bluuebunny/crossref_metadata_2025 huggingface dataset:
Stormproof Boll in Upland Cotton. II. Heritability and Agronomic Relationships1
Authors: Quisenberry J. E. , Dilbeck R. E. , Roark Bruce
Published: July 2010

The stormproof boll is an important characteristic of cotton (Gossypium hirsutum L.) cultivars grown in regions where severe weather prevails after bolls open and where once‐over stripper‐type harvesters are used. The objectives of the study were to determine the heritability of the stormproof trait and to evaluate the relationships among stormproofness and other agronomic and fiber characteristics. A composite cross population was developed from six stormproof and four nonstormproof cultivars. From this population, 79 random F3 plants were advanced by self‐pollination to the F4 and F5 generations. The study was conducted at two locations in 2 years.

At both locations the mean stormproofness of the F4 was significantly larger (by 1.5%) than the mean of the F5 in the same year, indicating residual dominance of the stormproof boll after three generations of selling in the population. Heritability was high for the stormproof trait when calculated by parent‐offspring regression, but was more consistent over locations and years when it was calculated in standard deviation units. Of the 10 agronomic and fiber traits measured, seed size, fiber length, and fiber strength exhibited a consistent positive association with stormproofness. High stormproof values were related to larger seed and longer, stronger fiber. We speculate that the relationships with fiber length and strength were associated with the tendency of fiber in stormproof bolls to be caught in the folds of the carpel walls. Positive correlations between lint yield and stormproofness at both locations in a year with severe environmental stress was explained as a physical holding of the fiber in the boll (rather than as a genetic effect).
Improvement of Sugarcane Fertility by Modification of Cross‐pollination Environment1
Authors: Berding Nils , Skinner J. C.
Published: July 2010

For routine cross‐pollinatlon of sugarcane (Saccharum sp.), the Queensland Bureau of Sugar Experiment Stations maintains cut flowering stalks in sulfurous acid solution, with panicles enclosed in sheltered, pollen‐proof, cotton bags (lanterns) that are hung in roofed sheds sheltered from wind by light forest. Experiments were conducted in 1975 and 1977 to determine whether seed setting could be improved by modifying the lantern environment (temperature, relative humidity, and light) or by relocating the lanterns. Eight treatments were assessed with a factorial polycross of four female and four male clones, each male being isolated in a separate lantern. When pollination finished, spikelet availability on each panicle and the condition (healthiness) of each flowering stalk were subjectively assessed. Age at harvest, “seed” yield, germination/1 g “seed” sample, and total number of seeds germinated were determined for each panicle. Males were also assessed for pollen fertility in lanterns.

The number of seeds germinated from female panicles was approximately doubled by heating an insulated lantern wi th a 60 W incandescent bulb; heat without light was slightly better than heat with light. A heated but uninsulated lantern gave a 50% improvement in seedlings germinated over the control. A lantern with a clear plastic panel facing the morning sun also performed well but has practical limitations. Lanterns located in a temperature controlled building gave poor results despite temperatures being favorable.

Pollen fertility was not affected by the treatments. Environmental assessment using cross‐pollinated females differed from that with self‐pollinated males, indicating that selection of environments for cross‐poliinatlon based on results with self‐pollination is inappropriate.
Relationships Between Apparent Nitrogen Fixation and Carbon Exchange Rate in Alfalfa1
Authors: Sheehy J. E. , Fishbeck K. A. , Phillips D. A.
Published: July 2010

The distribution of genetic potentials for symbiotic N fixation and carbon exchange rate (CER) was examined in ‘Vernal’ alfalfa (Medicago sativa L.). Symbiotic fixation capability was correlated with whole‐plant CER in plants grown without combined N but was not correlated with innate photosynthetic efficiency measured as CER dm−2 leaf area in the presence of combined N. Values for individual leaf CER of 35 seedlings grown on combined N ranged from 24 to 82 mg CO2•dm−2•hour−1 at 300 ppm CO2 with 1,400 μE•m−2•sec ‐1 photosynthetically active radiation. Carboxylation efficiencies based on either internal or external CO2 concentrations, light and dark respiration of leaves, and leaf resistance also varied over a wide range, but there was little variation in the apparent quantum efficiencles and CO2 compensation points. Twenty‐five seedlings representative of the variation of CER observed in this initial screening were cloned, inoculated with Rhizobium meliloti strain 102F28, and grown without combined N. Leaf area, acetylene reduction, dry weight, and total N were measured for plants from each of the 25 clones. Whole‐plant CER was determined for eight selected clones that had shown high, medium, or low individual leaf CER when grown with combined N. Whole‐plant CER was correlated positively with leaf area, acetylene reduction, and total N of the eight selected clones. Leaf area was correlated positively with both acetylene reduction and total N of all 25 clones. Rankings of acetylene reduction, leaf area, total dry weight, or total N content for plants grown on N2, however, were not correlated with individual leaf CER ranking of the same genotypes grown on combined N. Six genotypes representing a wide range of photosynthetic efficiency and N fixation potential showed few corresponding differences in top growth through three harvests in the absence of combined N.
Predictive Equations for Maize Inbred Emergence1
Authors: Navratil R. J. , Burris J. S.
Published: July 2010

Accurate estimates of maize (Zea mays L.) inbred seedling emergence are currently unavailable. Inbred planting rates, therefore, are adjusted by using criteria normally applied to hybrid seed.

In this study, temperature‐dependent predictive equations that would assist the seedsman in estimating planting rates, to obtain acceptable stands during the planting season, were developed for 15 maize inbreds. The equations were developed on the basis of the multiple linear regression of field emergence on standard germination and days to 50% emergence for all dates of planting. The slopes of the regressions differed among inbreds.

The equations are applied by calculating the days to 50% emergence on the basis of the known number of growing‐degree units that a particular inbred would require to reach 50% emergence. Past meteorological data would be used to estimate the probable number of days required to accumulate the growing‐degree units for any planting date.

It was assumed initially that growing‐degree units to 50% emergence would remain constant while days to 50% emergence could vary for each inbred line and would vary for different field plantings. However, growing‐degree units to 50% emergence for lots within inbred lines, field plantings, and the field plantings by inbred line interactions were all significant at the 0.01 probability level.

Although the variability in growing‐degree units to 50% emergence indicates that we have not yet arrived at a final answer, the predictive equations show considerable promise in reducing the subjectivity presently involved in determining planting rates. The refinement and ultimate application of these equations, as superior predictors of field emergence, will require testing under actual production conditions and a more complete understanding of temperature effects, not accounted for in the formula used to compute growing‐degree units.
Effect of Long‐Term Subfreezing Storage of Seed on Legume Forage Production1
Authors: Rincker Clarence M.
Published: July 2010

Information is not available on the effect of long‐term subfreezing storage of seed on legume forage yields. A field study was conducted in 1978 in which two forage harvests were made in the year of establishment with fresh (3‐year) and old‐ (14‐ to 18‐year) seed of one cultivar of alfalfa (Medicago sativa L.), and two cultivars each of red clover (Trifolium pratense L.), alsike clover (Trifolium hybridum L.), and birdsfoot trefoil (Lotus corniculatus L.). The 14‐ to 18‐year‐old seed had been stored at about −15 C and 60% relative humidity since the year of harvest. Fresh seed of each cultivar was produced in 1975 from the same stock seed used to produce the older seed. Seed age had no effect on forage yields of alfalfa, red clover, birdsfoot trefoil, and one cultivar of alsike clover. Sixteen‐year‐old seed of ‘Iso’ tetraploid alsike clover, with 22% current germination, produced significantly less forage than the fresh Iso seed. One sample of 18‐year‐old ‘Dollard’ red clover seed thawed for 24‐hour periods at weekly intervals (over 900 times in 18 years) produced as much forage as fresh seed. It was concluded that forage yields would not be affected by long‐term subfreezing storage of seed if the seed had good germinability after storage.
Variation in the Response of Alfalfa Clones and Cultivars to Mycorrhizae and Phosphorus1
Authors: Lambert D. H. , Cole H. , Baker D. E.
Published: July 2010

A greenhouse study was conducted to evaluate alfalfa (Medicago saliva L.) clones for phosphorus efficiency and to assess the interactions of mycorrhizal inoculation and plant genotype as they affect shoot weight and element concentrations. Six clones from each of six cultivars were grown in partially sterilized, low‐P soil treated with either 0, 30, or 80 ppm P, O P and mycorrhizal inoculum, or 80 ppm P and mycorrhizal inoculum. In the O P treatments, plant growth without mycorrhizae was significantly less than growth of mycorrhizal (MR) plants, while at 80 ppm P growth of nonmycorrhizal (NMR) plants was greater than growth of the corresponding MR plants for most clones but less hi some. Cultivar ✕ MR and clones in cultivar ✕ MR interactions for plant growth were significant. Maximizing P deficiency to select P‐efficient clones was unsuccessful as dry weights of nonmycorrhizal, low‐P plants were not correlated with dry weights of any other treatments, and only the two mycorrhizal treatments were highly correlated. At the 80 ppm level of P, mycorrhizae increased P, Cu, Zn, and Fe, decreased Mg and Ca, and did not affect Mn and K concentrations. Cultivar ✕ MR interactions were significant for Cu and Zn concentrations and clones in cultivars ✕ MR interactions were significant for all elements. These results indicate that screening of alfalfa lines for P efficiency or for content of P, Cu, and Zn should be conducted under natural (mycorrhizal) conditions.
Laboratory Packed Sand Test for Measuring Vigor of Sugarbeet Seed1
Authors: Akeson W. R. , Widner J. N.
Published: July 2010

Emergence of sugarbeet (Beta vulgaris L.) seedlings is a major problem affecting stand establishment in sugarbeet production. Our objectlve was to evaluate a packed sand laboratory procedure for measuring vigor of sugarbeet seed and relate it to field emergence under a range of conditions.

Results from the packed sand test measuring percent emergence of seedlings through silica sand, 3.8 cm thick, 4% water (wt/wt), and 10 C, were highly correlated (r = 0.89 to 0.98) with field emergence in tests with seed lots of commercial cultivars, whereas standard germination was not a reliable indicator of emergence potential. The average field emergence of seed lots of four commercial cultivars, ‘GWH 45,’ ‘GWH 48,’ ‘GWH 93,’ and ‘GWH 115,’ ranged from 29.7 to 54.3, 34.3 to 68.8, 30.9 to 49.7 and 19.5 to 29.0%, respectively. Identification and utilization of high vigor seed lots would improve overall seedling emergence under most conditions. The procedure as described provides a tool for investigating cultural practices influencing emergence as well as a quality control test to aid in processing seed for improved seed vigor.
Antixenosis of Smooth Leaf Cotton to the Ovipositional Response of Tobacco Budworm1
Authors: Robinson S. H. , Wolfenbarger D. A. , Dilday R. H.
Published: July 2010

Cottons (Gossypium spp.) ranging from glabrous (Smooth leaf) to Pilose were compared to determine their effects on I he ovipositional response of the tobacco budworm moth, Heliothis virescens (F.). The numbers of trichome branches/cm on the margin, midrib, secondary vein, and petiole., and in an area of the lamina of young fully expanded cotton leaves were positively correlated with the number of eggs laid on cotton plants. Tobacco budworm moths laid fewer eggs on leaves of cottons with no more or fewer trichome branches than those found on ‘Deltapine Smooth Leaf’ than on the normally pubescent cultivar ‘Stoneville 213’ or on the densely pubescent (Pilose) line. Stoneville 213, a pubescent near‐isoline, and a Smooth leaf near‐isoline (Sm2) in Stoneville 213 background, were tested in solid and mixed plantings. Significantly fewer eggs were laid on the Smooth leaf cotton than on the pubescent cottons whether or not the tobacco budworm had a choice of hosts. In a laboratory test, bond paper, synthetic net, rayon, cheesecloth, and muslin fabric were compared in no‐choice and freechoice tests as ovipositional surfaces. Those with textures that had fibers with the highest numbers of loose ends (cheesecloth and muslin) were preferred by tobacco budworm females.
Inheritance of Slow Leaf‐rusting Resistance in Suwon 85 Wheat1
Authors: Kuhn Roger C. , Ohm H. W. , Shaner G.
Published: July 2010

The inheritance of slow leaf‐rusting resistance of the wheat (Triticum aestivum L. em. Thell) cultivar ‘Suwon 85’ was studied in crosses with susceptible cultivars ‘Monon’ and ‘Suwon 92.’ Plants were grown in the greenhouse and inoculated with Puccinia recondita Rob. ex Desm. f. sp. tritici. Two components of slow leaf‐rusting resistance, latent period and pustule size, were measured. The distribution of Suwon 85/Suwon 92 F3 family mean latent period indicated partial dominance for short latent period, but gave little evidence of distinct classes. A model that assumed two genes with equal effect and an equal degree of dominance (0.6) for shorter latent period was constructed from earlier data. F3 families were classified into F2 genotypes based on the family mean, range and apparent segregation. The resulting classification gave an acceptable fit to the two gene model. Thus, a lack of distinct classes in an F2 distribution should not be interpreted as proof of polygenic inheritance. Pustule size was correlated with latent period in the F3 (r = −0.55 to −0.63) but there were genetic differences between F3 families for pustule size even after adjustment for latent period differences. F1 and BCF1 latent period data from the cross Suwon 85/Monon appeared to fit the two gene model described above, but population size was too small to adequately confirm this model.
Influence of Planting Pattern on Estimated Digestibility of Smooth Bromegrass1
Authors: Ugherughe P. O. , Drolsom P. N. , Davis J. R.
Published: July 2010

Digestibility estimates of most forage grasses in the early stages of breeding programs are based upon samples obtained from spaced plants in nurseries rather than from solid stands as grown on farms. The purpose of this research was to examine the relationship between digestibility estimates of spaced plants and solid stands of smooth bromegrass (Bromus inermis Leyss.).

Whole plants and plant parts of 30 smooth bromegrass genotypes were evaluated for digestibility for 2 years. The acid‐pepsin and the modified two‐stage in vitro digestion techniques were used with three sampling dates each year.

In both years, genotypes differed significantly in stem, leaf, and panicle acid‐pepsin dry matter disappearance (APDMD) at each harvest under the two planting patterns, except for the first harvest of solid stands in the 2nd year. No differences were found among genotypes for whole plant APDMD under solid stands for each of the three harvests in 1978. Spaced plant harvests differed significantly in APDMD in the 2 years while there were no significant differences in APDMD among harvests of solid stands in 1978. Among the plant parts at the first harvest, the APDMD of leaves and stems correlated best with whole plant APDMD, with leaves the highest.
Comparison of Inbred vs. Single‐cross Testers and Estimation of Genetic Effects in Sunflower1
Authors: Miller J. F. , Hammond J. J. , Roath W. W.
Published: July 2010

The objectives of this study were to determine relative effectiveness of inbred versus single‐cross testers in identifying combining ability of inbred sunflower (Helianthus annuus L.) lines; to determine whether epistasis was significant in the genetic systems controlling selected traits; and to evaluate the importance of additive and dominance variance for traits not influenced by epistasis. The hybrids evaluated in this study were formed by crossing the inbred lines RHA 274 and RHA 278, and their single‐cross, RHA 274/RHA 278, to 10 randomly selected female inbred lines. The design used was a variation of the triple testcross, an extension of the Experiment III design.

The interaction of female ✕ restorer parent was significant, indicating that the three testers did not rank the female lines identically for yield. However, the three testers did identify three of the top four lines when a 40% selection criterion was applied. For oil percentage, the interaction of female ✕ male parents was nonsignificant indicating that the three testers gave very similar rankings. Utilizing any one of the three testers will differentiate or identify high‐yielding potential female lines for yield and oil percentage in a population improvement or inbred development program.

Epistasis was a minor factor in the overall genetic variation for all traits studied in these sunflower lines. Additive variances were most important, with dominance variances important only for yield. The estimate for degree of dominance for yield (0.62) indicated that partial dominance predominated, an observation with significant implications for breeders in countries that primarily use open‐pollinated cultivars. Improvement by development of high‐yielding synthetics or open‐pollinated cultivars should be continued. The results also indicate that breeders should develop population improvement schemes that utilize the large additive portion of genetic variance detected in this study.
Influence of Cultivar, Between‐row Spacing, and Plant Population of Fixation of Soybean1
Authors: Bello A. B. , Ceron‐Diaz W. A. , Nickell C. D. , El Sherif E. O. , Davis L. C.
Published: July 2010

An evaluation of the seasonal trends in nitrogen fixation by three soybean [Glycine max (L.) Merr.] cultivars differing in growth habits was made at two locations in Kansas. Two planting dates—May and June; two row spacings—38 cm and 76 cm—and two plant populations— 380,000 and 760,000 plants/ha were examined. Root samples were assayed weekly for acetylene reduction commencing from 3 weeks after planting until physiological maturity. The trends in N2‐fixation (acetylene reduction) for May and June plantings at both locations were similar for all cultivars, although more N2 was fixed at the location where the soil was sandy and low in available soil N. There was a linear relationship between N accumulation and N2‐fixation. After pod filling Wiliiams (indeterminate) fixed more N2 than the other cultivars. Elf (determinate) was consistently low in N2‐fixation ability throughout the sampling period. There was a significant positive response in Nrfixation to higher plant population at both locations. However, the effect of plant population was not evident in increasing total plant N uptake, seed N, or seed yield. The eariy planting date favored N2‐fixation by allowing a longer period of active fixation but showed no advantage in seed yield or total N accumulation.
Diallel Analyses of Resistance to the Adult Pea Leaf Weevil in Peas1
Authors: Auld D. L. , O'Keeffe L. E. , Murray G. A. , Smith J. H.
Published: July 2010

Plant Introductions (PI) of peas (Pisum sativum L.) resistant to the adulit pea leaf weevil, Sitona lineatus (L.) were crossed to cultivars of winter peas [P. sativum subsb. arvense (L.) Poir] and spring peas in a nonreciprocal diallel manner. The eight parental lines and F1 and P2 populations were evaluated for resistance to the pea leaf weevil under laboratory and/or field conditions. Combining ability analyses indicated that significant variation due to general combining ability (GCA) effects were present for resistance to the adult pea leaf weevil. Specific combining ability (SCA) had a significant effect on weevil resistance in only half of the eight analyses. There appeared to be sufficient GCA to support a breeding program for the development of weevil resistant cultivars. PI 263010 and PI 343983 had large negative GCA estimates and appear to be the best parents to use in the development of resistant cultivars. These PI's were generally more resistant than the commercial cultivars tested in both field and laboratory evaluations. The PI's expressed resistance under the intense pressure of 16 adult pea leaf weevils per plant in the laboratory.
Genetic and Soil Moisture Effects on the Branching‐Root Trait in Alfalfa1
Authors: McIntosh M. S. , Miller D. A.
Published: July 2010

The inheritance of the branching‐root trait in alfalfa, Medicago saliva L., was studied in diallels at two field locations. Diallel progenies of seven clones were grown in spaced plantings at Champaign‐Urbana and Brownstown, Illinois. Roots of 6‐month‐old alfalfa branched more at Brownstown than Champaign‐Urbana. At Champaign‐Urbana significant differences were found for general but not specific combining ability. At Brownstown, differences were significant for specific combining ability but not for general combining ability. General combining ability × location interaction also was significant. Reciprocal and selfing effects were not important at either location. Regression estimates of offspring on S1 parent were 0.128 and 0.002 for the Brownstown and Champaign‐Urbana locations, respectively.

A greenhouse experiment was conducted to determine whether moisture stress contributes to the genotype × environment interaction for the branching‐root trait. Progeny of six crosses, whose parents represented a wide range in rooting habit, were grown in pots with soil moisture levels increased daily to − ⅓) bar onto 50% of the − ⅓ bar moisture level. Low moisture levels resulted in plant stress exhibited as a decrease in plant height and dry weight. Plants grown in the low moisture regime also had a lower incidence of branching roots. The genotype × moisture interaction was nonsignificant. Among moisture‐stressed plants, height and weight were positively correlated with root branching (r = 0.81 and 0.60, respectively. Both are significant at the 0.01 level.). For unstressed plants, only plant weight was significantly correlated with the branching root habit (r = 0.49, significant at the 0.05 level.).
Differential Response of Kenaf to Gray Mold1
Authors: Campbell T. A. , O'Brien Muriel J.
Published: July 2010

The response of 11 cultivated and five wild types of kenaf (Hibiscus cannabinus L.) to gray mold, caused by Botrytis cinerea Pers. ex Fr., was studied at the 1‐weekold plant stage in the greenhouse and at the mature plant stage in the field. Highly significant differential responses were noted in the greenhouse and field. Greenhouse and field responses, however, were not totally consistent. Genetic variation may be sufficient so that resistant strains can be developed. Analyses indicate that the greenhouse technique may be effective in isolating strains that would demonstrate some level of field susceptibility but that the development of field resistance can only be accomplished by greenhouse or field screening of mature plants.
Variability of Protoplast‐derived Potato Clones1
Authors: Secor Gary A. , Shepard James F.
Published: July 2010

Sixty‐five selected clones of potato (Solanum tuberosum cv. Russet Burbank) regenerated from mesophyll protoplasts (protoclones) were analyzed for variability under field conditions. Protoclones were planted in randomized complete blocks replicated six times. During the growing season and after harvest a total of 35 characters were measured for each clone and compared with similar measurements from the parental ‘Russet Burbank’ and with another virus‐tested clone of the cultivar. Statistically significant variation was found for 22 characters, variation not amenable to statistical treatment in 4 characters, and no variation in 9 characters. Protoclones were nearly equivalent in most characters to both Russet Burbank standards. However, quantitative data showed that each protoclone differed from Russet Burbank in some trait(s). Variation ranged from a minimum of one character in three protoclones to a maximum of 17 characters in one protoclone. Differences in vine morphology, tuber yield and composition, maturity and flowering were observed. Some of the variability found should be an improvement over normal traits found in the normal cultivar. Further testing is necessary to determine both the stability of and the effect of the environment on this variability. However, the data do suggest that for potatoes, protoplast regeneration may offer a new means of generating variability of potential use for crop improvement.
Drought Stress and Its Effects on Maize Reproductive Systems1
Authors: Herrero Maria Pilar , Johnson R. R.
Published: July 2010

Moisture stress during pollination of maize (Zea mays L.) can greatly reduce kernel set, yet little quantitative information is available on the effects of plant water status on male and female floral development. The purpose of this study was to establish different drought stress regimes during pollination and to measure synchronization of male and female floral development, pollen viability, and diurnal silk elongation rates. Single cross hybrids were field‐grown in large pots and exposed to different soil moisture treatments at the time of tassel emergence. Compared to well‐watered control plants, mild (no visible wilting) and severe (visible wilting) drought treatments increased the interval from initial silking to initial pollen shed by an average of 3 and 4 days, respectively. Increasing moisture deficits caused no change in in vitro pollen germination even though the severest drought treatment caused visible symptoms of midday wilting and of lower leaf senescence. Diurnal silk elongation measurements indicated that on clear days the majority of silk elongation occurs at night when ear leaf water potentials are highest. At similar morning leaf water potentials, stressed plants maintained a lower silk elongation rate than well#x2014;watered plants. Positive silk elongation ceased at ear leaf water potentials of about #x2014; 9 bars in droughted plants and at #x2014; 14 bars in well—watered plants, suggesting that factors other than water potential may also regulate rate of silk growth. It is concluded that drought beginning at anthesis has a greater effect on female than male floral development.
Callus Initiation and Plant Regeneration from Triticale Embryos1
Authors: Sharma G. C. , Bello L. L. , Sapra V. T. , Peterson C. M.
Published: July 2010

This study was conduced to determine optimal concentrations of sucrose and combinations of growth regulators required for callus initiation and plant regeneration from immature embryos of 'Councill' and other triticales (X Triticosecale Wittmack) and to make histological observations of triticale callus during differentiation and organogenesis. Immature triticale embryos were cultured on a basal medium containing the salts of Murashige and Skoog and vitamins plus selected concentrations of sucrose and different auxins or cytokinins, alone or in combination. The optimal concentration of sucrose for increasing fresh weight of callus derived from hexaploid embryos was 20 g/liter. The addition of 2, 4‐D [(2, 4 dichlorophenoxy) acetic acid] to the basal medium was superior to the addition of IAA (indoleacetic acid), kinetin (6‐furfurylaminopurine) and auxin/cytokinin combinations for both callus initiation and growth. higher concentrations of 2, 4‐D (6 mg/liter) promoted callus initiation and growth, but prevented plant regeneration on callus subsequently subcultured to a medium without growth regulators. Histological observations gave evidence of formation of active growth centers or meristemoids in callus. These subsequently led to differentiated root primordia. Our study showed that triticale embryos behaved similar to other cereals in their callus initiation and plant regeneration traits.
Development of Short‐Statured Soybean Cultivars1
Authors: Cooper R. L.
Published: July 2010

A soybean [Glycine max (L.) Merr.] breeding program which emphasized short stature was carried out to alleviate the effect of lodging in reducing seed yields. The primary approach taken was to cross high yielding indeterminate (Dt1) Cultivars grown in the northern United States with high yielding determinate (dt1) cultivars grown in the southern U.S. with selection in the resultant progeny for high yielding determinate plant types adapted to the Midwest. From 150 crosses each year determinate, short‐statured progeny were selected in the F2 and subsequent generations and evaluated for yield, using an early‐generation testing procedure. Short‐statured selections with adaptation to high yield environments were developed that exceeded the yield of broadly adapted “universal” cultivars when grown in their specific area of adaptation. The determinate gene (dt1) and other genes which complement dt1 from southern U.S cultivars were most useful in producing the high yielding short‐statuted types. Introducing the dt1 gene from determinate isolines of indeterminate cultivars produced short‐statured progeny, but high productivity was not obtained. The addition of the E1 gene in combination with dt1 was also ineffective in producing high yielding short‐statured types. The short‐statured lines were more responsive to narrow rows and high seeding rates than indeterminate cultivars. Narrow row spacing (17‐cm) at a seeding rate of 75 seeds/m2 produced maximum yields. The short‐statured lines, because of their determinate growth type, were less able to compensate for early season moisture streess than standard‐height cultivars. Thus the short‐statured types selected produced very high yields in good environments, but with some loss in yield in poor environments.
Yield Stability of Forage Sorghum in Northeastern Brazil1
Authors: Faris M. A. , de Araujo M. R. A. , de A. Lira M.
Published: July 2010

Ten forage sorghum [Sorghum bicolor (L.) Moench] selections, one commercial sorghum cultivar, and one local maize (Zea mays L.) cultivar were grown in replicated trials at 12 locations in the semi‐arid tropics of northeastern Brazil for 3 years. Superiority of some of the new selections in forage dry matter production over the commercial cultivar and corn check was demonstrated.

The combined analysis revealed that entries (G), environments (E), and the G × E interaction were highly significant. However, some nonlinearity existed which necessitated transformation of the data to the logarithmic scale which gave better fitting regression lines. Two of the highest yielding entries possessed the greatest stability. The results showed that better data interpretation came from the log transformed data and that stability parameters should be considered in selection among high yielding cultivars.
Genes Conditioning Resistance of Hordeum spontaneum to Erysiphe graminis f. sp. hordei1
Authors: Moseman J. G. , Baenziger P. S. , Kilpatrick R. A.
Published: July 2010

Wild relatives of commercial crops have provided many useful genes for disease and insect resistance. In this study the number of genes that condition resistance to Erysiphe graminis DC. ex Merat f. sp. hordei (Em. Marchal), which incites barley powdery mildew, in five Hordeum spontaneum C. Koch accessions (a wild relative of barley, Hordeum vulgare L.) were determined using a technique of double inoculation with two pathogenic cultures. PI 282660 and PI 354937 had two genes; PI 284750 and PI 296836 had three genes, and PI 296800 had four genes conditioning resistance to the less virulent culture. Based on reactions to the more virulent culture, some resistance genes were no longer effective. PI 282660, PI 284750, and PI 354937 had one gene, PI 296836 had three genes, and PI 296800 had four genes conditioning resistance to the more virulent culture. The double inoculation technique is a powerful tool for determining the number of resistance genes, their relationships, and their effectiveness in conditioning resistance. H. spontaneum germplasm is and will continue to be a useful source of resistance genes to E. graminis hordei.
Seminal Root Morphology and Water Use of Wheat II. Genetic Variation1
Authors: Richards R. A. , Passioura J. B.
Published: July 2010

The resistance to the longitudinal flow of water through the seminal roots of a wheat (Triticum spp.) plant depends largely on the number of seminal axes and on the diameters of their main xylem vessels. With a view to increasing this resistance by breeding, the nature and extent of genetic variation in these root characters were investigated in over 1,000 accessions of both modern and primitive wheats with different ploidy levels and in populations derived from them. The diameter of the xylem vessel proved to be the more tractable character. This was because (1) no accession, or line derived from different F2 populations, had substantially fewer seminal axes than average, whereas some land‐race wheats with acceptably narrow vessels were found, and (2) parent‐offspring regressions established that the heritability of vessel diameter was considerably higher than that of the number of axes. Vessel diameter can be manipulated genetically as was shown by the significant responses to selection in different populations.
Critical Stages of Development for Defoliation of Soybean1
Authors: Fehr W. R. , Lawrence B. K. , Thompson T. A.
Published: July 2010

One objective of our research was to define the most critical stages for defoliation of indeterminate and determinate soybean [Glycine max (L.) Merr.] strains. The second objective was to determine if yield loss from defoliation at R4.5 could be predicted by the average of loss at R4 and R5 and if loss at R5.5 could be predicted by the average of loss at R5 and R6. Response to 100% defoliation for an indeterminate cultivar, ‘Beeson,’ and a determinate experimental strain, A72‐407R, was evaluated at Ames, Iowa during 3 years. The strains were defoliated at R4 (full pod), R4.5, R5 (beginning seed), R5.5, and R6 (full seed).

The indeterminate strain had an average yield loss across stages of 59% compared with 80% for the determinate strain, but the strain × stage interaction was not significant. The most critical stage for defoliation varied among environments, but was either R5 or R5.5 for both strains. The average yield loss at R4.5 of 72% was slightly greater than the average of loss at R4 and R5 of 68%. The average yield loss at R5.5 of 80% was significantly greater than the average of loss at R5 and R6 of 69%. Yield response to defoliation at R4.5 and R5.5 should be considered in estimating yield reduction from factors that cause defoliation of soybeans.
Monogenic Male‐sterility in Rice: Induction, Identification and Inheritance1
Authors: Singh R. J. , Ikehashi H.
Published: July 2010

Monogenic male‐sterility has not been utilized so far in the improvement of rice (Oryza sativa L.) because it is not available to breeders in an agronomically useful genetic background. The objective of this study was to induce male‐sterility in a widely grown rice cultivar ‘IR36.’

One hundred grams each of dried seeds of the rice cultivar IR36 were treated with 0.2, 0.4, 0.8, 1.2, and 1.6% concentrations of ethyleneimine for 1 or 3 hours to obtain monogenic male‐sterile mutants. Seed treatments with higher concentrations and longer durations had greater reductions in the percent seed germination than treatments with lower concentrations and shorter durations. Treatments for 1 hour with 0.4% and for 3 hours with 0.2% concentrations reduced seed germination to 69 and 30%, respectively, and were considered more satisfactory than other treatments. In four M2 progenies, male‐sterile plants with normal meiosis were crossed with control IR36 and segregation in F2 indicated that one recessive gene controlled inheritance for male‐sterility in each of these lines. The male‐sterile plants showed high seed set from outcrossing. Possible use of recessive genes for male‐sterility in rice improvement was discussed.
Inheritance of Bean Seed Globulin Content and its Relationship to Protein Content and Quality1
Authors: Mutschler Martha A. , Bliss F. A.
Published: July 2010

Globulin‐1 (G1) protein, the major storage protein fraction of common bean, Phaseolus vulgaris L., was measured in mature seed using rocket immunoelectrophoresis. Percentage total protein was measured by infrared reflectance. Heritability estimates were calculated for the protein traits and seed yield, and correlations between traits were determined using parental, F2 and F3 populations.

Among the six parents grown in the field in 1977, ‘Endogava Z.N.’ had the highest percentage protein (27.8% protein), while PI 229815 produced the most G1 protein (136.5 mg G1/g flour). Both were low yielding, producing 12 and 13 g seed/plant compared to the highest yielding parent, ‘Bonita’ that produced 66 g seed/plant. Bonita showed the most favorable combination of traits, with levels of 24% protein and 108 mg G1/g flour, in addition to high yield. ‘Swedish Brown’ and WI 74‐2047 had the lowest levels of total protein, (17.4 and 18.5%, respectively) as well as G1 protein (75 and 61 mg/g flour, respectively).

Analyses of 5 of the 15 F2 populations derived from crosses among the six parents were presented in detail. Inheritance of both percentage protein and mg/g flour was quantitative with broad sense heritability estimates ranging from 0.19 to 0.65 and 0.37 to 0.95, respectively. Narrow sense heritability estimates ranged from 0.59 to 0.86 and 0.43 to 0.74 for percentage protein and mg G1/g flour, respectively in four populations.

Mean F2 values of populations resulting from crosses between parents that differed widely for protein amounts were usually intermediate between the two parents. The average values of the five F2 populations resulting from one common parent produced rankings similar to those based on parental values for percentage protein and mg G1/g flour.

Moderate positive correlations between mg G1/g flour and percentage protein were observed in F2 and F3 populations. There was no correlation between yield and mg G1/g flour and low negative correlation between yield and percentage protein. No obvious consistent relationship between available methionine and G1 content was seen, perhaps because of variation in other constituent fractions or the confounding effects of seed tannins. Implications of genetic manipulation of protein fractions and total protein on protein quality improvement are discussed.
Inheritance of Dwarfness in Three Oat Crosses and Relationship of Height to Panicle and Culm Length1
Authors: Marshall H. G. , Murphy C. F.
Published: July 2010

A stiff‐strawed, dwarf oat (Avena sativa L.) line (CI 8447) was crossed to its parental line (NC 2469), a medium‐height cultivar (‘Otee’), and a tall cultivar (PI 258595). All F1 plants were semidwarf for plant height, and all F2 distributions for height were skewed toward the dwarf‐parent mean. Variation for plant height was continuous in the F2 populations from all crosses, but F3 families were readily classified into discrete dwarf, tall, and segregating families. The ratios of parental to segregating families fitted those expected for a model with a difference for one gene. The continuous variation for plant height in the F2 and minor variation within parental type F3 families was attributed to minor effects of modifying genes plus environment. The symbol Dw‐7 was assigned to the single, partially dominant gene. This gene may be useful in developing semidwarf, lodging‐resistant cultivars.

In all three crosses, panicle and culm length were correlated with total plant height and the relationship was linear.
A Genetical Scheme for Isolating Cotton Cultivars1
Authors: Lee Joshua A.
Published: July 2010

When the diploid cotton (Gossypium davidsonii Kell.) species, is crossed with cultivars of the tetraploid species, G. hirsutum L. and G. barbadense L., the hybrid embryos abort, or the seedlings become necrotized and moribund shortly after germination. A complementary lethality intereaction is indicated, the cultivated cottons contributing the factors Le1 and Le2, whereas G. davidsonii contributes at least one factor, Ledav.

A rare genotype in G. barbadense is le1le1le2le2. Crosses between plants of this genotype and G. davidsonii yield viable triploids. Using the technique of hexaploid bridging, I transferred Ledav from G. davidsonii to the cross‐compatible stock, 15‐4. The resulting stock—genotype le1le1le2le2LedavLedav—is not cross‐compatible with a series of cultivars of G. hirsutum and G. barbadense.

Utilizing the le and Ledav alleles, I produced stocks of G. hirsutum that proved to be genetically isolated from a series of G. hirsutum cultivars under both greenhouse and field conditions. The use of the le ‐ Ledav genetical system for isolating cotton cultivars grown for special purposes, such as gossypol‐free seeds, is discussed.
Histology of Healthy and Diseased Orchardgrass Leaves Subjected to Digestion in Rumen Fluid1
Authors: Edwards M. T. , Sleper D. A. , Loegering W. Q.
Published: July 2010

Few studies have been conducted on the effects of stem rust caused by Puccinia graminis Pers. f. sp. dactylidis Guyot et Massinot on forage quality in orchardgrass (Dactylis glomerata L.). Orchardgrass grown in the field was infected with the pathogen or kept free of the pathogen by spraying twice a week with a fungicide to study the effect of the pathogen on digestibility. Cross sections (12μ) of healthy and diseased leaves were examined under a microscope after 2 to 48 hours of digestion in rumen fluid. After 48 hours, 6 to 7 mm sections from healthy leaves were completely digested except for lignified structures, whereas sections from diseased leaves showed no apparent digestion of tissues under uredia and only partial digestion of adjacent tissues. Stem rust of orchardgrass not only reduces forage yield but also reduces forage quality.
Description and Evaluation of a near Infrared Reflectance Spectro‐Computer for Forage and Grain Analysis1
Authors: Shenk J. S. , Landa I. , Hoover M. R. , Westerhaus M. O.
Published: July 2010

Near infrared (NIR) reflectance has been proposed as a procedure to determine the nutritive value of forages and feedstuffs. A Neotec model 6100 scanning monochromator interfaced to a PDP‐11 minicomputer was used for this study. Instruments of this type are called spectro‐computers. Ten computer programs developed at University Park, Penn. were used to operate and test the instrument. The scanning range of the spectro‐computer was from 1,100 to 2,500 nm. Wavelength accuracy was ± 1.0nm, wavelength precision ± 0.01 nm, stray light <0.10%, and system peak to peak and root mean square noises were 0.33 × 10‐3 and 0.05 × 10‐3, respectively, expressed as log (1/R). This high level of monochromator performance permits the spectro‐computer precision to compare favorably with that of the standard laboratory procedures.

Two hundred forage samples were used to test the accuracy of the spectro‐computer system. These samples represented a broad array of species and mixtures, stages of maturity, and harvest locations. Protein and in vitro dry matter disappearance were predicted best with NIR data treated as log of 1/R, resulting in standard errors of prediction of 0.96 and 3.18%, respectively. Other quality parameters were predicted better when the log (1/R) NIR data were transformed to the second derivative. They were acid detergent fiber ± 1.99%, neutral detergent fiber ± 2.27%, lignin ± 1.13%, cellulose ± 1.27%, Ca ± 0.16%, P ± 0.04%, and K ± 0.37%.Further study of the prediction of protein in 90 Canadian wheat (Triticum aestivum L.) samples resulted in a prediction error of 0.17%. We believe this spectro‐computer system is suitable for use in forage and grain analysis.
Leaf Photosynthesis, Leaf Permeability, Crop Growth, and Yield of Short Spring Wheat Genotypes Under Irrigation1
Authors: Fischer R. A. , Bidinger F. , Syme J. R. , Wall P. C.
Published: July 2010

Because of the expected importance of photosynthetic activity to yield, the relationships of leaf photosynthetic traits to crop growth rate and yield in 48 genotypes of spring wheat, were examined under irrigation in northwest Mexico. There were three tall and 33 short (Norin 10‐derived) bread wheats (Triticum aestivum L.), eight short durum wheats (T. turgidum L.) and four triticales (X Tritosecale Wittmack). Photosynthetic activity (A) and leaf permeability viscous air flow (LP) were measured weekly using 14CO2, uptake and an air flow porometer, respectively.

Genotypic effects on A (range 14.7 to 20.4 mg CO2 dm‐2 hour ‐1) and LP (range 5.7 to 11.1 permeability units) were highly significant but species effects were small and nonsignificant. Looking now exclusively at the short bread wheat group, A was unrelated to specific leaf weight or to LP. A on the first sampling at 4 weeks before anthesis and preanthesis crop growth rate (g ‐2 day‐1) were weakly correlated (phenotypic r = 0.42, significant at the 0.05 level), and both these traits were positively correlated with mature plant height (r = 0.56, significant at the 0.01 level, and 0.68, significant at the 0.05 level, respectively). A was also positively correlated with crop growth rate during grain filling (r = 0.46, significant at the 0.01 level) and with yield (r = 0.45, significant at the 0.01 level; yield range 516 to 860 g m‐2). These correlations arose because of the positive influence of days to anthesis on all three traits and probably reflect an increase in sink size (more kernels ‐z) with later anthesis. Yield was positively correlated with LP (r = 0.56, significant at the 0.01 level); the correlations remained significant (r = 0.46, significant at the 0.01 level) after allowance for the negative effect of plant height on both (LP was unrelated to anthesis date). While the cause of this correlation may be indirect, the testing of LP as an early generation selection criterion is suggested. Effects of major Norin 10 dwarfing genes on these relationships are discussed.
Methods for Evaluating Semolina Color in Early Generations1
Authors: Johnston R. A. , Quick J. S. , Donnelly B. J.
Published: July 2010

The feasibility of evaluating seed samples from single plants of durum wheat (Triticum turgidum L.) for semolina color was examined by comparing the relative precision of different combinations of sample sizes and milling methods. Four sample size and mill combinations were used with 10 durum cultivars. The 200‐g sample size milled on the Brabender Quadramat Micromill was the most sensitive test. Data were highly correlated with those from 2‐ and 1‐g sample sizes milled on the Udy Cyclotec mill (r = 0.85 and 0.90, respectively). Consequently, screening for semolina color using 2‐ or 1‐g samples should be effective.