bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selection in Six Crops of Sugarcane. I. Repeatability of Three Characters
Authors: Miller J. D. , James N. I. 
Published: July 2010

Phenotypic correlation coefficients for three characters among 6 crops of sugarcane (Saccharum sp.) showed that repeatability for stalk diameter among plant crops was somewhat higher than that for stalk number and Brix, which were about equal. Repeatability for stalk number and diameter was about equal between plant crops and first ratoon crops, but Brix was more repeatable among ratoon than among plant crops.Stalk number and Brix in seedling crops and 1.2‐m clonal crops were not significantly correlated with yield in 4.6‐m clonal crops. Stalk diameter in seedling crops and 1.2‐m clonal crops was significantly correlated with yield in 4.6‐m clonal crops and ranged from 0.17 to 0.34 (.01 level of significance). Thus, stalk diameter was a better selection criterion for yield in early stages of selection than was stalk number or Brix.Since Brix and cane yield were not associated, it should be possible to select high‐yielding clones that also have high Brix.
Seed Production by Ryegrass‐Fescue Hybrid Derivatives in Muslin‐Covered Cages1
Authors: Berg Clyde C. , Hill R. R. 
Published: July 2010

Clones of ryegrass‐fescue (Lolium‐Festtica) hybrid‐derivative origin were used to produce syn‐1 generation seed of eight 4‐clone synthetics under muslin‐covered isolation cages. Cages, about 1.5 m wide ✕ 5.2 m long ✕ 15 m high, were constructed over plots containing 16 space‐planted ramets of each of the four clones of each synthetic. The cages were covered with muslin a few days before anthesis.Very large differences, which could be attributed to cages (or synthetics) and to clones within synthetics, were observed in 1966 and 1968. Some clones produced very little seed. Although differences between years were large, the correlation between seed production in 1966 and 1968 was highly significant (r = 0.478).The effects of several cage treatments on seed production were evaluated on plots established to one 4‐clone synthetic. The cage treatments were: no fan, fans, and fans plus dehumidifier in 1970; open cage, no fan, and fans in 1971; and open cage, no fan, one fan, and two fans/cage in 1972.The presence of fans in the cages significantly increased seed yields in 1970, but not in 1971 or 1972. Using a dehumidifier did not increase seed production over that with fans alone. Seed production outside cages was always significantly greater than production in cages, regardless of the cage treatment. Although smaller than variations due to cage treatments and clones, significant clone by cage treatment interactions were observed each year. This interaction suggests that seed produced under different conditions could be genetically different. Seed of experimental ryegrass‐fescue hybrid‐derivative populations can be produced in isolation under muslin‐covered cages. However, more research is needed to determine the effect of cage environments on the genetic composition of the seed produced and on techniques to reduce interactions.
Determining Lock Tenacity in Pima Cotton1
Authors: Young E. F. 
Published: July 2010

These investigations were initiated to develop a technique for estimating storm resistance under field conditions in Pima cotton (Gossypium barbadense L.). A 500‐g force gauge was used for field determination of lock tenacity. Lock tenacity was measured for fully open bolls. The pull of the lock was made parallel to the suture opening when the gauge was held horizontally. The most consistent readings were obtained from bolls located in the upper two‐thirds of the open‐boll zone. Storm resistance was overestimated if diseased locks or bolls not fully open were measured.Field estimates of lock tenacity of several Upland cotton (G. hirsutum L.) cultivars were close to earlier laboratory estimates. Highly significant differences in lock tenacity among Pima cultivars and consistent ranking of cultivars over experiments showed that they differ genetically for lock tenacity. The force gauge effectively measures the trait in a breeding program.
Heritability of Oil Content in Sunflowers1
Authors: Fick G. N. 
Published: July 2010

Seed oil content in sunflowers (Helianthus annuus L.) was determined by nuclear magnetic resonance (NMR) for parent, F1, F2, and backcross generations of the cross P‐21 VRl/Menn RR‐18‐1 and for the F2 and F3 generations of the cross cmsPI 343765/HA 119//HA 62‐4‐5/3/T66006‐2.Broad and narrow‐sense heritability estimates on an individual‐plant basis in the F2 generation of the cross P‐21 VRl/Menn RR‐18‐1 were 0.72 and 0.61, respectively. The ratio of narrow to broad‐sense estimate indicated that genetic effects were largely additive. Heritability in the F2 generation of the second cross, as estimated by the parent‐progeny regression method, was 0.52. Actual gain in F3 from simulated selection for high oil content in the F2 generation was in good agreement with that predicted from the regression estimate. The heritability values were of sufficient magnitude to encourage selection for high oil content on individual plants in early generations.
Photosynthetic‐respiratory Responses of ‘Merion’ Kentucky Bluegrass and ‘Pennlawn’ Red Fescue at Reduced Light Intensities1
Authors: Wilkinson J. F. , Beard J. B. , Krans J. V. 
Published: July 2010

The objectives were to characterize the photosynthetic‐respiratory responses of Kentucky bluegrass (Poa pratensis L. ‘Merion’) and red fescue (Festuca rubra L. ‘Pennlawn’) to reduced light intensities. Merion and Pennlawn were grown in separate growth chambers at light intensities of 2.7, 10.8, and 43 klux. Light quality, soil moisture, and soil temperature were standardized among chambers. Infrared CO2 analysis was used to measure assimilation rates, light saturation levels, and light compensation points of both swards and individual plants.Both species had decreased net photosynthesis (PN) and dark respiration (RD), lower light saturation levels, and decreased light compensation points under reduced light intensity. Swards generally had lower PN and RD rates but higher light saturation levels and light compensation points than individual plants.Both species responded similarly to reduced light intensity in terms of PN, light saturation levels, and light compensation points. These factors could not be associated with the ability of Pennlawn to provide a more desirable turf than Merion in the shade. RD of individual plants of Pennlawn was reduced at the lowest light intensity, whereas the RD of Merion was not. This response may contribute to the positive CO2 balance of Pennlawn at reduced light intensities and thus to its shade adaptability.
Inheritance of Plant Height in Cotton. I. A Cross Between Lubbock Dwarf and Texas Marker‐1
Authors: Quisenberry J. E. 
Published: July 2010

In Upland cotton (Gossypium hirsutum L.), plant height is determined primarily by the number and length of the main stem internodes, but it can be significantly modified by variation in the node on the main stem where fruiting branches are first initiated. F1, F2, and backcross populations from a cross between the inbred lines of Lubbock Dwarf and Texas Marker‐1 provided estimates about the inheritance of plant height, number of main stem nodes, length of main stem and fruiting branch internodes, and node of the first fruiting branch. Phenotypic correlations were computed from the F2 population for all character combinations.The parental lines differed in plant height, main stem and fruiting branch internode lengths, and the node of the first fruiting branch. The parental lines were not different in the number of main stem nodes; only environmental variation occurred for this character. Each of the other characters were quantitatively inherited with additive genetic effects, without any indication of significant dominance genetic effects. Plant height was shown to be associated with the number of main stem nodes (r = 0.57), main stem internode length (r = 0.88), and node of the first fruiting branch (r = 0.38). A significant association was also found between the number of main stem nodes and node of the first fruiting branch (r = 0.34). The lack of significant association between the main stem internode length and the fruiting branch internode lengths suggested that these characters can be manipulated by traditional breeding techniques independently of each other.
Inheritance of Fiber Properties Among Crosses of Acala and High Plains Cultivars of Upland Cotton1
Authors: Quisenberry J. E. 
Published: July 2010

Although High Plains and Acala cultivars of cotton are taxonomically classified as Gossypium hirsutum L., their pedigrees suggest that they have remained largely discrete populations during cultivar development. To evaluate the genetic control associated with certain fiber properties when High Plains and Acala cultivars are hybridized, a factorial mating design was used to cross randomly‐ selected High Plains and Acala lines. The hybrid populations that resulted from those crosses were used to obtain estimates of genetic variances for fiber length, strength, elongation, and fineness.Additive genetic variance predominated for fiber length, strength, and elongation. Most of the phenotypic variance for fiber fineness was due to the environmental component; however, a statistically significant, nonadditive component was observed. The results suggested that in general, within segregating populations derived by hybridizing High Plains and Acala cultivars, lines can be selected that have desirable combinations of fiber length, strength, and elongation, but that genetic gain for fiber fineness will probably be difficult.
Comparison of Three Selection Procedures for Yield in Soybeans1
Authors: Boerma H. R. , Cooper R. L. 
Published: July 2010

Four segregating soybean [Glycine max (L.) Merr.] populations were used to evaluate the effectiveness and efficiency of three selection procedures in isolating highyielding lines; early‐generation yield testing (EGT), pedigree selection (PS), and single‐seed‐descent selection (SSD). Lines were obtained from the PS procedure in the F4 generation and from the EGT and SSD procedures in the F5 generation. These lines were yield‐tested and selected in either the F6 or F7 generation in each procedure. In the F8 generation of each cross the selected lines in each procedure were compared.The means of all selected lines, the means of the five highest‐yielding lines, and the highest‐yielding line from each population showed no consistent differences in procedures. The lines from the EGT procedure were consistently later in maturity than the lines from the other two procedures. This was attributed to the yield‐testing in unbordered plots in the early generations by the EGT procedure. The SSD procedure emerged as the most efficient procedure, because it required less selection effort than the EGT and PS procedures, allows a rapid advance of the early‐generation segregating populations, and did not use expensive yield‐testing until later generations, when yield‐testing is more efficient.
Eragrostis curvula: Influence of Low Temperatures on Starch Accumulation, Amylolytic Activity, and Growth1
Authors: Hilliard Joe H. 
Published: July 2010

AbstractFour varieties of Eragrostis curvula (Schrad.) Nees (weeping lovegrass) were evaluated for growth at reduced temperatures, amylolytic activity, and diurnal changes in leaf starch content in order to ascertain whether the variety with the most relative growth at reduced temperatures would retain the least amount of leaf starch after a cool night. Growth was measured by dry matter production; amylolytic activity by the ability of a leaf extract to hydrolyze starch; and leaf starch by enzymic hydrolysis of the starch followed by a glucose assay.It was found that growth at reduced temperature was positively associated with amylolytic activity and negatively associated with leaf starch retention after a cool night. Differences in amylolytic activity were due to the total amount of enzyme activity present and not due to differences in enzymic resistance to cool temperatures. The Q10 for amylolytic activity of all varieties was 2.0. These findings suggest that amylolytic activity and leaf starch measurements might be useful selection criteria in the search for cool temperature resistant tropical grass forages.
Heterosis and Combining Ability in Chili Peppers by Diallel Analysis
Authors: Lippert L. F. 
Published: July 2010

AbstractSignificant heterosis was recorded from hybrids in a nine‐parent diallel of chili peppers (Capsicum annuum L.) for dry fruit wt/plant (27.4%**, significant at the 1% level), fruit length (7.3%**), and percentage mature fruit at harvest (3.0%*, significant at the 5% level). Additive effects (GCA) were more important than nonadditive (SCA) in explaining variability among Fl's for fruit number, dry fruit wt/plant, fruit length and width, and total carotenoids of the fruits.Performance, predicted in synthetic populations formed from parents selected on the basis of carotenoid concentration, is presented, and breeding procedures applicable to chili pepper improvement are discussed.
Effect of Field Production Techniques on Hybrid Wheat Seed Quality1
Authors: Miller J. F. , Rogers K. J. , Lucken K. A. 
Published: July 2010

AbstractSeed quality characteristics of hybrid and male‐sterile wheat seed [Triticum aestivum L. em. Thell with T. timopheevi (Zhuk.) Zhuk. cytoplasm] were investigated in field‐scale production experiments that tested 1:1, 2:1, and 3:1 ratios of female to male parent. Drill‐strip widths ranged from 3.1 to 11.0 m. Test weight, seed protein percentage, kernel weight, and seed set percentage were evaluated. Seed harvested from the male‐sterile line was lower in test weight, higher in protein percentage and kernel weight, and had a faster rate of germination than seed of the normal line. The 1:1, 2:1, and 3:1 ratios had mean seed set percentages of 64, 51, and 45, respectively. Test weights of male‐sterile seed decreased from the 1:1 to the 3:1 ratio, and seed protein percentage increased.Seed set and quality of sequential seed samples harvested within each of the three female drill‐strip widths also were determined. Seed set and test weight decreased, protein percentage increased, and kernel weight decreased toward the center of the male‐sterile drill strips within the 2:1 and 3:1 ratios. This decrease in seed quality adversely affected the emergence and subsequent yield of hybrid wheat.These differences may be a factor determining field arrangements for commercial seed production. If conditions conducive to good production are not present, seed quality as well as seed set percentage may fall below acceptable levels.
Responses of Upland Cotton to Selection for Fiber Length and Fineness in a Nonirrigated Semiarid Environment1
Authors: Quisenberry J. E. , Ray L. L. , Jones D. L. 
Published: July 2010

AbstractFiber length and fineness were used as the selection criteria in the development of four groups of lines from a composite‐cross of upland cotton (Gossypium hirsutum L). These groups consisted of lines with long‐coarse, longfine, short‐coarse, and short‐fine fibers. These fiber groups were used to evaluate selection for fiber length and fineness on fiber strength and elongation, lint yield, earliness of crop maturity, stormproofness, lint percent, lint index, and seed index. All selections and evaluations were made in a semiarid environment without irrigation. Orthogonal comparisons, based on the fiber groups, were used to determine the response of these characters to selection for fiber length and fineness. Comparisons of linear regression coefficients from the parental and selected lines were used to estimate the changes in character relationships that occurred during selection.Significant residual variation for most characters, existed among the selected lines within each group. This residual variation suggested that selection had not eliminated all genetic variance. The orthogonal comparisons showed that fiber length was associated with fiber fineness and elongation, lint yield, stormproofness, lint percent, and seed index and that fiber fineness was associated with fiber strength and elongation, earliness of crop maturity, stormproofness, lint percent, lint index, and seed index. Correlation coefficients from the parental and the selected lines suggested that the relationships between fiber length and both lint yield and lint percent did not change during the selection process, but that the associations between fiber length and earliness of crop maturity, stormproofness, lint index, and seed index did change. The relationships between fiber fineness and both fiber strength and lint index were the same in both the parental and selected lines, whereas fiber elongation, earliness of crop maturity, stormproofness, and seed index did not show the same degree of relationship with fineness in the parental and selected lines.
Determination of Yield, Yield Components, and Fiber Properties as Influenced by Selective and Nonselective Samplings1
Authors: Meredith William R. , Ramey H. H. , Bridge R. R. 
Published: July 2010

AbstractWe compared two methods of sampling cotton (Gossypium hirsutum L.) at Stoneville and Scott, Miss. We used 14 of the cultlvars from the 1971 regional high quality test. Each entry was replicated four times at each location, with two‐row plots, 16‐m long and l‐m wide. In the selective‐sampling method, individual samplers picked 75 bolls from throughout the plot. For nonselective samples, all bolls were counted and harvested from two random areas (about 0.8 m of row) in the plots. The samples from the first two replications and the last two replications were bulked to form two composite samples at each location.Selective sampling resulted in the computation of higher yields (4.4%), lint percentage (4.4%), boll size (15.2%), seed index (2.5%), lint index (10.0%), and seeds/boll (9.5%), and a lower number of bolls/ha (12.8%). Interactions of sampling methods and locations were significant for yield, bolis/ha, lint percentage, boll size, lint index, and seeds/boll. Cultivar by sampling method interactions were significant for yield, bolls/ha, and boll size, and three factor interactions were detected for seed index, lint index, and seeds/boll. Although these interactions were small compared to that for cultivar, they do imply that selective sampling causes cultivar misevaluation.As a result of selective sampling, yarn strength, 50% span length, 2.5% span length, length uniformity, reflectance, yellowness, and micronaire were 1.6, 2.8, 0.0, 3.3, 2.8, 0.1, and 8.0% higher, respectively, than that of the nonselective samples. Sampling by location interactions were detected for 2.5% span length, reflectance, and yellowness.There are implications for genetic evaluations.
Swelling Response of Alfalfa Seedlings to Initial Stem‐nematode Infection1
Authors: Elgin J. H. , Evans D. W. , Faulkner L. R. 
Published: July 2010

AbstractWe tested seedlings of seven alfalfa (Medicago sativa L.) cultivars inoculated with stem nematodes [Ditylenchus dipsaci (Kűhn) Filipjev] to study relationships between initial nematode infection 3 days after inoculation, 3‐day symptoms, 24‐day symptoms, and nematode reproduction. Cultivars differed significantly for initial infection, 3 and 24‐day symptoms, 24‐day nematode populations, and rate of population growth. At 3 days, individual seedling symptoms varied with the initial numbers of nematodes infecting the cotyledonary node. Symptom ratings for individual plants did not change greatly between 3 and 24 days.Because seedling symptoms at 3 and 24 days depended on the initial numbers of nematodes infecting the cotyledonary node, and because nematode infection is seldom uniform, the breeder may be able to select more effectively if he uses repeated inoculations and waits until differences in nematode reproduction make it possible to distinguish between resistant and susceptible plants.
Effects of Temperature and Light Intensity on the Expression of a Variegated Leaf Pattern in Bermudagrass1
Authors: Johnston Roy A. , Taliaferro Charles M. 
Published: July 2010

AbstractIn 1971 a variegated plant was found among an F1 bermudagrass [Cynodon dactylon (L.) Pers.,] population growing on the Agron. Res. Stn. at Stillwater, Okla. The variegated “Zebra” pattern consists of alternating green and chlorotic stripes that occur horizontally across the leaf blades. Occurrence of the Zebra pattern on the original plant and its progeny seemed to be environmentally dependent. Consequently, this study was designed to ascertain the effects of temperature and light intensity on the development and expression of the Zebra pattern. Two growth chamber tests, four temperature regimes (16, 21, 27, and 32 C), and two light intensities (16,150 and 32,300 lux) were used. A photoperiod of 14 hours at constant temperatures was used. Expression of the mutant character was primarily dependent on light intensity, with an increased amount and prominence of chlorotic stripping at the high intensity exposure (32,300 lux). Maximum expression of the character occurred on plants growing at 21 C and 32,300 lux of light. Plants growing at 27 C developed only slightly less chlorotic strippingthan those grown at 21 C, while those growing at 32 C developed no chlorotic strips at 16,150 lux and developed only slight stripping at 32,300 lux. Plants growing at 16 C and 16,500 lux had little stripping whereas those grown at 16 C and 32,300 lux had only a moderate reduction in stripping as compared to optimum temperature‐light regimes.
Monosomic Analysis of Photoperiod Response in Wheat1
Authors: Pirasteh B. , Welsh J. R. 
Published: July 2010

Identification of specific chromosomes containing the genes for photoperiod response in common wheat (Tritlcure aestivum L. era. Thell.) was undertaken. F1 and F2 progenies from crosses of a photoperiod insensitive spring wheat (‘Sonora 64’) with 21 diferent monosomic lines of a sensitive winter wheat (‘Cheyenne’) were grown with the parental cultlvars under a 10‐hour photoperlod. A disomic F2 population was used to measure the standard segregation pattern.The vernalized winter parent was still in the vegetative state after 152 days under a 10‐hour photoperiod. The spring parent headed, on an average, 54 days after planting. The F1 population headed, on an average, 66 days after planting. Disomlc F2 population segregation under a 10‐hour photoperiod indicated that three gene pairs, with dominant epistasis for earliness of one of the factors, controlled this character. Heading response of the F2 progenies of the monosomic line for chromosome 2D showed that this chromosome is the carrier of the Ppd 1 gene with the dominant epistatic effect. Two of the four chromosomes 2B, 4B, 3D, and 6D are possible carriers of the other two genes.