bluuebunny/crossref_metadata_2025 huggingface dataset:
Partitioning and Remobilization of Nitrogen during Regrowth in Nitrogen‐Deficient Ryegrass
Authors: Ourry A. , Boucaud J. , Salette J.
Published: July 2010

Little is known about the relative importance of different sources of N during crop regrowth after defoliation. This study was conducted to determine the effect of N deficiency on N uptake and redistribution throughout plants during a 14‐d period of regrowth following cutting in ryegrass (Lolium perenne L.). Eight‐week‐old plants grown in hydroponic culture, were labeled for 5 d with 15N prior to cutting treatment. Regrowth occurred during 14 d with a low or high N supply in the growth medium and 15N amounts recovered in plants were used to estimate both N uptake from the medium and N remobilization from roots and stubble to regrowing leaves. Comparison of clipped plants regrowing under nonlimited and limited N conditions showed that N deficiency reduces the growth of leaves. Nitrogen starvation decreases N uptake from the medium and protein N remobilization of roots, while N remobilization from stubble remains unaffected. After 14 d on N‐starved medium, about 69% of N in new regrowing leaves was obtained from endogenous compounds accumulated in roots and stubble, while only 40% was remobilized from these tissues in plants grown on a nonlimited N medium. Consequently, there is an important deficit between net N outflow and net N inflow, particularly in stubble of N limited plants. The overall results demonstrated that stubble tissues contribute to remobilization of N compounds during regrowth after defoliation in proportion to the level of N deficiency in the medium, while remobilization of protein N of roots was decreased with a low supply of N in the medium.
Allelopathy and Autotoxicity in Alfalfa: Characterization and Effects of Preceding Crops and Residue Incorporation
Authors: Hedge Ramesh S. , Miller D. A.
Published: July 2010

Alfalfa (Medicago sativa L.) is known to be both autotoxic and allelopathic. Greenhouse and laboratory experiments were conducted to determine if ‘WL‐316’ alfalfa exhibits short‐term autotoxicity and long‐term autotoxicity and allelopathy. Long‐term autotoxicity and allelopathy of alfalfa were verified at Urbana, IL, by comparing the germination and growth of alfalfa and sorghum [Sorghum bicolor (L.) Moench] on Flanagan silt loam (fine, montmorillonitic, mesic Aquic Argiudoll) previously cropped to alfalfa (alfalfa‐soil) and sorghum (sorghum‐soil). Short‐term autotoxicity of alfalfa was investigated by studying the effect of incorporating its roots only and both roots and shoots on the germination and growth of alfalfa in alfalfasoil and sorghum‐soil. The data were further supported by a laboratory bioassay of seedling exudate and shoot leachate of alfalfa and sorghum. Plant height and fresh weight per plant of alfalfa and fresh weight per plant of sorghum were lower on alfalfa‐soil than on sorghum‐soil. Germination percentages of both alfalfa and sorghum and plant height of sorghum were unaffected by the preceding crop. The two soils differed in nutrient content, but fertility was high and should not have been limiting to the growth of either crop. As a result, allelopathic/autotoxic compounds in alfalfa‐soil were implicated in the growth inhibition of the two crops. Soil incorporation of fresh alfalfa roots only or both roots and shoots reduced alfalfa emergence, plant height, and dry weight per plant. Primary effects of water‐soluble inhibitory compounds from alfalfa shoot appeared to be on germination and radicle elongation, the latter being apparently more sensitive than the former. Alfalfa allelopathy seems to be more severe than autotoxicity. A flow diagram describes different kinds of allelopathy and autotoxicity and various situations that verify the existence of a particular kind of allelopathy or autotoxicity
Corn Hybrid‐Starter Fertilizer Interaction for Yield and Lodging
Authors: Teare I. D. , Wright D. L.
Published: July 2010

The value of placing small amounts of soluble fertilizers in close proximity to the seed at corn (Zea mays L.) planting was debated in the early 1980s for corn grown in a high‐yield environment, but is becoming an accepted practice in the southeastern USA. The objective of this study was to evaluate yield and lodging of several corn hybrids to starter fertilizer application in a high‐yield environment. Starter and no‐starter were the two fertility treatments. Starter was applied as NH4‐polyphosphate (10‐15‐0) in a band on the soil surface at planting. Rainfall was measured, and irrigations scheduled with tensiometers. Starter fertilizer significantly increased grain yields compared to no‐starter. Hybrid ✕ year and hybrid ✕ starter treatment interactions were significant. Certain corn hybrids were identified as positive changers (Funks G4733, Asgrow RX777, Sunbelt 1880, Pioneer 3320, Jacques JX247, Jacques 8400, Northrup King PX9581, and Coker 8680) that consistently yielded more with starter than others identified either as nonchangers or as negativechangers. Percent lodging generally was greater with no starter fertilizer (year ✕ starter and hybrid ✕ starter interactions were nonsignificant). Hybrid ✕ year interactions for percent lodging were significant. Certain corn hybrids (Jacques JX247, DeKalb DK748, and Jacques 8400) consistently exhibited less lodging than the hybrid mean when fertilized with a starter. The management implication is that certain corn hybrids may be profitably fertilized with a starter fertilizer but others may not, since they either do not respond (nonchangers) or respond negatively to starter fertilizer.
Alkali‐Labile Cell‐Wall Phenolics and Forage Quality in Switchgrasses selected for Differing Digestibility
Authors: Gabrielsen B. C. , Vogel K. P. , Anderson B. E. , Ward J. K.
Published: July 2010

Alkali‐labile cell‐wall phenolics have been implicated in previous research as factors that affect forage digestibility by ruminants. Alkali‐labile cell‐wall phenolics, in vitro dry matter digestibility (IVDMD), neutral‐detergent fiber (NDF), acid‐detergent fiber (ADF), lignin (permanganate‐oxidation), and crude protein (CP) were determined in three switchgrass (Panicum virgatum L.) strains differing genetically for IVDMD to determine relationships between these quality parameters and IVDMD during the grazing season. Grazed (upper 1/3 of grazed plants) and ungrazed (whole plants in caged exclosures) forage was collected weekly from replicated 0.4− ha pastures of ‘Trailblazer’ (high IVDMD), ‘Pathfinder’, and a low‐IVDMD strain during three grazing seasons from 1983 to 1985. The principal alkali‐labile phenolics (g kg−1 NDF) detected were p‐coumaric acid (PCA) and ferulic acid (FA). Increased PCA concentration due to increased maturity averaged >70% during each grazing season and corresponded with increased NDF, ADF, and lignin and decreased IVDMD, CP, and FA/PCA ratio. Ferulic acid concentration either declined slightly or remained unchanged. Averaged across 3 yr, Trailblazer had higher (P < 0.06) IVDMD, lower (P < 0.09) PCA and higher (P < 0.10) FA/PCA ratio than a divergently selected low‐IVDMD strain. Differences between strains in detergent‐fiber constituents, FA, and CP were either not apparent or inconsistent with strain differences in IVDMD. Results were consistent with both grazed and ungrazed switchgrass and indicate that alkali‐labile cell‐wall phenolic composition in switchgrass is heritable and genetically correlated to IVDMD.
Heat‐Shock Protein Synthesis and Accumulation in Diploid Wheat
Authors: Vierling Richard A. , Nguyen Henry T.
Published: July 2010

Plants synthesize a set of proteins, called heat‐shock proteins (HSPs) under high‐temperature stress. These proteins may play a role in the genetic control of thermal tolerance in plants. The objective of this study was to determine if genotypic differences exist in the synthesis and accumulation of HSPs in diploid wheat Triticum monococcum L. Plants of three T. monococcum accessions were heat shocked at 37 °C in a controlled condition for 1 h and HSPs were labeled in vivo with 35S‐methionine for 3 h. Analysis of HSPs separated by two‐dimensional (2‐D) gel electrophoresis showed qualitative and quantitative diversity of HSP synthesis in T. monococcum. In order to study HSP accumulation, plants were heat shocked at 37 °C for 8 h and 2‐D separated HSPs were visualized by silver staining. Both qualitative and quantitative diversity of HSP accumulation was observed. Optical density (visible light) of 34 HSPs ranged from 0.33 to 44.64 on silver‐stained gels and from 0.21 to 37.64 on labeled gels. Heat‐shock proteins unique to individual accessions were identified. The identification of genetic variability in HSP synthesis within diploid wheat provides a useful tool for genetic and physiological studies of the role of HSPs in higher plants.
Backcrossing Tetraploidy into Diploid Medicago Falcata L. Using 2n Eggs
Authors: Bingham E. T.
Published: July 2010

Chromosome manipulation may be useful in germplasm enhancement where wild and cultivated forms are at different ploidy levels. In this study, tetraploidy was backcrossed into a diploid Medicago falcata L. synthetic (2x WISFAL‐1) in a series of five 2x‐4x backcrosses using 2x WISFAL‐1 as the recurrent parent and the 4x M. sativa L. as the nonrecurrent parent. Since nearly all 2x M. falcata plants produced a low background frequency of 2n eggs, it was necessary to pollinate only =500 2x flowers with 4x pollen to obtain one to five tetraploid hybrids per 2x plant. The new tetraploid form of M. falcata, designated 4x WISFAL‐1, contains 98% M. falcata germplasm and 2% M. sativa. The broad‐based synthetic 4x WISFAL‐1 has all the characteristics of 2x WISFAL‐1 except that it has larger vegetative and reproductive organs, and crosses directly with cultivated alfalfa. The 4x WISFAL‐1 can be used for gene transfer from M. falcata to cultivated alfalfa. The yellow flower color of 4x WISFAL‐1 also can be used as a codominant flower‐color marker at the tetraploid level. Two narrow‐based tetraploid populations were developed by backcrossing to PI 231731 and PI 258754, respectively, using 4x WISFAL‐1 as the nonrecurrent parent. Thus, 4x WISFAL‐1 is also useful in germplasm enhancement of individual diploid Pis by elevating them to the tetraploid level for direct crossing with cultivated M. sativa.
Soybean Seed Coat Structures: Relationship to Weathering Resistance and Infection by the Fungus Phomopsis phaseoli
Authors: Kulik M. M. , Yaklich R. W.
Published: July 2010

The fungus Phomopsis phaseoli (Desmaz.) Sacc. (syn. P. sojae Lehman) incites a serious disease of soybean [Glycine max (L.) Merr.] seeds. This study was conducted to determine if an impermeable seed coat reduces infection by this fungus. Seeds of four soybean cultivars found in blotter tests to be infected by P. phaseoli in very low amounts (0–5%) and seeds of four other cultivars with high amounts of infection by this fungus (65–83%) were studied under scanning electron microscopy. Seed coats of cultivars with low P. phaseoli infection were found to lack pores, whereas those with high infection had multiple pores. In addition, seeds of the four cultivars with low infection had closed micropyles, whereas those with high infection had relatively open micropyles. This was reflected in their measurements: closed micropyles had an average area of 0.17 mm2, compared with 0.44 mm2 for the open ones. The percentage of impermeable seed coats in the eight cultivars was determined by soaking seeds in distilled water for 1 h. The average percentage of seeds with an impermeable seed coat was 75% for the four cultivars with low infection and 5% for those with high infection. In a field study, in which pairs of cultivars with either normal or impermeable seed coats were compared, there were significant differences between the two seed coat types in amount of P. phaseoli infection at maturity and after field weathering. This study supports the theory that the resistance of certain soybean cultivars to infection by P. phaseoli is due to the physical characteristics of impermeable seed coats.
Carbon Isotope Discrimination and Water Use Efficiency in Four Cool‐Season Grasses
Authors: Johnson Richard C. , Bassett Lynn M.
Published: July 2010

Carbon isotope discrimination (Δ) has been correlated with water use efficiency (WUE) in several C3 plant species and may be useful as a plant selection factor for improving WUE in crops. Research was undertaken to determine if differences in Δ could be found in grass accessions from the National Plant Germplasm System and if Δ of field grown plant tissue could be linked to WUE in greenhouse pots (pot WUE). Leaf Δ was measured on several accessions of Agropyron desertorum (Fischer ex Link) Schultes (standard crested wheatgrass), Festuca arundinacea Schreb. (tall fescue), Dactylis glomerata L. (orchardgrass), and Lolium perenne L. (perennial ryegrass). Accessions were established and grown under irrigated and dryland conditions at Central Ferry, WA and dryland conditions at Pullman, WA in the spring and summer of 1988. Differences in Δ among accessions within species were significant, but the environment by accession (within species) interaction was not, indicating that accession differences in Δ were generally consistent across environments. Measurements of pot WUE (dry weight/pot evapotranspiration) were made under greenhouse conditions on accessions of Dactylis, Festuca, and Lolium that had high and low field Δ and dry matter productivity. Accessions selected for low field Δ always had higher pot WUE based on shoot dry weight than high Δ selections under well‐watered and drought‐stressed conditions. This was also true of pot WUE based on whole‐plant dry weight in all cases except Festuca under drought‐stress. Accessions with low field Δ had higher water potential, solute potential, and turgor pressure than high Δ accessions in the greenhouse experiment, suggesting a more favorable water status for growth. The results link pot WUE with field Δ in a way consistent with theoretical expectations and suggest that Δ can be effectively used to evaluate C3 grass germplasm for WUE.
Potassium and Aldicarb‐Disulfoton Effects on Verticillium Wilt, Yield, and Quality of Cotton
Authors: Minton Earl B. , Ebelhar M. Wayne
Published: July 2010

Optimum cotton (Gossypium hirsutum L.) yield with good fiber quality requires healthy vigorous plants throughout the season. Recently, verticillinm wilt (Verticilllum dahllae Kleb.) and K deficiency symptoms occurred during August and September in cotton grown on sandy loam soils of the Mississippi Delta. Symptoms developed earlier and faster in some caitivars compared with others. In a field study, applications of K and pesticides on verticillium wilt‐K deftciency symptoms, yield and fiber quality of ‘DES 119’ and ‘Stoneville 825’ cottons were evaluated. Broadcast application and topsoil incorporation of 112 kg K ha‐1 yr‐1 reduced verticillium wilt‐K deficiency symptoms from 12 to 7%, averaged across both cultivars, but did not affect lint yield. The root‐gall [caused by Meloidogyne incognita (Kofoid & White) Chitwood] index was reduced from 2.7 to 2.5 and from 2.7 to 2.4 by K and aldicarb‐PCNB‐ETMT [5% 2‐methyl‐2‐(methylthio)propionaidehyde‐O‐(methylcarbamoyl)oxime + 10% pentachloronitrobenzene + 2.5% 5‐ethoxy‐3‐(trichloromethyi)‐l,2,4‐thiodiazole; 0.56 + 1.12 + 0.28 kg a.i. ha‐1], respectively. Fiber strength (kN m kg‐1) was increased from 20.4 to 20.9 by K and micronaire reading was increased from 3.99 to 4.13 by aldicarb treatment. Yield, fiber quality, verticillinm wilt‐K deftciency symptoms, and root‐gall index differed between euitivars. In soil infested with V. dahliae and M. incognita, K could be used to reduce verticillium wilt‐K deficiency symptoms and root‐gall index and to increase fiber strength of cotton. Aldicarb also can be used to reduce root‐gall index. Knowing the reaction of cotton cultivars to K and to pesticides should help cotton breeders develop better adapted cultivars.
Identification of Effective Indicators of Erect Plant Architecture in Dry Bean
Authors: Acquaah G. , Adams M. W. , Kelly J. D.
Published: July 2010

Applying the concept of ideotypes in a breeding strategy presupposes that the breeder already knows what traits to select. This study was conducted to determine the substantive indicators of erect plant architecture in dry bean (Phaseolus vulgaris L.). In the first of two field studies, data on 17 architectural traits were collected at two locations on parental plants and progenies originating from five distinct cycles of a phenotypic recurrent selection program. In the second study, similar data were collected at one location on 480 F3 lines from six crosses. A stepwise multiple regression procedure was used to determine traits that are effective indicators of erect plant architecture. Hypocotyl diameter, plant height, branch angle, and pods on the main stem and especially in the midsection were selected for inclusion in the regression model, suggesting their important contributory role in a dry bean ideotype. Dry bean breeders should emphasize these four traits for effective selection and efficiency in a breeding program for erect plant architectures.
Heterosis and Mixing Effects in Winter Oilseed Rape
Authors: Léon J.
Published: July 2010

Open‐pollinated synthetics and lineal cultivar structures of rapeseed (Brassica napus L. var. napus) are used for commercial production. All are different in degree of heterozygosity and heterogeneity. This study was conducted to determine heterosis and mixing effects, and their interactions on yield and yield stability. From four randomly‐chosen winter oilseed rape cultivars the F1, F2, two‐component cultivar mixtures and Syn1 were produced using a diallel design. Furthermore, three two‐component F1 mixtures were produced. The cultivars, cultivar mixtures, F1's and Syn1's were tested at four locations in northern Germany in 1982–1983 and 1983–1984. The F2's and F1 mixtures were tested in 1983–1984. Mixtures of cultivars outyielded cultivars by 6%. The F1's outyielded cultivars (by 15%), cultivar mixtures (by 8%), and Syn, (by 6%). The F1 mixtures outyielded F1's in pure stands by 6%. The F2's surpassed cultivars by 4%, but yielded less than expected based on the parental and F1 results. The stability parameter ecovalence revealed a positive effect of increasing heterozygosity and heterogeneity on yield stability. The effect of heterogeneity on yield stability was greater than the effect of heterozygosity. The F1 mixtures showed high yield and high yield stability. The results suggest that heterogeneous hybrid structures of winter rape may be superior to homogeneous hybrid structures.
Yield and Composition of Soybean Seed from Parents with Different Protein, Similar Yield
Authors: Hartwig E. E. , Kilen T. C.
Published: July 2010

Soybean [Glycine max (L.) Merr.] seed yields often show a negative association with seed protein. The objective of this study was to determine if this association could be minimized by crossing a high and a normal protein line of equal seed yield. An F2 population of 1000 plants was grown. Plants were harvested individually and seed evaluated for oil content using the nuclear magnetic resonance technique. Two bulk populations were developed: one included the 8% having the highest oil and the other the 8% having lowest oil. With the high negative correlation between seed protein and oil, the low oil population was expected to provide lines having high seed protein concentration. The two populations were advanced in bulk through the F6 generation, after which 200 plants were harvested individually from each population and 200 F7 lines grown from each. The F7 lines were harvested individually and seed analyzed for seed protein and oil. The 18 lines having the highest protein and the 18 lines having the highest oil were selected for further evaluation in replicated trials. Lines were evaluated in five environments for seed yield, protein, and oil. The overall mean seed yield of the high protein lines averaged 6% less than the overall mean of the lines selected for high oil; however, when seed yield of the two highest protein lines at each environment were compared with the two highest oil lines, the high protein lines had a 1% advantage in seed yield, an 18% advantage in seed protein, and a 20% reduction in oil. The results demonstrate the potential for developing soybean lines high in seed protein and equal in seed yield to lines having high oil content.
Grain Yield vs. Spike Number in Winter Wheat in a Humid Continental Climate
Authors: Aguilar‐Mariscal I. , Hunt L. A.
Published: July 2010

Wheat (Triticum aestivum L.) yields often are closely related to spike number per unit ground area. This study was conducted to determine whether, for soft white winter wheat in a region with a humid continental climate, this relationship is determined primarily by changes in total dry weight accumulation (TDW), harvest index (HI), or both. The study involved several field experiments in which seeding density varied from 6 to 24 g m−2, sowing dates ranged from 14 September to 1 November, alternate rows were removed in May and early June, row spacing varied from 0.16 to 0.32 m, a growth regulator (chloroethyltrimethylammonium chloride) was applied 9.6 kg a.i. ha−1, and 11 genotypes (both gibberellic acid sensitive and insensitive) were used. These treatments were used to create range of final spike numbers. Grain yields ranged from 180 to 570 g m−2, and increased with spike numbers per m2. Total dry weight, which ranged from 720 to 1670 g m−2, also increased with spike numbers per m2, such that HI remained unchanged as spike number per unit area increased. Harvest index, however, decreased with spike number per plant, and was related to kernel weight but not to kernel number per spike. Positive relationships of grain yield to spike number per unit land area thus seem to arise from increased TDW rather than enhanced HI. Examination of the reasons for high dry matter production at high spike numbers appears worthwhile for subsequent research.
Simplified Methods for Screening Cowpea Cultivars for Manganese Leaf‐Tissue Tolerance
Authors: Wissemeier A. H. , Horst W. J.
Published: July 2010

In cowpea [Vigna unguiculata (L.) Walp.) dark brown speckles on old leaves are typical symptoms of Mn toxicity and indicate Mn sensitivity of leaf tissue. Induction and subsequent quantification of brown Mn speckles in leaf tissues were used to screen cowpea cultivars for Mn leaf‐tissue tolerance using three different techniques: (i) leaf cuttings cultured for 22 d in solution culture with 20 μM MnSO4, (ii) leaf rings mounted on leaves of intact plants and filled with 500 μM MnSO4 for 5 d, and (iii) leaf disks floated for 3 d on 500 μM MnSO4. Density of brown speckles differed considerably among the six cultivars tested, and was not related to the Mn concentrations of the leaf tissues. There were close relationships between genotypic Mn‐toxicity symptom expression and depression of dry matter production of the cultivars at high Mn supply in a long‐term sand culture experiment. The floating leaf‐disk method is particularly suited for screening large numbers of cowpea cultivars for Mn leaf‐tissue tolerance because it requires only 3 d. The ranking of the cultivars for Mn tolerance was highly correlated (r2 = 0.95) to Mn tolerance of intact plants.
Physiology of Oil Seeds: IX. Effects of Water Deficit on Peanut Seed Quality
Authors: Ketring D. L.
Published: July 2010

The peanut (Arachis hypogae L.) crop is frequently subjected to water deficit during the growing season. This study was conducted to determine the effect of water received by the crop on the germinability and vigor of the subsequent seed generation. Two peanut genotypes, ‘Comet’ and breeding line OK‐FH15, were grown under both rainfed and irrigated conditions on a Teller sandy loam (fine, mixed, thermic Udic Argiustoll) soil in 0.91‐m wide rows using standard agronomic practices. Pods were harvested, dried, and shelled. Only mature seeds(those with smooth seed coats and riding at least a 5.95 by 19.05 mm slotted screen) were used in the tests. Seeds were germinated at 29 ± 1 °C in 2‐L flasks fitted with two sheets of 15.0‐cm Whatman no. 5 filter paper. Ethylene and CO2 were quantitatively determined by gas chromatography. Germination ranged from 94 to 100%, but was lowest for seeds produced under water deficit. Maximum C2H4 production occurred at 22 to 24 h of germination during hypocotyl‐radicle emergence. Carbon dioxide production was maximized 24 h later, or rose slowly thereafter. Water deficit during seed production affected both C2H4 and CO2 production during subsequent germination. The most consistent response to water deficit was reduction in the fraction of rapidly growing seedlings (those with hypocotyl‐radicle longer than 20 mm at.72 h of germination. Thus, water deficit during seed development affects subsequent growth of seedlings and could pose a problem in establishment for the succeeding crop. A minimum of 500 mm of water was necessary to produce a crop of seeds with high potential for germination and a high proportion of vigorous seedlings.
Outcrossing in Aeschynomene
Authors: McKellar M. A. , Deren C. W. , Quesenberry K. H.
Published: July 2010

Plant breeders shape breeding and seed increase programs, in part, according to the percent outcrossing in the species. Previous reports indicated that aeschynomene, Aeschynomene americana L., was almost entirely self‐pollinated. The objective of these experiments was to determine percent outcrossing under greenhouse and field conditions. A completely dominant trait, glabrousness, was used to determine percent outcrossing in a pubescent line of aeschynomene in the presence of honey bees, Apis spp., in the greenhouse and natural pollinators in the field. Mean percent outcrossing during two seasons in the greenhouse was 24%. Mean percent outcrossing was 30% at two Florida locations separated by 450 km. This level of outcrossing suggests that more rigorous isolation requirements than those currently used may be needed in breeding programs and seed increase fields where two or more lines are grown nearby.
Heritability and Early‐Generation Selection for Resistance to Early and Late Leafspot in Peanut
Authors: Anderson W. F. , Holbrook C. C. , Wynne J. C.
Published: July 2010

The genetic nature of resistance to early (Cercospora arachidicola Hod) and late [Cercosporidium personatum (Berk. & Curt.) Deighton] leafspot of peanut (Arachis hypogaea L.) is quantitative, making selection for resistance difficult in segregating populations. In many areas of peanut production, without fungicide application one or both diseases may significantly reduce yields. A study was conducted to obtain heritability estimates, responses to selection, and relationship of resistance of two peanut populations for early and late leafspot resistance. Selection based on F2 family means in the F3 generation via defoliation, infection, and sporulation was performed for early and late leafspot in North Carolina and Georgia, respectively, within populations of PI 314817/[TG3/EC 76446 (292)] and (PI 314817/ICGS 4). Divergent selections for each disease were evaluated in the F4 generation at the same locations the following year for resistance by visual rating of infection and defoliation. Broad‐sense heritability estimates ranged from low to high (0.12–0.88) for components of resistance to each leaf‐spot disease. Narrow‐sense heritability estimates from parent‐offspring regression (0.18–0.74) and realized heritability (0.60–1.41) were significant for late leafspot resistance and early leafspot resistance in the PI 314817/[TG3/EC 76446 (292)] population. Results indicated that selection based family means would be successful. Selection of individual plants within families did not significantly improve genetic progress. Moderate to high correlations (0.41–0.86) existed between early and late leafspot disease components indicating possible genetic linkage or host‐plant physiology that conferred resistance to both diseases in one population.
Grain Phytic Acid and Protein are Highly Correlated in Winter Wheat
Authors: Raboy Victor , Noaman Maher M. , Taylor G. Allan , Pickett Suewiya G.
Published: July 2010

Phytic acid (myo‐inositol hexakisphosphate), the major storage form of P in seeds, is believed to have a negative impact on nutritional quality. Since breeding for low phytic acid has been proposed for several cereals and legumes, it is important to predict the effects of selection against phytic acid on other major grain components. Experiments were conducted to determine the quantitative relationship between grain phytic acid P, total P, and protein in two winter wheat (Triticum aestivum L.) populations, each consisting of F6 progeny of a double cross. Substantial variation in phytic acid P was observed, with the range in values equal to 30 and 48% of the respective population mean. Observed variation in phytic acid P was highly and positively correlated with variation in grain total P (r 0.93 and 0.96 in Populations 1 and 2, respectively), and with variation in grain protein (r = 0.65 and 0.87, respectively). The dose correlation of phytic acid P with both total P and protein indicates that selection against grain phytic acid would lead to undesirable reductions in both grain total P and protein.
Genetic Analysis of Quantitative Traits in Wild Emmer (Triticum turgidum L. var. dicoccoides)
Authors: Cantrell R. G. , Joppa L. R.
Published: July 2010

Utilization of related wild species for genetic improvement of durum wheat (Triticum turgidum L. var. durum) has been limited by the lack of suitable cytogenetic stocks. This study was conducted to identify the chromosomal location of genes influencing quantitative traits in wild emmer (T. turgidum L. var. dicoccoides). Thirteen of the possible 14 disomic substitution lines of ‘Langdon’ durum wheat (LDN), each containing a different individual chromosome pair of T. turgidum var. dicoccoides (accession FA‐15‐3 = DIC), were compared with each other and with the recipient parent LDN in a replicated experiment at Langdon and Prosper, ND, in 1988 and 1989. Some genotypes with a DIC chromosome 4A or a 4B pair exhibited an average of 39% higher grain yield than LDN. Genotypes with DIC chromosomes 6B had the highest grain protein yield (14.0 g m−2) compared with LDN (10.6 g m−2) and did not differ significantly from LDN for kernel weight. Genotypes with DIC chromosomes 5B had the highest kernel weight (42.3 mg) of all of those tested. The earliest‐maturing genotypes contained the DIC chromosome pair 6A. Genotypes possessing a DIC chromosome pair 4A, 5A, 5B, 6B, or 7B were significantly taller than LDN. Results indicated that important agronomic traits in cultivated durum wheat can be improved by introgressing genes from wild emmer using chromosome substitution lines that overcome many of the problems of conventional wide hybrids. It is important to derive several genotypes that possess a particular DIC chromosome pair, since genetic heterogeneity was detected even after five backcrosses to LDN.
Genetic Linkage of the Rj2 Gene in Soybean
Authors: Devine T. E. , O'Neill J. J. , Kiang Y. T. , Bult C. J.
Published: July 2010

Several genes controlling nodulation response in soybean, Glycine max (L.) Merr., have been found and their use in restricting nodulation with less desirable strains of Bradyrhizobium japonicum has been postulated. However, little is known of their linkage relationships with other genes. This report details genetic linkage tests of the Rj2 locus with 20 other loci: T, P1, L1, Y13, Adh1, W1, F, Rj1, Idh1, Fr1, Y9, Aco2, Dia1, Fr2, Got, Mpi, Pgdl, Pgm1, Y10, and Y17. Only one of the genes tested showed evidence of genetic linkage with Rj2. The estimated distance of Aco2 from Rj2 was 44.7 ± 2.1 genetic map units.
Source‐Sink Control of Grain Composition in Maize Strains Divergently Selected for Protein Concentration
Authors: Wyss C. S. , Czyzewicz J. R. , Below F. E.
Published: July 2010

A long‐term divergent selection program for concentration of grain protein in maize (Zea mays L.) has produced the Illinois High (IHP) and Low (ILP) Protein strains, which differ greatly in yield and grain composition. The objective of this study was to determine the relative contribution of maternal (source) and zygotic (sink) factors in eliciting the characteristic differences in grain protein concentration. Changes in accumulation and partitioning of dry matter and reduced N during the grain‐filling period were determined on field‐grown plants in 1984 and 1985. Immature kernels of both strains were also grown to maturity in vitro on liquid media that contained various concentrations of N (amino acid mixture ranging in N from 0 to 100 mM). In both years, field‐grown IHP plants had greater total N accumulation (79% more at physiological maturity), more extensive N remobilization from vegetative tissue (43% of that present at anthesis, compared with 19%), and higher N partitioning values (62 vs. 43%) than ILP plants. When grown in vitro, N supply had a large effect on grain protein percentage for IHP but a small effect for ILP. In contrast, dry weight of ILP kernels responded markedly to N supply, while the response of IHP was more tempered. Based on these data, it appears that the distinction in grain protein composition between IHP and ILP results from the coordination of genetic differences in assimilate uptake and remobilization by the vegetation with different utilization efficiencies of the kernel.
Hydration‐Dehydration Treatments to Protect or Repair Stored ‘Karamu’ Wheat Seeds
Authors: Nath Suresh , Coolbear Peter , Hampton John G.
Published: July 2010

Although presowing hydration treatments are known to be capable of improving the germination performance of wheat seeds, no comprehensive information is available, especially with regard to the effectiveness of such treatments on seeds subjected to deterioration under different conditions. This study reports an attempt to understand the responses of a single high‐quality seed lot of wheat (Triticum aestivum L.) to two different storage regimes (100% relative humidity, 40 °C for up to 6 d or at a constant seed moisture content of 0.15 g H2O g−1 fresh weight at 35 °C for up to 50 d). At the same time the relative abilities of three presowing hydration‐dehydration treatments to protect or repair the deteriorating seeds were compared. Although losses of viability and increases in radicle emergence rates followed a similar pattern for both regimes, assessments of electrical conductivity of seed leachate and seedling growth indicated that the mechanisms of deterioration varied under the two aging conditions. A 2‐h prestorage hydration treatment at 25 °C followed by drying allowed maintenance of germinability in storage, but only had marginal effects when applied after aging. Longer hydration treatments (24 h at 15 °C in water or 20 h at 20 °C in −0.37 MPa polyethylene glycol solution) applied after storage were effective at restoring germination rates of seeds that remained viable. if applied before storage, however, these two treatments severely increased the seeds' susceptibility to deterioration. These results demonstrate that (i) not all aspects of deterioration in wheat seeds are irreversible, and (ii) losses of seed vigor and viability are not necessarily features of the same continuum of deteriorative metabolism. Such combinations of treatments and storage conditions should provide useful systems for the systematic study of deteriorative metabolism in aging wheat seeds.
Enzyme Inhibition by Sericea Lespedeza Tannins and the Use of Supplements to Restore Activity
Authors: Petersen J. C. , Hill N. S.
Published: July 2010

Low forage quality of sericea lespedeza [Lespedeza cuneata (Dum.‐ Cours.) G. Don] herbage is associated with the presence of condensed tannins in the leaves, and tannin‐protein complexes that render digestive enzymes inactive. Experiments were conducted to (i) determine the type of inhibition of the cellulase complex caused by tannins, (ii) evaluate N‐containing supplements that preferentially bind to tannins and restore cellulase activity, (iii) determine the effect of such supplements on the in vitro dry matter digestibility (IVDMD) of cellulose, and (iv) determine their effect on IVDMD of high‐ and low‐tannin sericea herbage. The type of enzyme inhibition was determined by Michaelis‐Menten kinetics; a double‐reciprocal plot of the data revealed that tannins inhibited cellulase enzymes noncompetitively. Cellulase activity in tannin‐containing solutions increased with increasing amounts of N‐containing supplements, except for urea. Ovalbumin, polyvinylpyrrolidone (PVP), and gelatin resulted in greatest saccharification: hemoglobin and β‐casein were less effective. Gelatin, hemoglobin, PVP, and ovalbumin partially overcame the effects of exogenous tannins on IVDMD of cellulose, but the proteins were more effective than PVP. The IVDMD of herbage from high‐ and low‐tannin cultivars was greatest when PVP or ovalbumin were added; less supplement was needed in the low‐tannin cultivar. We conclude that N‐containing supplements improve digestibility and, consequently, may improve the performance of animals consuming sericea lespedeza forage.
Regeneration of Peanut and Perennial Peanut from Cultured Leaf Tissue
Authors: McKently A. H. , Moore G. A. , Gardner F. P.
Published: July 2010

Successful utilization of biotechnology for the improvement of peanut, Arachis hypogaea L., will be made possible through development and optimization of tissue culture regeneration systems. This study evaluated plant development via organogenesis from in vitro‐cultured immature leaf tissue of the cultivated peanut and a perennial peanut species, A. glabrata Benth. Leaflets, 5 mm in length from peanut seedlings and 5 to 10 mm in length from perennial peanut plants, were cultured in vitro on Murashige and Skoog medium supplemented with 1 mg L−1 1‐naphthaleneacetic acid (NAA) and four concentrations (1, 3, 5, and 10 mg L−1) of 6‐benzylaminopurine ( BA). Bud regeneration occurred from the adaxial surface of the cultivated peanut explants on all BA concentrations, with the largest quantity produced on 5 mg L−1. Eighty‐four percent of the cultures with bud tissue continued growth and differentiation into shoots within 120 d. These shoots developed roots within 30 d of transfer to basal medium supplemented with 1 mg L−1 NAA. Plantlets transferred to soil and placed in a greenhouse developed successfully, matured, and set seed. Phenotypic variation was not observed. A wide range of cultivated peanut genotypes was evaluated for organogenic responsiveness. The perennial peanut leaf explants callused and produced shoot meristems within 50 d of culture. Ten percent of the meristems continued growth and development into whole plants.
Genetic Variation for Forage Yield and Quality among Grain Oat Genotypes Harvested at Early Heading
Authors: Chapko L. B. , Brinkman M. A. , Albrecht K. A.
Published: July 2010

Few studies have evaluated grain oat for forage yield and quality when harvested before heading, even though this is the current recommended practice when oat is used as a companion crop. The purpose of this research was to assess the amount of genetic variation that existed among grain oat (Avena saliva L.) genotypes for forage yield and forage quality when harvested at early heading (2–3 spikelets emerged from the boot), and to evaluate the relationship between forage yield, forage quality, and nine other agronomic traits. Sixty four elite grain oat genotypes were evaluated in the field on a Piano silt loam (fine‐silty, mixed, mesic Typic Argiudoll) at Arlington, WI, in 1987 to 1989. There was substantial genetic variation for forage yield and forage quality traits as indicated by relatively large genotypic variance (σ2g) components. The σ2g for forage yield was six times as large as the genotype ✕ year interaction variance (σ2gy), while σ2g for acid detergent fiber (ADF) and neutral detergent fiber (NDF) were twice as large as the σ2gu. Although year ✕ genotype interaction mean squares were significant for all traits, relatively large σ2g and small σ2gy indicate that selection for forage yield and quality traits should be effective in this germplasm when based on multiple year evaluations. Tall, late genotypes typically had high forage yield and low forage quality. Phenotypic correlations between grain yield and forage yield (−0.29), and between grain yield and forage quality traits (−0.02 to 0.14) were small. Other agronomic traits had stronger associations with forage yield (r = −0.67 to 0.60) than with forage quality (r = −0.38 to 0.45). We concluded that grain genotypes must be evaluated individually before heading for forage quality to accurately assess their forage value.
Interrelationships between Panicle Weight, Grain Yield, and Grain Yield Components in Oat
Authors: Chapko L. B. , Brinkman M. A.
Published: July 2010

The value of panicle weight as a selection criterion for improving grain yield in oat (Avena sativa L.) is largely unknown. Panicle weight in oat combines two of the three primary yield components, spikelets per panicle and seed weight, into a single trait that is easy to measure. Three oat populations were evaluated in 1987 through 1989 for the effect of selection for panicle weight on grain yield. Genotypes in each population were identified as having either high, intermediate, or low panicle weight in F5 progeny rows, and progenies were evaluated for panicle weight and grain yield in the F6 and F7 generations. A random group of genotypes in each population served as a control. The high panicle weight group did not differ from the random group for mean panicle weight and mean grain yield in all three populations. However, the low panicle weight group had the lowest mean panicle weight and mean grain yield in two (X4020‐15‐l/‘Ogle’ and ‘Centennial’/‘Coker 81‐32’) of the three populations. The correlation between F5 panicle weight and F6 and F7 grain yield was 0.34, 0.06, and 0.56 for X4020‐15‐l/Ogle, ‘Don’/X3530‐47, and Centennial/Coker 81‐32, respectively. Panicle weight had a high positive phenotypic correlation with spikelets per panicle (0.57 to 0.90), but a high negative correlation with number of panicles per unit area (−0.54 to −0.81). Although high panicle weight was not consistently associated with high grain yield, the fact that low panicle weight identified low grain yielding genotypes in two of three populations suggests that low panicle weight would be useful in a truncation selection approach for grain yield improvement. Visual selection, however, would probably be as effective and require less resources.
Association of Selected Plant Traits with Lodging of Four Determinate Soybean Cultivars
Authors: Mancuso Nora , Caviness C. E.
Published: July 2010

Lodging of soybean [Gfycine max (L.) Merr.] frequently reduces seed yield and quality, especially in high‐yield environments. Breeding for resistance to plant lodging is high priority in most soybean programs, but information is limited on effective techniques to evaluate this trait. This study was conducted to measure the association of selected plant traits with lodging score at maturity. Field and laboratory experiments were conducted to evaluate lodging of four determinate Maturity Group V cultivars: Essex, Narow, Forrest, and Mack. Based on four environments, Essex had the lowest lodging score (least lodging), Mack the highest score, and Narow and Forrest were intermediate. Lodging score was significantly (P ≤ 0.01) correlated with plant height at three reproductive stages, R4, R6, and R8, but not at the V8 stage. Length and diameter of basal and centrally located internodes generally were not significantly (P > 0.05) associated with lodging score. Bark percentage at Stage R8 was negatively correlated with lodging score. In contrast, there was a significant (P ≤ 0.05) positive association between lodging score and xylem width and xylem percentage at Stages R6 and R8. The capacity of the plant to recover a more vertical position, measured by the angle of the stem from horizontal after bending for 4 s at R6 and R8, was negatively correlated with lodging score at maturity. Stem stiffness was measured in the laboratory by the distance a specific weight bent the stem and by the weight required to bend the stem a specific distance. Stem stiffness generally was not associated with resistance to lodging. Results indicate that plant resiliency rather than stem stiffness is associated with lodging resistance in these soybean cultivars. Plant height and bark and xylem percentage also were associated with plant lodging and may be of value in breeding for this trait.
Genetics of Wheat Curl Mite Resistance in Wheat: Recombination of Cmc1 with the 6D Centromere
Authors: Thomas J. B. , Whelan E. D. P.
Published: July 2010

Wheat streak mosaic is a destructive disease of common wheat (Tritium aestivum L. era. Thell.) that is vectored by the wheat curl mite, Erlophyes [Acerla] tulipae (Keifer). Resistance to colonization by this vector has been transferred to wheat from several host grasses but has not been reported in wheat perse. Resistance to wheat curl mite was transferred from Aegilops sqnarrosa L. to common wheat where it was shown to be conditioned by a single dominant gene (Cmc1) located on the short arm of Chromosome 6D. Compared with other, more alien transfers, the linkage block containing Cmcl is not expected to interfere with crossover and recombination on this chromosome. This study was undertaken to estimate recombination frequency in the chromosome segment proximal to the Cmcl locus. Recombination between Cmc1 and the 6D centromere among female gametes of plants monotelodisomic for Chromosome 6Ds occurred in 56 out of 107 cases (about 52.3%). The 95% confidence interval for this sample lies between 42.9 and 61.8. Correction of the lower limit for double crossovers showed (P > 0.95) that Cmcl was further than 64.3 centimorgans from the centromere of 6Ds.
Dry Matter Production and Carbohydrate Accumulation in Three Meadowfoam Lines
Authors: Fiez Timothy E. , Norberg O. Steven , Jolliff Gary D.
Published: July 2010

The literature lacks information on seasonal patterns of meadow foam (Limnanthes R. Br. spp.) dry matter production and nonstructural carbohydrate quantities and their relationship with seed yield. To provide this information, three meadow foam lines (85‐765, 85‐729 and ‘Mermaid’) with contrasting seed yield performance were grown in 1987‐1988 and 1988‐1989 at the Oregon State University Schmidt Farm. Organ dry weights and leaf area indices (LAI) were measured at 13 dates in 1987‐1988 and 11 dates in 1988‐1989. Carbohydrates were quantified at anthesis and physiological maturity. There were no differences in season‐long patterns of dry matter accumulation or leaf area development (predicted from regression equations) in either season. Maximal LAI occurred prior to flowering; LAI was less than 0.2 at last bloom each season, while averaged across lines, 35 and 40% of the seed‐fill period occurred after last bloom in 1987‐1988 and 1988‐1989, respectively. During flowering, stems and flowers contained 283 and 148 g kg−1 ethanol‐soluble carbohydrates, respectively, averaged across lines and years. Seed yield was correlated with the amount of potentially remobilizable carbohydrate accumulated during anthesis (r = 0.54, P < 0.01). Results suggest that developing seeds obtain substantial amounts of assimilate from sources other than current leaf photosynthesis.