bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating Fusarium Wilt Reactions of Cotton Genotypes1
Authors: Kappelman A.J.
Published: July 2010

Fusarium Wilt reaction of certain cultivars of cotton (Gossypium hirsutum L.) were estimated for years in which they were not actually tested. Actual and estimated or predicted values weret hen compareads were methodosf prediction. Estimatedv alues of the percentage of wilting due to Fusarium oxysporum Schlect. f. vasinfectum (Atk.) Snyd. & Hans. or a given cultivar cotton, calculated as ratios of the susceptible check ‘Rowden,’ were not greatly different from observed wilting percentages. When Rowden was used as the predictive base, only four of 48 values calculated using the ratio method of estimating means fell outside of the 95% confidence limits of estimates made using the least squares regression technique. When the resistant check, ‘Auburn 56,’ was used as the predictive base, 29 of 48 means were outside the 95% confidence limits. However since Rowden was planted much more frequently in all tests, wilting for the cultivar was based on a much larger number of plants grown over the widest range of environments. Reliable estimates of wilting percentages for cotton cultivars not actually grown a given year can then be made using simple ratios based on Rowden.
Inheritance of Resistance to the Wartelle Race of Root‐knot Nematode in Soybeans1
Authors: Boquet D. , Williams C. , Birchfield W.
Published: July 2010

The inheritance of root‐knot nematode (RKN) [Meloidogyne incognita (Kofoid and White) Chitwood] resistance in soybeans [Glycine max (L.) Merr.] was studied in the F1, F2, and F3 generations of a cross between resistant D69‐6344 and susceptible D69‐8178.

Resistant and suspectible parents gave a consistent reaction to RKN regardless of inoculum density. F1 plants, however, were moderately resistant under low RKN densities, moderately susceptible under medium densities, and highly susceptible at higher inoculum densities. These data indicated that susceptibility to RKN was partially dominant. Frequency distributions of segregating populations indicated inheritance of resistance to RKN was a qualitative character conditioned by one major gene with at least one modifying gene.
A Dominant Round Leaf Mutant in Cotton1
Authors: Percival A. E. , Kohel R. J. , Dilday R. H.
Published: July 2010

In 1966, R. H. Dilday found a mutant cotton (Gossypium hirsutum L.) plant showing a combination of the characteristics of the marker mutants round leaf (rl), frego bract (fg), strap leaf (s), Smooth leaf loci (Sm1,Sm2, Sm3), and open bud (ob). Inheritance and linkage tests showed that the mutation was conditioned by a dominant gene. In the homozygous state the new mutant is functionally lethal, and therefore it must be maintained as a heterozygote. Linkage associations were not found between the new mutant and 17 marker loci tested. However, the glabrous and abnormal bract expressions of the new mutant were epistatic to the expressions of the Pilose (H2) and fiego bract (fg) markers. It is proposed that this new mutant be named Round leaf‐2 and assigned the gene symbols Rl2,Rl2.
Environmental Stability and Adaptation of Several Cotton Cultivars1
Authors: Bilbro J. D. , Ray L. L.
Published: July 2010

We studied the stability, adaptation, and yields of several diverse cotton (Gossypiutn hirsutum L.) cultivars that had been grown at several locations in one or more of three, 3‐year periods of testing. We used as environmental indexes the mean lint yields of three “standard” cultivars that were common to all tests. The yields of the remaining cultivars were regressed upon these indexes. The regression coefficients (6 values) were used as measures of adaptability, and the coefficients of determination (r2 values) were used as measures of stability. Analyses of variance of lint yields also were computed.

In comparison with the three standards, most of the other cultivars were adapted to all environments (b = 1.0), and all but one were stable. However, there were several significant yield differences among the cultivars within each of the three periods of testing. Thus, yield level was the most divergent parameter measured, adaptation was next, the stability was the least divergent. Because we found significant differences among commercial cultivars in both adaptation and stability, we believe that the use of these two parameters in conjunction with yield would be of significant benefit in breeding material evaluation.
Some Genetic Relationships Between Gland Density and Gossypol Content in Gossypium hirsutum L.1
Authors: Wilson F. D. , Smith J. N.
Published: July 2010

The experimental cotton line 247‐1 (Gossypium hirsutum L.) is heavily glanded and has a high gossypol level in flower buds. The most logical (but not the only) interpretation of data from crosses of 247‐1 and stocks homozygous for various combinations of gland‐determining alleles at the gl1 gl2, and gl3, loci was that the high‐gossypol content of 247‐1 could be explained by the presence of a high‐potency allele at the gl3 locus, plus another factor, or factors, independent of the gland‐determining alleles.
Photosynthesis of 22 Alfalfa Populations Differing in Resistance to Diseases, Insect Pests, and Nematodes1
Authors: Chatterton N. J.
Published: July 2010

Breeders have successfully produced alfalfa (Medicago sativa L.) lines with resistance to a number of insect, disease, and nematode pests. Little is known about the effect of selection for pest resistance on photosynthetic capacity. In this study, carbon dioxide exchange rates of alfalfa populations previously selected for resistance to diseases, insects, and nematodes were compared with the populations from which they were developed. No statistically significant differences in carbon dioxide exchange rates were observed among 22 alfalfa lines grown in a glasshouse and measured in controlled environment chambers at 24 C, 75% relative humidity and 34 klux illuminance. Apparently, selection for pest resistance did not affect the photosynthetic capacity and, with one exception, did not affect leaf area of alfalfa.
Effects of Puccinia sorghi Rust on Yield and Several Agronomic Traits of Maize in Hawaii1
Authors: Kim Soon Kwon , Brewbaker James L.
Published: July 2010

Ten paired doublecross hybrids of maize (Zea mays L.), genetically similar except for the gene Rp‐d conferring resistance to Puccinia sorghi Schw., were studied under natural rust epiphytotics in an area with continuous corn production in Hawaii. Data on eight agronomic traits are summarized from April and November plantings, including grain yield, plant weight, ear length and diameter, 1,000‐kernel wt, plant and ear height, and days to silk. Rust was severe in both seasons, and slightly more so in winter (6.0 vs. 5.2 on a seven‐point scale). In this area, winter corn yields are characteristically about half those of summer, due to reduced light intensity and daylength.

The rust affected all traits significantly when data combined over the two seasons were considered. Average reductions caused by rust were 35% for grain yield, 27% for fresh plant weight, 11% for ear length, 10% for kernel wt and ear diameter, and less than 5% for plant and ear height and days to silk. Highly significant interactions of season with treatment (resistant vs. susceptible hybrids) were detected in grain yield and plant height, with the rust effect generally enhanced in the winter planting. Grain yield reductions by rust were best correlated with changes in kernel weight (r = 0.78), but clearly reflected major effects on ear lengths and diameters as well. In areas of continuous corn production, uncontrolled P. sorghi rust can be a serious disease affecting essentially all components of yield.
Seed Cleaning System for Plot Combines1
Authors: Clark R. C. , Fehr W. R.
Published: July 2010

A seed cleaning system was developed for self‐propelled plot combines used to harvest soybeans [Glycine max(L.) Merr.]. With this cleaning system, a seed sample free of debris can be obtained with minimum seed loss. The cleaning system has four components that have not been used previously on plot combines: a moving seed deflector, a conveyor under the top sieve, a conveyor under the bottom sieve, and a second cleaning fan.
Canopy Photosynthesis and Transpiration of Cotton as Affected by Leaf Type1
Authors: Pegelow E. J. , Buxton D. R. , Briggs R. E. , Muramoto H. , Gensler W. G.
Published: July 2010

Cotton (Gossypium hirsutum L.) plants with okra or superokra leaves have several agronomic characteristics which could make them better adapted to narrow‐row culture than plants with normal leaves. This study was conducted to investigate the effect of these leaf types on canopy photosynthesis and transpiration of narrow‐row cotton. A portable, open‐chamber system was used in plant communities grown at high and low densities. In 1973 the three leaf types (normal, okra, and superokra) had dissimilar genetic background with the okra and superokra leaf lines being similar in appearance and leaf area. Maximum leaf area index (LAI) these canopies was approximately 2.8 compared to 4.6 for normal leaf plants. Near‐isogenic lines were used in 1974. Although morphologically distinctive, the okra and normal isolines had maximum LAIs of approximately 5.2, compared with 3.5 for the superokra leaf isoline. Apparent photosynthesis was positively associated with LAI, although correlation coefficients were low (0.23 to 0.54). Plant population had little effect on canopy photosynthesis. When data were averaged across populations, normal leaf plants had CO2 exchange rates 20 and 29% higher than superokra leaf plants in 1973 and 1974, respectively. Okra leaf plants were intermediate. Leaf type effects on transpiration were small and inconsistent during the 2 years. Although differences in photosynthesis to transpiration ratios statistically nonsignificant, the trend was normal>okra> superokra. Thus, the okra leaf types do not appear to be associated with improved efficiency of water use.
Inheritance of Harves Index and Related Traits in Oats1
Authors: Rosielle A. A. , Frey K. J.
Published: July 2010

Harvest index of cereals is the ratio of grain to total plant yield. Harvest index and its components, plant weight and grain yield, and heading date, plant height, and 100‐seed weight, were studied in 15 crosses among 30 oat (Arena sativa L.) lines. F2‐derived lines from each cross, parents, and 10 check cultivars were tested in hill plots in 3 experiments. One experiment contained F2 derived lines tested in both F3 and F4, enabling direct comparisons between the two generations.

Dominance was not of major importance in the inheritance of heading date, plant height, and 100‐seed weight. These traits showed small deviations of cross means from midparental values, little change of means and variances from F3 to F4, and no appreciable skewness. Plant weight and grain yield showed substantial dominance, as indicated by large deviations of cross means from mid‐parental values, large reductions in means and variances from F3 to F4 and negative skewness. Harvest index showed primarily additive gene action, although this conclusion was complicated by the occurrence of negative skewness. Crosses between parents that were both high in harvest index tended to show small phenotypic variation for harvest index and other traits.
Sampling Technique for Estimation of Root Production of Kentucky Bluegrass1
Authors: Canode C. L. , Hiebert A. J. , Russell T. S. , Law A. G.
Published: July 2010

This research was initiated because of the variability encountered in previous root samplings of Kentucky bluegrass (Poa pratensis L.) and the expense and time used in securing root weights. Root weight uniformity trials were conducted in two fields of ‘Merion’ Kentucky bluegrass to determine the number of samples and replications needed to measure production at various levels of precision. The most precision which appeared practical was about a 5% error of the sample mean. In experiments having four replications and a root sample mean of about 8.5 g/core, a 5, 6, 7.5, and 10% error of the mean could be expected with 12, 8, 4, and 2 samples per plot, respectively. The number of samples taken from each experimental unit was the primary factor in reducing variability; shape of the plot had little influence on variability.
A Newly Bred ‘Gigas’ Form of Bread Wheat (Triticum aestivum L.): Morphological Features and Thermo‐photoperiodic Responses1
Authors: Atsmon D. , Jacobs E.
Published: July 2010

Individual segregants, as well as uniform F6 to F8 lines, originating from one group of spring wheat (Triticum aestivum L.) crosses, had a series of striking characteristics setting them apart from the typical spring type. Tillering was limited, and in some lines nearly all of the plants were uniculms. Spikes were large and proliferous with maximum expression of 30 spikelets per ear, and 62.5 mg per kernel, and 12 florets and nine grains per spikelet have been recorded either in individual segregants or for certain lines. Vegetative parts were robust and vigorous, including broad, thick, dark green leaves, thick, stiff straw, and thick, large rachises, glumes and lemmas. Harvest index was higher than in a standard cultivar of regular growth habit. This complex set of characters typified plants of the new type only when grown in short (but increasing) day length and low temperature conditions (Mediterranean winters). Tests indicated a special thermo‐photoperiodic sensitivity in this material. Plants or lines included a wide spectrum of agronomic types with respect to plant height, size and quality of grains, and morphology of spikes and vegetative parts. The normal (2n = 42) chromosome complement of T. aestivum was found in 10 randomly sampled unicum plants.
Screening Sainfoin for Resistance to Root and Crown Rot Caused by Fusarium solani (Mart.) Appel and Wr.1
Authors: Auld D. L. , Ditterline R. L. , Mathre D. E.
Published: July 2010

Root and crown rot drastically decreases persistence and forage yield of sainfoin (Onobrychis viciifolia Scop.). We evaluated four techniques of inoculating sainfoin with Fusarium solani (Mart.) Appel and Wr, a cause of root and crown rot, for the purpose of locating resistant germplasm. Techniques evaluated included the rootcut‐soak, crown injection, aerial spray, and toothpick insertion methods of inoculation. The root‐cut‐soak inoculation technique applied to 6‐week‐old sainfoin seedlings resulted in 77% seedling infection, produced the most severe disease symptoms, and had low seedling mortality from physical injury to the seedlings. This inoculation technique gave repeatable results and detected differences in disease resistance among genotypes. The root‐cut‐soak inoculation technique was used to screen 181 accessions of the world collection of Onobrychis for sources of resistance to root and crown rot. The accessions and the 11 species which they represent exhibited differential disease resistance, but none was immune to the disease.
Starch Storage in C4 vs. C3 Grass Leaf Cells as Related to Nitrogen Defeciency1
Authors: Gallaher R. N. , Brown R. H.
Published: July 2010

Starch has been shown to accumulate in chloroplasts of plant cells and carbohydrates have been shown to accumulate in leaves of nitrogen (N) deficient plants. No information could be found on the localization of starch in various cell types in relation to N nutrition. Therefore, this study was conducted under greenhouse conditions to determine this relationship in a species having the C4 Pathway of CO2 fixation, bahiagrass (Paspalum nolatum L. Flugge cv. ‘Pensicola’), vs. a species having the C3 Pathway, tall fescue (Festuca mundinacea Schreb. cv. ‘Kentucky 31’). Leaf sections from N deficient and well fertilized plants were stained with iodine (I) to observe starch localization. Starch was concentrated in bundle sheath cells of bahiagrass but not in tall fescue. Bundle sheath cells of N deficient bahiagrass were almost completely stained with I, indicating large quantities of stored starch. Bundle sheath cells of N sufficient leaves of bahiagrass were either not stained with I or only slightly stained indicating much less starch storage. Starch stained with I occurred on chloroplasts in mesophyll tissue of tall fescue but no relationship with N was observed.
Heritability and Combining Ability for Gossypol Content in Six Lines of Upland Cotton1
Authors: Yang H. C. , Davis Dick D.
Published: July 2010

Six lines of upland cotton (Gossypium hirsutum L.), selected for different levels of gossypol and other terpenoids in flower buds, were intercrossed in all combinations, including reciprocals. Parents and F1 hybrids were grown in a complete diallel set with three replications m one environment. Analysis of variance of gossypol level, using the methods of Grilling, revealed a large and highly significant component for general combining ability, and a small nonsignificant component for specific combining ability. There was also a very small, but significant, estimate for reciprocal effects. We concluded that gossypol in flower buds is inherited in an additive manner (94% narrow sense heritability) and should thus be readily selectable.

Analysis of the same materials using Hayman's technique confirms the highly significant and predominant additivity of inheritance, but also suggests that dominance cannot be completely ruled out as a source of significant variation.
Degrees of Differentiation Obtained in Tissue Cultures of Glycine Species1
Authors: Beversdorf W. D. , Bingham E. T.
Published: July 2010

Tissues of soybean, Glycine max (L.) Merr., and several wild Glycine species were cultured with the goal of regenerating whole plants from callus. Hypocotyls and ovaries were cultured on semi‐solid and liquid media with varying concentrations and combinations of hormones. Maximum callus fresh weight accumulations after 28 days occurred on a medium with 0.4 to 0.8 mg/liter, 2,4‐D and 0.25 to 0.5 mg/liter kinetin (6‐furfurylaminopurine). All concentrations of kinetin tested repressed root development below that of basal medium. Development of compact growth centers in liquid cultures occurred over a range of auxin‐cytokinin combinations. Cultures in liquid medium with 2,4‐D at 1.0 mg/liter and indoleacetic acid and kinetin each at 0.5 mg/liter developed many growth centers, most of which developed single roots and then recallused. Cultures in liquid medium with 2,4‐D and kinetin at 0.5 and 0.01 rag/liter, respectively, developed growth centers that initiated fewer roots, but frequently elongated and developed into structures similar in appearance of embryos. Such growth centers could be reproduced at will but could not be cultured to complete plants. Three of 56 soybean cultivars tested appeared to have a greater capacity to develop non‐root structures from callus tissue. Cultures of one cultivar developed many advanced embryo‐like structures in liquid cultures, although none developed into a plantlet.
Development of Zero‐Alpha Hop Genotypes1
Authors: Haunold Alfred , Likens S. T. , Nickerson G. B.
Published: July 2010

Hop (Humulus lupulus L.) cultivars normally contain both alpha and beta acids in varying amounts. Alpha acids are the principal flavoring substances for malt beverages. The closely related beta acids are of less importance for brewing because of their low solubility in cold wort. The progeny of a cross between two low‐alpha acid hop genotypes showed significant transgressive segregation for alpha and beta acid content. One male and eight female siblings contained no detectable alpha acids in their lupulin glands. A highly significant correlation was found between quality analyses on a cone basis and on a lupulin basis.

Zero‐alpha hops will be useful for studying the inheritance of beta acids independently of alpha acid content. Such hops may also allow brewing chemists to measure the contribution of beta acids to beer flavor.
Effects of Irrigation History on Responses of Cotton to Subsequent Water Stress1
Authors: Cutler J. M. , Rains D. W.
Published: July 2010

Experiments were designed to test the hypothesis that the internal water relations and stomatal and growth responses to water status of cotton plants (Gossypium hirsutum, ‘Acala SJ 2’) can be modified by prior tissue water deficits. Different levels of stress conditioning were achieved by varying irrigation frequency during a pretreatment period.

Growth was limited by water stress under conditions of low and moderate irrigation frequency during the pretreatment period. During the final drought period, tissue water desorption characteristics, stomatal closure thresholds, and (inferentially) turgor sensitivity were different in stress‐conditioned plants from those in plants not subjected to prior stress. Analysis of the relationships of water potential to relative water content suggested that osmotic adjustment might play a role in the reduced sensitivity of hardened plants. The altered behaviors of prestressed plants were in the right direction to explain differences observed between the responses of controlled. environment and field‐grown plants and suggest that stress‐conditioned plants are less sensitive to tissue water deficits.
Performance of Randomly selected Soybean Lines with Semideterminate and Indeterminate Growth Habits1
Authors: Green D. E. , Burlamaqui P. F. , Shibles Richard
Published: July 2010

To compare their performance, 60 lines (30 indeterminate and 30 Semideterminate) of soybeans (Glycine max (L.) Merr.) from each of two crosses were grown in row spacings of 30 and 100 cm in 1972 and 1973. The narrow rows averaged 33% higher in seed yield than the wide rows. In one cross the Semideterminate and indeterminate lines were of equal maturity, and gave equal seed yields. In the other cross the indeterminates were higher yielding than the semideterminates, probably due to a later maturity and longer reproductive period. An expected yield advantage of the Semideterminate lines in narrow rows was not borne out by the data. Advantages of the Semideterminate lines were shorter plant height and less lodging.
Heterosis and Combining Ability of Seed Protein, Yield and Yield Components in Long Bean1
Authors: Mak C. , Yap T. C.
Published: July 2010

Seven cultivars of long bean (Vigna sesquipedalis Fruw.) were crossed in diallel; the parents and F1's were evaluated in the field in 1973. Out of 42 hybrids, only three had seed protein contents significantly greater than the higher parent values. A majority of the hybrids yielded more than the higher parent. The amount of heterosis ranged from 40.7% below to 63.2% above the higher parent values. Of these, however, only two were statistically significant. Among the yield components, pods per plant showed the greatest amount of heterosis. Heterosis in seeds per pod, pod length, and seed weight were relatively low.

Both general combining ability (GCA) and specific combining ability (SCA) were important for all traits measured except pod yield where only GCA was significant. Good combiners for pod yield were poor combiners for seed protein content and the SCA effects for yield depended mainly on the SCA values of the yield components.
Inheritace of Plant Height in Cotton. II. Diallel Analyses Among Six Semidwarf Strains1
Authors: Quisenberry J. E.
Published: July 2010

Semidwarf cultivars of upland cotton (Gossypium hirsutum L.) have been developed to meet the requirements of narrow‐row, high‐population cotton production. Six semidwarf stocks, the diallel set of F1 hybrids among those stocks, and a “normal‐height” stock were used to compare plant height and crop maturity characters among the semidwarf stocks and the normal‐height stock and to evaluate the inheritance of those characters among the semidwarf stocks. The characters studied were plant height, mainstem and fruiting‐branch internode length, number of mainstem nodes, node of the first fruiting branch, and mean maturity date. Diallel analyses were used to estimate genetic and environmental components. Comparisons between the normal‐height and the semidwarf stocks showed that the semidwarf stocks were gen. erally shorter in plant height, had shorter mainstem and fruiting‐branch internodes, initiated their fruiting branches at a lower mainstem node, and were earlier in crop maturity than the normal‐height stock. Diallel analyses indicated that the genetic variation for the plant height and maturity traits among the semidwarf stocks was primarily additive, with a small, although significant, dominance component associated with all the traits except number of mainstem nodes. Heritability was relatively low for plant height and mainstem internode length, intermediate for number of mainstem nodes and node of the first fruiting branch, and. high for fruiting‐branch internode length and mean maturity date.
Leaf Anatomy and Water Relations of Plants Grown in Controlled Environments and in the Field1
Authors: Van Volkenburgh E. , Davies W. J.
Published: July 2010

Structure and physiology of plants grown in controlled environments and in the field are compared. Cotton (Gossypium hirsutum ‘McNair 511’) and soybean (Glycine max ‘Ransom’) plants were grown from seed in 1:1 vermiculite and gravel mixture contained in 25‐cm plastic pots in the field, in an air‐conditioned greenhouse at 30 C/26 C, and in growth chambers at 30 C/26 C and 28 C/17 C day and night temperatures. In both species, leaves of field grown plants were considerably thicker than leaves of plants grown in chambers at 30 C/26 C. (field soybeans, 119 µ; chamber soybeans, 58 µ, field cotton, 139 µ; chamber cotton, 101 µ). Leaves of both species were as thick when grown in chambers with a 28 C/17 C regime as when grown outdoors. Stomatal frequency was 2 to 5 times greater on the lower than on the upper sur. face of cotton leaves and 3.5 to 8 times greater on the lower than on the upper surface of soybean leaves. The ratio of lower stomata to upper stomata in cotton leaves varied from environment to environment as follows: field > greenhouse > 30 C/26 C chamber > 28 C/17 C chamber, but for soybean the order was field > 28 C/17 C chamber > greenhouse > 30 C/26 C chamber. The environment had little effect on stomatal size in cotton, but upper stomata of field‐grown soybeans were larger (18.7 µ) than those of chamber‐grown plants (12.0 µ). Transpiration resistance was greater for the upper surfaces of leaves of both species grown in all environments (soybeans 1.2 to 4.2 s cm‐1, cotton 1.0 to 8.2 s cm‐1). In both species a waxy bloom was evident on the lower surface of leaves of field‐grown plants and not on the lower leaf surface of greenhouse or warm chamber plants. Soybeans grown in the 28 C/17 C chambers had more lower surface bloom than soybeans grown in warm chambers. In general, soybean leaf development was more sensitive to the environment than cotton leaf development.
Application of Restricted Selection Indexes for Improvement of Economic Value in Oats1
Authors: Rosielle A. A. , Eagles H. A. , Frey K. J.
Published: July 2010

The dollar return from growing oats Avena sativa L. in the midwestern United States is a function of both grain and straw yields. Restricted selection indexes were used to determine the effect of restricting heading date and height on selection potential for economic value among F9‐derived lines from a bulk populatiou of oats. Four unrestricted and eight restricted selection methods were considered. The eight restricted methods comprised two economic values, optimum and base methods, and two degrees of restriction on heading date and height. Expected and actual advances were calculated.

Direct selection for increased economic value saved lines with late heading dates and tall plants. Holding heading date and height to the means of the unselected population removed correlated responses in heading date and height, but decreased advance from selection for economic value. More severe restrictions on heading date and height reduced the advance in economic value to near 0.0. Restrictions on heading date and height had a more severe effect on straw yield than on grain yield.

Optimum restricted selection indexes, in which grain and straw yields were entered as separate traits, were only slightly more efficient than base restricted indexes in which the two traits were combined into the single character economic value.

Changing the relative economic values of grain and straw had little effect on expected or actual advances. Restricted selection for economic value was effective with measurements on plant weight, heading date, and height only; i.e., without measuring grain yield.

Expected and actual advances for heading date and height agreed closely for all methods. Expected advances for grain yield, straw yield, and economic value were overestimates of actual advances with unrestricted methods, but agreed closely with actual advances for restricted methods.
Stalk Number in Sugarcane in Spaced and Competitive Plantings1
Authors: Lyrene P. M. , Miller J. D. , James N. I.
Published: July 2010

Twenty random F1 sugarcane (Saccharum sp.) clones from three crosses were grown as spaced stools in a 21‐replication, randomized block experiment. They were also planted at the commercial planting rate in competitive tests with eight replications. The objective was to examine, for a series of genotypes, the relationship between stalk numbers in spaced stools and competitive plots. For the 20 clones, there was a positive correlation (0.69) between mean stalk number per stool and mean stalk number per competitive plot. The 20 clones were more variable in the spaced‐stool test than in the competitive test, with clonal means ranging from 4.90 to 14.72 stalks per stool in the spaced test (5% confidence interval ± 1.18) but only from 108.7 to 162.9 stalks per 7 m2 plot (5% confidence interval ± 15.2) in the competitive test. It appears possible to select, in the single‐stool stage, clones that will produce high stalk populations in commercial plantings. However, to provide adequate precision, the spaced stool test must be replicated.
An Evaluation of Gossypium barbadense L. Chromosomes 6 and 17 in the G. hirsutum L. Genome1
Authors: Kohel R. J. , Endrizzi J. E. , White T. G.
Published: July 2010

The phenotypic contributions of two individual Gossypium barbadense L. chromosomes in a G. hirsutum L. background were evaluated. Monosomes 6 and 17 of G. hirsutum were used to transfer the individual intact homologues from a G. barbadense line (3‐79) into G. hirsutum. Following transfer, backcross‐derived substitution lines with 25 pairs of G. hirsutum chromosomes and one pair of G. barbadense chromosomes (6 or 17) were evaluated for the following agronomic properties: date of first flower; earliness; yield; boll size; lint percent; lint index; seed index; fiber length; fiber coarseness; fiber strength; and fiber elongation. Significantly associated with substitution line 6 was later flowering, higher lint percent, and finer fibers. Short fiber length was significantly associated with substitution line 17. However, no characteristic feature of 3‐79 was associated with either substitution line.
Protein Body Size and Distribution and Protein Matrix Morphology in Various Endosperm Mutants of Zea mays L.1
Authors: Baenziger P. S. , Glover D. V.
Published: July 2010

Maize (Zea mays, L.) protein body size and distribution and matrix morphology were studied to determine their relationship with endosperm lysine content and kernel density and vitreousness. Thirteen near‐isogenic (Bc 6) endosperm mutant genotypes, their double mutants with opaque‐2, and the normal Oh43 inbred were studied. Two endosperm mutants, sugary‐2 (su2) and waxy (wx), and their double mutant with o2 each near‐isogenlc (Bc 6) inbreds B37, C103, and W64A and their normal and opaque‐2 counterparts were also studied. Mature kernels of these genotypes were thin sectioned, destarched, and studied using interference‐contrast light microscopy.

Protein bodies were observed and measured in amylose. extender (ae), dull (du), floury‐1 (fl1), soft starch (h), su2 and wx endosperm of Oh43 and in the normal counterpart. Protein body size was significantly different among genotypes and decreased going into the center of the kernel from the aleurone layer.

No protein bodies were visible in o2, floury‐2 (fl2), sugary‐1 (su1), shrunken‐1 (shl), shrunken‐2 (sh2), brittle‐1 (btl), and brittle‐2 (bt2). The endosperm mutants with high lysine levels had no visible protein bodies while the mutants with intermediate lysine levels had fewer and generally smaller protein bodies than did the mutants with the lower lysine levels.

Opaque‐2 and the double mutants with o2 did not have visible protein bodies and the matrix was generally thinner than in the single mutants. Sugary‐2 opaque‐2 had a thicker, more extensive matrix than observed in o2 endosperm.

Protein bodies were visible in the su2 and wx isogenic conversions of Oh43, B37, C103, and W64A and their normal counterparts. Differences among inbreds, genotypes, and the interaction of inbred × genotypes were highly significant. No protein bodies were visible in o2 and the double mutants with o2. The data suggest that protein matrix may be involved in the expression of kernel density and vitreousness. The matrix of vitreous su2o2 kernels resembled the matrix of vitreous sue kernels and not that of o2 kernels.
Breeding for Mg, Ca, K, and P Content in Tall Fescue1
Authors: Sleper D. A. , Garner G. B. , Asay K. H. , Boland R. , Pickett E. E.
Published: July 2010

Diseases such as hypomagnesaemia (grass tetany) have been associated with deficiencies of certain minerals in tall fescue (Festuca arundinacea Schreb.) and in other forage species. To overcome these deficiencies through breeding, information is needed on the inheritance of accumulation of these minerals. Objectives of our investigation were to measure the heritability of the accumulation of Mg, Ca, K, P, and a ratio, K/(Ca+Mg), and their interrelationships in tall fescue. Two diallel mating sets, each with six parents, were randomized and planted in one experiment. Forage was analyzed for Mg, Ca, K, P, and K/(Ca+Mg) for three harvest dates in 1974 and in 1975. Parents and progenies differed significantly for all minerals studied except that progenies were not significantly different for K in one of the diallel sets for the first harvest date. Estimates of general combining ability were more important than estimates of specific combining ability in the inherited uptake of these minerals. Heritability values calculated by the progeny‐parent regression and standard unit method indicated that progress can be made in breeding for higher mineral levels of most minerals at most harvest dates. Since the K/(Ca+Mg) ratio was highly heritable, progress in breeding a tall fescue with low hypomagnesaemia potential should be possible. Correlation of Mg between years was highly significant in one diallel but not in the other. Correlation of K/(Ca+Mg) between years was highly significant at all sampling dates for both diallels. Correlations coefficients between years for Ca, K, and P were more erratic.
Studies on Nitrate Reducing System in Developing Wheat Ears1
Authors: Nair T. V. R. , Abrol Y. P.
Published: July 2010

Developing wheat (Triticum aestivum L.) ears (grains and glumes) are sites of nitrate reduction. Nitrate reduced by the developing ear was incorporated into grain protein. In a field experiment, when no N was supplied, nitrate reductase (NR) activity (µmoles NO2‐/g.f.w./hour) in the glumes and grains was not significantly different from that in the flag leaf blade. Application of N significantly enhanced the NR activity of the flag leaf blade but not that of glumes and grains.

Total NR activity (NR activity/g.f.w./hour ✕ fresh weight) of the developing ears equalled that of the leaf blades on the main shoot at low N (0 & 90 kg/ha) levels. At high N (180 kg/ha) level the total NR of the leaf blades was significantly higher than that of the developing ears.

In detached culm experiments, flag leaf blade as well as glumes responded to nitrate in the medium even when the detached culms were obtained from plants grown at high N (I80 kg/ha) level. This suggested that under field conditions the enzyme, NR, was operating at sub‐optimal levels. The magnitude of response of glumes was lower than that of the flag leaf blade suggesting preferential flow of nitrate towards the leaf blade or translocational barrier to nitrate movement to the ear.

NR activity in the grains was neither enhanced by soil N application nor by additional supply of nitrate to the detached culms.
Inheritance of General Resistance in Maize to Puccinia sorghi Schw.1
Authors: Kim Soon Kwon , Brewbaker James L.
Published: July 2010

Genetic studies were made of general resistance in maize (Zea mays L.) to common rust, Puccinia sorghi Schw., by means of diallel and generation mean analyses of crosses among 11 inbreds. Most populations were grown under severe natural epiphytotics on Oahu, Hawaii with rust spore burdens from the time of emergence. Susceptible checks averaged 6.8 on the 1 to 7 rust scale, where 7 represented infections covering more than 40% of mature leaf surface. Few inbreds, including Oh545 and CM105 (Cuban Flint origin), displayed effective general resistance under these conditions. The nine parents of a diallel showed high general combining ability (gca) for resistance, and a high coefficient of linear determination (r2 = 0.91) between parental averages and their gca effects. Heterosis was not evident for resistance, and specific combining ability effects were small although statistically significant. Generation mean analysis was made of 20,000 plants from 25 sets of biparental crosses and their F2 and backcross progenies. Heritability estimates were 83.4% (broad‐sense) and 47.0% (narrow‐sense) for the summarized data, and substantially higher for the highly resistant sources Oh545 and CM105. From crosses with the highly susceptible inbreds — B37, CM104 (India) and AA8 (Hawaii) — Oh545 was inferred to carry two major, partially dominant resistance genes.
Variability and Selection Advance for Photosynthesis in Iowa Stiff Stalk Synthetic Maize Population1
Authors: Crosbie T. M. , Mock J. J. , Pearce R. B.
Published: July 2010

Photosynthesis is a primary trait influencing yield potential, and it should be improved in a yield‐potential selection program. Information concerning the genotypic variability and inheritance of photosynthetic efficiency in maize (Zea mays L.) must be obtained before a yield‐potential selection program is initiated.

We used CO2‐exchange rate (CER) of sections from excised leaves to estimate photosynthetic efficiency of 64 random inbred fines of maize derived from Iowa Stiff Stalk Synthetic (BSSS). Our study was conducted for years at one location. Measurements of CER taken during vegetative growth (CER 1) and during grain filling (CER 2) were used to estimate genotypic variances and heritabilities and to calculate selection advances for these two stages of plant development. We also evaluated the possibility of using specific leaf weight and leaf thickness as index traits for CER selection.

Results showed that estimates of additive variance were 1.7 and 4.9 times larger than estimates of genotype ✕ environment variance at CER 1 and CER 2, respectively. Narrow‐sense heritabilities were 0.58 for CER l and 0.80 for CER 2, and realized heritability values were 0.72 (CER 1) and 0.66 (CER 2). A high genotypic correlation between CER at CER 1 and CER 2 indicated selection at either developmental stage would produce nearly identical results. Actual selection advances (15% selection intensity) represented increases of 14 and 22% above population means for CER 1 and CER 2, respectively. Our data suggested that measurement of two replications of four plants/plot grown in two environments would provide most efficient selection advance for inbreds. We concluded that selection for improved CER in BSSS would be possible and that selection must be for CER per se.
Inheritance of Resistance to Bacterial Blight in Rice1
Authors: Petpisit V. , Khush Gurdev S. , Kauffman H. E.
Published: July 2010

The mode of inheritance and allelic relationships of the genes for resistance to bacterial blight, caused by Xanthomonas oryzae (Uyeda and Ishiyama) Dowson, in rice (Oryza sativa L.) cultivars ‘IR20’, ‘IR22’, and breeding lines ‘IR1529‐680‐3’, ‘IR1545‐284’, and ‘RP291‐7’ were studied. The study of F1, F2, F3 and reciprocal backcross populations of crosses between resistant parents and the susceptible cultivar ‘TNI’ revealed that resistance in these cultivars and selections is under monogenic control. The resistance of IR20, IR22 and IR1529‐680‐3 is incompletely dominant, and that of IR1545‐284 and RP291‐7 is recessive. Evidence from allele tests indicates that IR20, IR22 and IR1529‐680‐3 have the same dominant gene for resistance. This gene is designated Xa4. IR1545‐284 and RP291‐7 have the same recessive gene for resistance which is designated Xa5. Xa4 and xa5 assort independently of each other.
Relationship Between Laboratory Indices of Soybean Seed Vigor and Field Emergence1
Authors: TeKrony D. M. , Egli D. B.
Published: July 2010

There have been few comparisons of the relationship between laboratory estimates of soybean [Glycine max (L.) Merr.] seed vigor and field emergence under adverse soil conditions. These studies were conducted in 1973‐75 to compare the results of standard germination, two vigor tests (accelerated‐aging germination and 4‐day germination), and several vigor indices to field emergence in varying soil environments. Each vigor index was computed by converting the results of each laboratory test into a vigor rating ranging from 0 to 10. The three vigor indices evaluated and the tests used in each were: VR‐1 (standard germination, 4‐day germination, and accelerated‐ aging germination), VR‐2 (standard germination and accelerated‐aging germination) and VR‐3 (standard germination and 4‐day germination). The prediction accuracy (those seed lots that emerged in the same performance level in the field as predicted in the laboratory) was determined for each laboratory test and index. All laboratory tests consistently overpredicted field emergence when seed was planted in adverse soil conditions (severe crusting and cold soil temperatures). The prediction accuracy for all seed lots averaged across years with adverse field conditions was very low (8.3%) for standard germination and improved to 46.7% for accelerated‐aging germination and 56.9% for 4‐day germination. The prediction accuracy increased to 65.0% and 68.3% for the VR‐3 and VR‐1 vigor indices for the same comparisons. The VR‐1 index, using all three laboratory tests provided a better estimate of field emergence than either vigor index (VR‐2 and VR‐3) when only two tests were used. The prediction accuracy of the VR‐1 vigor index was approximately 25% higher than averaging the results of the same three tests. The vigor index concept offers the possibility of combining additional laboratory parameters that relate to seed and seedling vigor.
Anatomical Variation in Stalk Internodes of Sorghum1
Authors: Schertz K. F. , Rosenow D. T.
Published: July 2010

Anatomical features of stalks of 12 diverse lines of Sorghum bicolor (L.) Moench were observed. Most prominent differences were in number of cells with lignified walls and in wall thickness. Lignification differences occurred in the epidermis, subepidermis, and vascular bundles.
Effects of Leaf Aging Upon Stomatal Resistance in Bean Plants1
Authors: Davis S. D. , van Bavel C. H. M. , McCree K. J.
Published: July 2010

The effect of leaf age on leaf resistance to gaseous diffusion was separated from three factors inherently related to leaf age: (a) progressive shading of lower leaves, (b) plant development, and (c) changes in stomatal size and density. Bush beans (Phaseolus vulgaris L., ‘Contender’) were grown and studied in an environmental chamber under constant conditions. Measurements of leaf resistance, light level, and stomatal density were made throughout the life of the plant (10 to 60 days from plant emergence). It was found that in a fully expanded leaf, exposed to constant light, the diffusive resistance of the whole leaf increased continuously with age until leaf abscission. The same was found true for leaves that were continuously shaded at 15% of the full light level (1,150 μ;einsteins m‐2 s‐l), but the resistances were higher. The rate of change in leaf resistance with time varied among the leaves within a plant, but the differences were eliminated when the time scale was expressed as the fractional lifespan of each leaf.

Further, the effects of correlated factors such as shading, stage of plant development, and stomatal densities were negligible; and the leaf age effect occurred not only during the latter stages of senescence, when the leaf was becoming chlorotic or necrotic, but as a continuous process, beginning at leaf maturity and continuing until leaf abscission.
Evaluation of Recurrent Selection for Specific Combining Ability in Two Open‐pollinated Maize Cultivars1
Authors: Walejko R. N. , Russell W. A.
Published: July 2010

We evaluated recurrent selection for specific combining ability in two open‐pollinated maize (Zea mays L.) cultivars, ‘Kolkmeier’ and ‘Lancaster’. A common, singlecross tester, WF9 ✕ Hy, was used in the first cycle, but inbred Hy was used in the four subsequent cycles. The principal basis of selection was grain yield of half‐sib progenies. Progress for population improvement was evaluated in five environments by measuring yields in the Kolkmeier and Lancaster populations per se, the Hy ✕ Kolkmeier Cn (n = 0, 1,2 …, 5) and Hy ✕ Lancaster Cn test‐crosses, the Kolkmeier Cn ✕ Lancaster C. population crosses, and the Cn and C5 populations of both cuitivars in crosses with Alph C0, Alph C5, BI4A, B73, and Mo17. Kolkmeier per se did not show a significant change in yield; Lancaster per se, however, had a significant negative linear trend, −0.95 ± 0.45 q/ha/cycle. The rates of yield gain (q/ha) for Hy ✕ Kolkmeier Cn and Hy ✕ Lancaster Cn were 2.75 ± 0.45 and 2.23 ± 0.45, respectively. The rate of yield gain (q/ha) for Kolkmeier Cn ✕ Lancaster Cn was linear and significant, 2.45 ± 0.45. Similar yield gains were expressed with the C0 and C5 populations in testcrosses with other unrelated testers, except B73 for which there were no differences between testcrosses of the C0 and C5 populations. The recurrent selection program has been successful in increasing frequencies of genes with favorable yield effects in crosses, and overdominance was relatively unimportant in the change in yield potential of the two cultivars. Recurrent selection by using an inbred line tester seems to be an efficient method to improve breeding populations. The obvious tester would be a line that is already widely used in the seed industry. As the program progresses, this line can be replaced by a better line with no deleterious results relative to the population improvement achieved by the earlier tester.
Aflatoxins in Cottonseed: A Comparison of Two Cultivars1
Authors: McMeans J. L. , Brown C. M. , McDonald R. L. , Parker L. L.
Published: July 2010

Two cotton cultivars, S‐1322 and Deltapine‐16, (Gossypium hirsutum L.) were compared in field plots in Imperial Co., Calif. in 1973, to determine causes of differences in severity of seed infection by Aspergillus flavus Lk. ex Ft. and in accumulation of aflatoxins. S‐1322 was not as susceptible as Deltapine‐16 because rapid moisture loss from the bolls creates an unfavorable environment for growth of A. flavus, and more bolls escape the pink bollworm [Pectinophora gossypiella (Saunders)] because of its flowering characteristics.