Download or read book Association of Selected Traits with Visual Selection for Yield in Wheat Triticum Aestivum L Em Thell written by Michael E. Marciniak and published by . This book was released on 1983 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Visual selection for grain yield may be a limiting factor in identifying superior yielding genotypes in a breeding program. This investigation was conducted (1) to compare the effectiveness of visual selection for grain yield by three selector groups representing different levels of plant breeding experience, and (2) to examine the association of selected traits with the process of evaluating plots visually for grain yield. The germplasm evaluated consisted of fifty non-segregating, diverse genotypes selected to include a wide range of expression for phenotypic characters. They were grown in solid-seeded, two-row plots with three replications in a randomized block design during 1981-1982. Data were collected on a plot basis for grain yield and twenty-two agronomic traits. Eighteen selectors were placed in three groups comprised of two plant breeders, eight graduate students, and eight summer student workers, respectively, from the Oregon State University cereal breeding program. Evaluations were made on two separate days by scoring each of the 150 plots on a scale of 1 to 5 for grain yield. The plant breeder selectors were the most successful of the three groups in discriminating both high and low yielding plots. The two best graduate student selectors were similar in ability to the plant breeders in scoring plots for high yield, although not in scoring for low yield. The remaining graduate student and summer worker selectors were generally not able to score more low and high yielding plots "correctly" than would be expected if selection were done at random. Considered individually, the most effective selectors failed to select several high yielding plots. However, when selections of the four most effective selectors were combined, only one of the twenty highest yielding plots was omitted. Results comparing trait association with actual plot grain yield and with selector scoring for plot grain yield suggested "biases" for or against certain traits. Biases for later heading and maturing plant types with wide flag leaves were common to all selector groups when visually selecting for high yield, as were earlier heading and maturing entries with narrower flag leaves when selecting for low yield. The plant breeder selectors were notable for lack of trait biases relative to other selector groups. In contrast, the summer worker selectors tended to overemphasize several spike characteristics whether selecting for high or low yield. Results suggested several other trait biases of individual selectors and selector groups.

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 Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1 957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 29 (thesis year 1984) a total of 12,637 theses titles from 23 Canadian and 202 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 29 reports theses submitted in 1984, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.

Download or read book Progeny Tests for Predicting Grain Yield and Selected Agronomic Traits in Single Three way and Double Crosses in Wheat Triticum Aestivum L Em Thell written by Vichien Petpisit and published by . This book was released on 1979 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combining Ability and Associations of Agronomic Traits Involving Three Sources of Dwarfism in Wheat Triticum Aestivum L Em Thell written by Jose Luis Maya de Leon and published by . This book was released on 1974 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three genetically different dwarf cultivars of spring wheat were evaluated as potential sources of short stature to use in a wheat improvement program. The study involved a five parent diallel cross which included a semidwarf, a standard height and three dwarf cultivars. The genetic sources of dwarfism included a Norma 10 derivative named Vicam 71, a derived line from Tom Thumb called Tordo, and Olesen dwarf. Experimental material consisted of parental lines, F1, F2, and both backcrosses to the parents space planted in a randomized block design. The agronomic characters measured on an individual plant basis were: (1) plant height, (2) days to heading, (3) number of tillers, (4) number of spikelets per spike, (5) head length, (6) days to maturity, (7) grain yield, (8) harvest index, (9) kernel weight, (10) number of kernels per spikelet, (11) rachis internode length, (12) grain filling period and, (13) head grain weight. Estimates of gene action were determined by heterosis, heterobeltiosis, broad and narrow sense heritabilities and combining ability analyses. Associations among traits were estimated by phenotypic, environmental, and genotypic correlations as well as path-coefficient analysis for grain yield and eight of the variables. There were significant differences among the parental lines, their crosses, and generations for all traits measured. Either partial dominance for tallness or no dominance was manifested for those crosses involving the dwarf cultivars Vicam 71 and Olesen. Tordo, when crossed to taller wheats showed dominance for short stature. All three genetic sources of dwarfism and their resulting progenies manifested desirable agronomic characteristics. Vicam 71 was a good parent in terms of grain yield and number of tillers per plant. Tordo was the best source for increasing the number of spikelets per spike, kernel weight and head grain weight. Olesen was a good progenitor for increasing number of kernels per spikelet. All three dwarf cultivars displayed some advantage(s) over the other two and all could be used to breed short statured wheats with a possibility of success. Plant height did not appear to have a direct effect on plant grain yield in any of the 10 crosses. With the exception of number of tillers per plant and grain yield, a major proportion of the phenotypic variability observed for all characters studied was due to genetic factors. A large portion of the total genetic variability associated with days to heading, maturity, height, rachis internode, spikelet number, kernels per spikelet, kernel weight, and harvest index was mainly a result of additive gene action. Both additive and non-additive genetic effects were involved in the expression of grain filling period and head weight. The nonadditive portion of the genetic variance associated with tiller number and grain yield per plant was relatively large when compared with the additive portion. Therefore, selection for increased expression of tillers and yield should be delayed until the F4 or later generations where a large degree of homozygosity has been obtained. The genetic correlations for individual crosses indicated that only a few of the traits studied were associated in the same manner in most or all the 10 hybridizations. High positive genetic correlations were found between plant grain yield vs tiller number and kernels per spikelet, tiller number vs days to maturity, kernels per spikelet vs head grain weight, plant height vs head weight, and head length vs rachis internode length. High negative genetic correlations were found between kernel weight vs days to maturity, plant height vs harvest index, and days to heading vs grain filling period. Most correlations among agronomic traits were different in value and/or sign from one cross to another suggesting different gene associations in the parental cultivars. Genetic correlations between components of yield showed this type of inconsistency. Therefore, grain yield could be increased by a combined increase of more than one component of yield without compensatory oscillation among them because tiller number, spikelet number, kernels per spikelet and kernel weight were often not correlated between one another and sometimes were positively correlated. Path-coefficients analysis indicated that number of tiller per plant had a high direct effect on grain yield in all crosses. With the exception of two crosses, indirect effects of this trait were negligible. In the latter two crosses tiller number had a high negative indirect effect on plant grain yield via head grain weight. Kernels per spikelet and kernel weight had no direct effects on grain yield but their indirect effects via head weight were positive and significant. Large amounts of additive gene action were observed in the expression of plant height. This trait was also highly negatively correlated with harvest index; therefore, phenotypic selection for restricted plant height would be useful in obtaining lines with high grain to straw ratios. In general, crosses that showed high specific combining ability effects involved parents with low general combining ability. However, there were some exceptions to this rule. Crosses of high x high and high x low general combiners presented high specific combining ability effects, suggesting that some additive gene action may be involved in the superior performance of these combinations. Also the F 2 generation did not differ from the F1 in assessing general cornbining ability. A wheat breeder should be aware of those genetic associations between agronomic traits that could be used to select superior cultivars. However, the genetic correlations in this study suggested that each cross represented a different set of gene associations depending upon the parents involved. If some progress is to be made in using the genetic variability available in the crop, the breeder should not try to select exactly the same type of plant from every cross. Every hybridization is potentially a source of better lines if they are well planned and the reasons they were made are remembered during selection. It is very important to realize what are the contributions of each parental line in a cross and what are the most important trait associations present in each parent. Superior rural genetic variability existing in the crop.

Download or read book Nature of Inheritance Genotype environment Interaction and Association of Selected Agronomic Characters in Crosses of Winter X Spring Wheats Triticum Aestivum L Em Thell written by P. Brajcich and published by . This book was released on 1980 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation was motivated by the apparent increase in genetic variability resulting from the systematic combining of gene pools represented by winter and spring types of wheats. It was the objective of this study to provide information regarding the nature of this genetic variability for nine agronomic characters in populations resulting from winter x spring crosses. Evaluations were made for: 1) the amount of total genetic variability; 2) the nature of the gene action making up this genetic variability using parent-progeny regression and combining ability analysis and 3) possible direct and indirect associations for traits which influence grain yield. Experimental populations which involved parents, Fl, F2 and backcross generations were grown at two locations where a spring and a winter environment could be utilized. At the winter site, the research was evaluated over a two year period. When the two experimental sites were compared, greater genetic diversity was observed at the spring site for maturity date, plant height, tillers per plant, kernel weight and grain yield. At the winter site, heading date, grain filling period, harvest index and kernels per spike were found to have more total genetic variation. From the expected mean square values, it would appear that the winter parents contributed more to the total genetic variation for most traits measured at both locations. A large genotype-location interaction was also noted suggesting that estimates of gene action and selection for adapted plant types can be done only at the specific winter or spring site. A large portion of the total genetic variation controlling the traits measured was due to additive gene action. However, at the winter site there was also a large influence of non-additive gene action associated with heading date, plant height, harvest index, tillers per plant, kernel weight, kernels per spike and grain yield. Of special interest was that at the winter site the most promising parental combinations could be predicted based on the general combining ability effects of the individual cultivars for each trait studied. Such data were not available for the spring site. Consistent and high correlations were observed between tillers per plant, kernels per spike and, to a lesser extent, kernel weight and grain yield at the winter location. Some negative associations were observed at the spring location between these traits and grain yield suggesting that yield component compensations were involved in the final expression of grain yield. The other characters measured did not reflect significant correlations with yield. When the correlation values were considered in terms of direct and indirect effects for specific traits, a large direct effect was noted for the three components and grain yield. The other traits exhibited small or no direct effects on grain yield but did have a slight influence on grain yield through tillers per plant, kernels per spike or kernel weight.

Download or read book Effect of Selection for Certain Grain Characters on Yield in Bread Wheat Triticum Aestivum L Em Thell written by Behari Lal and published by . This book was released on 1976 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic Variation for Protein Content and Its Association with Yield Related Traits in Recombinant Inbred Lines Rils Population of Bread Wheat Triticum Aestivum L Em Thell With CD Copy written by Pinki and published by . This book was released on 2014 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 An Analysis of the Effectiveness of Selection in Early Generation Trials for Grain Yield of Wheat Triticum Aestivum L Em Thell written by Ross Forrest Gilmour and published by . This book was released on 1988 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effectiveness of Early generation Single plant Selection in Common Wheat Triticum Aestivum L written by Ramesh Bhauraoji Thakare and published by . This book was released on 1975 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Characterization of Tiller Number Trait in Wheat Triticum Aestivum L Em Thell written by Rizwana Maqbool and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The applied part of my research focused on targeted use of marker-assisted selection for rapid introgression of genes and development of breeding lines. Using marker assisted background selection; two-gene imidazolinone resistance was transferred to Louise cultivar. Lines with desirable quality and yield were selected for field trials.

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 of Yield Its Components and Morpho physiological Traits in Wheat Triticum Aestivum L Em Thell Under Heat Stress Conditions written by Ravinder Singh Sudan and published by . This book was released on 2004 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Stability Analysis of Yield and Yield Attributing Characters of Promising Bread Wheat Triticum Aestivum L Em thell Genotypes With CD Copy written by Vijeta Gupta and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Dissection of the Association of Spike Traits and Grain Yield Attributes in Bread Wheat Genotypes and F1 Hybrids Derived from Line X Tester Mating written by R.K Yadava and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present investigation was undertaken with the objective to evaluate the nature and magnitude of genetic variability and correlation of different spike traits and other character association with grain yield. Eighteen diverse bread wheat (Triticum aestivum L.em Thell.) genotypes and 72 F1 lines were evaluated to estimate the extent of association with respect to spike traits and grain yield. The coefficient for genotypic correlation for most of the character combination was higher in magnitude, as compared to corresponding phenotypic correlation coefficient, indicating largely the strong inherent nature of traits recorded in the present investigation. The yield per plant exhibited positive and strong association with all the traits except with 100 grain weight. From the present investigation, it could be suggested that breeder has to work cautiously for any breeding program aimed at improving particularly the 100 grain weight.