bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship of Sunflower Germination and Vigor Tests to Field Performance1
Authors: Anfinrud M. N. , Schneiter A. A.
Published: July 2010

Currently, only the standard germination test is used to evaluate sunflower (Helianthus annuus L.) seed quality. Accurate evaluation of seed quality and related field performance are difficult to obtain with this test since it determines germinability of seed under optimum conditions. Additional seed quality evaluations such as vigor tests, are often valuable in estimating seed quality. Common tests of seed vigor such as germination at cool temperatures, accelerated aging, cold soil, seedling vigor classification, seedling growth rates, seed leachate electrical conductivity, tetrazolium, and mitochondrial efficiency were evaluated to determine their applicability for evaluating sunflower seed quality. Percent seedling emergence in the field was compared with laboratory vigor test results to determine which laboratory method(s) most accurately evaluated seed‐seedling vigor of sunflower. Seed leachate electrical conductivity tests, seedling vigor classification, germination at 10°C, and accelerated aging tests resulted in significantly higher correlations with percent seedling emergence in the field than did the germination test at 21°C.
Development of a Self‐Pollinated Meadowfoam from Interspecifc Hybridization1
Authors: Jolliff G. D. , Calhoun W. , Crane J. M.
Published: July 2010

Protandry in meadowfoam Limnanthes alba Benth. is believed to hinder seed yield through the interaction of honey bees (Apis mellifera L.), as essential pollinators, with environmental variables. The objective of this research was to develop a self‐pollinating meadowfoam having an L. alba plant type. Interspecific hybridization of L. alba with the autogamous L. floccosa Howell was used. Three subspecies of L. floccosa (pumila, bellingeriana, and grandiflora) were crossed with 10 selections of two subspecies of L. alba (alba and versicolor) during a 3‐year period. Only the L. floccosa ssp. grandiflora ✕ L. alba ssp. alba produced viable, fertile, self‐pollinating F1 hybrid plants. Selections for plant type, autogamy, and high seed yield were made in the F2, F3, and F4 generations. The results of this research show that it is possible to develop a self‐pollinating meadowfoam cultivar with an L. alba plant type.
The Influence of Soil pH on Leaf Area and Yield of Wheat1
Authors: Johnson J. W. , Ohki K.
Published: July 2010

Seven soft red winter wheat (Triticum aestivum L. em. Thell.) cultivars were grown to study the influence of soil pH on morphological traits and to determine the specific leaf weight of flag leaves. Cultivars were grown in the field at two surface soil pH levels (5.2 and 6.1). Measurements of flag leaves from primary stems were recorded at the milk and dough stages. Low soil pH significantly reduced dry weight, flag leaf area, and grain yield. Linear regression equations of leaf area vs. leaf weight accounted for approximately 94 and 92% of variation at pH 6.1 and 5.2, respectively. Dry weight of flag leaves could be used to rank cultivars for flag leaf area. Leaf area was correlated with dry weight (r = 0.98**, significant at the 0.01 level.). Grain growth was related to soil pH but was not related to flag leaf area. The stage of growth did not affect leaf weight:rarea relationships.
Genotype ✕ Environment Interactions for Cane and Sugar Yield and Their Implications in Sugarcane Breeding1
Authors: Kang M. S. , Miller J. D.
Published: July 2010

Genotype ✕ environment (GE) interactions limit the effectiveness of selection when selection is based only on mean yields. This study evaluated three methods of partitioning GE interaction into stability‐variance components assignable to each cultivar in sugarcane (Saccharum spp.) cultivar evaluation tests. An unbiased stability‐variance parameter (σ̂21) developed by Shukla and an ecovalence stability index (w) developed by Wricke were calculated separately for plant‐cane and ratoon crops for Brix (%), grams of sugar per kilogram of cane, and tons per hectare of cane and of sugar for 11 cultivars. A cultivar ✕ location component of variance (σ̂2c1) proposed by Plaisted and Peterson was also calculated. Within each crop, σ̂21 and w had identical cultivar rankings (rs = 1.00**) (**, Significant at the 0.01 level.) for each of the four traits studied. We propose that w sum of squares for each cultivar be expressed as w mean square and the latter be tested for significance in the same manner as σ̂21. Those cultivars with a significant mean square were judged to be unstable. Shukla's method allowed use of a covariate of fertility and cultural practices at different locations to remove heterogeneity variance (nonadditivity) from the GE interaction, and partitioning of the remainder of variance assignable to each cultivar (ŝ21). Certain cultivars were judged stable after the covariate adjustment, indicating that the instability Was introduced by the linear effect of the covariate. Methodology for computing the σ̂2CL component is cumbersome and would have little application when a large number of genotypes are evaluated. Repeatability of stability‐variance parameters between crops (individual repeatability) was relatively low for the four traits studied.
Genetic Relationship between Turgor Maintenance and Growth in Cotton Germplasm1
Authors: Quisenberry J. E. , Cartwright G. B. , McMichael B. L.
Published: July 2010

Seventeen photoperiodic sensitive cotton (Gossypium hirsutum L.) stocks were grown for 2 years (1980 and 1981) at Big Spring, Tex. to evaluate the relationship between turgor maintenance and shoot dry matter accumulation (growth). During each year, leaf‐cutter thermocouple psychrometers were used to measure predawn and midday leaf water and osmotic potentials and to estimate turgor pressure at 50 and 80 days after planting (DAP). Shoot dry weights were measured also at 50 and 80 DAP. The 1st year was hot and dry while the 2nd year had about average temperatures and rainfall. Linear regressions between predawn and midday water and turgor potentials were used to estimate turgor maintenance as i) the change in turgor pressure per unit change of water potential (slope) and, ii) the osmotic potential where zero turgor pressure occurred (X intercept). Significant differences did not occur among the stocks for changes in turgor pressure per unit change in water potential (slope), but they did occur among stocks for osmotic potential at zero turgor (πo) all four sampling dates. Analysis over‐all of the sampling dates, identified a consistently low (T178) and high (T292) stock for πo. Linear correlation and regression coefficients between shoot dry weights and πo were negative and statistically significant during the sampling period (80 DAP, 1980) when the plants were water‐stressed. The linear correlation and regression coefficients were negative, but not statistically significant during the other sampling periods (50 DAP, 1980, and 50 and 80 DAP, 1981). Linear correlation coefficients between the change in shoot dry weights between 50 and 80 DAP in 1980 and the change in πo were negative (r = ‐0.82) and statistically significant. These relationships suggesthat if selection pressure is directed towards enhancing osmotic adjustment under water stress, a reduced growth potential may result.
Interrelationships between Rates of Leaf Appearance and Tillering in Selected Tall Fescue Populations1
Authors: Zarrough Khames M. , Nelson C. J. , Sleper D. A.
Published: July 2010

Tiller density and yield/tiller are yield components associated with dry matter productivity of grasses. Breeding programs may benefit by exploiting the mechanisms that control growth and development of these components. Our objective was to evaluate the relationship between leaf appearance and tillering in seedlings of tall fescue (Festuca arundinacea Schreb.). Plants were fourth‐cycle progeny from a recurrent restricted phenotypic selection program for high (H) and low (L) rates of leaf area pansion. Four half‐sib populations were used to represent each selection direction. Seedlings were grown in a controlled‐environment chamber for 12 weeks at 25/20°C and a 14‐h photoperiod. Photosynthetic photon flux density was 500 μmol m−2 s−1. Plants remained vegetative during the growth period. In general, there were few differences among L or among H populations for the characters measured. Herbage yield of the H populations averaged 12% greater than that for the L populations. Relative tillering rate (tillers/tiller/day) for the L populations was 32% greater than for the H populations. The L populations had a 12% greater appearance rate of fully‐collared leaves on each tiller, and consequently, more potential sites available for tillering. They also had 11% greater utilization of tillering sites than did the H populations. Collectively, data showed differential genetic control of tillering rate in these contrasting populations. Tillering rate was not dependent on concentration of water‐soluble carbohydrates in leaf, root, and especially stem base tissues as concentrations were less in L than in H populations. Leaf elongation rate and yield/tiller were positively associated with herbage yield. The H populations averaged 28% greater in specific leaf weight than the L populations. Specific leaf weight was positively associated with yield/tiller and herbage yield. Carbon dioxide exchange rate of single leaves was not altered by selection. Genetic improvement of both tiller weight and tillering rate may be difficult using simultaneous selection.
Callus Induction and Plantlet Formation from Mature Embryo Explants of Kentucky Bluegrass1
Authors: McDonnell R. E. , Conger B. V.
Published: July 2010

Primary objectives of this research were to demonstrate callus induction and plantlet regeneration from mature embryo explants of Kentucky bluegrass (Poa pratensis L.) and to determine if the mode of plantlet regeneration was by organogenesis or embryogenesis. Mature embryos of six cultivars or strains were plated on a modified Schenk and Hildebrandt agar medium in a series of three experiments. Results of the first experiment, testing three synthetic auxins at varying concentrations, showed that dicamba (3,6‐dichloro‐o‐anisic acid) at 20 μM and picloram (4‐amino‐3,5,6‐trichloropicolinic acid) at 60 μM produced the best callus growth and most germination suppression. Results of the second experiment comparing plant regeneration of cultivars varying in their percent of apomictic reproduction indicated variation in callusing and plant regeneration among entries, low frequencies of plantlet formation and no relationship between apomixis and plant regeneration. Chromosome counts showed no definitive differences between cultivar reference and regenerated plants. Results of the third experiment comparing culture temperature (25 vs. 15°C) both with and without a 4°C cold treatment for 7 days showed 15°C with a cold treatment increased plant regeneration in ‘Ram I.’ A histological examination of calli in the latter two experiments showed the mode of plant regeneration to be organogenesis.
Genotype ✕ Environment Interaction for Reed Canarygrass Forage Yield1
Authors: Casler M. D. , Hovin A. W.
Published: July 2010

Plant breeders interested in broadening the adaptation and improving the performance of crop cultivars in different environments have used several stability measures as selection and evaluation criteria toward these goals. The objective of this study was to determine if genotypic variation exists for mean forage yield and for stability measures of spring and summer forage yield of reed canarygrass (Phalaris arundinacea L.). Forty‐eight reed canarygrass entries (10 clones, 10 topcross families, 25 single‐cross families, and 3 check entries) were evaluated during a 3‐year period at four diverse Minnesota locations. Stability measures for spring and summer periods included mean yield response to environments, deviation mean square (s2d), coefficient of determination, sensitivity, and stability variance (σ̂2). Differences among genetic entries were detected for mean forage dry matter yield, s2d, and (σ̂2). Extremely low and variable heritability estimates indicated that selection for low s2d or σ̂2 would not be effective in this reed canarygrass population. Due to low correlations between s2d and mean forage dry matter yield, selection for improved spring or summer yield would not be expected to alter s2d. Stability analysis of early‐generation reed canarygrass breeding materials is probably not warranted and would not be worth the required time and labor.
Correlated Responses of Yield and Other Agronomic Traits to Recurrent Selection for Stalk Quality in a Maize Synthetic1
Authors: Martin M. J. , Russell W. A.
Published: July 2010

Changes in plant, ear, and grain traits after three cycles of S1 recurrent selection for resistance to Diplodia stalk rot (SR) and mechanical stalk breakage (MS) were evaluated in the BSI maize (Zea mays L.) synthetic. The cycle populations (BS1 and C1 C3 for BSISR and BSIMS for stalk‐rot and stalk‐strength selection, respectively), populations crossed to a single‐cross tester, and crosses between populations of each procedure of selection were evaluated in replicated experiments in 1980 and 1981. The two procedures of selection gave contrasting responses in plant traits. The BSIMS populations showed increased plant height, internode number and length, and delayed anthesis, whereas the BSISR populations showed a trend toward earlier anthesis, with reduced plant height and internode length. Most of the changes for plant traits occurred during the initial cycle of selection when there was no control on flowering date of selected Sl lines. Grain yield was reduced from 7.08 t ha−l in BSI to 4.95 and 5.42 t ha−1 in BSIMSC3 and BSISRC3, respectively. Although the population crosses also showed significant yield reductions, they yielded higher than either parent. No significant yield change was observed in testcross performance. All yield components except kernel weight also were reduced by both selection procedures. Ear diameter and length, however, had the highest correlations with yield and contributed most to yield reductions observed in the improved populations for stalk quality. Thus, mild selection should be practiced for yield and other agronomic traits of importance when undertaking a population improvement program for stalk quality.
Reciprocal Full‐Sib Selection in Maize1
Authors: Hallauer Arnel R.
Published: July 2010

Reciprocal full‐sib selection was initiated in BS10 and BS11 maize (Zea mays L.) populations to emphasize selection for specific combining ability. Grain yield was the primary trait under selection, but consideration also was given to maturity and lodging resistance. Selection was based on performance of full‐sib progenies, and S1 progenies of the parents of the superior full‐sib progenies were intermated to synthesize the next cycle population. The original populations and their population cross, and the most advanced cycle populations and their crosses, also were included in most evaluation trials to provide information on relative response to selection. The primary objective of this paper is to summarize results of seven cycles of reciprocal full‐sib selection in BS10 and BS11. Direct response in the population cross was 2.1% per cycle for yield. Correlated response in BS10 and BS11 was 2.7 and 2.4%, respectively. Gradual improvement was realized in BS10 and the population cross, but most of the improvement in BS11 was made in the first cycle of selection. Relative to the mean of the six check hybrids included in all trials, the mean yield of the full‐sib progenies increased six standard deviations. There was no evidence that the variability among full‐sib progenies had decreased with seven cycles of reciprocal full‐sib selection. Evidence suggested that maturity was not later in advanced cycles and that stalk quality was improved. Percentage of root lodging and dropped ears did not show any trend with selection. Direct and correlated responses of reciprocal full‐sib selection in BS10 and BS11 were similar to those reported for other recurrent selection methods in other populations. Reciprocal full‐sib selection is somewhat more complex than other methods of recurrent selection, but it seems useful in certain situations where desired to select for general and specific combining ability.
Genetic Diversity in Soybeans for Leaf Canopy Temperature and the Association of Leaf Canopy Temperature and Yield1
Authors: Harris D. S. , Schapaugh W. T. , Kanemasu E. T.
Published: July 2010

A hand‐held infrared thermometer was used to measure the leaf canopy temperature of 20 soybean [Glycine max (L.) Merr.] genotypes under both irrigated and nonirrigated conditions. In 1980, 14 canopy temperature measurements were made end 9 were made in 1981. Canopy temperature differentials (Td = canopy temperature ‐ air temperature) were consistently larger under dryland conditions. Values of Td were averaged, within a year, to derive the mean canopy temperature deviation (T̄d). T̄d was found to be correlated negatively with yield in both the irrigated and dryland treatments in 1980, but not correlated significantly with yield in either irrigation treatment in 1981. In 1980, evaporative demand was great, with air temperatures abnormally high, and moisture was limiting, with rainfall well below normal. A reversal in environmental conditions occurred in 1981 with air temperatures at or below normal and rainfall above normal. In both years, genotypic differences for T̄d existed, but genotypic response was not the same across years. The lack of association of T̄d with yield in 1981 seemed to be due to the lack of moisture stress and the relatively low evaporative demand that existed in that season.
Influence of Leaf Morphology on Lint Yield of Cotton—Enhancement by the Sub Okra Trait1
Authors: Meredith William R.
Published: July 2010

Sub okra leaf (L14) is a trait in cotton (Gossypium hirsutum L.) which displays greater indentation of sinus and more lobing than does normal leaf (l). This study was initiated because previous research on the influence of this trait for lint yield or its components had been reported. In 1981, 48 populations descending from 24 crosses were initiated to compare the influence of this trait on yield relative to that of normal and two other mutant leaf types. The populations developed were from crosses of eight normal with three mutant leaf types of cotton. The eight normal leaf cultivars and strains wee ‘Deltapine 26’, ‘Deltapine 5540’, ‘Stoneville 825’, ‘SC‐I’, ‘DES 422’, ‘Tamcot CAMD‐E’, MD 69, and DES 2–10. The mutant leaf types were La 1363Lsne, La 500C, and HYC 79‐6 which possessed the super okra (L1), okra (L0), and sub okra (L14) leaf traits, respectively. Tw o populations were produced from each cross, i.e., one normal and one homozygous for the mutant leaf type. In 1982, the 48 F3 populations were grown in replicated experiments at three locations near Stoneville, Miss. Mean lint yield ranged from 870 to 1175 kg/ha for the three locations and from 927 to 1099 kg/ha for the eight sources of normal leaf types. No interactions with the eight sources of normal types were detected with environments, mutant leaf source types, or normal vs mutant types. Super okra populations averaged 95 kg/ha (8.8%) less lint yield than their corresponding normal populations. No differences in lint yield of okra vs normal leaf populations were detected, averaging 1053 and 1055 kg/ha, respectively. In contrast, lint yield of sub okra was significantly higher, averaging 47 kg/ha (4.8%) more than its corresponding normal populations. The yield superiority of sub okra over normal at the three locations ranged from 18 to 83 kg/ha. This investigation indicates a potential increase in the lint yield of cotton grown in the Mississippi Delta through the incorporation of the sub okra leaf trait.
Alfalfa Root Growth, Cambial Activity, and Carbohydrate Dynamics during the Regrowth Cycle1
Authors: Rapoport H. F. , Travis R. L.
Published: July 2010

Anatomical studies of the alfalfa (Medicago sativa L.) taproot during three regrowth cycles revealed a close relationship between cambial cell division activity, subsequent growth patterns, and total nonstructural carbohydrates. Narrow, band‐like patterns of cambial cells occurred with greatest frequency 2 to 3 weeks after cutting, indicating a flush of coordinated cell division. The narrow bands of cells were observed more often in fascicular than interfascicular cambial zones; this is indicative of greater cell expansion rates in the interfascicular zones. Radial expansion of the wood (xylem) occurred in all regrowth cycles during the season. Radial expansion of the bark (phloem) was limited, probably due to the crushing and centrifugal expansion in that tissue resulting from wood growth. Areas of both wood and bark increased during the second half of the regrowth cycle with the concurrent accumulation of carbohydrates.
Genetic Variability Within U.S. Hybrid Maize: Multivariate Analysis of Isozyme Data1
Authors: Smith J. S. C.
Published: July 2010

Electrophoresis of isozymes coded by 21 loci was carried out for 111 widely grown U.S. hybrid cultivars of maize (Zea mays L.). The objectives were to compare levels of genetic diversity among elite and exotic germplasm, to assess the potential of isozyme data in cultivar identification and in the quality control of hybrid seed production, and to reveal relationships among hybrids using multivariate analysis of these data. Allele frequencies among U.S. and Canadian hybrids did not differ greatly but elite materials showed a reduction in numbers of alleles and an increase in numbers of monomorphic loci when compared to exotic and wild germplasm. Residual segregation among those inbred lines that were available for analysis was generally uncommon and the level of occurrence of unexpected homozygosity and heterozygosity suggested that selfing and outcrossing, respectively, were factors contributing to polymorphism in at least 30% of all hybrids. Principal componenat nalysis revealed that approximately 90% of the hybrids had different allele frequencies. However, differences among many hybrids were due to minor deviations in allele frequencies at few loci. Isozyme data could be useful in characterizing inbred lines and hybrids, provided representative seed sources were used. These data could be used to select hybrids representing different germplasm, thereby increasing genetic variability across regions of cultivation. Isozyme variability appeared to be sufficient to allow for the rapid checking of purity of U.S. hybrid maize under laboratory conditions.
A Method for Identifying Populations Containing Favorabel Alleles Not Present in Elite Germplasm1
Authors: Dudley J. W.
Published: July 2010

Often, particularly in breeding programs attempting to use exotic germplasm to improve quantitative traits, the breeder needs to know which of several populations carry favorable alleles that are not present in elite germplasm. This knowledge would allow concentration of breeding efforts on a few populations where the probability of successful improvement of existing germplasm is relatively high. To provide this information, a method for identifying populations carrying favorable dominant alleles, not present in an elite single cross, is developed. In its simplest form, the method requires evaluation of the elite single cross, its inbred parents, and crosses of the populations to be evaluated to the two parents of the single cross. If the elite single cross is designated P1 ✕ P2, and the populations to be tested Py, the expression lp̄1μ = {[(P1 ✕ Py)• P1][(P1 ✕ P2) − P2] − [(P2 ✕ Py) − P2][P1 ✕ P2) − P1]}/2(P1 − P2) is an estimate of the product of the relative number of loci (lμ) not containing at least one favorable allele in P1 ✕ P2 and the average frequency of favorable alleles (p̄1) at such loci in Py. The method may be particularly useful for identifying populations of exotic germplasm which contain useful new alleles.
Variability Within and Among F1 Families from Diverse Three‐Parent Soybean Crosses1
Authors: Wilcox J. R. , Khalaf Abdul Ghafour M. , Brossman Gary D.
Published: July 2010

In three‐parent crosses, gametes produced by the F1 of the two‐parent cross differ genetically. Therefore, variability will exist among families derived from different F1s of the three‐parent crosses. The objective of this study was to determine the relative variability for agronomic characteristics among and within different F1 families from crosses involving plant introductions and cultivars. Four lines within each of 20 F1 families from each of two three‐parent soybean [Glycine max( L) Merr.] crosses ([cultivars ✕ plant introductions] ✕ cultivars) were evaluated for 2 years at West Lafayette, IN. Differences among F1 family means were significant for seed yield, date of maturity, lodging, and plant height. Variability among lines within families was at least 1.4 times as great as variability among families for all characteristics except maturity in one cross. In both crosses the highest yielding 10% of the lines were from different F1 families than the lowest yielding 10% of the lines. In one cross, lines witht he earliest maturity, shortest plant height, and lowest lodging scores all came from different F1 families than lines with late maturity, tall plants, and high lodgings cores. In the second cross one family contained lines in both the highest and lowest 10% of the population for maturity and lodging scores. Two families contained lines in both the highest and lowest 10% of the population for plant height. The data suggest there maybe merit in maintaining the identity of lines from individual F1s in diverse three‐parent crosses. Selection for individual lines could then be concentrated in those families with high mean performance for specific characteristics.
Interactions of Seleted Glycine soja Sieb. & Zucc. Genetypes with Fast‐ and Slow‐Growing Soybean Rhizobia1
Authors: Keyser H. H. , Cregan P. B.
Published: July 2010

Seven genotypes of Glycine soja Sieb. & Zucc. (wild soybean) weree xaminedfo r effectiveness of N2‐fixing symbiosesw ith fastand slow‐growing soybean rhizobia. Some genotypes were identlfied whichd emonstrated ifferential effectiveness with the two rhlzobia groups, while other lines had no apparent preference. Two genotypes with opposite preferences were tested with six strains of each rhizobia group. Glycine soja PI 342434 formed very effective symbioses with the slow growers, fixing over three times as much N with this group of strains as with the fastgrowing strains. Conversely, PI 468397 formed the most effective symbioses with the fast growers, fixing about three times as much N as with the slow growers. The demonstration of greater symbiotic effectiveness with the fast‐growing rather than the slowgrowing rhizobia has not previously been reported in Glycine species. PI 468397 was the genotype from which one of the fastgrowings trains was originally isolated. Thus, differential rhizobia group (fast or slow) interactions found in G. soja genotypes indicate that G. soja possesses a greater diversity of reaction to the two rhizobia groups for this characteristic than common North American G. max genotypes.
Production of 2n Pollen and Further Characterization of the Calyx Carpellaris (cc) Trait in the Pea1
Authors: Myers J. R. , Gritton E. T. , Struckmeyer B. E.
Published: July 2010

Many genes are known to affect floral development in the pea (Pisum sativum L.), but few of these traits have been extensively studied. Flower abnormalities that confer self‐sterility may be of interest to the breeder for the purpose of facilitating outcrossing because the pea is highly self‐pollinated in North American environments. Among th mutants affecting self‐fertilization, the structural steriles are generally male and female fertile; but structural malformations inhibit transfer of pollen to the stigma of the same flower. A structurally sterile mutant of spontaneous origin was observed in the line X1415 and was provided to us by L. G. Cruger, Del Monte Corp. A study was undertaken to describe its floral anatomy and cause of sterility and to determinites inheritance and possible linkage. Flowers of the mutant are carpelloid with extra gynoeciad ifferentiated from the calyx and androecium and exhibit reduced male and female fertility. The corolla is reduced or absent. The mutant produces varying amounts of 2n pollen via parallel spindles during Meiosis II. 4× ✕ 2× crosses are difficult, but possible. F2 segregation of three marker genes in sexually derived tetraploids showed tetrasomic inheritance. The mutant is allelic to calyx carpellaris (cc) in the G.10B line and probably is the same gene. The mutant is conditioned by homozygous recessive alleles at a single locus; and linkage was demonstrated among the cc, r, tl, and coch loci. The gene order is r‐tl‐cc‐coch on Chromosome 7. Under field conditions, 13% of the structurally sterile F2 plants set pods with an average of 1.6 pods per plant. The progeny were mostly the result of self‐fertilization, but at least one‐third were the result of outcrossing.
Near Infrared Reflectance Spectroscopy Analysis of Forage Quality in Four Legume Species1
Authors: Marten G. C. , Brink G. E. , Buxton D. R. , Halgerson J. L. , Hornstein J. S.
Published: July 2010

Near infrared reflectance Spectroscopy (NIRS) technology needs verification as to its utility for forages that represent diverse species, environments, and managements. Our objectives were to determine whether single NIRS calibration equations could reliably assess components of the feeding quality of alfalfa (Medicago saliva L.) grown to a range of maturities in several environments and whether single equations could be developed to simultaneously analyze components of the quality of total forage and plant parts of alfalfa, birdsfoot trefoil (Lotus cornieulattis L.), red clover (Trifolium pratense L.), and white clover (Trifolium repens L.). In the first experiment, we assayed four forage quality components in 234 alfalfa samples from eight cutting schedules of two cultivars grown in two locations in each of 2 years. In Exp. II, we assayed five quality components in 167 samples of total forage and plant parts selected from seven harvests from two growth periods of two cultivars of each of four perennial legume species. Calibration equations for in vitro digestible dry matter (IVDDM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) were obtained by multiple linear regression of known conventional laboratory assay values on NIR spectra from up to 204 samples using a scanning monochromator NIR spectre‐computer system. Equations were validated with up to 49 additional samples that had been selected from the original populations. From three to nine wavelengths were required to develop the best calibration equations for the various quality components. The squared coefficients of determination (R2) of these equations ranged from 0.93 to 0.99. These equations allowed NIRS analysis of quality values in verification samples within standard errors (dag/kg) of 1.56 to 2.06 for IVDDM, 0.42 to 1.0 for CP, 1.46 to 2.23 for NDF, 1.30 to 1.70 for ADF, and 0.63 for ADL. We concluded that our NIRS system can quickly evaluate the feeding quality of perennial legumes to a degree of accuracy similar to that of laborious conventional analyses and that several species can be evaluated simultaneously with single calibration equations nearly as well as can single species.
Comparison between Free‐Choice and No‐Choice Seedling Bulk Tests for Evaluating Resistance of Rice Cultivars to the Whitebacked Planthopper1
Authors: Saxena R. C. , Khan Z. R.
Published: July 2010

During a screening of rice, Oryza sativa L., cultivars for resistance to the whitebacked planthopper Sogatella furcifera (Horváth) by the routinely used free‐choice seedling bulk test, a significantly higher insect population was observed to move over to the susceptible check cultivar soon after infestation. This uneven distribution of insects caused unbalanced infestation among the test cultivars. To avoid this shortcoming, a no‐choice seedling bulk test was conducted in which each row of test cultivar seedlings was excluded from the other by an intervening, vertical, mylar plastic partition, and was exposed to equal insect infestation. The resistance scores of 10 genetically diverse cultivars—‘Muskhan 41’ (Wbph 1), ‘N22’ (Wbph 1), ‘N32’ (Wbph 1), ‘ARC 10239’ (Wbph 2), ‘ADR 52’ (Wbph 3), ‘Podiwi A8’ (wbph 4), ‘Colombo’ (Wbph 2 + 1 recessive ?), ‘WC 1240’ (Wbph I + 1 recessive ?), ‘1R 2035‐117‐3’ (Wbph 1 + Wbph 2), and ‘Taichung Native 1’ (no resistance gene)—from free‐choice and no‐choice seedling bulk tests were compared. Podiwi A8 and N22, rated as moderately resistant and resistant in the free‐choice test, proved to be susceptible and moderately resistant, respectively, in the no‐choice test.

The no‐choice test ensures an even distribution of test insects on cultivars and excludes any possibility of their escape from infestation. The technique has important implications in screening for resistance against a number of mobile insect pest species on a wide variety of plants.
Comparison of Canopy and Flag Leaf Net Carbon Dioxide Exchange of 1920 and 1977 New York Winter Wheats1
Authors: Gent Martin P. N. , Kiyomoto Richard K.
Published: July 2010

An increase in net carbon dioxide exchange (NCE) of the canopy or of flag leaves may have contributed to the historical trend toward increased yields of New York winter wheats (Triticum aestivum L.). This hypothesis was tested by growing ‘Honor’, a tall, awnless cultivar released in 1920, and ‘Houser’, a semi‐dwarf, awned cultivar released in 1977, in a replicated field study as vernalized seedlings in 1982 and in normal biennial culture in 1983. Throughout development and simultaneously for both cultivars, small areas of canopy were placed within clear‐walled chambers and canopy NCE was measured in an open system for 24‐h periods. At anthesis and for several weeks thereafter NCE of individual flag leaves was determined by a carbon dioxide depletion method. In both years Honor grew more rapidly through stem elongation and maintained a greater stem weight from this stage to maturity. The total biomass at maturity was the same for the two cultivars and seed yield of Houser was significantly greater than that of Honor in 1983. In both years Honor had greater canopy NCE per unit land area than Houser until stem elongation but after this stage no difference was observed between cultivars. There were no consistent differences between clutivars in flag leaf NCE per unit leaf area. During grain filling, NCE of Houser was superior to Honor only at high irradiance extrapolated to full light interception but this advantage was offset by more dark respiration per unit dry weight. The yield advantage of the modern cultivar, Houser, over the older one, Honor, was due to a greater harvest index rather than increased photosynthesis.
Effect of Three Genes (Pd, Rpsa1, and ln) on Plant Height, Lodging, and Seed Yield in Indeterminate and Determinate Near‐Isogenic Lines of Soybeans1
Authors: Cooper R. L. , Waranyuwat A.
Published: July 2010

Prior research indicated that the three genes, Pd (dense pubescence), Rpsal (Phytophthora resistance), and ln (narrow leaflet), tended to stimulate the vegetative growth of indeterminate soybean [Glycine max (L.) Merr.] near‐isogenic lines but failed to significantly increase seed yield or, in some environments, significantly decreased yields. It was postulated that this lack of a yield increase, or the occurrence of a yield decrease, may be due to the increased lodging often associated with the increased vegetative growth. These three genes were crossed into the indeterminate (lodging susceptible) and determinate (lodging resistant) near‐isogenic lines of the soybean cultivars, ‘Clark’ and ‘Harosoy’ and yield tested in the field at Urbana, IL in 1974 and 1975 to test this hypothesis. The addition of the Pd and Rpsal genes to the indeterminate near‐isogenic lines increased plant height and lodging but decreased yield. In the determinate near‐isogenic lines, where no lodging occurred, plant height was increased and yields were either increased or there was no difference in yield. The effect of the ln gene was similar to the Pd and Rpsal genes in the Clark cultivar, but differed in the Harosoy cultivar. Results of this research strongly support the hypothesis that failure of the vegetative growth stimulating genes, Pd and Rpsal, and to a lesser extent the ln gene, to increase seed yields, or in some cases significantly decrease yields, in the indeterminate near‐isogenic lines is duet to the increased lodging associated with the increased vegetative growth. These data indicate that in evaluating genes which stimulate vegetative growth, care should be taken to evaluate them in a genetic background where lodging does not become the yield limiting factor.
Near‐Isogenic Analyses of Soybean Pubescence Genes1
Authors: Specht J. E. , Williams J. H. , Pearson D. R.
Published: July 2010

Soybean [Glycine max (L.) Merr.] pubescence morphology can be altered by various qualitative genes. Such alterations have potential for the development of cultivars adapted to unique production environments. Near‐isogenic lines of ‘Clark’ and ‘Harosoy’, which possessed alleles (singly and in combination) for pubescence morphology (i.e., pa1, pa2, Pb, pc, Pd1, Pd2, Ps, Ps2, and Pd1), were evaluated for their agronomic performance in irrigated vs. nonirrigated experiments for 2 years. Analyses of the data in terms of “allelic means” indicated that the pa1pa2 combination (appressed pubescence) consistently enhanced seed yield in the Clark genetic background, but not in Harosoy. The Pd1 allele (dense pubescence) had little effect on seed yield in Harosoy, but reduced seed yield in Clark. The latter results contrast with previous studies where the Pd1 allele increased seed yield in Harosoy, but had no effect in Clark. All other alleles were either deleterious, or at most neutral, in their effects on soybean yield. Only the Pd1 and Pd2 alleles resulted in greater plant height; the other alleles had either no effect or reduced plant height. The Pd1 and pa1pa2 alleles may thus offer adaptive advantages in cultivars for certain production environments.
Evaluation of Seeds of Sunflower Species for Several Chemical and Morphological Characteristics1
Authors: Seiler Gerald J.
Published: July 2010

The genus Helianthus contains 50 species representing much genetic diversity. Wild sunflower species are important sources of disease and insect resistance, but several species have not been evaluated for oil and fatty acid concentration and morphological characteristics of the seeds. Evaluation of seeds for these characteristics would give a better idea of the potential value of these species when used in a sunflower breeding program. One problem in evaluating oil and fatty acid concentrations is that it varies greatly depending on the environmental conditions under which it develops. Growing plants at a common location can reduce the environmental variation and give a better idea of the genetic control of oil and fatty acid concentrations. The objectives of this study were (i) to evaluate seeds of 24 annual and perennial species of Helianthus for oil and fatty acid concentrations and morphological characteristics and (ii) to compare the oil and fatty acid concentrations of seeds from 22 perennial species sampled in their native habitats with those from the same species grown at a common location. Helianthus anomalus Blake had the highest average seed weight (7.3 mg/seed) and also the highest average oil concentration (344 g kg−l). The commercial ‘Hybrid8 96’ had a seed weight of 37.3 mg/seed and oil concentration of 398 g kg−l. Linoleic acid concentrations ranged from a high of 832 g kg−l in one collection of H. porteri (A. Gray) Heiser to a low of 473 g kg−l in one collection of H. arizonensis R. Jackson. Linoleic acid concentrations in excess of 680 g kg−l were found in 16 of 24 species evaluated. Oleic acid concentrations ranged from 411 g kg−l in one collection of H. arizonensis to 55 g kg−l in one collection of H. porteri. Accessions of H. hirsutus Raf., H, silphioides Nutt., and H. atrorubens L. had an average oleic acid concentration above 450 g kg−l. Commercial Hybrid 896 had a linoleic and oleic acid concentration of 488 g kg−l and 395 g kg−l, respectively. Seeds of 7 of the 22 perennial species grown at a common location had significantly different oil concentrations than seed from the original habitats. Oleic acid concentrations changed significantly in different environments in 10 of the 22 species, and linoleic acid concentrations were significantly affected in 5 of the 22 species. The species examined appear to contain variability in chemical and morphological characteristics that could be useful for enhancing sunflower germplasm.
An Evaluation of Honey Bee Foraging Activity and Pollination Efficacy for Male‐Sterile Cotton1
Authors: Waller Gordon D. , Moffett Joseph O. , Loper Gerald M. , Martin Joseph H.
Published: July 2010

The effectiveness of honey bees, Apis mellifera L., as pollinators of male‐sterile cotton, Gossypium hirsutum L., was evaluated using 649 colonies located adjacent to 53 ha of cotton grown on Pullman clay loam (fine, mixed, thermic Torrertic Paleustoll) near Plainview, TX. The planting pattern used was 2A (male‐sterile seed parent): 2B (male‐fertile maintainer) rows throughout. Colonies were evaluated for population, brood, and weight changes. Observers recorded bee visits to flowers of both A‐line and B‐line plants. Flowers were tagged over a 5‐week period to determine the percentage of bolls setting and the yield of seed and lint. Most colonies had less than 10 frames of bees and less than 3 frames of brood. Honey bee visits to the A‐line flowers varied from 0.4 to 1.7% over a 5‐ week period of observation. The bee activity on the B‐line flowers was much less, with a range of 0.1 to 1.2% visits. The authors concluded that 5 colonies/ha with 28 000 bees per colony would adequately pollinate male‐sterile cotton under the conditions of this test.
Effect of Water Stress and Infection by Ustilago striiformis or Urocystis agropyri on Leaf Turgor and Water Potentials of Kentucky Bluegrass1
Authors: Nus Jeffrey L. , Hodges Clinton F.
Published: July 2010

Plant tolerance to water stress can be measured, in part, by calculating the plants ability to maintain turgor during periods of water stress. Kentucky bluegrass (Poa pratensis) systemically infected by either Ustilago striiformis (Stripe smut) or Urocystis agropyri (Flag smut) exhibits greater mortality than noninfected plants during periods of water stress suggesting decreased drought tolerance with infection. The effects of water stress and systemic infection by the smut producing pathogens, Ustilago striiformis or Urocystis agropyri, were evaluated for their effects on leaf turgor and water potentials of Kentucky bluegrass ‘Merion’ grown in nutrient solution. Infection by either pathogen decreased leaf turgor and water potentials during light and dark periods as compared with noninfected controls. In addition, noninfected plants maintained higher leaf turgor and water potentials than infected plants as nutrient solution osmotic potentials were lowered with polyethylene glycol. Moisture release curves for single leaves from noninfected, U. striiformis‐, and U. agropyri‐infected plants were established to evaluate plants for osmotic adjustment by estimating leaf osmotic potentials and relative water contents at zero turgor as plants were grown in nutrient solution and nutrient solution amended with polyethylene glycol to increase water stress. Turgid weight/dry weight ratios also were calculated for noninfected and diseased leaves before and after water stress. Water stress lowered leaf osmotic potentials and relative water contents at zero turgor and decreased the turgid weight/dry weight ratios of noninfected and infected leaves. Noninfected plants exhibited lower osmotic potentials at zero turgor and maintained smaller turgid weight/dry weight ratios after water stress than infected plants, suggesting that infection by either pathogen inhibited osmotic adjustment and cell wall thickening in leaves of Kentucky bluegrass in response to water stress.
Responses of C4 Grasses to Atmospheric CO2 Enrichment. II. Effect of Water Stress1
Authors: Sionit Nasser , Patterson David T.
Published: July 2010

Changes in leaf water potential, photosynthesis, and stomatal conductance in response to atmospheric COs enrichment at two watering regimes were studied in :Four species of C4 grasses: Echinochloa crusgalli, Digitaria sanguinalis, Eleusine indica, and Setaria faberi. Plants were grown in controlled environment chambers at 350 and 675 μmol mol‐1 CO2 with 1000 μmol m‐2 s‐1 photosynthetic photon tux density (PPFD). One group plants of each of the COs concentrations was subjected to water stress by withholding irrigation for 10 days starting 21 days after planting. Water potentials of the leaves of plants grown at 350 #tool mol‐1 CO2 declined more rapidly and reached lower values at the end of the stress period than the water potential of those grown at 675 μmol mol‐1 CO2. High COs‐grown plants maintained higher turgor pressures than low CO2‐grown plants. All plants had lower rates of photosynthesis during water stress compared to non‐stressed conditions. However, the net photosynthetic rates of the plants grown at high CO2 concentration did not decline as rapidly as the rates of plants grown at low CO2 when subjected to water stress. The maintenance of turgor along with CO2 enrichment during water stress development in plant leaves may be responsible for the higher rates of net photosynthesis observed in high CO2‐grown plants compared to those in low CO2‐grown plants.
Genetic Variability of Alpha‐Tocopherol and Gamma‐Tocopherol in Corn Embyros1
Authors: Galliher H. L. , Alexander D. E. , Weber E. J.
Published: July 2010

Vitamin E is an essential component of animal diets. Two predominant isomers were known to exist in different ratios, as well as concentration, in corn (Zea mays L.) grain. Furthermore, the biological value of the alpha isomer is substantially greater than gamma. The primary objective of this effort was to establish the magnitude of variation of the isomers and to estimate the rate of progress that might be expected through selection for the isomers individually or for total concentration. Alpha‐ and gamma‐tocopherol are the predominant vitamin E isomers in the embryos of corn. Tocopherol concentrations were determined in embryos of selfed seed of 100 S1 families derived from RSSSC, a corn synthetic, grown in two replications of a replicates within block design in 1980 and 1981. Tocopherols were extracted, separated by high‐performance liquid chromatography on a silica absorption column, and quantified by ultraviolet absorbence detection. Concentrations of alpha‐tocopherol ranged from 0.0 to 138.2 μg/g embryo while concentrations of gammatocopherol ranged from 0.0 to 409.3 μ/g embryo. Average concentrations were 61.4 and 194.4 μ/g embryo for alpha‐ and gamma‐tocopherol, respectively. Family heritability estimates of 0.62 ± 0.16 and 0.68 ± 0.15 for alpha‐ and gamma‐tocopherol indicate that selection would be effective for either of these isomers.