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 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 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 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 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 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 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 Association and Inheritance of Earliness and Winterhardiness in Four Winter X Spring Wheat Crosses Triticum Aestivum Vill Host written by Kamil Yakar and published by . This book was released on 1976 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study was to determine the nature and amount of genetic variation and possible associations between winterhardiness and earliness in winter x spring wheat crosses. Four winter wheat cultivars selected for differences in earliness and winterhardiness were crossed with a nonhardy, day length insensitive spring wheat cultivar. The following year, experiments containing parents, F1, BC, and F2 populations were planted at two environmentally diverse sites located at the Sherman Branch Experiment Station, Moro, Oregon (250 mm of moisture) and the Hyslop Agronomy Farm, Corvallis, Oregon (1000 mm of moisture). The amount and nature of genetic variation involved were determined by obtaining broad and narrow sense heritability estimates, evaluating the degree of dominance and estimating the number of genes influencing both earliness and winterhardiness. Also frequency distributions were developed for each of the populations. Both broad and narrow sense heritability estimates for earliness were higher than those observed for winterhardiness. Both winterhardiness and earliness appeared to be conditioned by both additive and nonadditive gene action. Degree of dominance estimates for the four wheat crosses grown at two locations differed for each cross and location. Earliness was influenced by one to six genes while winterhardiness appeared to be controlled by two genes. The estimation of genetic advance indicated that the crosses with high narrow sense heritability estimates and high phenotypic variance in F2 generation would result in greater gains under selection for both traits. Based on the results of this study, it seems that Moro is a proper site to select for winterhardiness and Corvallis for earliness. However, it might be better to select for both traits at the same time at another site such as Pendleton, Oregon, where a realistic selection pressure can be applied for winter survival and drought would not influence the selection procedure. Such a site could also provide an opportunity to evaluate earliness at the same time. Correlation coefficient estimates showed the presence of a positive association between earliness and winterhardiness. The possibility of using leaf damage readings to measure the winterhardiness levels in wheat populations also appears promising.
Download or read book Agronomy News written by and published by . This book was released on 1978 with total page 712 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 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 A Study of Methods of Parental Evaluation Using Testers to Predict Subsequent Progeny Performance in Winter Wheat Triticum Aestivum L written by William Larry Alexander and published by . This book was released on 1980 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three winter wheat parents were chosen as the experimental material, based on their known performance as parents. Yamhill and Pullman Selection 101 are recognized as cultivars with good combining abilities for grain yield. Crosses with Nugaines have been disappointing, even though the cultivar itself is high yielding. Each parent was crossed to a series of five testers. These testers were chosen on the basis of their genetic diversity, especially for the components of yield. This parent x tester crossing scheme was analyzed as a 3 x 5 factorial, where the main effects due to parents and testers were their general combining ability effect estimates. The interactions of these main effects were their specific combining abilities. F1 hybrids were evaluated for two years and F2 populations for one year to characterize the parents' capacity to transmit selected attributes to their resulting progeny. These generations were evaluated on a per plant basis for their grain yields and the primary components of yield, tillers per plant, kernels per spike, and 1000 kernel weight. The four methods of evaluating parents assessed were parental performance, midparent-progeny correlations, examination of individual crosses, and combining ability analysis. Midparent-progeny correlations usually were not significant within the progeny of each parent. Significant differences were not found for grain yields among the parents in either year. However, significant differences existed for their expressions of yield components. Parental expressions of the yield components were generally more erratic than those of their F1 progenies. Significant differences occurred for estimates of general combining ability effects in both years and for each generation in all traits. These estimates for a particular parent were relatively consistent. Specific combining ability was not found to be a dependable means of identifying superior combinations. Associations between the parental general combining ability effect estimates for kernels per spike and 1000 kernel weight were positive. Relationships between other yield component combinations were negative with regard to general combining ability effects. Trends observed in single crosses reflected the relative general combining abilities of the parents. Crosses involving Yamhill generally had fewer tillers with a higher number of kernels per spike, heavier kernel weights, and superior grain yields to those of the other parents. Progeny of Pullman Selection 101 were usually high in tillering, intermediate for number of kernels per spike, low in kernel weights, and intermediate for grain yields. The progeny of Nugaines were characterized by high tillering, a low number of kernels per spike, low kernel weights, and also low grain yields. The parent x tester crossing scheme was found to be an effective way of determining the potentials of the three parents by estimating their general combining abilities, as well as minimizing the number of crosses required. If, as found in this study, the general combining ability effect estimates of the parents for grain yield accurately predict performance of later generations, this parent x tester crossing scheme would be an efficient method of assessing the potentials of prospective parents in breeding programs.
Download or read book Early Generation Bulk Testing to Evaluate the Introgression of Unadapted Wheat Triticum Aestivum L Germplasm Into Adapted Spring Wheat written by Ana Maria Procopiuk and published by . This book was released on 1999 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluating Grain Yield as Influenced by Biological Yield and Harvest Index in Four Winter Wheat Triticum Aestivum Crosses Involving Near isogenic Lines written by Mohammad Moznur Rahman and published by . This book was released on 1988 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crosses between four near isogenic lines for height reducing genes Rht1 and Rht2 and one agronomically superior dwarf line, including generations through F3 with reciprocal backcrosses constituted the experimental materials. Mean, range and standard deviation values for eleven traits pertaining to the different generations were obtained. Heterosis and inbreeding depression along with broad and narrow sense heritability estimates for the traits provided information regarding nature of gene action. Possible relationship between selected traits were also determined. The amount of genetic diversity between crosses depended upon the number and specific dwarfing genes involved. A limited number of traits were different in crosses involving either Rht1 or Rht2 isolines. This may have resulted since 'Yamhill Dwarf also carries the Rht1 allele. For generations, differences were detected for all eleven traits measured. The cross involving the standard height isoline (rht1rht2) and Yamhill Dwarf registered the highest mean values for plant height, grain yield, 300-kernel weight and biological yield; but had the lowest value for harvest index. Increased grain yield was more a function of higher "biological yield" than "harvest index" in all crosses and populations examined. Consistent and positive associations were also found between grain yield and biological yield; however the same was not true for grain yield with harvest index where little or no associations were detected for any of the crosses. Heterosis estimates were high for most traits in rht1Rht2/Yamhill Dwarf cross and low in the cross Rht1rht2/Yamhill Dwarf. Inconsistent broad and narrow sense heritability estimates were observed in several crosses for most traits measured. The one exception was for 300-kernel weight, being relatively high and consistent in all crosses except Rht1Rht2/Yamhill Dwarf. In some instances, negative narrow sense heritability estimates were realized. This was particularly true for the cross between the standard height isoline (rht1rht2) and Yamhill Dwarf. Also, depending on the cross and trait measured, larger narrow sense heritability estimates were obtained when compared to the broad sense estimates. This could reflect some sampling error or a large genotype X environmental interaction which was observed.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1970 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of Yield and Other Traits in a Diallel Cross Involving Eleven Winter Wheat Alien translocation Lines written by Paul Gregory Sebesta and published by . This book was released on 1980 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Methods for Predicting Yield in Early Generations of Winter Wheat Crosses written by Surendra Prasad Sinha and published by . This book was released on 1963 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
