bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seedling Screening for Lysine‐Plus‐Threonine Resistant Maize1
Authors: Phillips R. L. , Morris P. R. , Wold F. , Gengenbach B. G. 
Published: July 2010

Over 200 maize (Zea mays L.) strains were evaluated for seedling growth on lysine‐plus‐threonine supplemented media in an attempt to find feedback resistant mutants. Five of 92 inbreds, most of which were developed for use in hybrid production, were resistant (i.e., root length on lysine + threonine medium exceeded 50% of control). Resistant inbreds B37 and B76 were from the Iowa Stiff Stalk Synthetic (BSSS) population. Nine of 103 random line isolates from the BSSS population were resistant. From 16 of the 17 original BSSS component lines tested, only Ill. 12‐E was resistant. Seven broad base maize populations did not yield resistant types.Resistance was expressed only when seedlings were derived from germinating whole kernels. Seedlings derived from dissected embryos of resistant strains were inhibited. Studies of kernel aspartokinase and homoserine dehydrogenase activities indicated that alterations in the feedback regulation of these enzymes were not the basis of the observed lysine + threonine resistance.The opaque‐2 version of B37 was inhibited. This observation and amino acid data led to the tentative hypothesis that resistance is a function of the relative amounts of methionine and lysine (M/L ratio) in the kernel with a high M/L ratio leading to resistance and a low M/L ratio leading to inhibition. All three resistant strains analyzed had a high M/L ratio compared with four inhibited strains. Kernels of one strain, BSSS 53, had approximately 21% more total methionine than the other four inbreds analyzed (two resistant, two inhibited) yet retained the typical dent kernel phenotype. Kernels of the resistant strains also tended to have higher percent protein. Specific approaches are suggested for selecting high methionine or high lysine maize.
Expression and Inheritance of Resistance to Hessian Fly in Synthetic Hexaploid Wheats Derived from Triticum tauschii (Coss) Schmal.1
Authors: Hatchett J. H. , Martin T. J. , Livers R. W. 
Published: July 2010

Seventeen synthetic hexaploid (SH) wheats, derived from crosses between six tetraploid Triticum species and a diverse group of diploid T. tauschii (Coss.) Schmal., were evaluated for resistance to biotype D of Hessian fly, Mayetiola destructor (Say). Resistance was identified in four of the SH wheats. Based on rections of the tetraploid × diploid crosses and the parental Triticum species to larval feeding, resistance was derived from specific lines of T. tauschii. Other lines of T. tauschii and the tetraploid Triticum species were homozygous susceptible. Resistance of the SH wheats and T. tauschii was expressed as antibiosis in that larvae died in the first instar of development.Two resistant SH wheats were crossed with susceptible common wheat (T. aestivum L. em Thell.) cultivars ‘Amigo’ and ‘Eagle’ to study the inheritance of Hessian fly resistance derived from T. tauschii. F2 populations segregated in a 3:1 ratio of resistant to susceptible plants, an indication that resistance was conditioned by a single dominant gene. Segregation ratios of F3 lines and F3 plants within segregating lines supported the single‐factor resistance hypothesis. F4 lines derived from homozygous resistant F3 lines bred true for resistance, On the basis of present knowledge of genetic relationships among wheat genes for resistance to Hessian fly, T. tauschii appears to be a new source of resistance that can be readily transferred to hexaploid wheat.
Release of Soluble Protein and Nitrogen in Alfalfa. I. Influence of Growth Temperature and Soil Moisture1
Authors: Walgenbach R. P. , Marten G. C. , Blake G. R. 
Published: July 2010

The influence of climatic and soil factors during growth on release of soluble protein from alfalfa (Medic ago saliva L.) has not been studied. Herbage proteins soluble in sodium male ate buffer (pH 6.9) have been proposed as possible estimates of ruminant bloat potential in comparative studies. Our objectives were to determine whether growth temperature or soil moisture availability at different growth temperatures would influence concentration of several N fractions released from alfalfa.‘Ramsey’, ‘Saran ac’, and ‘Desert’ alfalfa cultivates were grown at 18/10, 26/18, and 34/26 C (day/night) with a 16 hour photo period (3 × 3 factorial). Total (TN), total soluble N (TAN), soluble non protein (SPN), and soluble protein N (SPN) were determined.As the temperature increased, the mean concentration of TN, TAN, and SPN increased in leaves, stems, and total forage. The greatest concentration of SPN in leaves occurred at 26/18 C (x̄ of 11.5 mg/g dry wt), compared to 18/10 C (x̄ of 9.9) or 34/26 C (x̄ of 10.4). The mean SPN concentration in stems increased as temperature increased from 2.7 mg N/g dry wt at 18/10 C to 3.0 mg at 26/18 C and 3.7 mg at 34/26 C. The total forage of any cultivate grown at any temperature contained approximately 6.6 mg SPN/g dry wt, except Desert grown at 18/10 C contained 5.6 mg SPN/g dry wt.We conclude that the apparent bloat potential, estimated as SPN release, of alfalfa leaves of all cultivates grown at 26/18 C was greater than that of leaves grown at 34/26 and 18/10 C. Little difference in apparent bloat potential occurred in total forage regardless of cultivate or temperature during growth.Ramsey and Saran ac alfalfa were grown at 18/10 and 26/18 C with a 16 hour photo period. Three soil moisture regimes (R) were imposed at each temperature; soil matrix potentials between −0.1 to −0.5 (R I), −1.0 to −6.0 (R 2), and −6.0 to −15.0 bars (R 3) were established before the soil was restored to field capacity (2 × 3 factorial within each temperature).With a few exceptions, the concentrations of the N fractions in leaves, stems, and total forage of both cultivates generally increased as the soil moisture content decreased from R 1 to R 3 at each temperature. The leaves, stems, and total forage of both cultivates grown at 26/18 C contained greater concentrations of all N fractions than did those of cultivates grown at 18/10 C, which confirmed results of Experiment I.Apparent bloat potential, as estimated by SPN release, of leaves, stems, and total forage increased slightly with moistur6 Stress at 18/10 C. At 26/18 C, apparent bloat potential only of stems increased with moisture stress. Insofar as moisture stress occurs in practice more often at warm temperatures, it is not likely to influence alfalfa bloat potentially instigated by soluble protein release.
Seed Width to Pod Width Ratio for Identification of Green Soybean Pods that have Attained Maximum Length and Width1
Authors: Rodriguez de Cianzio S. , Frank S. J. , Fehr W. R. 
Published: July 2010

Efficient indirect selection for seed weight in a soybean [Glycine max (L.) Merrill] breeding program on the basis of the width or length of green pods requires a rapid technique for determining maximum dimensions of the pods. Our objective was to determine if the ratio of seed width (SW) to pod width (PW) could be used to establish when green pods have attained maximum width and length. Seed and pod development of nine soybean lines differing in seed weight were evaluated in Ames, Iowa, and in two environments at Isabela, Puerto Rico. Width of the seeds and pods were measured from suture to suture and pod length (PL) was measured from the base of the sepals to the tip of the pod.Differences among lines and environments were statistically significant in the combined analysis of variance for the SW/PW ratio at the earliest time that maximum PW and PL occurred. Among lines and environments, seeds were 28 to 50% as wide as the pods when maximum PW and PL first occurred. Data combined over environments indicated that all lines attained a SW/PW ratio of 50% within 4 days after the earliest time that maximum PW or PL occurred. The results indicated that 50% would be a conservative SW/PW ratio for assuring that a green pod had reached its maximum width and length. Use of the SW/PW ratio is an efficient method of determining the earliest time that green pods can be measured for indirect selection of seed weight in soybeans.
Optimal Population Density and Random vs. Selective Elimination of Genotypes Under a Modified Single‐Seed Descent Method with Spring Oats1
Authors: Cisar G. , Howey A. E. , Brown C. M. 
Published: July 2010

A modified single‐seed descent (SSD) method of generation advance is used in the Univ. of Illinois spring oat (Avena Saliva L.) breeding program. The method couples high plant density with limited soil fertility and moisture levels to produce a population with a high proportion of single or few seeded plants, along with some barren plants. Questions regarding the technique are twofold: 1) what population density will yield a high proportion of plants with one or very few seeds and a minimum of barren plants, and 2) are the genotypes which are lost due to barrenness randomly or selectively eliminated?In a series of population densities, ranging from 10 to 150 seeds per 15‐cm clay pot in 10 seed increments, 30 to 40% of the plants grown at densities of 100 to 150 seedlings per pot produced single seeds. Populations of 120 to 150 seedlings per pot allows adaptation of the technique to the SSD principle with a considerable savings in harvest time and greenhouse space.To determine whether barren plants were randomly or selectively eliminated, progenies of two segregating crosses were grown at high (60 seedlings per pot) and low (10 seedlings per pot) population densities. After two generations of modified SSD, 34.5% of the original population was lost due to barrenness at the high density in one cross and 26.5% in the other. Seed of surviving genotypes was increased for a replicated field trial where maturity (days after 1 June), plant height (cm), oil content (nuclear magnetic resonancevalue), and grain yield (g/hill plot) were measured. Means and variances between progenies advanced under high or low densities generally did not differ for any of the traits, leading to the conclusion that the genotypes eliminated due to barren plants were randomly and not selectively eliminated due to selection pressures of the technique.
Hilum Color Variation in Soybean Seed with Imperfect Black Genotype1
Authors: Taylor B. H. , Caviness C. E. 
Published: July 2010

Hilum color of soybean [Glycine max (L.) Merr.] seed is one of the traits commonly used to differentiate offtypes for seed certification. Variation in hilum color in imperfect black genotypes has resulted in difficulty in classification. The objective of this research was to determine the accuracy of visual classification of hilum color in genotypes with imperfect black hila.Seeds with buff hila were selected from the cv. ‘Pickett 71’ which normally produces seed with imperfect black hila. Forty‐two percent of the plants grown from these seeds produced plants that had seeds with typical imperfect black hila which were the Pickett 71 genotype. Progeny tests showed that the remaining 58% were offtypes. These data clearly showed that visual selection of buff offtypes from the Pickett 71 cultivar was not an accurate method of identifying hilum genotypes. Plants must have gray pubescence, purple flowers, and the R gene to produce seeds with imperfect black hila; therefore, certain offtypes can be quickly identified by growing seedlings and observing hypocotyl color. Seedlings with green hypocotyls will produce white flowers. Seeds that produce seedlings with green hypocotyls definitely are not imperfect black genotypes, but seeds with buff hila that produce seedling with purple hypocotyls may not be offtypes.
Respiration, Carbohydrate Content, and Leaf Growth of Tall Fescue1
Authors: Moser L. E. , Volenec J. J. , Nelson C. J. 
Published: July 2010

Tall fescue (Festuca arundinacea Schreb.) was grown in controlled environment chambers with a 14‐hour photoperiod, and then kept in darkness for 8 days in one experiment and 20 days in another. The objectives were to determine concentrations of total nonstructural carbohydrates (TNC) and relate them to leaf elongation rates (LER) and to rates of dark respiration (RD). After various times in darkness, leaf terminal meristems in vegetative tillers, root tips, and center‐sections of collared leaf blades were excised, and oxygen consumption was measured.Oxygen consumption was generally highest in terminal meristems, intermediate in root tips, and lowest in mature leaf blades. For the first 6 days the daily LER was greater in plants growing in darkness compared with those in 14‐hour photoperiods. From 6 to 12 days of darkness, LER was similar on both sets of plants. After 12 days the dark‐grown plants had lower LER. By extrapolation of the LER/RD, relationship to zero LER, maintenance respiration of leaf terminal meristems was estimated to be about 0.95 μ1 02‐mg structural dry weight (SDW)‐1.hour‐1, which represented 24% of the oxygen consumed. Collared leaf segments approached maintenance levels of RD after 2 days of darkness and root tips after 8 days. However, terminal meristems had a high TNC concentration and continued to support leaf growth actively for up to 16 days of darkness. The RD, TNC, and LER were all directly associated. Maximum RD in terminal meristems occurred at 35% TNC while LER remained similar when TNC levels were higher than 28%. In mature leaf tissue about 60% of the oxygen consumption was associated with maintenance respiration.
Cultivar Differences in Canopy Apparent Photosynthesis and Their Relationship to Seed Yield in Soybeans1
Authors: Wells R. , Schulze L. L. , Ashley D. A. , Boerma H. R. , Brown R. H. 
Published: July 2010

Differences in leaf photosynthesis among soybean [Glycine max (L.) Merr.] genotypes have not been shown to be correlated with seed yield, probably because leaves selected for measurement have not been representative of the soybean canopy. In order to obtain a measure more representative of photosynthesis by plant communities and to explore the relationship of canopy apparent photosynthesis (CAP) to seed yield, field experiments were conducted during 2 years. Four soybean cultivars in each of four Maturity Groups (V through VIII) were grown in field plots in 1975 and two of each Maturity Group were grown in 1976. Measurements of CAP were made throughout the reproductive period by placing a large plastic covered chamber over a square meter segment of the canopy and measuring CO2 depletion during a 1 to 2 min period. Measurements were made near noon when solar radiation was above 0.9 Ly/min.Maximum values of CAP were 4 to 6 g CO2m‐2hr‐1 during the early reproductive stages and decreased with age throughout pod filling. The decrease was most rapid for Maturity Group V and slowest for Group VIII. Dates when CAP dropped to zero were mid‐September for the Group V cultivars and mid‐October for Group VIII. Differences in CAP among cultivars occurred during seed development for all Maturity Groups. These differences could not be attributed to leaf area index or light interception since differences in CAP occurred while light interception was above 97%. Seed yield also differed among cultivars within Maturity Groups, the range in yield being from about 2,000 to 3,600 kg/ha in both years. Correlation coefficients for the association between yield and CAP measured during seed development were significant and ranged from 0.43 to 0.62. An integral of the CAP measurements from the full‐pod stage of development (R‐4) to maturity was correlated with yield with a coefficient of 0.66 in 1975 and 0.59 in 1976. Data from these experiments indicate that yield differences among cultivars are partially accounted for by differences in photosynthetic capacity of the plant canopy during seed development.
Regeneration of Proso Millet from Embryogenic Calli Derived from Various Plant Parts1
Authors: Heyser J. W. , Nabors M. W. 
Published: July 2010

Totipotency in cereal tissue cultures is often lost soon after callus initiation. Work by others with embryogenic cultures derived from various plant parts suggests that long term totipotent cultures can be obtained for some cereals and grasses. Long term totipotent tissue cultures of proso millet (Panicum miliaceum L.) which readily regenerated normal fertile plants were sought.Calli were initiated from immature embryos, mature seeds, mesocotyls, and leaf and stem segments cultured on Linsmaier and Skoog medium (L and S), 4% sucrose, 1% agar, and variable levels of 2,4‐D or 2,4,5‐T. For seeds, most callus was initiated on 1 mg/1 2,4,5‐T. Less callus was initiated by dark‐cultured seeds than by light grown seeds on 2,4‐D. Only dark‐grown seeds and immature embryos produced embryogenic callus on the first (initiation) passage. In light grown secondary callus, embryogenic and nonembryogenic calli had similar growth during a 6 week culture period. After 24 weeks in culture, 32% of embryogenic calli formed shoots as compared with 2% of non‐embryogenic calli cultured on no auxin.
Morphology and Yield in Winter Wheat Grown in High Yielding Conditions
Authors: Ledent J.F. 
Published: July 2010

To reassess the relations of morphological characters and yield components in high yielding field conditions measurements were taken on a series of modern cultivars of winter wheat (Triticum aestivum L. em. Thell.) over 4 years. Morphological traits measured were leaf area, leaf dry weight, leaf area duration, specific weight of each of the three uppermost laminae, maximum width of the two upper laminae, dry weight and length of the flag sheath and peduncle, and of ear weight at anthesis. The relationships of these characters with yield/m2, yield/shoot, and yield components (no. spikes/m2, kernels/spikelet, spikelets/spike, kernel weight) were investigated across cultlvars using simple correlation, canonical correlation, multiple regression, factor, and principal components analyses.Yield/shoot but not yield/m2 was related to plant morphology. Dry weight of the flag sheath and of the second or third uppermost laminae were associated with the components of yield per shoot. Leaf area, leaf area duration and specific leaf weight were poorly associated with yield/shoot or yield/m2. There was a consistent negative relationship between yield/shoot and number shoots/m2. No yield component ranked consistently above the others in its relation to yield/shoot. The relationships with yield/shoot were not simply due to the association among vegetative areas producing assimilates and plant parts using them to grow in a predominantly source limited situation. The results could be explained by developmental correlations arising during the period of rapid stem elongation preceding anthesis.
Relationships among Seedling and Mature Root System Traits of Maize1
Authors: Arihara J. , Crosbie T. M. 
Published: July 2010

Maize (Zea mays L.) breeders often have resorted to various techniques, which measure root strength or type, in an effort to select for decreased root lodging. Seedling root traits of S1 lines selected for high and low mature root‐pulling resistance in the field from C0 and C8 cycles of Iowa Stiff Stalk Synthetic [BSSS(R)] and Iowa Corn Borer Synthetic #1 [BSCB1(R)] were studied in a preliminary experiment. Also, we used 90 S1 lines from each of the C0 and C8 cycles of BSCB1(R) to estimate genetic parameters for seedling root‐pulling resistance.Estimates of heritability for seedling pulling resistance were 0.56 ± 0.15 and 0.42 ± 0.16 for 90 random S1 lines from each of the C0 and C8 cycles of BSCB1(R). Predicted genetic advance was 0.7 kg/plant for BSCB1(R)C0 and 0.6 kg/plant for BSCB1(R)C8. Estimates of S1 line × environment interactions for seedling pulling resistance of selected, low and high lines from C0 and C8 cycles of BSCB1(R) were not significant when measured in two greenhouse environments. Rank and genotypic correlation coefficients, however, between seedling root‐pulling resistance and mature rootpulling resistance measured at two dates and between seedling pull and lodging were small (all r‐values were lower than 0.33). Selection differentials for root pulling resistance at any stage suggested that selection would be more effective in discarding lodging‐susceptible lines than in identifying those with superior lodging resistance. We have concluded that selection for high seedling root pulling resistance has limited utility in improving mature root strength of these populations.
Assimilate Distribution in Soybeans as Affected by Photoperiod During Seed Development1
Authors: Cure J. D. , Patterson R. P. , Raper C. D. , Jackson W. A. 
Published: July 2010

The duration of the seed filling period for soybean [Glycine max (L.) Merr.] may be limited by rapid nutrient diversion from leaves to seeds resulting in reduced leaf assimilation capacity. In this study, the effect of short‐day and long‐day photoperiods on the duration and rate of seed filling and on nutrient remobilization were examined in two determinate genotypes, ‘Ransom’ and ‘D72‐8126’. The photoperiod treatments were imposed during the seed development phase in controlled‐environment chambers. Dry matter and N distributions throughout reproductive development were measured.Under long days, both genotypes maintained far greater leaf area and attained greater total and vegetative growth relative to short days. Reproductive growth was decreased 11% for Ransom but was increased 16% for D72‐8126 under long day conditions. The rates of growth and N accumulation per seed also were reduced by long days for Ransom but were unaffected for D72‐8126. The duration of the seed filling period was not extended for either genotype. Seed number was increased 5 and 18% by long days for Ransom and D72‐8126, respectively.Ransom plants grown under long days had higher N concentrations in vegetative parts and lower seed N concentrations than short day plants as the reproductive phase progressed. Long‐day photoperiods caused a similar increase in vegetative N concentrations for D72‐8126, but by final harvest reproductive N concentration under long days was equal to that under short days. Nitrogen remobilization from leaves to seeds under short days did not appear to limit the dry matter or N assimilation efficiency of either genotype.
Genetic Control of Seed Longevity in Soybeans1
Authors: Kueneman E. A. 
Published: July 2010

Soybean [Glycine max (L.) Merr.] seeds have a short storage life, especially in humid, tropical environments. However, a few varieties have been identified recently that have superior seed longevity. The purpose of this study was to determine if seed longevity is under maternal plant influence as is the case with many seed characteristics.Four reciprocal crosses were made between genotypes with good and poor seed longevity. A modified accelerated ageing test, followed by evaluations of seedling emergence from soil, was used to predict seed longevity of F1 seeds for three of the four crosses; for one cross the test was repeated. Differences between reciprocal crosses were significant for all four tests. A hot water stress test was also used to predict seed longevity of reciprocal F1 seeds for two crosses; two tests were run for each cross. The difference between reciprocal F1's was significant in one of the four tests. These results suggest that the maternal plant genome can influence the longevity of soybean seed.The fact that emergence of F1 families was often different from their respective maternal parent and that pooled F2 variances (seed from individual F1 plants) were larger than pooled parental variances, suggests that the genotype of the seed also may influence it's longevity. F2 seeds were examined for differences between reciprocals for one cross. The difference, though relatively small compared to reciprocal F1 differences, was statistically significant suggesting that cytoplasmic gene action may also be involved in expression of seed longevity. Because of the large noncytoplasmimc aternal plant influence, it is suggested that selection for seed longevity be delayed at least until the F3 generation.