bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ryegrass Companion Crops for Alfalfa Establishment: I. Forage Yield and Alfalfa Suppression
Authors: Sulc R. M. , Albrecht K. A. , Casler M. D. 
Published: July 2010

AbstractAlfalfa (Medicago sativa L.) is often established with a small grain companion crop in the northcentral USA. Information on alternative companion crop species is limited. This study was conducted to evaluate forage yield and alfalfa establishment when ryegrasses (Lolium spp.) are used as companion crops. Five ryegrass cultivars representing four species were sown at 215, 430, and 645 seeds m−2 with alfalfa at two locations in Wisconsin in April of 1988, 1989, and 1990. Alfalfa was also established alone or with oat (Avena saliva L. ‘Ensiler’). Three harvest schedules, based on oat maturity at the first harvest, were imposed during the seeding year. The ryegrass‐alfalfa mixtures usually had lower forage yields in the seeding year than the oat companion treatment. But mixtures with the diploid annual ryegrass (L. muliflorum Lam. ‘Surrey’) yielded up to 1.17 Mg ha−1 more than the oat companion treatment in environments with adequate rainfall. When rainfall was limiting during early establishment, alfalfa predominated in all ryegrass‐alfalfa mixtures, and forage yield and alfalfa plant density the next year were excellent in the ryegrass companion treatments. Ryegrass was very competitive with alfalfa in seeding years with adequate rainfall, and forage yield and alfalfa plant density the next year varied considerably with ryegrass cultivar, ryegrass seeding rate, and harvest schedule. The diploid annual ryegrass (Surrey) sown at 215 seeds m−2 was the most suitable ryegrass companion crop for alfalfa establishment because it established rapidly, produced high forage yields in the establishment year, and had the least detrimental effect on forage yield and alfalfa plant density the year after seeding.
Production and Water Use Efficiency of Three Old World Bluestems
Authors: Philipp D. , Allen V. G. , Lascano R. J. , Brown C. P. , Wester D. B. 
Published: July 2010

ABSTRACTInformation on water use efficiency (WUE) of forage grasses is needed to select appropriate species for improved productivity in semiarid environments. Three old world bluestem species—[Bothriochloa bladhii(Retz) S.T. Blake ‘WW‐B. Dahl’], [Bothriochloa ischaemum(L.) Keng. var.ischaemum(Hack.) ‘WW‐Spar’], and [Bothriochloa caucasica(Trin.) C.E. Hubbard ‘Caucasian’]—were surface drip‐irrigated with zero (dryland) and low, medium, and high levels to determine dry matter (DM) yield and WUE in 2001, 2002, and 2003 in Lubbock, TX. Water applied in the high irrigation level equaled 100% of grass reference evapotranspiration (ETo); low and medium levels were calculated as 33 and 66% of irrigation applied in the high level; the dryland treatment received no irrigation. Maximum DM yield was obtained withB. caucasicaunder high irrigation (18.0 Mg ha−1) vs.B. bladhii(15.2 Mg ha−1) andB. ischaemum(12.6 Mg ha−1) averaged over all years. The WUE ofB. caucasicaunder low, medium, and high irrigation was higher thanB. ischaemumin 2001 (P< 0.05), andB. ischaemumandB. bladhiiin 2003. Maximum and minimum WUE of all treatment combinations and years were 24 and 6 kg DM ha−1mm−1inB. caucasicawith low irrigation andB. bladhiiunder dryland, respectively. Results showed that differences exist in WUE among species ofBothriochloaunder irrigation. On the basis of WUE and potential DM yield,B. caucasicamay be better suited for forage production in the Texas High Plains than eitherB. bladhiiorB. ischaemum.
Pollen‐Mediated Gene Flow in Wheat at the Commercial Scale
Authors: Matus‐Cádiz M.A. , Hucl P. , Dupuis B. 
Published: July 2010

ABSTRACTCurrently, information is lacking on gene flow in common wheat (Triticum aestivum L.) at distances greater than 300 m based on commercial‐scale fields. The objective of this research was to measure pollen‐mediated gene flow rates from a blue‐aleuroned pollinator (T. aestivum cv. ‘Purendo‐38’) to neighboring commercial fields of common wheat grown within a 10‐km radius of a central pollinator field. In the 2‐yr study, 33‐ha (2002) and 20‐ha (2003) fields of Purendo‐38 were sown 200 km east‐northeast of Saskatoon, Saskatchewan. Sixty‐nine fields in 2002 and 76 fields in 2003 were identified as having overlapping flowering relative to Purendo‐38. At maturity, up to 2 m2 samples were harvested from each corner of each recipient field. Gene flow was identified by the expression of a light‐blue pigment in the aleurone layer of F1 hybrid seed. In 2002 one case of gene flow was confirmed at 190 m northeast of the pollinator at a rate of 0.01%. In 2003 nine putative hybrid seeds were confirmed to be the result of gene flow between Purendo‐38 and the recipient field using gliadin fingerprinting. Consequently, gene flow was confirmed at 0.01% at 500 m northeast, 630 m southeast, and 2.75 km northwest from the pollinator. In commercial production, gene flow in wheat occurs at trace levels (≤ 0.01%) at distances up to 2.75 km.
Male Sterility and Partial Male Sterility in Sunflowers1
Authors: Putt Eric D. , Heiser Charles B. 
Published: July 2010

Two types of genetic male sterility in sunflowers are described. The first, discovered at Bloomington, Indiana, produces no pollen or pollen grains of uneven size which are clumped and do not stain with aceto‐carmine. The second, found at Morden, Manitoba, always produces pollen. The grains are smaller than normal, nonstaining and not clumped. Three crosses of the Bloomington stock indicated the character is controlled by a single recessive gene and two others indicated duplicate genes. More consistent results with the Morden stock showed a single recessive gene governs the male sterility in it, and that this gene is not linked to a recessive gene for branching or to another for dwarf plant. The F1 of reciprocal intercrosses of the two stocks was normal indicating that genetic control of the male sterility in them differs.Partial male sterility, characterized by varying proportions of normal pollen, occurred in breeding material of two lines. It appears possible to select lines with only 10 to 20% normal pollen and that such lines can be maintained easily. These lines cross well when naturally pollinated and it is concluded that they offer a better prospect for producing commercial hybrid seed of sunflowers than the genetic male sterility.
Nitrate Reductase Activity of Maize Hybrids and Their Parental Inbred1
Authors: Schrader L. E. , Peterson D. M. , Leng E. R. , Hageman R. H. 
Published: July 2010

Field experiments were conducted over a 4‐year period to compare the level of nitrate reductase (NR) activity of corn hybrids with their respective inbred parents. From previous experiments, two groups of inbreds, ranked “high” and “low” with respect to seasonal mean NR activity were selected and used to obtain FI hybrids representing the following categories: “high ✕ high”, “high ✕ low”, and “low ✕ low”.The level of NR activity in the lq hybrid appeared to differ from category to category. In the “high ✕ high” category, the level of NR activity of the hybrids of all three sets of material was lower than the mean of the respective parental inbreds. In the “high ✕ low” category, the hybrids were essentially intermediate in NR activity with respect to their parental inbreds and lower, in all cases, than the higher inbred parent. Two hybrids of the “low ✕ low” category exhibited heterosis for this character. That is, the level of NR activity of the hybrids was significantly higher than the level of the higher inbred parent. Other hybrids of this category were not significantly different in NR activity than the mean of their respective inbred parents or the higher inbred.Since it is accepted that the mechanism of gene action is at the biochemical level through the control of protein synthesis, this work provides some insight into the mode of gene action and outlines an approach to the knowledgeable synthesis of hybrids with specified metabolic characteristics.
Foam Formation from Extracts of 27 Legume Species in Vitro1
Authors: Cooper Clee S. , Eslick Robert F. , McDonald Paul W. 
Published: July 2010

Twenty‐seven legume species were evaluated for bloat potential by determining foam formation from legume extracts. A good relationship was found between foam formation and known bloat potential. Extracts from legumes such as birdsfoot trefoil and sainfoin formed negligible amounts of foam whereas extracts of legumes known to cause bloat formed relatively large amounts of foam.Foam formation from extracts of mixtures of a lowfoaming legume, sainfoin, and a high‐foaming legume, alfalfa was measured. The amount of foam formed from extracts from a mixture containing one part sainfoin and three parts of alfalfa was far in excess of that predicted. Mixtures containing a larger proportion of sainfoin formed amounts of foam below that expected at one sampling date but slightly above at another sampling date.
Scissor‐Emasculation of Bromus inermis Leyss1
Authors: Wright J. A. , Dunn G. M. 
Published: July 2010

Bromus inermis was emasculated by clipping the florets with scissors, including about 25% of the anthers, a few days before anthesis. The objectives were: (a) determine the effectiveness of scissor‐emasculation for bromegrass; (b) to determine when scissor‐emasculation should be done in relation to anthesis; and (c) to compare seed set following scissor‐emasculation, manual removal of anthers, and open pollination.Scissor‐emasculation was quite effective in the greenhouse but less effective in the field. Emasculation 4 days before anthesis produced maximum seed set in the field. This treatment produced higher seed set than did manual removal of anthers and only slightly less than the controls. Scissor‐emasculation appears more satisfactory than methods previously used if only limited seed is required.
Inheritance of Resistance to Diplodia Stalk‐Rot in Corn1
Authors: Kappelman A. J. , Thompson D. L. 
Published: July 2010

Inheritance of resistance to Diplodia zeae in eight populations of corn was studied. Generation mean analyses were used to detect the types of gene action important in host resistance to stalk‐rot of corn caused by D. zeae. Six of 8 populations studied consisted of P1, P2, F1, F2 B1, and B2 generations. Two populations had an additional generation, a composite F3. All plants were artificially inoculated and subsequently rated for stalk‐rot development on a scale from 0 to 6.Additive gene effects were significant for all 8 populations, dominance effects were significant for 6 populations and deviations were significant for 3 populations. It was concluded that selection among inbreds for stalk‐rot resistance should be effective, but that it would probably be necessary to invoke additional breeding techniques to obtain maximum resistance in hybrid combination.
Proline Accumulation in Wilted Ladino Clover Leaves1
Authors: Routley D. G. 
Published: July 2010

Ladino clover plants were allowed to wilt in the field and in the greenhouse to determine the effects of wilting on soluble nitrogen compounds. Wilting caused a slight decrease in total nitrogen but little change in amount of soluble nitrogen. A large increase in free proline occurred in all wilted leaves. Free asparagine was abundant in unwilted leaves but varied considerably during wilting. Other free amino acids occurred in small amounts. Only traces of glutamine were found.Two light intensities were used in the greenhouse experiment. During severe wilting, the higher intensity stimulated proline synthesis. The results suggest that proline accumulation during wilting is influenced by available carbohydrate.The results of these experiments show that marked changes in free nitrogen compounds occur during wilting. These changes may aid in conserving nitrogen and carbon during moisture stress.
Seed Set in Alfalfa as Related to Pollen Tube Growth, Fertilization Frequency, and Post‐fertilization Ovule Abortion1
Authors: Sayers E. R. , Murphy R. P. 
Published: July 2010

A technique employing the fluorescent properties of pollen tubes stained with aniline blue dye was utilized to determine the extent to which pollen tube growth, frequency of fertilization, and post‐fertilization ovule abortion influenced self‐ and cross‐fertility in alfalfa.It was found that the frequency with which fertilization occurred and the incidence of ovule abortion were the two main factors controlling the differential self‐ and cross‐fertility observed among clones. Selling generally led to a lower frequency of fertilization and a higher incidence of ovule abortion than did crossing. The frequency with which fertilization occurred after both selling and crossing appeared to be controlled by the number of pollen tubes gaining entry into ovaries, by the depth of pollen tube penetration in ovaries, and by the frequency with which pollen tubes entered ovules. The number of pollen tubes entering an ovary was controlled in turn by the receptivity of the stigma to penetration by pollen tubes. None of these factors associated with seed set varied significantly when different pollen parents were used in pollinating a commonfe male.
Development of Photosynthesis in Cotton Seedlings, Gossypium hirsutum L.1
Authors: Richardson G. L. 
Published: July 2010

An infrared gas analyzer was used to follow CO2 exchange (dark respiration and net photosynthesis) through the first 248 hr of germination of cotton seeds. The following events were noted: (a) dark respiration was first detectable 6 hr after placing the dry seed in water (planting); (b) the photosynthetic cempensation point was reached 86 hr after planting and 24 hr after emergence and occurred during the unfolding of the cotyledonary leaves; (c) maximum rates of net photosynthesis (33 mg CO2/dm2/hr at 64.8 kilolux with 500 ppm CO2) were attained by 200 hr after planting and remained at this level during the remainder of the test period (48 hr); and (d) photosynthetic rates increased as light and CO2 concentrations were increased. The fully expanded cotyledonary leaf stage (200 to 248 hr after planting) of the cotton seedling is suitable for photosynthetic studies cause of the stability and uniformity of the photosynthetic rate.General Electric Cool Beam lamps were found to be equally as effective as sunlight in providing energy for fixation of CO2.Dark respiration rates, determined throughout the experiment, increased from 0 to a maximum by 120 to 130 hr after planting and remained constant for the next 24 hr.
Relationships Between Leaf Area Index and Apparent Photosynthesis in Alfalfa (Medicago sativa L.) and Ladino Clover (Trifolium repens L.)1
Authors: Wilfong R. T. , Brown R. H. , Blaser R. E. 
Published: July 2010

Experiments were conducted to study the relationship between LAI, light penetration, and apparent photosynthesis in alfalfa and ladino clover stands intercepting between 80 and 100% of the incident sunlight. LAI‐light interception patterns for ladino clover and first growth alfalfa differed from those of second and third growths of alfalfa.NAR decreased as LAI increased; the relation appeared to be curvilinear. This indicated that optimum LAI occurred over a broad rather than a narrow range. LAI‐apparent photosynthesis curves for alfalfa remained constant above the initial optimum LAI, although the curve for clover appeared to decline slightly beyond this point.Initial optimiuni LAI coincided with the LAI's that intercepted approximately 95% of the incident light, indicating that Pa was near maximum at this point. LAI higher than required to intercept 95% of the light showed little effect on photosynthesis in the LAI range of 2 to 6. Dark respiration rates per unit of leaf area decreased as LAI increased. This may partially explain the leveling off of the LAI‐apparent photosynthesis curves at high LAI values.
Changes in Reduction and Assimilation of Nitrogen During the Growth Cycle of Winter Wheat1
Authors: Harper James E. , Paulsen Gary M. 
Published: July 2010

Changes in nitrate reductase activity and nitrate and water‐soluble protein contents of field‐grown ‘Pawnee’ wheat were studied throughout the growth cycle.Crown tissue was analyzed during cold hardening and dehardening periods. Nitrate reductase activity was initially low, increased slightly during maximum hardening, and increased rapidly with dehardening. Water‐soluble protein and nitrate contents decreased with hardening and increased with dehardening.During spring, aerial plant parts were analyzed separately. Nitrate reductase activity and water‐soluble protein contents were highest in the blades, with decreasing levels in sheaths, heads, and culms, respectively. Nitrate concentrations were highest in the culms, with less in sheaths, blades, and heads, respectively. Upper blades and sheaths contained greater nitrate reductase activity and water‐soluble protein, while nitrate concentrations were highest in lower blades and sheaths. All components measured decreased with maturity in all plant parts. Significant positive correlations were found between nitrate reductase activity and water‐soluble protein and between nitrate reductase activity and nitrate in crown, blade, and sheath tissues when these factors were compared within plant parts over sampling dates.
Estimates of General and Specific Combining Ability in F1 Hybrids for Grain Yield and Its Components in Grain Sorghum, Sorghum vulgare Pers.1
Authors: Beil G. M. , Atkins R. E. 
Published: July 2010

The performance of 40 F1 hybrid populations of grain sorghum, obtained by crossing each of 5 male‐sterile lines to 8 pollen‐fertility restoring lines, was evaluated from tests conducted at 3 locations over a 2‐year period. Measurements for grain yield, number of heads per plant, weight of 100 seeds, and number of seeds per head were analyzed to obtain estimates of the relative magnitude of general and specific combining effects. Significant differences among general combining ability effects of the lines were obtained for all characters, while significant differences among specific combining ability effects were expressed only for 100‐seed weight. An evaluation of variance components revealed that the variances for general combining ability for grain yield were three times larger than the component for specific effects. A similar ratio for the two effects was obtained for both number of heads per plant and weight of 100 seeds. For number of seeds per head, the ratio of general to specific effects was markedly larger than the ratio observed for the other characters. Specific combining ability effects were usually more stable than general effects over the environments of this experiment, particularly for grain yield and seeds per head.Correlations for the association of grain yield with its components disclosed that number of seeds per head was the component most highly related to yield, and that the expressions for yield were not affected appreciably by 100‐seed weight. While the ranges observed for number of heads per plant were relatively small in this experiment, significant negative associations for this trait with grain yield were observed for both the hybrids and parental lines.
Germination of Immature Kernels of Winter Wheat1
Authors: Robertson Larry D. , Curtis Byrd C. 
Published: July 2010

Immature kernels of five winter wheat varieties were germinate as fresh and as air‐dried kernels at 7 C and 15 C in blotters and in soil. The kernels were collected at 3‐day intervals from 15 days after anthesis until the kernels were ripe, about 39 days after anthesis.Air‐dried kernels (dried 3 days) germinate better than fresh kernels in the more immature stages. The 7 C temperature gave much higher germination than the 15 C temperature, particularly for air‐dried kernels.
Assimilation and Movement of Radioactive Carbon in Alfalfa and Reed Canarygrass1
Authors: Wolf D. D. 
Published: July 2010

Alfalfa (Medicago sativa L.) and reed canarygrass (Phalaris arundinacea L.) were exposed in the field to radioactive carbon dioxide. Plants were treated at several maturity stages and C14 was measured in various plant parts at several dates following exposure. Carbon‐14 moved to the tap root during the 15‐min exposure time and accumulated with time in the tap root to a greater extent when exposed in the more mature stage (bud stage of alfalfa and early head stage of reed canarygrass) than when exposed in the vegetative stage.Relative CO2 assimilation as influenced by several light intensities was measured by C14 in leaves after exposing plants to labeled carbon dioxide. Each reduction of light intensity resulted in reduced C14 in leaves. Light saturation (maximum C14O2 uptake) throughout the profile did not occur with 50% of full sun intensity. Measurable uptake of C14 occurred with 0.1% of full sun but may have been due in part to dark fixation.Labeled carbon fed into one tiller of a plant as fructose and glucose was translocated throughout the underground rhizome system of a reed canarygrass clone and throughout all parts of an alfalfa plant. Carbon‐14 from fructose, the predominant building block of nonstructural carbohydrates in reed canarygrass, moved to a lesser degree than C14 from glucose. Carbon‐14 from glucose, the predominant building block of nonstructural carbohydrates in alfalfa, moved to a lesser degree than C14 from fructose.
Natural Outcrossing in Dwarf‐Internode Castor, Ricinus communis L.1
Authors: Brigham Raymond D. 
Published: July 2010

Four groups of spineless (ss) dwarf‐internode castor plants derived from the variety ‘Baker 296’ were grown adjacent to or surrounded by normally spined (SS) plants, to determine frequency of natural outcrossing for the High Plains area of Texas. Wind velocity in this region ranges from 8 to 48 km (5 to 30 miles) per hour during the pollinating season. Progenies were classified as sparsely spined (Ss) as follows: ExperimenIt — single row of 20 ss plants, 42.2%; Experiment II — three adjacent rows of 20 ss plants at two locations, 46.3%; ExperimentIII — single ss plants interplanted with SS plants of various lines, 70.5%; and Experiment IV — single ss plants found in experimental plantings and commercial fields, 76.2%Three of nine progenies in Experiment IV produced over 90% outcrossing, ranging from 54.1 to 100%. This group probably gave the best estimate of percentage outcrossing, as the ss plants were similar in flowering date, size, and genotype to the surrounding SS plants. Natural outcrossing of dwarf‐internode castor can well be in the range of 70–90% for the Texas High Plains.