bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Variation in Root and Shoot Growth of Sorghum in Hydroponics1
Authors: Jordan W. R. , Miller F. R. , Morris D. E. 
Published: July 2010

Thirty sorghum (Sorghum bicolor L. Moench) genotypes were grown in hydroponics and characteristics of their shoot and root growth compared to determine if genetic variability exists in the balance of growth between shoots and roots and within the crown root system. A demonstration that such variability exists is a necessary first step in systematic improvement of root systems.All genotypes were compared relative to RTx2536, a standard common to all experiments. Comparisons were based on the ratios of leaf area (LA) to crown root length (RL) and shoot dry weight (S) to root dry weight (R), which reflect overall shoot to root balance, and on the ratio of RL to total root volume (RV) which describes the balance between crown root axes and lateral root branches. Standard breeding lines RTx7078, BTx3197, BTx378 and RTx7000 were similar to RTx2536 in all three ratio comparisons. This similarity may reflect the narrow genetic base available to breeders when these lines were developed, or similar environments during selection.Recent breeding efforts have yielded lines which differ from standard lines as measured by the three ratios. Eight of the 30 entries had LA/RL ratios which differed from RTx2536; seven ratios were higher while only one was lower. Of the seven entries with higher LA/RL ratios, six also had higher S/R ratios. Seven entries had RL/RV ratios different from RTx2536, four entries had higher ratios, and three had lower ratios. Genotypes with low RL/RV ratios did not have more or fewer crown roots and the frequency of lateral roots was not different from RTx2536, but growth and branching of lateral roots was more extensive. We conclude that sufficient variability exists in shoot and root growth characteristics to warrant further study on the problem of systematic improvement of sorghum root systems which may allow superior crop performance in specific environments.
Glandular Secretory System of Alfalfa Species1
Authors: Kreitner Gerald L. , Sorensen E. L. 
Published: July 2010

We studied the functional secretory activity of glandular trichomes on annuals (diploid Medicago disciformis DC, tetraploid M. scutellata (L) Mill.) and perennials (diploid M. prostrata Jacq., tetraploids M. sativa L. subsp. sativa and praefalcata) to help explain plant defense against alfalfa weevils [Hypera postica (Gyllenhal)]. Light and electron microscopy were used to documenthe secretory function of erect and procumbent glands. Glands matured and secretion initiated on unelongated parts within the plant terminal. Pressure exerted by the secretion caused the cuticle to separate from the underlying cell wall, creating a subcuticular space. In erect glands, uplifting of the cuticle from the cell wall was initiated most often along common walls of adjacent secretory cells of the gland head. Procumbent glands formed a single subcuticular space in the gland apex. Photomicrographs suggested that the secretion was released by teanng or splitting of the cuticle. Only the two terminal cells of procumbent gland heads participated in the release of secretion.The sudan stain for Hpids reacted positively with the gland exudate. Dense patches of sudanophilic material appeared on heads and stalks of glands after staining. The affinity for stain was less in procumbenthan in erect gland secretions.
Diffusion and Adoption of Semidwarf Rice Cultivars as Parents in Asian Rice Breeding Programs1
Authors: Hargrove Thomas R. 
Published: July 2010

The first widely grown semidwarf cultivars of rice (Oryza sativa L.) were ‘Taichung Native 1’ (TN1), released in 1956, and ‘IR8’, in 1967. To determine the impact of new semidwarf cultivars on the genetic diversity of the world's rice crop, the International Rice Research Institute (IRRI) traced the diffusion and adoption of improved rice cultivars as parents among national breeding programs at 14 agricultural research centers in seven Asian nations from 1965 to 1975.Sixty‐one percent of the 1965–67 crosses and 84% of the 1974–75 crosses involved at least one semidwarf parent. Crosses that involved a tall cultivar decreased. In 1965–67, 28% of the total gene pool was semidwarf and 40% tall. Ten years later, the percentage of semidwarfs almost doubled and that of talls dropped sharply. Apparently, breeders were increasingly crossing semidwarf parents to other semidwarfs.TN1 and IR8 were the most popular gene sources in 1965–67; each was used in about 20% of the crosses. Use of TN1 and IR8 dropped to only 1 to 3% by 1974–75, while use of other IRRI semidwarfs increased significantly. But the strongest trend was the growing use of locally developed semidwarfs — from 2% of the 1965–67 crosses to 49% in 1974–75. The genetic makeup of those local semidwarf parents was traced back two generations; 76% were progeny of IR8 or other IRRI rices.Breeders in India adopted TN1 and IR8 earlier, and more extensively, than breeders in the six other countries. By 1974–75, 75% of Indian crosses involved a local semidwarf. In the six other countries, IRRI remained the major source of semidwarf breeding material but breeders increasingly used local semidwarfs. The semidwarf indica rices largely replaced japonica, ponlai, and other races in the breeding programs.
Breeding Cicer Milkvetch for Improved Seedling Emergence1
Authors: Townsend C. E. 
Published: July 2010

Cicer milkvetch (Astragalus cicer L.) has not been grown extensively because of its relatively poor seedling emergence. Therefore, selection for rapid seedling growth at two temperature treatments in environmental chambers and selection for rapid seedling emergence in the greenhouse were evaluated as methods for improving seedling emergence under field conditions. In the environmental chambers with a 15‐hour photoperiod, one cycle of recurrent selection was more effective at the 20 C day/15 C night than at the 25 C day/20 C night regime. Percentages of progeny in which seedling emergence was significantly higher than that of the reference were 44 and 15 for the 20/15C and 25/20C regimes, respectively. Because of concern for inbreeding depression, intercross progenies were evaluated for seedling emergence prior to the second cycle of recurrent selection. Of the intercross progenies selected, seedling emergence was significantly improved in 53% from the 20/15 C and in 17% from the 25/20 C regime.Selection for rapid seedling emergence from a 3.8‐cm depth of planting hi the greenhouse was not an effective method for improving seedling emergence in the field. Only 8% of the selected polycross progenies were significantly better than the reference progeny. Seedling emergence was poor in polycross progenies of other populations not selected for rapid seedling growth at 20/15 C. Only about 2% of such progenies were significantly better than the reference progeny. Selection of seedlings for rapid growth in a 20/15 C environment was an effective method of improving seedling emergence of cicer milkvetch under field conditions
Genotypic Evaluation for Iron Deficiency Chlorosis in Soybeans by Visual Scores and Chlorophyll Concentration1
Authors: Rodriguez de Cianzio S. , Fehr W. R. , Anderson I. C. 
Published: July 2010

A comparison was made of the effectiveness of visual scores (Vs) and concentrations of chlorophyll a (Ca), chlorophyll b (Cb), and total chlorophyll (Cab) for evaluating the response of soybean [Glycine max (L.) Merr.] genotypes to Fe deficiency chlorosis. A total of 400 entries, including breeding lines, parents, and check cultivars, were evaluated in replicated tests on calcareous soils at two locations in Iowa. Visual scores and chlorophyll concentration were determined on the first trifoliolate leaf when it was fully developed. Visual scores ranged from I, no yellowing, to 5, severe yellowing, and chlorophyll concentration in mg dm‐2 leaf area was determined by acetone extraction.There were significant differences among entries for the four characters. Highly significant correlations from 0.97 to 0.99 were observed among Ca, Cb, and Cab. Vs had highly significant negative correlations from −0.89 to ∓0.90 with the chlorophyll concentrations on an entry mean basis. The four characters were equally effective in selecting lines with superior chlorosis resistance on the basis of simulated selection experiments. Vs would be the most efficient procedure for direct comparison of genotypes because it requires considerably less labor than chlorophyll determination. Chlorophyll determination may be preferred, however, for research studies in which an objective measure of chlorosis is needed, particularly if different environments and persons are involved.
Influence of Five Gossypium Species Cytoplasms on Yield, Yield Components, Fiber Properties, and Insect Resistance in Upland Cotton1
Authors: Meredith W. R. , Meyer Vesta , Hanny B. W. , Bailey J. C. 
Published: July 2010

The influence of five exotic cotton (Gossypium spp.) cytoplasms on yield, yield components, fiber properties, and insect populations was determined at Stoneville, Miss. The five cytoplasms were G. herbaceum L., G. arboreum L., G. anomalum Wawra ex Wawra & Peyr., G. barbadense L., and G. tomentosum Nutt. ex Seem. The five cytoplasms were combined by repeated backcrossing into the following upland cotton (G. hirsutum L.) cultivars: ‘B3080’, ‘Coker 201’, ‘Delcot 277’, ‘Deltapine 16’, and ‘Stoneville 213’. The average number of backcrosses into G. hirsutum was 10.1 and into the specific cultivars, 6.5.The characteristic most influenced by exotic cytoplasms was yield. Cytoplasm from G. arboreum decreased yield I8%, averaged for all cultivars. Exotic cytoplasms in general decreased yields, but this trend was not consistent for all cultivars. The average 1977 decrease in yield was 80, 61, 41, 17, and −5 kg/ha for Deltapine 16, Coker 201, Stoneville 213, B3080 and Delcot 277, respectively. The foreign cytoplasms had no strong deleterious effects on yield components and fiber properties.No evidence of variations in tolerance to tarnished plant bugs (Lygus lineolaris Palisot de Beauvois) was detected in the 1977 study. In 1978 no differences due to cytoplasms were detected in numbers of tarnished plant bugs and white flies (Trialeurodes abutilonea Haldeman). However, the AD3 (G. tomentosum) cytoplasm resulted in a 70% increase in numbers of leafhoppers (primarily Empoasca spp.) and a 35% decrease in weights of 7‐day old larvae of tobacco budworm (Heliothis virescens F.).The interaction of some nuclear genes and exotic cytoplasms was compatible for yield and significant for some pest damage. This result suggests that a back‐up cytoplasmic system could be developed to help reduce the danger of major ephiphytoties or damage by insects.
Evaluation of Vigor Tests in Soybean Seeds: Relationship of ATP, Conductivity, and Radioactive Tracer Multiple Criteria Laboratory Tests to Field Performance1
Authors: Yaklich Robert W. , Kulik Martin M. , Anderson James D. 
Published: July 2010

Laboratory tests for ATP content, conductivity of seed steep water, and the multiple criteria were performed on soybean seeds [Glycine max (L.) Merr.] in 1975 and 1976. Results of laboratory tests were compared with emergence and stand data obtained from the same seed lots on two sites (sandy and heavy soil types) and three dates of planting (early, pre‐optimum, and optimum) each year. Yield data were obtained for the heavy soil type, optimum planting date.Conductivity, leachate, and protein synthesis were laboratory test measurements that were significantly correlated with emergence for the various sites and dates of planting each year. The magnitude of the correlations was conductivity > leachate > protein synthesis. The soluble radioactive fraction from the multiple criteria test was correlated with emergence in 1975 and ATP content and water uptake were correlated with emergence in 1976. Conductivity/gram seed wt. gave the highest correlations both years (r ≥ 0.670).Correlations of the laboratory tests by cultivar with field emergence showed differences both years. For the conductivity test, ‘Essex’ in 1975 and 1976 and ‘York’ and ‘Adelphia’ in 1976 gave non‐significant correlations. Leached radioactivity from the multiple criteria gave similar results with ‘Beeson’ and ‘Wayne’ being the only two cultivars giving significant results both years. Overall correlations between conductivity and leachate showed significance in 1975 but not in 1976. Correlations by cultivar demonstrated significance in 1975 but not in 1976 with Essex showing no significance either year. Resuits are discussed in reference to possible genetic dif. ferences, sample size, and year to year variation.
Genetic Variability for Seedling Root Numbers in Wild and Domesticated Wheats1
Authors: Robertson B. M. , Waines J. G. , Gill B. S. 
Published: July 2010

Genetic variability for seedling root number within the genus Triticum was characterized to determine if this trait could be used in wheat breeding. Average seedling root numbers were determined in the laboratory for 143 accessions of wheat including the diploid species Triticum boeoticum Boiss., T. monococcum L., and T. urartu Tum.; the tetraploid species T. araraticum Jakubz., T. dicoccoides Körn., T. turgidum L. var. dicoccon Schrank and var. durum Desf., and T. timopheevi Zhuk.; the hexaploid species T. aestivum L. var. aestivum, vat. compactum, var. macha, var. spelta, var. sphaerococcum. and var. vavilovii, and T. zhukovskyi Men. & Er. Significantly differently mean root numbers were found within each ploidy level and, in most cases, within each species or variety. The highest mean root number, 6.45, was found in an accession of T. turgidum var. durum, the lowest, 2.50, in accession of T. araraticum. Seed weight was positively correlated with mean root number (r = 0.71) but within each ploidy level accessions having similar seed weights and significantly different mean root numbers were found. Progeny tests of 15 diploid and seven tetraploid accessions showed that seedling root number was stable from one generation to the next. A test of 33 of these accessions and progeny in a greenhouse experiment showed this trait was stable (r = 0.91) across the two environments tested.Embryos sectioned by hand showed that all accessions tested had about five seminal root primordia present. In general, greater seedling root number may be selected for by selecting for higher seed weight, but exceptions to this rule were observed.
Effect of Increasing Foliage Reflectance on Yield, Growth, and Physiological Behavior of a Dryland Cotton Crop1
Authors: Moreshet S. , Cohen Y. , Fuchs M. 
Published: July 2010

The effect of kaolin reflectant sprays on the yield, physiological activity, and growth of ‘Acala SJ‐2’ dryland cotton (Gossypium hirsutum L.) was studied during 2 successive years in separate field experiments. In the first experiment the treatment increased yield by 12.6%. In the second experiment a significant increase in the number of flowers resulted from the kaolin spray, but subsequent high rates of abscission prevented this spray from producing a significant increase in yield.The reflectant sprays decreased the rate of 14CO2 uptake due to a reduction in light absorption. A reduction in epidermal conductance due to partial physical blockage of the stomata was believed to cause the slower decrease in xylem leaf water potential which followed reflectant treatment. Plant growth, characterized by the stand's height, leaf area index, and dry weight, was not significantly affected.
Natural Resistance to Thrips Injury in Cotton as Measured by Differential Leaf Area Reduction1
Authors: Quisenberry J. E. , Rummel D. R. 
Published: July 2010

Ten entries of cotton (Gossypium hirsutum L.) were evaluated for 2 years to measure their relative resistance to injury from thrips (Thripidae). Resistance was measured as the percentage of leaf area reduction associated with thrips damage. Leaf area was determined three times at weekly intervals during each year.Pilose (H2) was associated with a high level of resistance to thrips. Other morphological traits such as Okra‐leaf shape (L°), Red plant color (R1), glandless (gl2, gl3), nectariless (ne1, ne2), or smooth leaf (Sm1, Sm2) did not provide the plant with resistance. Significantly less leaf area damage occurred on the pubescent ‘Tamcot SP‐37’ cultivar than on the glabrous ‘Tamcot SP‐21’ cultivar.
Collection and Evaluation of Avena Fatua for Use in Oat Improvement1
Authors: Rines H. W. , Stuthman D. D. , Briggle L. W. , Youngs V. L. , Jedlinski H. , Smith D. H. , Webster J. A. , Rothman P. G. 
Published: July 2010

More than 2,200 samples of the wild oat (Avena fatua L.) were collected from western North Central U.S. as part of a program to preserve natural variant populations of this species and to further evaluate its potential as a germplasm source for the improvement of cultivated oats (A. sativa L.). This report summarizes the results of screening these samples for tolerance to barley yellow dwarf virus (BYDV), resistance to cereal leaf beetle (Oulema melanopus L.), and resistance to oat stem rust (Puccinia graminis Pers. f. sp. avenae Eriks. and E. Henn.), plus analyses of groat protein and amino acid composition.High level tolerance to BYDV was identified in 34 of 483 samples tested. Tolerance appeared to be more frequent among samples collected in areas with a higher incidence of disease. Low level resistance to cereal leaf beetle was observed in 20 of 400 samples. The occurrence of resistance was unrelated to the incidence of the beetle. No resistance to the highly virulent race 94 of oat stem rust was identified in more than 1,600 samples tested. Groat protein levels ranging from 16.7 to 27.1% were observed among 723 A. fatua samples analyzed, whereas amino acid profiles of 70 A. fatua samples tested were similar to those reported for cultivated oats. The A. fatua collection described in this report not only provides potential new sources of BYDV tolerance and high groat protein percentage but also constitutes a valuable germplasm reservoir.
Response of Oats to Atrazine1
Authors: Brinkman M. A. , Langer D. K. , Harvey R. G. , Hardie A. R. 
Published: July 2010

The popularity of atrazine [2‐chloro‐4‐(ethylamino)‐6‐ (isopropylamino)‐s‐triazine], a persistent corn (Zea mays L.) herbicide, has caused problems for oats (Avena sativa L.) grown in rotation with corn. Despite frequent inquiries about the response of oats to atrazine, very little testing for cultivar differences to atrazine has been conducted. Therefoxe, the objective of this study was to evaluate the response of current oat genotypes to atrazine.Twenty oat genotypes were evaluated for response to atrazine for 2 years. Five atrazine treatments, 0, 1.12, 2.24, 3.36, and 4.48 kg/ha, were applied postemergence to corn land during each of the years prior to growing the oats. Atrazine damage to oats grown in 1976 was light because of wet conditions during the last half of 1975, while damage to oats grown in 1977 was more severe because of dry conditions during the last half of 1976.Grain and straw yield responses of the genotypes were evaluated on the combined data from the 2 years of testing with a regression procedure. Tolerant genotypes were expected to have a high mean and a regression coefficient less negative than −1.0, while intolerant genotypes were expected to have a low mean and a regression coefficient more negative than −1.0. There was significant genetic variability for grain yield response to atrazine. Froker, Lang, Mackinaw, X2078‐1, and X1839‐1 were more tolerant of atrazine than Dal, Lyon, Otee, and Allen. There also was significant variability for straw yield response to atrazine, but grain and straw yield responses (regression coefficients) were not significantly correlated. Straw yield response to atrazine was closely associated with plant height.The influence of atrazine on kernel quality was evaluated in a subset of eight genotypes. Groat protein percentage was increased by higher levels of residual atrazine, but groat protein yields were reduced because of the grain yield reductions. Groat percentage and 100‐seed weight were not reduced in 1976 when atrazine damage was light, but both were reduced in 1977 when damage was severe.Although there was significant genetic variability for response to atrazine among the 20 genotypes tested, the variability probably is not sufficient to warrant intercrossing them in an effort to develop genotypes with improved tolerance. A thorough search of the World Oat Collection for more tolerant genotypes is recommended.
Root Growth and Dry Matter Distribution of Soybean as Affected by Phosphorus Stress, Nodulation, and Nitrogen Source1
Authors: Cassman K. G. , Whitney A. S. , Stockinger K. R. 
Published: July 2010

In the field, plant root development is of primary importance under P deficient conditions. Two sand culture experiments were conducted to examine the effects of P stress, nodulation, and N source on the growth, dry matter distribution, and root development of ‘Clark 63’ soybean (Glycine max L. Merr.). In both experiments two levels of N (0 and 5.0 mM N) were employed: plants were either solely dependent upon symbiotic N fixation (N‐fixing), or primarily dependent upon uptake of combined N from the nutrient solution (N supplied). Nodule dry weight of N‐fixing plants grown at the highest P level (2.0 µ/ml) comprised 9% of total plant dry weight and 61% of root dry weight of 35‐day‐old soybeans. A decrease in the P supply inhibited nodule growth relatively more than either root or shoot growth. For N‐supplied soybean, a decrease in the P supply affected shoot growth relatively more than either nodule or root growth. When grown at intermediate P levels (0.02 to 0.5 µ/ml), the root + nodule:total plant dry weight ratio was similar in both N‐fixing and N‐supplied plants. However, the rootttotal plant dry weight ratio of N‐fixing plants was was less than that of N‐supplied plants at all P levels. There was an inverse relationship between nodule mass and total root length although the number of first‐order lateral roots on nodulated and nonnodulated plants was the same.The data suggest that two functional equilibria operate in the N‐fixing plant, namely, the partitioning of dry matter between (i) the underground portion of the plant and the shoot and (ii) the root and nodules. Phosphorus stress affected the root‐nodule equilibrium relatively more than the partitioning of dry matter between below‐ground and above‐ground parts of the plant.