bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transport of 14C‐Assimilates to Cottonseed: Integrity of Funiculus During Seed Filling Stage1
Authors: Benedict C. R. , Kohel R. J. , Schubert A. M. 
Published: July 2010

Early work suggested the vascular connection from the ovary wall to the ovules in cotton plants (Gossypium hirsutum L.) degenerates 32 days after fertilization. A minimum of 50 days after fertilization is required for the maturation of cottonseed. From a yield viewpoint, it is important to establish if leaf assimilates are transported to the developing cotton ovules throughout the seed maturation period.The incorporation of 14C‐assimilates into ovules in different age cotton bolls was measured by: (i) pulse‐labeling cotton plants (which contained a wide distribution of different age cotton bolls at a plant stage of maximum fruit load) with l4CO2 for 10 min, and (ii) allowing photosynthetically assimilated 14CO2 to be transported to the different age bolls for 20 hours.The rate of incorporation of 14C‐assimilates into fibers in different age cotton bolls was similar to the rate of dry weight increase in the different age bolls. The 14C‐assimilate was incorporated into the fibers during a period of active cellulose deposition in these fibers. 14C‐assimilate was incorporated into ovule wall, sugars, amino acids, organic adds, oil, and protein in 1‐ to 45‐day‐old bolls. This incorporation of photosynthate into the ovules probably reflects transport of 14C‐assimilate through the vascular connection. An alternate route of assimilate transport through the carpel wall, into the locule cavity, and absorption by the ovules, is not important because (iii) the carpel wall chloroplasts do not fix 14CO2 into 14C‐assimilate, and (iv) the transport of leaf and bract 14C‐assimilate to the carpel wall is completed in 30‐ to 35‐day.old bolls.The boll opening period for these cotton plants was 49 to 56 days after anthesis. The results in this paper show that assimilates are transported to cottonseed throughout the maturation period. The majority of this incorporation occurs through the vascular connection and the funiculus does not break 32 days after fertilization.
Soil Reflectance Effects on Net Carbon Dioxide Exchange Rates of Sorghum1
Authors: Hiebsch C. K. , Kanemasu E. T. 
Published: July 2010

Net carbon dioxide exchange (NCE) rates of sorghum (Sorghum bicolor (L.) Moench) canopies were measured in the field using large plastic chambers and an infrared gas analyzer to assess the effect of soil reflectance on photosynthesis. Increasing soil reflectance, by applying white reflective clay, kaolinite, to the soil surface enclosed by the chambers, increased NCE by as much as 16% when crop cover was sparse. The effect decreased as crop coverage increased.Spectral‐reflectance data taken over kaolinite‐treated and nontreated soil showed that reflected light over the treated plots decreased as crop cover increased so by 2 August treated and nontreated plots differed little in the amount of reflected light. Increases in NCE as calculated from spectral‐reflectance data approximated measured values.
Stability and Performance of Hard Red Spring Wheat Bulks for Grain Yield1
Authors: Busch R. H. , Hammond J. , Frohberg R. C. 
Published: July 2010

Twenty‐eight hybrid populations resulting from crosses among eight high‐yielding parents of hard red spring wheat (Triticum aestivum L. em Thell.) were evaluated as F1's in one environment, as F2 bulks in six environments, and as F3 bulks in five environments. The average yields of the F2 and F3 bulks were similar to midparent performance across environments. Neither the F2 nor the F3 bulk generations exhibited superior yield performance in stress environments when compared to their midparents. Performance of the bulks varied from 95.9 to 110.9% of midparent across environments. The yield rank of each generation bulk was generally consistent from F2 to F3 (r=0.87, significant at the 0.01 probability level) since the same seven crosses (top 25%) would have been chosen with either generation yield test. The F2 bulk yields also were associated with midparent yields (r=0.73, 0.01 level) and F1 yields (r=0.73, 0.01 level). Parents were included in each trial, however, the Fa bulks were tested together with F2 bulks in only two of the environments. The F2 bulk yields, averaged over environments, correlated as well with the F1 yields as with midparent.Regression analyses of response to environments for yield indicated that bulks had the same range of b values as parents. Average deviations from regression were smaller for bulks than for parents, but the deviations did not differ significantly. Parental deviations from regression for yield were correlated with gca (general combining ability) effects of their progeny (r=0.72, 0.05 level), but gca effects for response (b) were not significantly associated (r=0.49). Deviations from regression apparently were inherited from the parents in a relatively more predictable manner than response (b) to environments.
Genetic Variance Components and Predicted Response to Selection Under Selfing and Full‐sib Mating in a Maize Population1
Authors: Cornelius P. L. , Dudley J. W. 
Published: July 2010

Genetic and environmental variance components in maize (Zea mays L.) Synthetic O.P. were estimated from covariances among 12 generations (1 noninbred, 7 sibmated, 4 selfed) in 1970 and 1971 experiments previously described (Crop Sci. 14:815–819). The results showed: a) significant variance due to multiple alleles for plant height and ear height in 1971 and for grain yield in a 2‐year analysis, b) significant variance due to dominance for plant height and ear height in 1971 and for grain yield in both years, c) satisfactory fit of an additive genetic model for percent moisture at harvest and percent oil, and d) significant lack of fit of an additive and dominance model for kernel weight. The additive, dominance, multiple‐allele model contains three additive components (σ2I, C, σ2A) and 2 dominance components (µ21,σ2D. The relative importance of was roughly proportional to inbreeding depression previously reported. was large for yield but negative for plant height and ear height. for yield was negative and an estimate of average degree of dominance suggested extreme overdominance. This may result from repulsion phase linkages of loci showing partial to complete dominance.Predictions of response to selection for general combining ability (GCA) and performance of lines per se (LPS) suggested a) at equivalent levels of inbreeding, selection under the two systems will be about equally effective if there has been no prior selection, but cumulative response to selection would be 1.5 to 2.0 times as great under sib‐mating as under selfing, b) a given amount of cumulative progress will be reached at a lower level of homozygosity under sib‐mating, and c) for yield, if substantial improvement in both LPS and GCA are desired, both must be evaluated.
Fertility Restoration in Soft Winter Wheat Hybrids1
Authors: Trupp C. R. 
Published: July 2010

The ability of a stable cytoplasmic male‐sterile wheat (Triticum aestivum L.) to produce pollen‐fertile hybrid progeny after pollination with a partially effective restorer parent was termed “ease of restoration” (EOR). Within the limits of measurement error, results using A/R crosses were equivalent to results nsing corresponding maintainer lines as pollen parents in R/B crosses.Using R/B crosses, EOR was predicted for advanced breeding lines of the Michigan State Univ. wheat breeding program, for current and historical commercial cultivars of Michigan, and for entries of the 1973 Uniform Eastern Soft Wheat Nursery. The materials tested were predicted to vary widely for EOR. Only a small portion of variability in EOR could be accounted for by the presence of minor genes for restoration in the maintainer line. Practical uses of extreme EOR types are discussed. EOR is a genetically controlled trait for which prediction can be accomplished with a fair degree of accuracy using partially effective restorer tester lines as female parents.
Sources and Inheritance of Resistance to Stemphylium Leafspot of Alfalfa1
Authors: Borges O. L. , Stanford E. H. , Webster R. K. 
Published: July 2010

Twenty‐three accessions of alfalfa were screened for resistance to Stemphylium leafspot. A high degree of resistance was found in collections of Medicago cancellata M.B., M. falcata L., M. coerulea Less., and M. hemicycla Grossh. However, all of the M. saliva L. introductions were susceptible to Stemphylium botryosum Wallr.The inheritance of resistance was investigated in selections from M. cancellata (2n=48), M. falcata (2n=32), and M. hemicycla (2n=16). The results showed that resistance in M. hemicycla was determined by a pair of dominant genes with duplicate effects. Our observations indicated that there is a dosage effect of dominant genes on the level of resistance. The mode of inheritance involved in the resistance of the M. falcata and M. cancellata selections was not clear.
Callus Induction and Plant Regeneration in Oats1
Authors: Cummings D. P. , Green C. E. , Stuthman D. D. 
Published: July 2010

Callus was initiated from immature embryos of 23 oat (Avena sativa L.) genotypes on Gamborg B5 or Murashige‐Skoog MS media containing 0.5 to 3 mg of 2,4‐dichlorophenoxyacetic acid (2,4‐D)/liter. These cultures were maintained by subculturing to B5 medium with 1 mg of 2,4‐D/liter every 4 to 6 weeks. Callus from the variety ‘Lodi’ has been maintained through 13 subcultures for 1 1/2 years and has retained the ability to regenerate plants. Callus capable of plant regeneration was also obtained from excised apical meristem tissues and germinating mature embryos on B5 medium containing 2,4‐D.Tiny green buds and leaves which developed from callus of 16 different genotypes formed shoots and plants when transferred to B5 medium without 2,4‐D. Ninety percent of the regenerated plants transplanted directly from culture medium to sterilized soil survived. One hundred thirty‐three plants representing 12 genotypes were grown to maturity. Most plants grew vigorously in the greenhouse and produced viable seed. Seed set ranged from complete sterility to 580 seeds from one regenerated plant. Although the growth of most of the regenerated plants appeared normal, some phenotypic and genotypic variability was observed. Cytological examination of meiotic cells from seven plants showed that two had the normal 21 bivalents at diakinesis while five exhibited aberrant meiotic configurations.The procedures used to regenerate large numbers of fertile plants from tissue cultures of many oat genotypes may ultimately prove useful in varietal improvement in oats and other species.
Effect of Kernel Maturation on Subsequent Seedling Vigor in Maize1
Authors: Knittle K. H. , Burris J. S. 
Published: July 2010

Production of high quality seed corn (Zea mays L.) would be facilitated by the harvesting of the seed at a kernel maturity which is highly correlated with maximum seedling vigor. This study attempted to correlate several kernel maturity indices with measures of seedling vigor in a maturing seed corn crop.Hybrid seed samples were taken from two field locations of production of maternal parents ‘A632’, ‘Va26’, ‘B73’, and ‘Mo17’ from 35 days to 98 days after silking. Kernel maturity indices evaluated were: 1) fresh kernel respiration rates, 2) black layer development, 3) moisture percentage, and 4) dry weight accumulation. After drying, the seed was grown on moistened, rolled paper towels in the dark for seven days at 25 C. Vigor measurements included germination percentage, shoot dry weight, and root dry weight. Although germination percentages were high over all harvest dates, both shoot and root dry weight were highly dependent on date of harvest. Distinct vigor maxima and minima were noted, and the first and last sample dates never corresponded to maximum shoot and root dry weight. Dates of maximum vigor and kernel maturity patterns were specific for each hybrid. Maximum kernel dry weight was correlated with maximum shoot and root dry weight, and the range of kernel moisture percentage corresponding to initial attainment of maximum kernel dry weight was small.
Stomatal Diffusion Resistance in Three Ploidy Levels of Smooth Bromegrass1
Authors: Lea H. Z. , Dunn G. M. , Koch D. W. 
Published: July 2010

Diurnal variations in stomatal resistance and the relationship of stomatal resistance to stomatal characters were investigated in tetraploid (4×), hexaploid (6×), and normal octoploid (8×) strains of Bromns inermis Leyss. Stomatal resistance of ‘Blair’ (8.6 sec/cm) was significantly higher than for the other six octoploid cultivars (5.8 to 6.5). The range of mean stomatal resistance between 0900 and 1600 hours (Eastern Standard Time) was approximately 4.0 to 9.0 sec/cm for 8×. Within a cultivar the diurnal pattern of stomatal resistance varied, dependent on the day of measurement; however, stomata of 4× and 6× plants consistently closed earlier in the evening than did 8× plants. Octoploid plants had the lowest mean stomatal resistance (5.1 sec/em), 6× intermediate (6.9), and 4× the highest (8.6), based on measurements between 0700 and 1930 hours for four measurement dates in June 1974.A highly significant negative correlation (r = −0.58) was obtained between stomatal resistance, measured with a diffusion porometer, and total stomatal aperture estimated as the product of stomatal width ✕ length ✕ frequency. Stomatal width was the most important single factor in estimating total stomatal aperture (r = −0.92) and stomatal resistance (r = −0.54). Stomatal resistance was not affected significantly by leaf position on the culm.
Effect of the Twin‐seeded Character on Sorghum Performance1
Authors: Casady A. J. , Ross W. M. 
Published: July 2010

The sorghum [Sorghum bicolor (L.) Moench] sessile spikelet normally contains two flowers. Usually, only the upper develops into a seed, but the lower also develops into a seed in some cultivars, resulting in twin seededness. A study of the influence of the twin‐seeded character on sorghum performance was made by use of isogenic lines. Isogenic single‐ and twin‐seeded A‐ and B‐lines of the sorghum cultivars ‘Combine Kafir‐60’ and ‘Redlan’ were developed by backcrossing. The twin‐seeded allele (Ts) caused sterility in some instances, especially in A‐lines. Attempts to develop twin‐seeded lines of ‘KS 24’ resulted in much sterility and multiple seededness of up to five seeds per spikelet.Comparisons were made of isogenic single‐ and twinseeded counterparts of the sorghum hybrids ‘KS652’, ‘RS610’, ‘RS702’, ‘RS650’, 62MH248, and 55MH19 at Manhattan, Kans. and Mead, Neb. The percentage of spikelets with twin seed was influenced by genotype and environment. Twin seededness had no effect on days to 50% bloom, plant height, and panicles per plant. There was little evidence that twin seededness affected test weight, although it decreased seed weight and the number of seed‐bearing spikelets per panicle while increasing the number of seeds per panicle. Grain yields of the single‐ and twin‐seeded counterparts of RS610 and RS702 did not differ significantly, but twin‐seeded counterparts of the remaining hybrids yielded significantly less grain than the single‐seeded counterparts.
Characterization and Inheritance of a Spotted Leaf Trait in Alfalfa1
Authors: Azizi M. R. , Barnes D. K. 
Published: July 2010

Few genetic markers are available in alfalfa (Medicago sativa L.) that do not reduce plant growth. A vigorous plant with spotted leaves was found in the ‘San Isidro’ variety. Spotted‐leaf plants were characterized by newly formed leaves that appeared normal but developed chlorotic spots within one week. Effects of two temperatures( 17 and 30 C) and three photoperiods (12‐ 16‐, and2 4‐hours) on the leaf‐spot trait were studied in both greenhouse and growth chambers. At 17 C the trait was readily expressed, but at 30 C no spotting occurred. Leaves developed at 30 C did not become spotted when subsequently exposed to 17 C. Conversely, spotted leaves that developed at 17 C did not show repair when exposed to 30 C. The development of spots was greatest with a 24‐hour light period. Cytological studies showed that palisade cells and a few spongy misspell cells of the spotted‐leaf tissue were deformed and deteriorated. The epidermal cells remained in tact.Genetic studies conducted at 17 C with a 24‐hour footprint dicated that the spotted‐leaf trait was controlled by two tetrasomic genes with random chromosome inheritance. The SA— sbsbsbsb, SA— SB— and sasasasa sbsbsb genotypes produced normal plants. The sasasasa SBSB— genotypes produced spotted‐leaf plants. Incomplete penetrance in sasasasa SBsbsbsb plants produced about 20% spotted‐leaf plants. It was hypothesized that severity of spotting was controlled by modifying genes and was not closely associated with the dosage of the SB allele. The spotted‐leaf trait was not maternally inherited.
Backcross Breeding to Increase Fiber Strength of Cotton1
Authors: Meredith William 
Published: July 2010

Three cycles of backcross breeding to increase fiber strength (T1) of cotton (Gossypium hirsutum L.) were studied at Stoneville, Miss. The objective was to measure the effectiveness of the backcross procedure for maintaining an adequate level of T1 and producing desirable combinations of yield and T1. The source of greater T1 was FTA 263‐20 (FTA) and the recurrent parent was ‘Deltapine 16’ (DPL 16). In each cycle, 480 F2 plants were grown. In both BC1F2 and BC2F2, 24 plants were selected. In BC1F3 and BC2F3, 12 and four progeny respectively, were used to initiate the next cycle. From each of the four families descending from the four selected BC2F3 progenies, 12 of 120 BC3F2 plants were selected. In 1974, four sets of families were grown at two locations with two replications each. In each replication of each set, two entries of DPL 16, FTA, and BC1F5 and BC2F4 parents, and one entry of each of the 12 BC3F3 progenies were evaluated for lint yield, yield components, and fiber properties.Mean T1's for DPL 16, FTA, BC1F5, BC2F4, and BC3F3 were 193, 230, 220, 211, and 216, respectively. Therefore, a satisfactory level of T1 was maintained by the backcross procedure. Assuming yield and T1 were uncorrelated, the observed average line yield of BC3F3 was 9.8% less than expected. The decrease in expected yield was partially caused by a lower than expected lint percentage. Significant variability in lint yield was detected among the four sets. The family with highest yield was only 5.3% less than expected and also had above average T1 (T1 = 217). These results suggest moderate success in developing desirable combinations of yield and T1 by the backcross procedure.
Field Studies of Boll Weevil Resistant Cotton Lines Possesing the Okra Leaf‐Frego Bract Characters1
Authors: Pieters Edward P. , Bird L. S. 
Published: July 2010

Cotton lines (Gossypium hirsutum L.) possessing the okra leaf (L°L°) — frego bract (fg fg) characters were evaluated in a 3‐year field study in the Coastal Bend area of Texas. Two locations were used in 1974 and 1975 and one location in 1976. The number of squares (flower buds) with boll weevil (Anthonomus grandis Boheman) ovipositional punctures was recorded on a total of forty cotton lines.Cotton lines possessing the okra leaf‐frego bract characters averaged about 60% fewer boll weevil ovipositional punctured squares than the broad leaf — normal bract cottons.
Recurrent Selection for High Seed Weight in Cicer Milkvetch1
Authors: Townsend C. E. 
Published: July 2010

Effectiveness of recurrent selection for high seed weight was determined in diallel cross and polycross populations of cieer milkvetch, Astragalus cicer L. To help prevent loss of vigor, selection was practiced for high vigor as well as high seed weight. In selecting parents of the second cycle from each population, selection pressure in one subpopulation was intense for mature‐plant vigor but was relaxed somewhat for seed weight. In the other subpopulation, selection pressures were reversed for the two characters.In the first cycle of selection, mean seed weight of the diallel and polycross populations was 3.99 and 3.97 g/1,000 seeds, respectively. This represented an increase in seed weight of about 13% over the original population (3.51 g/1,000 seeds).Two cycles of selection increased seed weight substautially. Mean seed weight of the four subpopulations ranged from 4.30 to 4.73 g/l,000 seeds, which represented increases of 22.5 to 34.8% over the original population. The percentage of increase in seed weight in cycle 2 over cycle 1 was greater for subpopulations in which selection pressure was higher for seed weight and lower for plant vigor. Vigor of some progenies in all subpopulations was high. A comparison of within‐plot variances for the subpopulations and clones indicated that genetic variance was still present after two cycles of selection. However, variance in the diallel snbpopulations was being depleted more rapidly than in the polycross subpopulations. This was attributed to the lower number of parents in the source population for the diallel group.
Intergenotypic Competition Between Rows and Within Blends of Soybeans1
Authors: Gedge D. L. , Fehr W. R. , Walker A. K. 
Published: July 2010

Intergenotypic competition among soybean (Glycine max (L.) Merrill) cultivars was evaluated in competing row plots and in two‐component blends. The objectives were to determine the importance of intergenotypic competition on soybean performance in unbordered plots and to evaluate the use of estimates of interplot competition for predicting intergenotypic competition in blends. Five soybean cultivars, ‘Chippewa 64’, ‘Hark’, ‘Corsoy’, ‘Provar’, and ‘Amsoy’, were grown in three‐row plots with 25, 50, 75, and 100 cm between rows. The center row was the test cultivar, and the border rows were either the cultivar itself (pure stand) or one of the four other cultivars. All possible pairs of the five cultivars were tested in a northern and a central Iowa location for 2 years. The average change in yield caused by intergenotypic competition increased from 2.6% in 100‐cm rows to 17.6% in 25‐cm rows. Significant yield changes occurred at all row spacings, particularly when Amsoy was either the test cultivar or the competing cultivar. Maturity, height, and lodging were not significantly affected by competition at any row spacing. Soybean yield tests with cultivars and growing conditions similar to Iowa should use bordered plots if no bias from intergenotypic competition can be tolerated.The soybean cultivars were grown in two‐component blends at the ratios 3:1, 1:1, and 1:3. The blends contained cultivars with different pubescence color so they could be harvested separately. The blends and pure stands of each cultivar were grown in bordered plots spaced 68 cm apart. The blend test was grown adjacent to the interplot competition test in all environments. Intergenotypic competition in blends was most closely predicted by competition between 25‐cm rows, but the relative competitive ability of cultivars in blends was not always the same as their relative competitive ability in adjacent rows.