bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stand Establishment of Wheat Lines under Different Levels of Water Potential1
Authors: Gul Azam , Allan R. E. 
Published: July 2010

Seedling emergence and the growth of seedlings of 93 wheat (Triticum aestivum L. em Thell.) lines, developed by recurrent selection for improved seedling vigor, and tour check cultivars were studied at four soilwater levels in laboratory tests and at different planting depths and locations in three field tests. Both studies revealed that the lines differed markedly in their emergence characteristics. Emergence rate index (ERI) was high for number of lines in all four soil water potentials (—2.2, —6.0, —10.2, —14.4 bars) and in field tests.The time required for emergence nearly doubled for each decrease of water potential of —4 bars within the range studied. Total stand, coleoptile length, seedling height, and root weight were similarly progressively reduced as water potential decreased.Total stand, coleoptile length, and seedling height were inconsistently related to ERI in laboratory tests, but were generally related in the field tests. Likewise, root weights of the nine promising lines were inconsistent with ERI at the three higher water potentials but were correlated (r = 0.93) at the lowest water potential the laboratory tests.
Crop Temperature Modification and Yield Potential in a Dwarf Spring Wheat1
Authors: Fischer R. A. , Maurer O. R. 
Published: July 2010

The influence of temperature on development, dry matter production, grain yield, and grain yield components of a high yielding dwarf spring wheat (Triticum aestivum L. em Thell ‘Yecora 70’) was studied at different stages of growth in the field. Crops were grown under conditions of high fertility and irrigation in northwest Mexico during 1972–73 and 1973–74. In each of four approximately 4‐week periods during the crop cycle, portions of the crop were enclosed in transparent chambers which were ventilated with cooled or heated air. Air temperatures inside the chambers averaged respectively, 1 to 2 C below or 2 to 7 C above air temperature outside.Development was retarded slightly by cooling and hastened considerably by heating. Total dry weight at maturity and grain yield were reduced by increased temperatures at any stage other than the first. The biggest effects were seen in the second and third periods (end of tillering to beginning of grain filling), where a 1 C rise in temperature was associated with a 4% reduction in grain yield. This was largely related to effects on grains/m2 via changes in spikes/m2 and grains/spikelet. Temperature increases during the fourth or grain‐filling period reduced kernel weight in some situations and had no effect in others. The relevance of these results to other temperature studies and to possible avenues for increasing grain yield in Yecora 70 is discussed.
Leaf Area and CO2‐exchange Rate as Determinants of the Rate of Vegetative Growth in Soybean Plants1
Authors: Kaplan Stuart L. , Koller H. R. 
Published: July 2010

The purpose of this experiment was to examine the interrelationships between CO2‐exchange rate (CER) and certain growth analysis variables in soybean [Glycine max (L.) Merr.] plants.Soybean plants representing 16 cultivars were grown in a controlled environment chamber. At 22 and 29 days after planting, leaf area and dry weights of the leaves, supporting tissue, and roots were measured for each plant. From these data, the rate of vegetative growth (GR) was determined for each cultivar as well as leaf area growth rate (LAGR), specific leaf weight (SLW), and other growth analysis variables.At 28 days after planting, the CER per unit leaf area of the terminal leaflet of the second trifoliolate leaf was measured. The resistance to CO2 diffusion was partitioned into boundary layer, stomatal, and mesophyll components. Gas exchange was measured independently for each leaf surface.Growth rate was negatively related to CER and SLW and positively related to LAGR. Furthermore, CER was positively and negatively related to SLW and LAGR, respectively. As the leaves increased in SLW and CER across the cultivars, their rate of area expansion decreased. Since GR was positively correlated with LAGR and negatively correlated with CER, it appears that increases in CER did not compensate for decreases in LAGR; consequently, differences in GR among the cultivars were detected.
Recurrent Mass Selection for Improved Seed Yields in Intermediate Wheatgrass1
Authors: Knowles R. P. 
Published: July 2010

The first cultivars of intermediate wheatgrass (Agropyron intermedium Host., Beauv.), released in North America had poor seed yields. At Saskatoon a breeding program of recurrent mass selection was carried out from 1955 to 1971 to develop more fertile strains. In each cycle of selection, 1,000 plants were evaluated visually for seed filling, and 50 of the most desirable plants were harvested. Seed of those with best seed yields and good seed quality was used to plant the nursery for the next cycle of selection. Open‐pollination (OP) seed was used for propagation in early cycles and controlled‐pollination (CP) seed was used in later cycles.The rate of seed yield improvement per cycle was 10.2% for OP propagation and 20.3 for the CP method. Slight concurrent improvements were made in forage yield, resistance to lodging, and seed quality. Herbage quality of selected lots was generally below that of the ‘Ree’ check cultivar but without a consistent trend.A single cycle of polycross breeding gave somewhat greater improvement than a single cycle of mass selection, but required more years to complete.Although selection was confined to a single station, the improvements obtained were noted regionally.
Influence of 2,4‐D, Pronamide, and Simazine on Dry Matter Production and Botanical Composition of an Alfalfa‐grass Sward1
Authors: Triplett G. B. , Keuren R. W. Van , Walker J. D. 
Published: July 2010

Pronamide [3,5‐dichloro (N‐l,l‐dimethyl‐2‐propynyl)‐benzamide], simazine [2‐chloro‐4,6‐bis(ethylamino)‐s‐triazine], and 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] were evaluated for management of species composition in established swards of alfalfa (Medicago sativa L.) which had become colonized by orchardgrass (Dactylis glomerata L.), Kentucky bluegrass (Poa pratensis L.), and dandelion (Taraxicum officinale Weber). Dormant application of 2,4‐D ester reduced seedling dandelions, but did not affect mature dandelions, alfalfa stands, or yields. Simazine did not affect total yield or botanical composition of forage in this study. Pronamide application reduced bluegrass and total forage yield in the first harvest. The alfalfa component of the forage and total yield of alfalfa increased with pronamide treatments. Total forage yield for the season was the same for all treatments.Counts of alfalfa plants per m2 were made for individual plots and multiple regression analysis was used to determine the association of percent alfalfa composition of the first harvest and plant density with alfalfa yield. In pronamide treated plots as few as 10 to 20 alfalfa plants per m2 utilized resources made available by reduction of other species and produced acceptable yields. These results contrast to the 50 to 60 plants per m2 commonly considered necessary for productive stands and suggest the possibility that herbicides may be used to extend the productive life of swards containing alfalfa.
Effects of Plant Water Status on Stomatal Activity, Photosynthesis, and Nitrate Reductase Activity of Field Grown Cotton1
Authors: Ackerson R. C. , Krieg D. R. , Haring C. L. , Chang N. 
Published: July 2010

The effects of varying degrees of water stress on stomatal activity, photosynthesis, and nitrate reductase activity were examined in field grown cotton (Gossyplum hirsutum L., cv ‘Dunn 56C’). A relationship between plant water status and activity of each measured physiological parameter was established.Slight increases in leaf diffusive resistance were observed as leaf water potentials decreased although complete stomatal closure due to water stress was not generally observed. In many cases, visibly wilted leaves with zero turgor potentials exhibited minimal diffusive resistances. Morning and afternoon values of leaf diffusive resistance were distinctly different even though no correlation between leaf water potential and diffusive resistance was evident.Water stress substantially reduced photosynthesis in both vegetative and reproductive leaves of cotton. Photosynthetic rates of each leaf type responded differently to declining leaf water potentials. The data suggest that the photosynthetic reduction could not be attributed to stomatal closure.The activity of nitrate reductase was adversely affected by declining leaf water potentials. The nocturnal activity of nitrate reductase (respiratory linked) was also reduced by severe water stress. However, the reduction from maximum daily activity to minimum night time activity was similar in both stressed and non‐stressed plants. These data suggest that inhibition of nitrate reductase activity could be due to long term water stress effects rather than temporal changes in plant water status.The data presented indicate that stomata of field grown cotton are relatively insensitive to water stress, at least within the range of leaf water potentials observed in this study. Measurement of stomatal activity may not be a good criterion for assessing plant water status of cotton. The measurement of one or more physiological processes may prove a better index of plant water status as well as providing sensitive selection criteria for breeding more drought tolerant varieties.
New Genes for Resistance to the Brown Planthopper in Rice1
Authors: Laksminarayana A. , Khush Gurdev S. 
Published: July 2010

The inheritance of resistance to brown planthoppers (Nilaparvata lugens Stal.) was studied in 28 rice (Oryzasaliva L.) cultivars in the greenhouse. Seven‐day‐old seedlings were infested with second and third‐instar nymphs of brown planthoppers and seedling injury was recorded at 7 to 8 days after infestation.Single dominant genes that are allelic to Bph 1 condition the resistance in ‘Balamawee’, ‘CO 10’, ‘Heenukkulama’, ‘MTU 9’, ‘Sinnakayam’, ‘SLO 12’, ‘Sudhubalawee’, ‘Sudurvi 305’, and ‘Tibiriwewa’. Single recessive genes that are allelic to bph 2 govern resistance in the cultivars ‘Anbaw C7’, ‘ASD 9’, ‘Dikwee 328’, ‘Hathiel’, ‘Kosatawee’, ‘Madayal’, ‘Mahadikwee’, ‘Malkora’, ‘M.I. 329’, ‘Murungakayan 302’, ‘Ovarkaruppan’, ‘Palasithari 601’, ‘PK‐1’, ‘Seruvellai’, ‘Sinna Karuppan’, and ‘Vellailangayan’. A single dominant gene also conveys resistance in ‘Rathu Heenati’, but it segregates independently of Bph 1 and is designated as Bph 3. Similarly, a single recessive gene conveys resistance in ‘Babawee’ but it segregates independently of bph 2 and is designated as bph 4. The resistance in ‘Ptb 21’ is controlled by one dominant and one recessive gene. The allelic relationships of these two genes to other genes are not known.
Genetic Analysis of Crosses among Corn Strains Divergently Selected for Percent Oil and Protein1
Authors: Dudley J. W. , Lambert R. J. , de la Roche I. A. 
Published: July 2010

All possible crosses, excluding reciprocals, among the nine strains [Illinois high oil (IHO), reverse high oil (RHO), switchback high oil (SHO), low oil (ILO), reverse low oil (RLO), high protein (IHP), reverse high protein (RHP), low protein (ILP), and reverse low protein (RLP)] in the Illinois long term selection experiment for percent oil and protein in corn (Zea mays L.) were grown to measure their performance and to study; 1) the effects of oil and protein percentage on grain yield and other agronomic traits, 2) the effects of selection for percent protein on components of percent protein, 3) the relationship of percent oil and protein to calorie production, and 4) the importance of genetic effects for several traits.Results obtained suggest that; 1) grain yield is negatively correlated with percent oil and percent protein, 2) percent protein in the kernel is primarily determined by percent protein in the endosperm, 3) calories per g dry matter are largely determined by percent oil while calories per kernel or ha are largely determined by kernel weight or grain yield, 4) the sum of squares (s.s.) due to heterosis accounted for only 5 and 7%, respectively, of the entry s.s. for percent oil and percent protein but over 50% of the entry s.s. for yield of grain and protein, and 5) evidence was obtained of dominance for both high and low percent oil.
Interspecific in Trifolium L. Sect. Trifolium Zoh. II. Fertile Ployploid Hybrids Between T. medium L. and T. sarosiense Hazsl1
Authors: Quesenberry K. H. , Taylor N. L. 
Published: July 2010

Interspecific hybrids of Trifolium medium L. ✕ T. sarosiense Hazsl. and reciprocal hybrids were produced by hand pollinations in a greenhouse. Hybrids of T. medium ✕ T. sarosiense were normal green and intermediate betweenthe two parents for morphological traits, but the reciprocal hybrids showed chlorophyll deficiencies including mottling and chimeras. Seed set from interspecific crosses was lower than from intraspecific crosses, but the small reduction in seed set represents only a minor isolation barrier between the species. All hybrids and both parents were self‐incompatible.Hybrids of T. medium 2n=72 ✕ T. sarosiense 2n=48 and the reciprocal hybrids had 2n=60 chromosomes except for two plants which had 2n=58 chromosomes. Meiotic analysis of chromosomes of T. medium and T. sarosiense revealed mean frequencies of 7.40 I, 32.30 II and 1.34 I, 23.33 lI respectively per PMC at metaphase I of meiosis. The hybrids (2n=60) of T. medium ✕ T. sarosiense and reciprocal exhibited mean frequencies ot 5.30 I, 27.29 II and 4.68 I, 27.66 II, respectively, per PMC at metaphase I. However, the two 2n=58 hybrids had a reduction in bivalents to 25.96 and 26.00, respectively. Mean pollen stainabillty of the two parents was greater than 95%, whereas mean stainability of all hybrids was 89%. Other lines of T. medium were later identified with 2n=64, 68, 70, 72, and 80 chromosomes. The 2n=64 and 80 lines showed mostly 32 II and 40 II, respectively, but cytotypes with 68, 70, and 72 chromosomes had 32 II and an increasing number of univalents. Although the complexity of ploidy level in the T. medium taxa complicates any conclusions concerning phylogenetic relationships, our results indicate strong evolutionary links between T. sarosiense and T. medium.
Grafting as a Tool in Soybean Breeding1
Authors: Kiihl R. A. S. , Hartwig E. E. , Kilen T. C. 
Published: July 2010

Grafting of soybean [Glycine Max (L.) Merr.] from different maturity groups was studied to determine its feasability for simplifying crossing. When grafted on early flowering genotypes, scions of later flowering genotypes flowered 21 to 50 days after grafts were made. About 95% of the grafts were successful.The grafting technique appears to be an excellent method of inducing earlier flowering on late genotypes to permit their use in a crossing program. It is also a means of producing seed on genotypes that otherwise flower too late for seed production in a particular geographical area.
Selection and Characterization of Amino Acid Analog Resistant Plant Cell Cultures1
Authors: Widholm Jack 
Published: July 2010

A method is outlined which may be useful for increasing the levels of specific free amino acids in plants.Carrot (Daucus carota L.) and tobacco (Nicotiana tabacum L.) cell culture lines have been selected which are resistant to growth inhibition caused by tryptophan, phenylalanine, lysine, methionine, and proline analogs. Most of these lines accumulate six to 30 times the normal levels of the corresponding natural free amino acid and these increases apparently cause the resistance to the analog, since exogenous amino acids will reverse the inhibition. At least in the case of lines resistant to 5.methyltryptophan and p‐fluorophenylalanine, the control enzymes in the tryptophan and phenylalanine biosynthetic pathways, respectively, have altered feedback control properties which apparently allow the oversynthesis of the endproduct amino acids. Studies of the enzymes in the lysine, methionine, and proline pathways have not been carried out.Increases in the free amino acid content can cause very marked increases in the total content of a particular amino acid. Regeneration of plants from such altered lines may give plants with increased levels of certain amino acids. With species where plant regeneration is not possible from established cultures, seedlings can also be screened by growing them in nutrient solution containing inhibitory amino acid analogs. Some evidence suggests that these approaches may be successful in increasing the levels of certain amino acids in plants, but only continued study can provide a definite conclusion.
Inheritance of Tolerance to Hoe 23408 in Corn1
Authors: Geadelmann J. L. , Andersen Robert N. 
Published: July 2010

We conducted experiments to determine the inheritance of tolerance in corn (Zea mays L.) to HOE 23408 (methyl‐2‐[4‐(2,4‐dichlorophenoxy) phenoxy]propanoate), an herbicide that has been effective in controlling volunteer corn in soybeans [Glycine max (L.) Merr.]. Three tolerant and three susceptible inbred lines, their 30 singlecross hybrids (Fl's) including reciprocals, and the sibbed Fl's (F2's) were grown in two adjacent experiments planted 4 weeks apart in 1975 near Rosemount, Minn. Each experiment contained three replications of pairedrow plots, and one row of each pair was sprayed over the top with 0.86 kg/ha of HOE 23408 when the corn had six to seven fully‐expanded leaves. Percent control was rated 3 weeks after spraying.Percent control did not differ significantly between experiments or among reciprocals. Genotype ✕ experiment interaction was significant but accounted for less than 5% of the variation among genotypes and experiments. Gene action for percent control was primarily additive, with 91% of the variation among F1 means accounted for by fitting only general combining ability effects. Analysis of F2 data also indicated a preponderance of additive gene action. Significant heterosis and nonadditive gene action were present, but they were not of major importance. Broad‐sense heritability values (individual F2‐plant basis) averaged 95.3%, and relative frequency distributions of percent control ratings on F2 plants indicated several loci controlled tolerance to HOE 23408. More than half of the F2 plants from tolerant ✕ tolerant and tolerant ✕ susceptible F1's were less than 75% controlled by HOE 23408. Therefore, satisfactory control of volunteer corn in soybeans by foliar application of HOE 23408 depends in part on the pedigree of corn hybrids grown the previous year.
Cultivar ✕ Environment Interactions in Soft Red Winter Wheat Yield Tests1
Authors: Campbell L. G. , Lafever H. N. 
Published: July 2010

Uniform Eastern Soft Winter Wheat Nursery data from nine locations and 3 years were used as a basis for examining cultivar selection and testing procedures in the northern soft red winter wheat (Triticum aestivum L. em Thell) region. Variance components for cultivars ✕ locations, cultivars ✕ years, and cultivars ✕ locations ✕ years indicated that the interaction of cultivars with environments was of considerable importance in determining relative yields. Progress in the development of high yielding adapted cultivars was apparent in comparisons of some of the new cultivars and experimental lines with ‘Trumbull’, a 1908 release. Newer cultivars tended to be more productive, more responsive to changes in environment, and more predictable in specific environments.Lafayette, Ind., appeared to be a better site for selection of widely adapted cultivars than Wooster, Ohio, with the other locations between these extremes. The results indicated that some selection for specific adaptation occurred in most breeding programs and that the site of early generation selection had a major role in determining the range of adaptation. Methods of numerical taxonomy were used to group locations and examine location similarities. The results indicated that cultivars should be tested more than 1 year; however, testing more than 3 years appeared to be of little value especially as the number of locations was increased.
Photosynthesis and Cold Hardening in Zoysia and Bermudagrass1
Authors: Rogers R. A. , Dunn J. H. , Nelson C. J. 
Published: July 2010

Objectives of this research were to evaluate ultrastructural and physiological factors associated with cold‐hardening in the field of three bermudagrass (Cynodon dactylon L.) and three zoysia (Zoysia spp.) cultivars. Cold tests of rhizome tissue in December showed that zoysia cultivars survived colder temperatures than bermudagrass cultivars which agrees with most field observations. Midwest zoysia and Midway bermudagrass were the most low temperature tolerant of their respective genera.During October, ultrastructural changes occurred which indicated differences between hardy and non‐hardy cultivars. For example, bermudagrass chloroplasts took on a globular shape compared with an elongated shape in late summer. Chloroplasts of zoysia cultivars usually showed no alteration in shape in October.During November in 1973 and 1974, plots of both zoysia and bermudagrass appeared to be only 10 to 12% green, but green tissue of zoysia was four to eight times more photosynthetically active than that of bermudagrass. Amylolytic enzyme activity was also higher in zoysia at that time. Grana lamellae of chloroplasts of green zoysia tissue were mostly still intact in November, but were usually damaged in bermudagrass. The higher photosynthetic rate observed in zoysia compared to bermudagrass during the cold hardening period would be an advantage since carbohydrate could be conserved or used to prepare the plant cells for winter when little or no growth was occurring.
Effect of Cyclic Selection for High and Low Crushing Strength on Rind, Pith, and Whole Stalk Composition in Corn1
Authors: Undersander D. J. , Bauman L. F. , Lechtenberg V. L. , Zuber M. S. 
Published: July 2010

Two synthetic corn (Zea mays L.) populations were selected for high and low crushing strength through five cycles of recurrent selection. Stalk sections from the second internode above the ground were collected from the fifth cycle plants. The stalk sections were separated into pith and rind components and analyzed for lignin and cellulose. In one synthetic (MoSQA) the lignin percentages in the stalk sections were 16.6 and 19.2 for low and high crushing strength selections, respectively. Lignin percentages were 15.9 and 17.6, respectively, for the low and high crushing strength selections in the second synthetic (MoSQB). However, stalk lignin percentages for the high and low selections in each population were not significantly different from stalk lignin percentages in the original unselected populations. Lignin percentage of the pith was not affected by selection for crushing strength. In MoSQA the lignin percentage of the rind increased with increased crushing strength. Lignin percentage of the rind in MoSQB did not change. However, the proportion of rind in the stalk changed from 75.8 to 82.1% due to selection for low and high crushing strength.The changes in stalk composition were small relative to the large differences in crushing strength and lodging percentage between the high and low selections. This suggests that crushing strength and lodging resistance can be increased considerably without greatly affecting the composition, and presumably, the digestibility of corn stover.