Download or read book Genetic and Environmental Factors Influencing the Effectiveness of Early Generation Selection in a Diallel Cross Involving Four Winter Wheat Cultivars Triticum Aestivum Vill Host written by Abderrazak Daaloul and published by . This book was released on 1974 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Early Generation Testing in a Diallel Cross Involving Four Winter Wheat Cultivars Triticum Aestivum Vill Host written by Abderrazak Daaloul and published by . This book was released on 1972 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Factors which influence the effectiveness of making early generation selections within bulk populations were investigated. Material utilized included the parents, F1, and F2 through F5 bulk populations resulting from a diallel cross. Information concerning the response of two traits, plant height and grain yield, was obtained for these populations at three diverse experimental sites. Estimates of gene action were determined by calculating heterosis, inbreeding depression, narrow-sense heritability, and combining ability values. Results obtained suggested that selections for plant height could be effectively made as early as the F2 generation since this trait was largely controlled by additive gene action. Grain yield was found to be influenced significantly by non-additive gene action; however most populations were stabilized by the F3 generations where high yielding populations could be identified and effective selection practiced. Results from this study suggested that genotype x environment interaction could influence early generation selection by masking the additive genetic effects. Under very favorable growing conditions the non-additive gene action x environment interaction dominated the additive effects for grain yield and to a lesser degree plant height. However, under dry land conditions both non-additive and additive genetic effects were masked by the environment and could not be expressed fully for grain yield. It is evident that for simply inherited traits like plant height, selection in the F2 generation must be practiced under an environment where there is full expression for that trait, while selection for grain yield must be conducted under the same environments where the potential varieties are to be grown. The use of Average Combining Ability as an indirect method to evaluate the contribution of parents to performance of the progency was found to be valid by the predicted results obtained for the simply inherited trait plant height. This method could be used with some confidence to estimate contribution of parents for a complex trait like grain yield. Two parents were identified as the best combiners for grain yield. This confirms what was learned about them after fifteen years of actual experience indicating the importance of a technique whereby the breeder can determine in a very short period of time which parents to cross and then concentrate his efforts within the more promising segregating populations.
Download or read book Plant Breeding Abstracts written by and published by . This book was released on 1976 with total page 1266 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 Pakistan Journal of Agricultural Sciences written by and published by . This book was released on 1979 with total page 746 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 1974 with total page 1152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1973 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1984 with total page 1086 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1973- include the following subject areas: Biological sciences, Agriculture, Chemistry, Environmental sciences, Health sciences, Engineering, Mathematics and statistics, Earth sciences, Physics, Education, Psychology, Sociology, Anthropology, History, Law & political science, Business & economics, Geography & regional planning, Language & literature, Fine arts, Library & information science, Mass communications, Music, Philosophy and Religion.
Download or read book Agronomy Abstracts written by and published by . This book was released on 1972 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes abstracts of the annual meetings of the American Society of Agronomy; Soil Science Society of America; Crop Science Society of America ( - of its Agronomic Education Division).
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 Comprehensive Dissertation Index Agriculture written by and published by . This book was released on 1984 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Four Quality Factors in a Selected Winter X Spring Wheat Cross Triticum Aestivum Vill Host written by Karen Sue Schumaker and published by . This book was released on 1979 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature of the genetic variation associated with a cross involving winter and spring wheat parents for four quality factors was evaluated. Yamhill, a soft white winter wheat, and Inia 66, a hard red spring wheat, were selected as parents for this study. They represented distinctly different phenotypes for the attributes measured. Parents, F1, F2 and reciprocal backcrosses were examined for protein and lysine content, kernel hardness, and sedimentation value. Significant differences were observed between the two parents for protein content. The F1 mean was lower than the low protein parent with the F2 mean intermediate between the two parents. This latter factor plus a high narrow sense heritability estimate suggest that the genetic variation associated with protein content was largely due to genes which act in an additive manner. Backcrosses to either parent shifted the population toward the mean of the recurrent parent. Transgressive segregation was observed in the F2 for both low and high protein content suggesting that selection for this trait should be effective in early generations. Parents differed significantly for lysine content with the winter parent, Yamhill displaying lysine values approaching the highest previously reported for wheat. Intermediate F1 and F2 population means and a high narrow sense heritability estimate suggest the genes involved function in an additive manner. The backcross progeny to Yamhill had a mean value approaching that of the recurrent parent. No transgressive segregation was observed in the F2 for lysine content higher than Yamhill. It appears that lysine content in this cross is qualitatively inherited and that selection for improved lysine content above Yamhill appears limited. The genetic variation associated with kernel hardness appears to be largely additive with F1 and F2 means intermediate between the two parents and a high narrow sense heritability estimate. Transgressive segregation was observed in the F2 generation for both soft and hard kernel types. Selection for this trait should be effective in early generations. Significant differences were observed for the parental types for sedimentation value. The F1 and F2 means were below the midparent value. No transgressive segregation was observed in the F2 for either low or high sedimentation value. One backcross to the low sedimentation parent brought the population back to the low parent mean. One backcross to the high sedimentation parent shifted the population toward the recurrent parent but no individuals were recovered that approached the high parent. From this study it appears that selection for high sedimentation value types would be very difficult. Evidence provided in this study supports the concept that winter x spring crosses can provide useable genetic variation for desirable quality factors.
Download or read book Ecology and the Environment written by University Microfilms International and published by . This book was released on 1976 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heritability Estimates and Associations for Protein Content and Grain Yield Involving Four Winter Wheat Crosses Triticum Aestivum Vill Host by Polat Solen written by Polat Solen and published by . This book was released on 1973 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four agronomically and genetically diverse winter wheat parents were utilized as the experimental organisms. Atlas 66 and NB 68513 were selected as cultivars with a high and stable protein content when grown under different environmental condidtions. They are intermediate for grain yield when grown in the Pacific Northwest. Yamhill and Hyslop represented low protein, high yielding cultivars adapted to the Pacific Northwest. Data were obtained from crosses between the two high protein cultivars and the two low protein cultivars based on the performance of the parents and the F1 and F2 generations. These experimental populations were grown in 1971 at the Pendleton Experiment Station and the Central Oregon Experimental site at Madras, Oregon. Measurements were made on an individual plant basis for protein content, grain yield, 50 kernel weight, kernels per spike, tillers per plant and plant height. Differences among and within crosses were determined by the analysis of variance. Information concerning the nature of inheritance was obtained by comparing the F1 and F2 means in relation to performance of the parents; the frequency distribution of the generations for protein content; and by determining broad and narrow sense heritability estimates for the six characters studied. The existence of possible phenotypic associations among the six characters studied was determined by using correlation coefficients. In order to evaluate the possible direct and indirect effects of grain yield and the components of yield on protein content, path coefficient analyses were employed. Significant differences were observed among and within crosses at both the Pendleton and Madras sites for most characters measured. The F1 and F2 mean values were found to be near the mid-parent of the two parents in all four crosses for plant height, 50 kernel weight and kernels per spike. There were several exceptions depending on the particular cross and specific character. Protein content mean values were also intermediate between the two parents for the F1 and F2 generations. In crosses involving Hyslop, the mean values tended to be near the highest parent. Little or no transgressive segregation was noted in the F2 generation. Evidence of non additive gene action was noted both for grain yield and tiller number in the F1 and F2 generations with the mean values exceeding the highest parent in all crosses for grain yield at the Pendleton site. Tillers per plant at Pendleton and both tillers per plant and grain yield at Madras also showed some degree of hybrid vigor, but the magnitude depended on the particular cross. The high broad and narrow sense heritability estimates obtained both at Pendleton and Madras for all traits suggested that there was a large amount of genetic variation present for the characters studied. The narrow sense estimates further suggested that a high percentage of the total genetic variation was due to genes which function in an additive manner. Significant negative correlations were noted between protein content and grain yield including some of the components of yield. In evaluating the direct and indirect effects with path coefficient analysis, these negative associations resulted from the large negative indirect effects of 50 kernel weight and kernels per spike on protein content via grain yield at the Madras site. At the Pendleton site, where moisture became a limiting factor, the negative association resulted largely as the indirect effect of 50 kernel weight on protein content through grain yield. The large environmental influence on protein content was particularly striking at the Pendleton site. With the spring application of nitrogen, a delay in maturity for Hyslop and Yamhill was noted and with the subsequent loss of moisture, shriveled grain resulted and hence a higher protein content with lower grain yield. This resulted in the grain protein of Hyslop and Yamhill being higher than that of Atlas 66 and NB 68513. The results of this study suggest that it may be necessary to compromise in attempting to develop high protein lines with maximum yield. However, it should be possible to increase the protein content two to three percent and still maintain the yielding ability of Hyslop and Yamhill.
Download or read book Evaluation of Three Methods of Selection in Relation to Yield and Yield Stability in Winter Wheat Triticum Aestivum Vill Host written by Terd Charoenwatana and published by . This book was released on 1971 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effectiveness of early generation selection for yield and yield stability and the possible identification of superior parental combinations were studied in winter wheat populations representing different levels of genetic diversity. Experimental material for evaluating yield stability consisted of nine bulk and seven modified bulk populations derived from nine parental combinations which represented the F, F9, and F10 generations. The F9 and F10 generations of nine bulk, nine modified bulk and two modified pedigree populations along with the respective parental populations were studied to determine the relationship of yield to genetic diversity. Linear regression of the mean yield of individual entries on the mean yield of all entries for each year was used to describe yield stability. Grain yield differences among populations and crosses were analyzed by a functional analysis of variance. The modified bulk populations were found to be superior to their respective parents in yield and to the bulk populations in yield and yield stability. The modified pedigree populations had the highest yield of all populations measured. It was concluded that populations with high genetic diversity not only do not produce the highest yield but may not provide the greatest stability of yield. Selection for grain yield in the F4 generation was effective in identifying superior segregates. It was also possible to develop populations which had more yield stability. The highest yielding progeny were obtained from crosses between the medium yielding parents rather than between the highest yielding parents. This suggested that parental performance was of limited value in predicting the yielding ability of their resulting progeny. Therefore, selection for suitable parental combinations could not be based on their individual performance in the present study. It appeared that genetic factors for adaptability are as important as the level of genetic diversity in determining yield stability. A breeding system that allows the breeder to identify and incorporate genetic factors for adaptability and still maintain some genetic diversity in a new variety is suggested. Such a breeding system would prolong the length of time a variety could remain in commercial production and would allow such a variety to be grown over a more extensive range of environments.
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 Genetics Abstracts written by and published by . This book was released on 1972 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt:
