Download or read book Factors Associated with Stand Establishment and Subsequent Grain Yield of Seven Wheat Cultivars and Selected Progeny Triticum Aestivum L Em Thell when Grown Under Three Diverse Environments written by Mohammad Ali Vahabian and published by . This book was released on 1976 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A checklist of academic theses produced with support from CIMMYT 1966 2000 written by John E. Woolston and published by CIMMYT. This book was released on 2000 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book O S U Theses and Dissertations 1970 1977 written by Oregon State University and published by . This book was released on 1980 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Physiology and Biochemistry of Seed Development Dormancy and Germination written by Anwar Ahmad Khan and published by . This book was released on 1982 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seed development and germination; Phenotypic maternal effect of photoperiod on seed germination; Seed dormancy and germination; Seed vigor, stress and seed germination.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1976 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Temperature and Moisture Effects on Stand Establishment of Seven Winter Wheat Cultivars and Selected Progeny Triticum Aestivum L Em Thell written by Michael Patrick Conway and published by . This book was released on 1977 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laboratory studies were conducted under different temperature and moisture regimes to evaluate the effects of temperature and moisture on stand establishment and seedling characteristics associated with stand establishment. Percent stand and days to 25% emergence were used as indexes of stand establishment. Seedling characteristics analyzed were: shoot length, coleoptile length, seedling dry weight, and Adenosine Triphosphate (ATP) content. Each of these characteristics were tested with regards to predicting stand establishment over a wide range of temperature and moisture conditions. Experiments on stand establishment were also conducted under field conditions at the Sherman Experiment Station in north-central Oregon. The degree of association between stand establishment estimates obtained in the field and estimates of stand establishments obtained in the laboratory was determined. Attempts were also made to determine the mode of inheritance of coleoptile length and Adenosine Triphosphate and the association of these characteristics with stand establishment in early generations. Seven soft white winter wheat cultivars (Yamhill, Moro, Stephens, McDermid, Hyslop, Luke, and Daws) were used in the laboratory and field experiments. Parents, F1 s, and F2s from crosses among four of the cultivars (Yamhill, Moro, McDermid, and Daws) were utilized in the inheritance studies of coleoptile length and ATP. Broad sense heritability estimates for coleoptile length were computed using the parental and F2 variances. Frequency distribution of coleoptile length were tested for their fit to normality by use of the chi square test. Narrow sense heritability estimates for coleoptile length and Adenosine Triphosphate were computed using the standard unit (correlation) and regression methods. Three temperatures levels 8, 15, and 22°C) and three soil moisture levels ( -2, -4, and -6 bars) were used to study the effects of temperature and moisture on stand establishment and stand establishment characteristics of the seven cultivars in the laboratory. Different temperature and moisture levels exhibited significant effects on percent stand, days to 25% emergence, shoot length, coleoptile length, seedling dry weight, and ATP. Increasing temperature from 8 to 22°C resulted in decreases in percent stand, days to 25% emergence, and coleoptile length. Shoot length, seedling dry weight, and ATP increased as temperature was increased from 8 to 22°C. Increasing moisture stress from -2 to -6 bars had a significant negative effect on percent stand, emergence rate, and each of the seedling characteristics studied. Coleoptile length was found to be the best predictor of percent stand over the entire range of temperature and moisture combinations utilized in the laboratory. Percent stand was observed to decrease whenever coleoptile length was less than the depth of planting. Shoot length was found to be the best predictor of days to 25% emergence over the entire range of temperature and moisture levels. Semi-dwarf cultivars produced poorer stands than tall cultivars due to their coleoptile length. This difference in stand establishment capability was most pronounced under the warmest temperature (22°C) and the greatest moisture stress ( -6 bars). Estimates of minimum gene number together with data obtained from frequency distribution indicated that the inheritance of coleoptile length was controlled by one to three major genes and possibly some modifier genes. The close agreement between broad and narrow sense heritability estimates indicated that the expression of coleoptile length is controlled primarily by additive gene action. This suggests that selection for coleoptile length in early generations should give reliable estimates of coleoptile length expression in later generations. The heritability of Adenosine Triphosphate (ATP) was found to be subject to cytoplasmic influence. Maternal effects in the F1 generation, the occurrence of considerable inbreeding depression in the F2 generation, and relatively low narrow sense heritability estimates suggest that ATP can not be used as a selection character for seedling vigor in early generations of wheat in a conventional breeding program. Several characteristics (coleoptile length, ATP, plant height, and seed weight) were tested for their association with percent stand in the F 1 and F2 populations. None of these characteristics were significantly correlated with percent stand. Of these characteristics, coleoptile length produced the highest correlations with percent stand in the F 1 and F2 generations. The use of coleoptile length as a selection character for percent stand in early generations appears promising.

Download or read book Agronomy News written by and published by . This book was released on 1977 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sept.-Oct. issue includes list of theses and dissertations for U.S. and Canadian graduate degrees granted in crop science, soil science, and agronomic science during the previous academic year.

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plant Breeding Abstracts written by and published by . This book was released on 1980 with total page 1282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 1977 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Agriculture Agronomy written by University Microfilms International and published by . This book was released on 1977 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Time and Duration of Growth Stages and Subsequent Grain Yield in Selected Wheat Cultivars Triticum Aestivum L Em Thell written by Byung Han Choi and published by . This book was released on 1982 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to develop a shorter life cycle wheat cultivar which would be more adapted to multiple cropping systems prompted this study. Thus the following information was obtained. Greatest variations in developmental patterns were found in the stem elongation, booting, inflorescence emergence and anthesis for five winter and five spring cultivars when planted at different dates. Differences among the ten winter wheat cultivars in time, duration and rate of grain filling was also observed. Generally later flowering cultivars had a more rapid rate of grain filling than early flowering cultivars with the net result being that physiological maturity was similar between the two groups. Actual grain filling period from flowering to physiological maturity varied among the cultivars, but larger differences were observed in lag period from heading to flowering. The duration of lag period contributed to the largest difference in total grain filling period from heading to physiological maturity. Changes in visual spike color of the glumes and main axis of a spike was satisfactory in identifying physiological maturity without destruction of the spike; however changes in kernel color was a more direct and precise method. Physiological maturity is a better measure of the optimum harvesting time to provide for maximum grain yield for planting sequential crops. Grain yield was positively associated with time of heading, flowering, physiological maturity, rate of grain filling and components of grain yield, but negatively associated with duration of grain filling period, lag period and harvest index. There was little association with the duration of the actual grain filling period and grain yield. However, a large association was observed between grain yield and the rate of grain filling. The direct effects of tiller number and rate of grain filling on grain yield were consistently positive and high. The indirect effects of rate of grain filling on grain yield were positive and high via time of heading, flowering and physiological maturity, components of yield and whole plant dry weight, but negative and high via duration of grain filling period, lag period and harvest index.

Download or read book Inheritance and Association of Earliness and Grain Yield in Four Winter X Spring Wheat Crosses Triticum Aestivum L Em Thell written by Ahmet Ertug Firat and published by . This book was released on 1977 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Parental and segregating populations derived from four winter x spring wheat crosses were investigated to obtain information concerning the inheritance and association of earliness, grain yield and yieldrelated traits. Feasibility of selecting in early generations for these characteristics was also evaluated. Four winter wheat cultivars (Hyslop, Yamhill, Bezostaia 1, and Sprague) and one spring wheat cultivar (Inia 66) were chosen on the basis of their relative maturity and contrasting agronomic characteristics. Parents, F1 s, F2' s, and reciprocal backcrosses to both parents were planted in the fall in a space-planted randomized complete block design. The two environmentally diverse locations selected were the Hyslop Agronomy Farm, Corvallis, Oregon (1000 mm of rainfall) and Sherman Experimental Station, Moro, Oregon (250 mm of rainfall). The effectiveness of early generation selection for the measured characteristics was evaluated by growing F3 lines identified as the earliest 1% and the highest yielding 1% of F2 individuals in each cross. These were grown along with the parents, F1s, BC1 s, BC2 s and F2' s under space-planted conditions at Hyslop Agronomy Farm. A study with the same populations was conducted by vernalizing and planting in the spring to gain further information on earliness. Analyses of variance were conducted for all characteristics measured. Frequency distributions for days to heading of F1, F2, backcross generations and parents were examined. From the data collected, estimates of F 1 -midparent deviations, degree of dominance, heritability in the narrow sense and genetic advance under selection were determined for each cross. The data were further analyzed by parent-progeny regression, correlation and path-coefficient analyses, polynomial and multiple regressions. Partially dominant major genes, varying in number between one to five depending on the particular cross, appeared to influence heading date. Modifying factors also seemed to affect the date of heading. The gene action involved in the inheritance of earliness was primarily additive indicating that selection for earliness would be effective as early as the F2 generation under both high and low rainfall conditions. Estimates of additive and nonadditive gene action suggested both were equally important in determining the yield components. Higher heritability estimates for the components of yield indicated that there was more genetic variability associated with the yield components than yield per se. Occurrence of additive genetic variation by location interaction implied that selection should be practiced simultaneously under different environments if wide adaptability of potential lines is desired. Since pronounced additive effect by year interactions occurred for the yield components, delayed selection for these traits may not be productive. Positive correlations were obtained between yield and the number of days to heading when all generations were combined. However, in the F2 generations, it appeared possible to select for the desired earliness with high yields as indicated by the low association between these two traits. The path-coefficient analyses suggested that tiller number had the highest direct effect on grain yield. However, because of a negative association between tiller number and kernel weight, selection pressures would have to be balanced between these two components. In most cases, linear relationships existed between grain yield and seven measured traits, respectively. The result of regression analyses also showed that grain yield may be described best as a linear function of its components.

Download or read book Possible Compensations of the Components of Grain Yield in Wheat Triticum Aestivum L as Influenced by Genotype by Environment Interactions written by David Bedoshvili and published by . This book was released on 1999 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite many investigations genotype by environment interaction remains one of the least understood factors in plant improvement. Understanding genotypic differences responsible for such interactions could assist in making more informed breeding decisions. The components of yield being less complex than grain yield per se may be useful for selection to improve adaptation of genotypes and enhance grain quality. However, the potential compensatory response among the components of yield could compromise their usefulness as selection criteria. To evaluate this aspect fifteen cultivars, including Soft White, Hard White and Hard Red wheats, were planted at three diverse locations over two growing seasons. Genotypes were ranked based on measurements for specific traits in each environment. The genotype by environment interaction for grain yield, protein concentration and hardness were investigated according to the AMMI model. Influence of environmental factors and genotype by environment interactions on associations among selected traits were determined. The results of this study showed that genotypic differences in adaptation to the Pacific Northwest and resistance to Septoria spp. were responsible for interactions for grain yield. However, no consistent patterns of response were found among the similar cultivars for quality traits. Those environments that favored expression of biomass and grain weight potential provided for enhanced performance of the adapted cultivars. The environments with suppressed biomass accumulation and grain filling interacted positively with the unadapted cultivars. A large compensatory relationship between tillering and apical growth was detected. No or low compensation was observed between grains per spike and thousand kernel weight. Two different strategies were proposed for improvement of Soft and Hard White wheat cultivars under the conditions of the Pacific Northwest. Both strategies accentuate importance of increasing biomass while maintaining harvest index. When selecting for higher yielding Soft White cultivars, plants with larger leaves, stronger stems, larger spikes and heavier grains should be emphasized. For Hard Whites - higher number of tillers and grains m−2 is desired, as they provide for harder grains with higher protein content.

Download or read book Duration and Rate of the Grain Filling Period and Subsequent Grain Yield in Crosses Between Facultative and Winter Wheat Cultivars Triticum Aestivum L Em Thell written by Beiquan Mou and published by . This book was released on 1985 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns about the genetic control and environmental influence of various stages of development including the grain filling period, and the relationship between early maturity and grain yield prompted this study. The experimental material consisted of two facultative and two winter wheat cultivars. A dial!el cross, excluding reciprocals, was also developed to provide an Fl generation. Information was collected for 14 traits and subjected to statistical analyses. Genetic differences among varieties were found for time of heading, flowering and physiological maturity, duration and rate of the grain filling period, grain yield and yield components. The facultative types, AI Feng 2 and Selection CB 83-52, showed earlier heading, flowering and physiological maturity, longer lag period (period between heading and flowering), and longer duration and lower rate of grain filling, resulting in lower grain yield. The winter cultivars, Stephens and Yamhill Dwarf, in contrast had later heading, flowering and maturity, shorter lag period, and shorter duration and higher rate of grain filling, giving higher grain yield. For the developmental stages after heading, larger differences were observed in the lag period while differences in duration of grain filling period were relatively small among the cultivars. Depending on the specific Fl population, there was a tendency toward dominance for early heading, a range from no to complete dominance for early flowering and no dominance for physiological maturity. Long duration and fast rate of grain filling were generally dominant. Grain yield was positively associated with the number of days to heading, flowering and physiological maturity. Also positive associations of grain yield were obtained with tiller number, kernel weight, grain weight per spike, biological yield and rate of grain filling. Negative associations of grain yield were noted with lag period and duration of grain filling period. No clear associations between physiological maturity and the yield components were found. Grain filling duration showed no association with yield components while grain filling rate exhibited positive association with tiller number and kernel weight. There was negative association between duration and rate of grain filling period. According to heading responses from different planting dates, Stephens and Yamhill Dwarf had high sensitivity while Selection CB 83- 52 and AI Feng 2 showed low sensitivity to vernalization. Genotype X environment interaction was observed with each cultivar responding differently for several traits depending on the planting dates.

Download or read book Evaluation of Parental Performance for Grain Yield in Two Populations of Wheat Triticum Aestivum Vill Host written by Maximino Alcala de Stefano and published by . This book was released on 1973 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Six winter wheat cultivars were evaluated for their breeding value in transmitting superior genetic factors for grain yield to subsequent progeny. The cultivars were selected on the basis of their potential grain yield and divided into two populations. Population I was comprised of three cultivars which have been in commercial production for several years and are regarded as intermediate for grain yield. Population II was represented by three recently developed cultivars which have superior grain yielding potential. Each of the three parents within each population were crossed in a diallel manner Hence, the parents and subsequent F1, F2, and BC progeny made up the experimental populations. These populations were grown at two environmentally diverse sites within the state of Oregon. Morphological characters measured were: (1) tillers per plant; (2) kernels per spike; (3) plant height; (4) weight of 300 kernels; and (5) grain yield. To detect which parental combination had the greatest potential for transmitting superior performance to the subsequent progeny for the components of yield and grain yield, the following parameters were determined for both populations: (1) the amount and nature of the genetic variance associated with each population; (2) average combining ability of each parent within the populations; (3) estimates of heterosis and heterobeltiosis in the F1 and (4) the possible influence of the genotype-environmental interactions on the parameters measured. Also information concerning the desirability of using top crosses and double crosses rather than single crosses was obtained. In an effort to compare the relative performance between the populations, Pullman Selection 101, which is a good general combining winter wheat cultivar, was used as a tester for both populations. The values obtained in this investigation reflect the properties of the populations studied and should not be interpreted as applying to all wheat populations. Considerable genetic variability was found within both populations for the characters studied. This variability was largely due to genetic factors which were additive. Tillers per plant and grain yield were influenced by both additive and nonadditive genetic variance. The higher yielding parents in Population II were found to be higher in their average combining ability for kernels per spike and grain yield per plant whereas the lower yielding parents in Population I were higher for tiller number, weight of 300 kernels and plant height. Parental combinations identified as being promising, for grain yield in a conventional program, where nearly homozygous lines are desired, were also the same parental combinations which resulted in a maximum expression of heterobeltiosis and would be of most interest in a hybrid program. The desirability of using multiple crosses to maximize the number of favorable factors need further study inctuding additional parents and different combinations plus an evaluation of the performance of such crosses in later generations. In this investigation, the single crosses appeared to be the most promising; however, inbreeding depression due to segregation within top and double crosses influenced the values obtained. Also, the population sizes should be increased to measure the total potential of such crosses. Significant genotype-environmental interactions were observed between locations for plant height and weight of 300 kernels. The estimates obtained for average combining ability, heterosis and heterobeltiosis for the other characters measured also suggested that it will be necessary to identify the most promising hybrid combinations based on the performance of the parents at the specific location. To make the most rapid progress in developing high yielding cultivars in either conventional or hybrid programs, the wheat breeder needs to emphasize crosses between unrelated high yielding cultivars. However, the need to provide superior parental lines which include such factors as disease resistance, should be evaluated. The development of elite germ plasm by geneticists will be mandatory if plant breeders are to continue to improve grain yield.

Download or read book The Effect of Row Spacing Rate and Date of Planting on Yield and Yield Components of Four Winter Wheat Cultivars Triticum Aestivum L Em Thell written by Benacef Nadjib and published by . This book was released on 1982 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four winter wheat cultivars, Bezostaya, Maris-Hobbit, Roussalka and Stephens, selected on the basis of the diversity of their pedigree and phenotype, were planted at Hyslop Experiment Station near Corvallis in Western Oregon to study their performance at three different row spacings (10, 16 and 24 cm), three seeding rates (100, 160, and 240 Kg/ha) and at two seeding dates (October 13 and November 12). A similar experiment was conducted at the Sherman Experiment Station, Moro in Eastern Oregon, using only two winter wheat cultivars, Stephens and Jackmar. Data were obtained on grain yield, tillers and spikes per square meter, heading and anthesis date, plant height, kernels per spike, 1000 kernel weight, test weight and harvest index. At Hyslop Experiment Station, Stephens, Bezostaya and Roussalka produced maximum grain yield at 10 cm row spacing and 160 Kg/ha seeding rate, and Maris-Hobbit at 24 cm row spacing and 160 Kg/ha seeding rate. At Sherman Experiment Station, 30 cm row spacing and 90 Kg/ha seeding rate constitutes the best combination for Stephens, and 30 cm row spacing and 120 Kg/ha seeding rate for the club wheat Jackmar. The interaction between row spacings x cultivars and seeding rates x cultivars indicated that all the cultivars produced high numbers of tillers and spikes per m2 at narrow (10 cm) row spacing and high (240 Kg/ha) seeding rate. There were no significant differences between row spacings for heading and anthesis date. Lower seeding rate resulted in later heading date. The cultivar Roussalka was the earliest and Maris-Hobbit the latest in average heading date, Plant height decreased with increased row spacing and increased with increased seeding rate. The plants of the four cultivars were shorter at the second date than at the first. More kernels per spike were produced at the second than at the first date. An increase in seeding rates was accompanied by a decrease in the number of kernels per spike. There were no significant differences between the three row spacings, the three seeding rates and the four cultivars for test weight. The different row spacings and seeding rates did not affect the TOGO kernel weight. Considering the cultivars, Stephens produced a higher 1000 kernel weight at the two seeding dates than Maris- Hobbit, Bezostaya and Roussalka.