bluuebunny/crossref_metadata_2025_split huggingface dataset:
Yield‐component Analysis of Oat Isolines that Produce Different Grain Yields1
Authors: Brinkman M. A. , Frey K. J. 
Published: July 2010

A series of early and midseason isolines of oats (Avena sativa L.) contain specific crown‐rust resistance loci, which were associated with significant grain‐yield deviations when tested in rust‐free conditions. To delineate specific causes for these yield deviations, yield components were measured in the isolines and their recurrent parents in six rust‐free environments.Increased grain yields in both isolines with the crownrust resistance allele from CI 8079, an Avena sterilis L. strain from Israel, were due primarily to significantly increased tiller production. A 3.0% increase in spikelets per panicle also contributed to the increased yield of CI 9170, the early‐maturing isoline.Although each donor parent was associated with contrasting yield‐component expressions in the early and midseason backgrounds in the remaining isoline sets, causes of deviant yields were evident. An increase in panicle number contributed to grain‐yield advantages of isolines derived from CI 7171, while seed weight improvement was the most important contributor to yield improvement in the midseason isoline. The significant yield reductions of X5501 and CI 9192, the early and midseason isolines with crown‐rust resistance derived from Arena strigosa Schreb., were caused primarily by fewer spikelets per panicle.
Multivariate Analysis and the Geographical Distribution of the World Collection of Finger Millet1
Authors: Hussaini S. H. , Goodman M. M. , Timothy D. H. 
Published: July 2010

Analysis of variance of 640 genetic stocks from the world collection of finger millet, Eleusine coracana (L.) Gaertn., indicated highly significant differences among entries for the 18 characters selected. Most of the vegetative characters measured were environmentally labile in contrast to reproductive characters, which were little affected by environment. Some vegetative characters, such as stem width and blade length, were found to be relatively little affected by the environment. The characters under study, in general, did not show high mutual correlation.The data were subjected to principal components analysis. Twelve broad groups have been identified as a result of plotting the first two standardized principal components. Indian material showed clinal variation, with southern and eastern samples forming the extremes. The pattern of variation in African material was distinctly different from that found in India. Ugandan material exhibited distinct separation and isolation from the rest of the material studied.Canonical variate analysis not only supported the above findings, but also distinctly separated the Ethiopian material (which the principal components analysis grouped with some Indian material) into a distinct group of its own.
Mechanisms of Canopy Development of Tall Fescue Genotypes1
Authors: Nelson C. J. , Asay K. H. , Sleper D. A. 
Published: July 2010

Little is known regarding the genetic control of yield components of forage grasses. We conducted four experiments to determine if genotypes of tall rescue (Festuca arundinacea Schreb.) differed in number of tillers and weight/tiller. The relationship between those traits and yield/plant was also investigated under low‐competition conditions.Genotypes selected for high number of tillers exhibited lower yield/tiller, and often a lower yield/plant than those with a low number of tillers, when cut following 18 to 24 days of regrowth. Among 225 plants from a 6×6 diallel series diallel series, tillers/plant was negatively correlated (r = —0.55) with yield/tiller. Path coefficient analyses revealed that the direct effect of tillers/plant on yield/plant was about 1.5 times greater than that of yield/tiller.Rate of leaf area expansion was related closely to yield/tiller among genotypes that were selected to represent a broad range in number of tillers/plant. The relationship was not as close (r = 0.43) among progenies of the diallel. Path coefficient analysis of the diallel progeny indicated that leaf elongation rate had 1.6 to 1.8 times more influence than did leaf width on leaf area expansion rate. Leaf area expansion rate may be an acceptable criterion for selection for yield/tiller. Concentration of water‐soluble carbohydrates in leaves and CO2 exchange rate of leaves were not related to number of tillers/plant, yield/tiller, or leaf area expansion rate.
Evaluation of Free Proline Accumulation as an Index of Drought Resistance Using Two Contrasting Barley Cultivars1
Authors: Hanson Andrew D. , Nelsen Charles E. , Everson Everett H. 
Published: July 2010

The two barley [Hordeum vulgare L.] cultivars, ‘Proctor’ and ‘Excelsior’, differ in their stability of grain yield under dryland conditions; Proctor produces a low yield in drought seasons and Excelsior a relatively high yield. This varietal difference in drought resistance was clearly expressed at the three to four‐leaf stage, both in soil‐grown plants in greenhouse tests and in perlite‐grown plants in growth chamber experiments. Water deficits were imposed either by withholding water from the soil, or by flooding the perlite rooting medium with polyethylene glycol 6000 (PEG) of osmotic potential –19 bars. Under both conditions the drought‐susceptible Proctor sustained more severe leaf kill than the resistant Excelsior.Leaf water potentials (ψleaf) and free proline concentrations in various zones of the second leaf blade were determined during the development of PEG‐imposed stress. In both cultivars, a gradient of decreasing ψleaf was established from the base to the tip of the blade; a ψleaf value lower than –30 to –40 bars in any leaf zone indicated leaf kill, i.e. failure of that zone to recover on relief of stress. The ψleaf at the mid‐blade zone always fell more rapidly in Proctor than in Excelsior, and consequently reached the critical –30 to –40 bar value earlier. In both varieties, free proline accumulated in leaf tissue as ψleaf fell, and reached the highest concentration as leaf kill became severe; at this stage much of the free proline was localized in the non‐viable leaf zone. Under stress, Proctor leaves always accumulated free proline more rapidly than Excelsior leaves. On relief of water stress, free proline levels declined in viable leaf tissue, but remained very high in the drought‐killed, desiccated leaf zone.These data demonstrate that reports of a simple positive correlation between proline‐accumulating potential and drought resistance in barley may be in error. Therefore, proline‐accumulating potential should not be utilized as a positive index of drought resistance in screening methods for cereal breeding programs.
Effect of Aphid‐Transmitted Soybean Mosaic Virus on Yields of Closely Related Resistant and Susceptible Soybean Lines1
Authors: Ross J. P. 
Published: July 2010

The effect of soybean mosaic virus (SMV) resistance on soybean yields during three growing seasons (1974, 1975, and 1976) was determined under circumstances of natural virus transmission by using closely related SMV‐resistant and susceptible lines (27 pairs). They were developed by backcrossing SMV resistance derived from PI 96983 or PI 170893 to cultivars ‘Dare,’ ‘Semmes’, ‘Pickett 71’, ‘Lee 68’, and ‘Ransom’. Susceptible lines in two of four pairs from the Dare backcross family manifested a “field resistance”, i.e., no significant yield reduction (5.2%). Yield reductions in other backcross families averaged from 35 (Semmes) to 20% (Lee 68 and Pickett 71); Ransom was intermediate at 27%.The relationship of SMV infection to seed quality was examined by scoring seed from 1975 visually and by plating out seed from 1976 on agar to determine the percent infection by Phomopsis sp. Seed of susceptible lines appeared inferior to seed of resistant lines in 16 of 26 comparisons; in 17 of 26 pairs, Phomopsis sp. was isolated with greater frequency from SMV‐susceptible lines than from SMV‐resistant lines (18.7%) vs. 4.5%).
Early Generation Bulk Hybrid Yield Testing of Adapted Hard Red Spring Wheat Crosses1
Authors: Cregan P. B. , Busch R. H. 
Published: July 2010

The parents, F1, F2 through F5 bulks, and 519 F5, lines from 28 crosses of a diallel produced from adapted high‐yielding hard red spring wheats (Triticum aestivum L.) were grown in standard nursery plots at two locations in 1975. Our objective was to determine the value of 1975 midparent, F1, and bulk generation yields and 1971‐73 midparent and bulk generation yields as predictive criteria for identifying crosses producing high proportions of superior‐yielding F5 lines in 1975. Except for the 1971‐73 midparental performance, all predictive criteria were significantly correlated with mean cross yield of F5 lines. The highest correlation (r=0.81. P≤ 0.01) was between F5 line means and the 1975 F2 bulk performance.Of the F5 lines which yielded at least two standard deviations above the overall line mean, 67 and 56% were derived from sets of seven crosses (upper 25%) chosen on the basis of the 1975 mean F2 + F3 bulk yields and the 1971‐73 mean F2 + F3 bulk yields, respectively. This compared with 37 and 43% respectively, when 1975 and 1971‐73 midparental performances were used to choose sets of seven crosses. While bulk yields were more useful than midparent yields in identifying superior crosses at the 25% selection intensity, the superiority of the bulks was not as great at a cross selection intensity of 50%.
Effect of Planting Density on Correlations among Yield and Its Components in Two Corn Populations1
Authors: Ordas A. , Stucker R. E. 
Published: July 2010

Forty‐eight S1 lines of corn (Zea mays L.) from each of two synthetic populations were grown at three planting densities at two Minnesota locations to estimate genotypic and phenotypic correlations between yield and its components (ears per plant, ear length, and kernel depth). A second objective was to assess predicted genetic gain for yield under S1 testing assuming direct selection for yield compared to progress for yield from selection for the components individually. A split‐plot arrangement in a randomized complete block design with two replications per location was used. Planting densities formed whole plots and split plots were S1 lines (arranged as blocks‐in‐replicates within whole plots).Phenotypic and genotypic correlations were, in general, of the same magnitude and tended to increase with increased planting density although there were exceptions to this trend. All genetic variance estimates were significantly different from zero. Only the variances for ears per plant were different from each other at the high and the low density. Predicted genetic gains from direct yield selection were greater than correlated responses. The correlated responses for yield with ears per plant as the selection criterion were important in both populations at the high planting densities. Ear length appeared to be a satisfactory selection criterion for yield progress at the high density in one population.
Effects of Reflectors, Black Boards, or Shades Applied at Different Stages of Plant Development on Yield of Soybeans1
Authors: Schou J. B. , Jeffers D. L. , Streeter J. G. 
Published: July 2010

Our objective was to determine the effects of a 2‐week period of light enrichment or reduction at various stages of plant development on the number of pods and on seed yield of soybeans (Glyclne max (L.) Merr.). Soybeans were field‐grown at uniform populations on Wooster silt loam soil (Typic fragiudalf, mixed mesic). In 1973 and 1974 aluminum foil reflectors were positioned at a 45° angle to the ground on the north side of east‐west rows for a duration of 2 weeks. Reflector treatments, which were established weekly, increased the amount of photosynthetically active radiation received by the plants 57%.In 1973 plants with light enrichment during late flowering and early pod formation, the period of greatest response, had 48% more pods (frults)/plant at maturity than controls. Stem plus fruit weight and total seed weight were increased 50 and 57%, respectively, over controls at maturity.In 1974, black boards (non‐reflective surfaces), positioned in the same manner as the reflectors, and shades that gave a light reduction of 63%, were included as treatments for 2‐week periods. Reflector and black board treatments imposed at late flowering or early pod formation caused a 31 and 28% increase, respectively, over controls in the number of pods/plant at maturity. Seed yield from plants treated at the same period with reflectors and black boards was 40 and 27%, respectively, greater than controls. The number of pods and seed yield for shaded plants was reduced as much as 16 and 29%, respectively, below that of the controls. All plants aborted a large percentage of pods (27 to 34%) from 12 August to maturity.
Developmental Allometry and Its Implication to Grain Yield in Barley1
Authors: Hamid Zakri A. , Grafius J. E. 
Published: July 2010

Five parental pairs of barley selections (Hordeum vulgate L. Emend. Lam) exhibiting differences in leaf area (S) and culm diameter (D) were used in this experiment. The crosses and backcrosses to each parent were allowed to self to the equivalent of the F4 at which time 20 random plant selections were drawn from each of the 15 populations. Seed was increased for two generations and standard nursery plot trials were conducted on the equivalent of the F7. The objectives were to observe the allometric relationships among leaf area, culm diameter, and the yield components, and to relate these relationships to differences in yield between the 15 populations.Evidence was presented to show that earlier‐developed organs have a profound influence on later‐formed structures. A striking relationship was observed between the number of fertile tillers per unit area (X) and all the other plant organs involved. It was found that X was negatively correlated at a highly significant level with culm diameter (D) and the average leaf area (S). The pattern was clear: when the number of tillers increased, the size of the organs on each tiller tended to decrease. In other words, a genotype with a high number of tillers tended to have smaller culm diameters, smaller leaves and smaller heads. In addition, highly significant correlations were observed among D, S, and Y (number of kernels per head).Grain yield (W) was not significantly associated with either D or S, although the two traits may be strongly correlated with one or more of the three components of yield. With this gene pool and in this particular growing environment, the components of yield were more limiting than the size of the photosynthetic surface in causing variation of grain yield among these cultivars.
Relationship of Photosynthetic Rate to Growth and Fruiting of Cotton, Soybean, Sorghum, and Sunflower1
Authors: Mauney J. R. , Fry K. E. , Guinn G. 
Published: July 2010

Cotton (Gossypium hirsutum L.), sorghum (Sorghum bicolor L.), soybean (Glycine max L.), and sunflower (Helianthus annuus L.) plants were exposed during daylight hours to an atmosphere enriched with CO2 to 630 ppm (v:v) (HiCO2) in a glasshouse. Temperature was trolled continuously to produce a daily maximum of 35 C and a minimum of 21 C. Days were cloudless and long, May to August, in Phoenix, Ariz. Average CO2 exchange rate (CER) increased 15% for cotton, 2% for sorghum, 41% for soybean, and 7% for sunflower compared to the CER of these species at 330 ppm CO2 (LoCO2). The increase in CER was not statistically significant for sorghum and sunflower. Measurements of relative growth rate and net assimilation rate showed the growth rate of all species increased during the juvenile stage (10d‐30d) in the enriched atmosphere. and were not higher in the enriched atmosphere after the juvenile stage, but cotton and soybean plants maintained their larger size and greater absolute growth.Final dry weights of cotton and soybean increased 110 and 380%, respectively, in HiCO2 compared to LoCO2. Lint yield of cotton was increased 180% by HiCO2 on a per‐plant basis and 88% on a unit leaf area basis. Became of growth fimitations imposed by terminal flowers, the final size of sorghum and sunflower plants in HiCO2 was not significantly larger than in LoCO2 These results imply that selection for CER will not effectively increase yield of determinate species such as sunflower and sorghum, but may effectively increase yield of indeterminate species such as cotton and soybean, if a sensitive assay for CER can be found.
Genetic Variability in Post‐harvest Respiration Rates of Sugarbeet Roots1
Authors: Wyse R. E. , Theurer J. C. , Doney D. L. 
Published: July 2010

Post‐harvest respiration rates were measured on whole sugarbeet (Beta vulgaris L.) roots from 97 inbred and hybrid breeding lines to determine the magnitude of the genetic variability. Measurements were made between 50 and 160 days of storage at 5 C on 19 hybrids and inbreds grown at two locations; on eight hybrids and inbreds in 2 successive years; and on 76 inbreds.A high correlation (r=0.90**) existed between the loss of sucrose and respiration rate. The respiration rate of the entries varied between years and between locations, but relative rankings remained consistent (rs=0.87** and 0.81**, respectively). The Spearman's coefficient for respiration rates between locations was similar to those for yield (rs=0.77**) and sucrose content (rs=0.89**). Single‐cross hybrids respired at a lower rate than the midparent mean and, in several cases, lower than the lowest component inbred. A range of 2.5‐fold in respiration rate was found within the 76 inbreds. No correlation existed between sucrose content or root size and respiration rate. Sufficient genetic variability exists within sugarbeet genotypes to sustain a breeding program designed to develop low‐respiring breeding lines.
Fertility of Eight Bermudagrass Clones and Open‐Pollinated Progeny from Them1
Authors: Richardson W. L. , Taliaferro C. M. , Abring R. M. 
Published: July 2010

We determined the percent of open‐pollinated (OP) seed set for eight bermudagtass (Cynodon dactylon (L.) Pers.) clones and for 420 of their OP progeny in 1969 and 1970, respectively. After selecting 30 of the most fertile of the 420 progeny, we determined their percent of OP and self‐pollinated (SP) seed set for 3 and 2 years, respectively. Objectives of the studies were to characterize the seed‐set potential of the clones and their progeny, thereby estimating the variation that exists among bermudagrass genotypes for cross and self‐fertility, and to provide information pertinent to the genetic improvement of bermudagrass seed production.The OP seed set was significantly different (P < 0.01) among the eight clones, ranging from 2.8 to 43.2%. Seed set of the 420 OP progeny ranged from 0 to 78.8%. Mean OP seed set of progeny families paralleled rather closely that of the maternal parent. Standard deviations for OP fertility of progeny clones increased as the OP fertility of the maternal clone increased.The 30 selected clones differed significantly in both OP and SP seed set each test year and for the combined averages. The seed set percentages averaged over clones differed significantly between years for OP but not SP seed set. The year ✕ clone interaction was not significant for either OP or SP seed set. The OP seed set of the 30 progeny clones averaged over 3 years ranged from 15 to 57%, most values being considerably lower than the initial ones used as indices for their selection. The 2‐year averages for SP seed set ranged from 0.10 to 8.09%. The selffertility of 24 of the clones was, however, less than 1%.
Variability in Soybean Progenies Developed by Single Seed Descent at Two Plant Populations1
Authors: Martin R. J. , Wilcox J. R. , Laviolette F. A. 
Published: July 2010

Progenies from three soybean (Glyelne max (L.) Merr.) crosses were advanced four generations by single seed descent in the greenhouse. Plants were grown at two populations, three plants/15 cm pot and nine plants/15 cm pot. Plant losses averaged 19% of the original population at the low density and 55% of the original population at the high density at the end of the four generations.Gene frequencies for flower and pubescence color did not deviate from theoretical frequencies in the low density populations. At the high density population, significant deviations from expected values occurred for flower color in two crosses andf or pubescencceo lor in all three crosses. In two crosses the incidence of plants heterozygous for the gene controlling reaction to race 1 of Phytophthora megasperma Drechs. var. sojae Hildebrand was higher than expected.A two replicate field test was used to evaluate progenies from the low and high density populations for maturity, lodging, plant height, and seed size. Progenies advanced from the high density population averaged 0.5 to 3.6 days later in maturity, 0.I to 0.2 higher in lodging score, and 0 to 4.3 cm taller than progenies advanced from the low density population.
Irradiance Response of Tall Fescue Genotypes with Contrasting Levels of Photosynthesis and Yield1
Authors: Wilhelm W. W. , Nelson C. J. 
Published: July 2010

The purpose of this study was to determine if genotype by irradiance interactions or genetic variation in diurnal trends of CO2 exchange rate (CER) influenced the CER‐yield relationship in tall rescue (Festuca arundinacea Schreb.). Genotypes were selected in the field for high CER‐high yield, high CER‐lowyield, low CER‐high yield, and low CER‐Iow yield. Responses of CER to photosynthetic photon flux density (PPFD) of these genotypes were determined using both growth chamber‐ and field‐grown material. The shapes of the PPFD response curves were similar for all genotypes, and saturation occurred at approximately 1,200 μE m‐2 sec‐1 (400 to 700 nm) under both growth conditions. In a growth chamber at 25/20 C (light/dark), all genotypes achieved near maximal CER and photorespiration within 1 hour of the beginning of the photoperiod and maintained these rates throughout the rest of the photoperiod, with high CER genotypes exhibiting about 30% higher rates than low CER genotypes. Photorespiration rates were significantly correlated (r = 0.80) with CER. Leaf diffusive resistance were similar for all genotypes throughout the photoperiod.Genotypic differences did not occur in PPFD‐response curves or diurnal patterns of CER. This suggests that differences in these two factors among genotypes are not the underlying cause of the poor relationship reported between short term measurements of leaf photosynthesis on recently collared leaves and forage yield. Other factors must be limiting genetic expression for CER in terms of yield.