bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the Growth Responses of Spring and Summer Plants of Alfalfa Red Clover, and Birdsfoot Trefoil1
Authors: Smith Dale , Soberalske R. M. 
Published: July 2010

Alfalfa (Medicago satlva L.), medium red clover (TriFolium prateuse L.), and birdsfoot trefoil (Lotus corniculatus L.) are important forage legumes in the northern United States. The current study was conducted to directly compare the growth of summer (second‐crop) plants with that of spring (first‐crop) plants. Soil cores spring plants were removed from the field before growth started and were stored at —2 C. When plants were at full bloom in the field, soil cores of plants again were removed and shoots were cut to leave 5‐cm (short) and 12‐cm (tall) stubbles. Spring and summer plants then were grown together under identical conditions. Spring and summer alfalfa plants produced essentially the same yields of herbage. In contrast, spring plants of trefoil and red clover produced significantly more herbage than summer plants. However, summer red clover plants yielded similarly at both stubble heights, while summer trefoil herbage yields were significantly higher with a tall than with a short stubble.We conclude that the differential yield between spring and summer plants of trefoil was due to differences in carbohydrate reserves, while differential yield between spring and summer plants of red clover was due to differences in shoot initiation. The results explain in part why alfalfa is normally a higher yielding species than red clover or birdsfoot trefoil. They also reconfirm that a tall stubble is needed for trefoil to produce a satisfactory regrowth after cutting.
Effects of Male Cytoplasm on Inheritance in Hybrid Maize1
Authors: Fleming A. A. 
Published: July 2010

It is generally thought the female and not the male gamete contributes the cytoplasm to the offspring. Suppose it is possible for the male parent to contribute some cytoplasm to the progeny. It would be advantageous to know if there is any measurable effect of the male cytoplasm on the progeny of a hybrid resulting from the union of female and male gametes in fertilization.Seed of a double‐cross maize hybrid (Zea mays L.) was prepared to obtain all possible combinations of the male and female cytoplasms. The eight entries were tested in randomized, complete block field experiments in paired plots 2 years with 10 replications/year. All four inbreds in the double‐cross were uniform long‐time inbreds. Data were obtained on 11 and 13 agronomic characters in the two experiments.This investigation indicates that the male cytoplasm can influence the hereditary expression of characters in the progeny. But, the expression of the male cytoplasm may be influenced by the female cytoplasm. One of the problems in the evaluation of cytoplasmic effects in breeding programs may be a cytoplasmic‐environmental interaction from year to year.
Variation in Chlorophyll Content of Maize Lines and Hybrids1
Authors: Fleming A. A. , Palmer J. H. 
Published: July 2010

Quantitative differences in chlorophyll, genetic implications, and the relationship of total chlorophyll to various agronomic characters were studied in 17 inbred lines and 24 single‐cross hybrids of maize (Zea mays L.). Differences occurred for total chlorophyll/g in fresh weight of leaf tissue, chlorophyll a;, chlorophyll b, visual chlorophyll ratings, Ca:Cb ratios, and yield/plant, both among inbreds and hybrids.Relationships were found in both inbreds and hybrids,respectively, for total chlorophyll to visual rating (∗0.76* and ∗0.69*, *significant at P −0.01) and for total chlorophyll to Ca:Cb ratio (∗0.91* and ∗0.84*). No relationships were detected between total chlorophyll and yield in grams of ear corn/plant. Thus, chlorophyll levels in these experiments were not a limiting factor for yield.Chlorophyll content of the hybrid was characteristically greater in all instances than the mean of the inbred parents. Results indicate that there can be heterosis for chlorophyll content and that the simplest explanation is the presence of more loci having a dominant or partially dominant gene in the hybrid than in either parent. There was a positive relationship between hybrids with high amounts of heterosis for yield and those with high amounts of heterosis for chlorophyll (r = 0.93*).Significant reciprocal effects for total chlorophyll and yield were obtained in two pairs of single‐cross hybrids.
Quantitative Gene Action for Protein Content in Oats1
Authors: Sraon H. S. , Reeves D. L. , Rumbaugh M. D. 
Published: July 2010

The objectives of this study were to determine gene action, heritability, and number of effective factors controlling protein content in oats (Avena spp.). One Avena sterilis L. and three A. sativa L. cultivars were crossed in a diallel, including reciprocals, with protein of 16.1 to 24.4%. The data showed additive gene action for groat protein percentage. Partial dominance for low protein percentage was observed. Narrow sense heritability was 41%. Protein percentage was inversely related to grain yield. The Avena sterilis L. parent exhibited recessiveness for high protein content.Estimation of the number of effective factors controlling protein content varied from 1 to 25 depending upon the genetic diversity of the parents and direction of the cross.
Heterosis, Inbreeding Depression, and Reciprocal Effects for Yield and Some Yield Components in a Cowpea Cross1
Authors: Kheradnam M. , Bassiri A. , Niknejad M. 
Published: July 2010

Two pureline cowpea (Vigna sinensis L.) cultivars, differing in many agronomic characters, were crossed and carried to the F2 generation. The parental cultivars and F1 and F2 generations were grown in the field in a randomized block design, and notes were taken on individual plants for number of branches, clusters, seeds/ pod, pods and 100‐seed weight and yield. Analyses of variance were performed and heterosis, inbreeding depression and reciprocal effects were calculated, each by two different methods, and tested for significance.The greatest heterosis with respect to the midparent was observed for seed yield and the lowest for number of branches. The mean values of F1 for number of clusters and pods and seed yield exceeded even the mean of the higher parent. For most characters studied, the mean values of F2 approached the values of the midparent, thus exhibiting inbreeding depression as a result of one generation of natural selfing. However, in general, the values obtained for heterosis were greater than those for inbreeding depression.Both methods used for calculation and testing of each criterion yielded similar results. Significant heterosis and inbreeding depression were found for all characters except the number of branches. No reciprocal effects were present for any of the characters studied. It was concluded that the production of hybrid seed for cowpeas could be commercially advantageous, if large‐scale methods of emasculation and crossing were developed for this species.
Distribution of Specific Alkaloids in Reed Canarygrass Cultivars1
Authors: Hovin A. W. , Marten G. C. 
Published: July 2010

Alkaloids in reed canarygrass (Phalaris arundinacea L.) are negatively associated with palatability and sometimes have undersirable effects on ruminant animals. Our objectives were to characterize several reed canarygrass cultivars with respect to alkaloid concentration and distribution patterns of specific alkaloids. Because current cultivars are difficult to describe morphologically, chemical characterization may aid in identifying or describing them.We determined frequency distribution of three primary indole alkaloids: 3‐dimethylaminomethylindole (gramine); N,N‐dimethyltryptamine (DMT); and 5‐methoxy‐N,N‐dimethyltryptamine (5‐MeO‐DMT), among spaced plants of selected reed canarygrass cultivars and experimental strains grown in the field in 1973. Alkaloid composition and concentration were also determined from solid‐stand plots in 1973 and 1974.‘Vantage’ was the only cultivar containing exclusively gramine. The presence of gramine was verified using forage from the six parent clones, plants from syn 1 generation and syn 2 generation seed, and from first growth and regrowth of solid‐stand plots. ‘Frontier,’ ‘Grove,’ ‘Rise,’ and three experimental strains contained both gramine and tryptamines. The experimental strain MN‐72 was differentiated from Grove, Rise, and two experimental strains by frequency distribution of gramine, DMT, and 5‐MeO‐DMT.The 47 to 49 plants used for alkaloid typing of each entry were possibly too few to characterize other cultivars and strains. Grove, MN‐72, and Frontier had significantly lower total alkaloid concentration (% dry wt) than did RC‐2, Vantage, and Rise when determined on 4‐week‐old second regrowth in 1973 but not on 4‐week‐old first or second regrowth in 1974. Differences among entries were also smaller and seldom significant when based on 6‐week‐old first regrowth in 1973. The 2‐year mean alkaloid values over all sampling dates were significantly lower for Grove and MN‐72 compared to Vantage, Rise, and RC‐2. Concentration of total indole alkaloids appears to distinguish some reed canarygrass cultivars, but only at specific conditions of growth.
Growth of Cotton Plants on Nitrate and Ammonium Nitrogen1
Authors: Radin J. W. , Sell C. R. 
Published: July 2010

Vegetative and reproductive growth of cotton (Gossypium hirsutum L.) were evaluated in the greenhouse on media containing nitrate or ammonium or both, to test for interactions between the two N sources on growth and yield. An inhibitor of nitrification was included in all treatments. Both N sources supported vegetative growth, although there was little response to increments of nitrate above meq/liter under the conditions of the test. Combinations of the two N sources did not support better growth than either one alone, except at low total N levels, perhaps because ammonium at ≥ 2 meq/liter inhibited in vivo nitrate reductase activity.Reproductive growth of the plants was enhanced by N; however, 9 meq/liter nitrate was less effective than lower concentrations of either source, or their combination, in promoting fruitfulness and N accumulation relative to the vegetative parts. The failure to find a synergistic interaction in response to the two sources suggests that cotton responds to N source differently from some other crop species.
Straw‐protein Percentages in Avena sterilis L.1
Authors: Frey K. J. , McCarty T. , Rosielle A. 
Published: July 2010

A group of 334 Avena sterilis L. strains was grown at Ames, Iowa, and measured for groat and straw‐protein percentages and heading date. F3 segregates from five crosses between A. sativa ✕ A. sterilis lines were measured for the same traits.Straw protein for the A. sterilis strains ranged from 5.5 to 14.6%. Three A. sativa lines used as checks had mean percentages from 5.6 to 6.7. Collections from Libya generally had higher levels of straw and groat protein than those from other countries, even though the strain with the highest straw protein, PI 324721, was from Greece.There was a positive correlation between heading date and straw‐protein percentage, but one A. sterilis strain, PI 324774, was early and had 12.1% straw protein. Groat protein and straw protein were uncorrelated for the A. sterilis strains.The inheritance of straw‐protein content probably was due to a small number of segregating effective factor pairs.
Genetic Variation in Enzyme Activity of Tall Fescue Leaf Blades1
Authors: Nelson C. J. , Treharne K. J. , Lloyd E. J. 
Published: July 2010

Plants show genetic variation in several physiological responses that involve enzymes. Our objective was to determine if genetic variation existed in some representative metabolic enzymes of tall fescue (Festuca arundinacea Schreb.). Fully developed leaves from 12 genotypes selected from six diverse populations growing in the field were sampled for activity of eight enzymes. Genetic differences were found for activities of all enzymes studied and often between genotypes from the same population. Expressing enzyme activity on a fresh weight, dry weight, or leaf area basis gave better discrimination between genotypes than expressing on a Lowry protein basis.Activities of ribulose 1, 5‐diphosphate carboxylase (RuDPc), phosphoenolpyruvate carboxylase (PEPc), and alanine aminotransferase (GPT) were positively correlated among genotypes. Phosphoglyceryl kinase (PGK) activity was correlated with RuDPc, GPT, and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH). Also, activities of malate dehydrogenase (MDH) and GAPDH were positively correlated with those of RuDPc and PEPc. Isocitrate dehydrogenase had a lower relative activity, but was positively correlated with MDH and GAPDH, two other respiratory enzymes. Activity of glucose 6‐phosphate dehydrogenase, an enzyme of the oxidative pentosephosphate pathway, was not correlated with that of any other enzyme studied. It is apparent that genetic variation exists, and that genetic studies of enzyme activity will become increasingly more important as rate‐limiting steps in growth and metabolism of crop plants become clarified.
A Design III Study of Linkage Disequilibrium for Percent Oil in Maize1
Authors: Moreno‐Gonzalez J. , Dudley J. W. , Lambert R. J. 
Published: July 2010

The objectives of this study were 1) to estimate additive and dominance genetic variance and the average degree of dominance for percent oil in the F2 and F8 randommated generations of a cross between Illinois High Oil (IHO) and Illinois Low Oil (ILO) maize (Zea mays L.) strains using Design III and 2) to measure the effect of linkage bias on such estimates.The following results were obtained: 1) The estimate of additive genetic variance was about eight ✕ larger than that of dominance genetic variance in the F2 and about four ✕ larger in the F6; 2) The estimate of additive variance in the F8 was half that in the F2 suggesting that many loci controlling percent oil were linked in the coupling phase in the parents; 3) The estimate of dominance variance in the F6 did not differ from the F2 indicating a lack of effect of linkage on dominance variance which could be interpreted as indicating that genes with dominant action are distributed throughout the genome with map distances approximating independent inheritance or that some genes are dominant for low oil while others are dominant for high oil; 4) Estimates of the average degree of dominance were 0.508 for the F2 generation and 0.681 for the F8. Both estimates are significantly different from zero and from one, but not from each other.
Modification of a Self‐Propelled Plot Combine for Harvesting Hill Plots of Soybeans1
Authors: Carlson B. E. , Bandstra T. J. , Fehr W. R. , Clark R. C. 
Published: July 2010

A self‐propelled plot combine was modified to facilitate the harvest of hill plots of soybeans (Glycine max (L.) Merr.). The modified combine reduces the amount of labor required by about 50% when compared with a stationary plot thresher.A conveyor was mounted on the side of the combine to transport the identification tag for each hill from the header to the person bagging the seed. The person bagging sits on a carnage mounted near the seed delivery spout. The seed bag and identification tag are tied together by an air‐powered tying machine. A hydrostatic transmission provides the combine with a variable‐speed cylinder.
Genetic Changes in Oat Bulk Populations under Winter Survival Stress1
Authors: Marshall H. G. 
Published: July 2010

Convergent crossing was used to produce 58 different winter oat (Avena by zantina K. Koch and A. sativa L.) bulk populations, and these populations were subjected to 4 years of winter survival stress in Pennsylvania. Two types of observations were subsequently made to determine the effect of natural selection on these populations. First, all populations were compared in the F8 and F7 generations to determine performance for juvenile growth habit, freezing resistance in a laboratory test, and winter survival in the field. Second, F8 and F7 individual plants were isolated from 12 populations and classified for juvenile growth habit, maturity, and plant height. Derived F1 and F8 lines from six of these populations were compared for freezing resistance.Thirty‐four of the 58 populations increased significantly in freezing resistance and changed similarly for winter survival in the field. The majority of the populations that changed greatly for these chadracteristics were low performers in the F3. Initially elite populations made small, nonsignificant changes under natural selection. Nonresponsiveness to natural selection in the latter populations did not reflect low genetic variability, since a wide range in freezing resistance was observed among derived lines, regardless of generation or population.In every population, the F3 growth habit ranged from intermediate to very erect. By the F7 generation, 28 populations were significantly more decumbent in juvenile growth habit. Plants from 10 out of 12 populations were significantly more decumbent by the F7 generation; and all populations were later in maturity. Plants with decumbent juvenile growth were latest in maturity, and these two characteristics were correlated within each generation of all populations. Five of 12 populations were taller by the F7 generation, and the others did not change in average plant height under natural selection. Changes in maturity and plant height were independent of natural selection on winterhardiness.If the bulk population approach is to be used for natural selection for winterhardiness, controlled selection pressure during one or more early generations may have to be applied so that the tendency to increase gone frequencies for lateness and tallness can be offset.
Altered Development of Ribonuclease Activity and Formation of Polyribosomes in Chilled Cotton Cotyledons1
Authors: Leffler H. R. 
Published: July 2010

Sensitivity of cotton (Gossypium hirsutum L.) seedlings to 6 C chilling was measured by following the development of ribonuclease (RNase) activity in cotyledons during the first week of germination. Increases in RNase activity observed in control tissues were delayed during chilling. Development of RNase activity was most sensitive to chilling during the second day of germination.Both total and specific activities of RNase preparations were similarly affected by chilling. Alterations of protein synthesis were suggested by comparisons of free polyribosome profiles from control and chilled tissues.Chilled seedlings partially recovered RNase activity following return to warm temperature. Recovery was slowest in seedlings that were chilled during both the second and third days of germination.
Growth of Kentucky Bluegrass Leaves and Tillers With and Without Defoliation1
Authors: Youngner V. B. , Nudge F. , Ackerson R 
Published: July 2010

Tillering rates, leaf emergence rates, and responses to defoliation are important to productivity, density, and ersistence of grasses. Breeding programs might benefit a more precise understanding of these responses. Studies were conducted in the greenhouse on individual plants of Kentucky bluegrass (Poa pratensis L.) ‘Merion’, ‘Newport,’ and ‘Windsor’ to precisely describe leaf and tiller growth and the effects of defoliation on growth of these structures.In the first of three studies, six plants of each cultivar, grown under uniform controlled conditions, were examined daily and leaf, tiller, and rhizome emergence recorded for 60 days. The second study differed from the first in that five plants of each cultivar were defoliated and five plants left intact. To provide uniform defoliation for all cultivars, entire leaf blades were removed at the time they reached full expansion. In the third study CO2 exchange as a measure of net photosynthesis was determined for all leaf surfaces and for leaf blade surfaces only by coating leaf sheaths with grease.Under these fairly constant conditions, leaf and tiller emergence on the main shoot proceeded at constant rates characteristic for each cultivar. On all cultivars the first leaf of the main shoot was dead before the sixth leaf had emerged. Thereafter leaf senescence and leaf emergence proceeded at the same rate so each shoot had a maximum of five functioning leaves. The same growth patterns were observed on primary and secondary tillers until affected by intertiller competition.Defoliation did not affect leaf emergence rates on any cultivar while reducing the rate of tiller emergence on Newport and Windsor but not on Merion.The cultivar Merion had a higher rate of net photosynthesis than Newport. Leaf blade photosynthesis rate did not differ significantly between the two cultivars. The higher rate for Merion was thus attributed to a higher rate for leaf sheaths. The greater tolerance to defoliation displayed by Merion could be due to the greater photosynthetic activity of its leaf sheaths.These results show that it may be possible to develop Kentucky bluegrass cultivars with higher rates of leaf and tiller emergence and greater tolerance to mowing. The potential for breeding strains more tolerant of mowing by selection of genotypes with higher leaf sheath photosynthesis should be explored.
Action of Temperature and Light on the Control of Seed Germination in Alta Tall Fescue (Festuca arundinacea Schreb.)1
Authors: Danielson H. Rodger , Toole Vivian K. 
Published: July 2010

Temperature, light, and their interactions were studied for their effects of germination of ‘Alta’ tall fescue (Festuca arundinaeea Schreb.) seeds. A thermogradient plate was used to study effects of 30 constant temperatures on germination in darkness. Germination was maximum at 12 through 18 C, although seeds germinated in varying number from 8 to 31 C during the 9‐day test period. Rates of germination increased with temperature and were highest between 16 and 19 C. Seeds exhibited a high temperature sensitivity and became more dormant with increased temperature above 18 C and with increased periods at high temperatures. Studies of alternating temperature cycles revealed that germination was significantly reduced when seeds were held longer than 16 hours at 25, 8 hours at 30, and 4 hours at 35 C in daily cycles with 15 C.The lowered germination at temperatures above 18 C was probably due to Pfr reversion and decay of total phytochrome (P). Seeds were more dormant at 30 than at 25 C. At 25 and 30 C a single saturating red light (R) treatment caused a germination increase of 25% above the dark controls. Repeated R irradiances caused significantly higher germination than one brief exposure at 25, but not at 30 C. However at 30 C, where reversion and decay of P would be greater, continuous R caused a significant increase in germination.Seeds held for 7 days at 35 C and then germinated at 15 and 25 C showed the typical reversible P reaction. Single, brief R again increased germination about 25 to 30% above the dark controls. Recovery from the 35 C treatment was greater at 15 C than at 25 C as shown by germination in darkness of 63 and 3%, respectively. Apparent P synthesis, which is also temperature sensitive, probably occurs at 15 but not at 25 C.The period required for Pfr action was 20 to 24 hours at 15 C. Germination of seeds following P conversion and Pfr action depended on temperature and was lower at 30 than at 25 C. Thus high temperature imposes a block to germination processes beyond that of Pfr action.