aflatoxin content. Significant differences were detected among seed parents for both aflatoxin accumulation and A. flavus infection in both 2003 and 2004. The effects of pollen source were not significant on aflatoxin contamination or A. flavus infection in either 2003 or 2004. These results are consistent with xenia having little or no effect on A. flavus infection or aflatoxin accumulation. The results further suggest that reliable evaluation of A. flavus infection and aflatoxin contamination can be gained from open‐pollinated field experiments.
Introgression of a Strawbreaker Foot Rot Resistance Gene from Winter Wheat into Jointed Goatgrass
Authors: Perez‐Jones A. , Mallory‐Smith C. A. , Riera‐Lizarazu O. , Watson C. J. W. , Wang Z. , Rehman M. , Zemetra R. S.
Published: September 2006

Strawbreaker foot rot (SFR) [Pseudocercosporella herpotrichoides(Fron) Deighton] is a disease of winter wheat (Triticum aestivumL.) in many wheat growing regions in the world. Resistance to SFR can be conferred by a single dominant gene (Pch1) fromAegilops ventricosaTausch that was transferred onto chromosome 7D of wheat. ‘Madsen’, a hexaploid winter bread wheat, carriesPch1and is highly resistant to SFR. Jointed goatgrass (Ae. cylindricaHost.) is a winter annual grass weed. Wheat and jointed goatgrass have the D genome in common and have been found to hybridize and backcross under field conditions. Since SFR resistance in winter wheat is controlled byPch1on the D genome, it is theoretically possible for resistance to be transferred to jointed goatgrass via backcrossing. A SFR resistant jointed goatgrass population would potentially have an ecological advantage in the presence of the disease. To evaluate the likelihood of gene introgression, Madsen, ‘Stephens’ (a SFR susceptible winter wheat), three jointed goatgrass accessions, and 15 artificially produced backcross progenies (BC2S2) were inoculated with SFR. The percentage of infection in Stephens, the joined goatgrass accessions, and the backcross progenies was 80% or greater except for one BC2S2progeny that had only 20% infection. Madsen had 0% infection. The presence ofPch1in the BC2S2progeny was confirmed using a biochemical marker linked to the resistance gene. These results show that a SFR resistance gene from winter wheat can be transferred to jointed goatgrass.
Forage Potential ofOpuntiaClones Maintained by the USDA, National Plant Germplasm System (NPGS) Collection
Authors: Felker Peter , Paterson Andrew , Jenderek Maria M.
Published: September 2006

Short term gas exchange measurements and long term field trials have confirmed the several fold greater water to dry matter conversion efficiency of cactus than C3 and C4 plants. The protein and dry matter digestibility ofOpuntiatypically are in the 60 to 70% range and are on par with other high quality forages. While the protein content is low (ca. 6%), as is usually observed in unfertilized rangeland, fertilization can increase the protein to 10 to 15%. The high mineral content (4.2% Ca and 2.3% K) would appear to be beneficial to lactating animals. The high water content, maintained in drought periods, is useful in meeting animal water requirements. In both Mexico and the USA spiny varieties have been utilized by burning off spines in the field with propane torches, or by use of stationary forage choppers at the dairy/feedlot. Spineless varieties require intensive fencing for protection against wildlife and uncontrolled livestock. Spineless varieties generally have less tolerance to freezing weather than spiny varieties. It has been estimated that about 400 000 ha of spineless varieties have been planted in Brazil, from 700 000 to 1 000 000 ha in northern Africa and that cactus was an important forage component on 3 million ha of grazing lands in northern Mexico. The majority of the spiny and spineless types used worldwide for forage are preserved in the USDA NPGS germplasm collection. This paper reviews the environmental adaptability and most important nutritional characteristics of major forage clones. Spineless clones are described that are adaptable to USDA cold hardiness zones 7, 8, and 9.
The Scientific Name of Narrow‐Leaf Trefoil
Authors: Kirkbride Joseph H.
Published: September 2006

The narrow‐leaf trefoil is a widely used forage plant in temperate and subtemperate areas. It is the object of extensive improvement programs and research, which has generated a large body of literature. A few decades ago it was discovered that its traditional scientific name, Lotus tenuis Waldst. & Kit. ex Willd., had to be superseded by an older name, L. glaber Mill. It was then proposed to permanently reject the name L. glaber, thus allowing L. tenuis to continue in use for the narrow‐leaf trefoil. The rejection proposal for the name L. glaber was finally accepted by the 17th International Botanical Congress (IBC) in July 2005, so L. tenuis is now the scientific name for the narrow‐leaf trefoil.
Response of Chickpea Yield to High Temperature Stress during Reproductive Development
Authors: Wang J. , Gan Y. T. , Clarke F. , McDonald C. L.
Published: September 2006

Minimizing the exposure of an annual crop to abiotic stresses may increase seed yield. A study was conducted to determine the effect of high temperature stress during reproductive development on pod fertility, seed set, and seed yield of chickpea (Cicer arietinum L). ‘Myles’ desi and ‘Xena’ kabuli chickpea were grown in a controlled environment under 20/16°C day/night air temperatures (control). High (35/16°C) and moderate (28/16°C) temperature stresses were imposed for 10 d during early flowering and pod development. Compared to the control, the early flower high temperature stress decreased (P < 0.01) pod production by 34% for Myles and 22% for Xena, whereas high temperature stress during pod development decreased (P < 0.05) seeds per plant by 33% for Myles and 39% for Xena. Consequently, the high temperature stress during pod development decreased (P < 0.01) seed yield by 59% for Myles and 53% for Xena. Yield reduction was greater due to the stress during pod development compared to the stress during early flowering. Plants recovered to a greater degree from the early flower stress compared to the pod development stress. The Myles desi produced 40 seeds per plant and the Xena kabuli produced 15 seeds per plant, whereas the Myles had smaller individual seed size than the Xena. Consequently, the Myles desi produced 26% greater seed yield than the Xena kabuli under the same conditions. Minimizing the exposure of chickpea to high temperature stress during pod development will increase pod fertility, seed set, and seed yield of the crop.
Increasing Kernel Density for Two Inbred Lines of Maize
Authors: Thompson Donald L. , Goodman Major M.
Published: September 2006

Improving grain quality of maize (Zea mays L.), including endosperm hardness and density, is often a breeding objective. Dense seed is preferred by dry millers and for alkaline processing, and can command a price premium at market. This study attempted to increase kernel density in a backcrossing program for two inbreds of maize using two selection techniques, specific gravity of kernels and the percentage of sinking kernels in a salt solution (or sinkers). Two inbreds, B73G and A632, were crossed with synthetics exhibiting apparent high kernel density, and several generations of backcrossing and self‐pollination followed. Examples of mean comparisons of backcross‐derived inbreds with the recurrent parents, B73G and A632 are as follows: B73G–Specific gravity, 1.251 and 1.206; Sinkers, 62.3 and 14.9%; and A632–Specific gravity, 1.266 and 1.250; Sinkers 45.4 and 29.1%. Both the specific gravity and sinkers techniques were successful for increasing kernel density during backcrossing.
Cytogenetically Engineered Rye Chromosomes 1R to Improve Bread‐making Quality of Hexaploid Triticale
Authors: Lukaszewski Adam J.
Published: September 2006

Hexaploid triticale (X Triticosecale Wittmack) is rarely used for human consumption because of its poor bread‐making quality. To create the genetic potential for bread‐making quality similar to that of bread wheat (Triticum aestivum L), rye (Secale cereale L.) chromosome 1R in triticale cv. Presto was cytogenetically engineered to remove secalin loci Sec‐1 and Sec‐3, and to introduce wheat storage protein loci Gli‐1 and Glu‐1 The manipulations were by homoeologous recombination between rye chromosome 1R and 1B or 1D of wheat, followed by homologous recombination of primary recombinants with translocation breakpoints in desired locations. This approach generated three classes of multi‐breakpoint translocation chromosomes named Valdy, FC and RM. Chromosome Valdy is a three breakpoint translocation with loci Gli‐D1, Sec‐1 and Glu‐D1; chromosomes FC1 and FC2 are five breakpoint translocations with loci Gli‐D1 and Glu‐D1, and chromosomes RM are six breakpoint translocations with loci Gli‐B1 and Glu‐D1 Preliminary tests of the effects of these chromosomes show a 230 to 250% increase of the SDS‐sedimentation value over the recipient triticale Presto. While the impact of these chromosomes on the agronomic value of triticale is not clear, they restore to triticale the genetic load of gluten‐encoding loci similar to that of bread wheat, thereby creating the genetic potential for breeding bread‐making triticales.
Genotype × Environment Interactions, Heritability, and Trait Correlations of Sinapate Ester Content in Winter Rapeseed (Brassica napus L.)
Authors: zum Felde Thomas , Becker Heiko C. , Möllers Christian
Published: September 2006

Improving the meal and protein quality for feed and food purposes is of increasing importance in canola (Brassica napus L.). The phenolic acid ester content contributes to the bitter taste, astringency, and dark color of rapeseed meal products. The predominant phenolic acid esters are sinapate esters (SE), which make up 1 to 2% of the seed dry matter. The objective of the present study was to analyze the genetic variation and the genotype × environment interactions for SE content and composition in three populations of doubled haploid lines. The populations were grown in three to four environments in Germany. The following SE were analyzed by HPLC: sinapoylcholine (sinapine), sinapoylglucose, and a minor group of other SE which includes sinapate. The three populations showed a highly significant variation for the total SE content, and sinapine was the predominant sinapate ester compound. The analysis of variance showed highly significant effects for the genotype (G), the environment (E) and the G × E interactions for all three populations. In two of the populations the G × E interaction variance components were less than half of the genetic variance, in one population it was slightly higher. The estimates for heritability of the individual and total SE were generally high and ranged from 0.57 to 0.93. A reduction of sinapate ester content was not associated with a change in oil, protein, and glucosinolate content.