Download or read book Heritabilities and Interrelationships of Spike Size and Other Traits in Two Winter Wheat Crosses Triticum Aestivum L Em Thell written by James Russell Larkins and published by . This book was released on 1979 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heritability Estimates and Gene Effects for Basal Spikelet Sterility and Other Agronomic Characters in Four Crosses of Winter Wheat Triticum Aestivum L Em Thell written by Raad Mahmoud Salman and published by . This book was released on 1981 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heritabilities and Interrelationships of Short stature and Other Agronomic Characters in the F3 and the F4 Generations of Two Wheat Crosses Triticum Aestivum L Em Thell written by Moravapalle Venkataramana Reddi and published by . This book was released on 1968 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Heritability and Interrelations of Yield and Yield related Traits in a Hard Red Winter Wheat Cross Triticum Aestivum L written by Raymond Joseph Sidwell and published by . This book was released on 1975 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heritability and Interrelations of Yield Yield related Traits and Post Flowering Morphology in Three Hard Red Winter Wheat Crosses Triticum Aestivum L written by Mohamed Ali Alhagi and published by . This book was released on 1981 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Combining Ability Estimates to Identify the Genetic Potential of Selected Winter Parental Lines Triticum Aestivum L em Thell written by Muhammad Shahid Masood and published by . This book was released on 1989 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major factor limiting the efficiency of plant improvement programs is the lack of knowledge as to which parental combinations to make when working with quantitatively inherited traits. The primary objective of this study was to provide information regarding the use of combining ability analysis to predict which cross combinations would result in the greater frequency of desirable segregates. Five winter wheat parents were used to develop a 5x5 diallel cross. Over a two year period parents, Fl, F2, F3, and F4 generations involving top cross populations were evaluated. Information was collected on an individual plant basis for seven traits: plant height, tiller number, spike length, spikelets per spike, biological yield, grain yield, and harvest index. Griffing's (1956) model 1, method 2 was used to estimate GCA and SCA in Fl and later generations. Narrow-sense heritability estimates were computed using regression in standard units across generations. Significant GCA estimates were obtained for most traits in all generations with the exception of tiller number and grain yield in the Fl during 1986-87. Specific combining ability estimates were also found to be important for all traits, except spikelets per spike in the Fl and F3 generations. High GCA to SCA ratios indicated a preponderance of additive gene action. Exceptions to the trend were grain yield and tiller number in the Fl during 1986-87. Low GCA and narrow-sense heritability estimates suggest that selection for these two traits would have to be delayed until later generations. When considered over generations, both GCA and SCA estimates were found to be significant. Significant SCA over generations indicated the presence of additive x additive epistasis. The GCA effects contributed by a particular parent were consistent over all generations indicating that F2 and F3 generations can be used effectively for combining ability analysis. However, the results did suggest that GCA estimates were more influenced by the environment than SCA. For the traits measured and in the populations used in this study, GCA effects did predict the best parental combinations for obtaining the highest percentage of desirable progeny in segregating populations.

Download or read book Genetics Abstracts written by and published by . This book was released on 1981 with total page 512 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 1985 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Heritability and Interrelationships of Yield Yield Components and Other Agronomic Characters in the F2 Generation of a Wheat Cross Triticum Aestivum L written by Jaime Angel Gonella and published by . This book was released on 1972 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nature of Inheritance and Association of Time Duration and Rate of Grain Filling and Subsequent Grain Yield in Crosses of Winter and Spring Wheats Triticum Aestivum L Em Thell written by Byung Han Choi and published by . This book was released on 1983 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability was observed for the traits measured in segregating populations resulting from crosses between winter and spring type wheats in contrast to spring x spring or winter x winter crosses. The one exception was plant height where more genetic variability resulted from spring x spring crosses. Narrow sense heritability estimates were high for time and duration of heading, anthesis, grain filling and physiological maturity and for plant height. Smaller values were noted for rate of grain filling, kernel number, harvest index, tiller number, kernel weight, whole plant dry weight and grain yield. Estimates of the coefficient of heritability and the parent-offspring correlation coefficient were similar in magnitude except for the traits grain yield, tiller number, kernel weight and whole plant dry weight where large variations due to the environment were encountered. Using the Jinks-Hayman model, no maternal effects were noted nor were any nonallelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast the winter parents had more dominant genes for the longer actual grain filling period. Estimates of general and specific combining ability provided similar evidence in terms of the nature of gene action. Both additive and nonadditive gene action was present for all traits, the relative magnitudes depending on the specific trait. Based on individual combining ability effects, the winter x spring cross Yamhill x Siete Cerros would appear to provide the highest proportion of desired segregates when combining earliness and acceptable grain yield. From the direct and indirect associations of grain yield, it would appear that a shorter duration of grain filling along with a shorter lag period from heading to anthesis are important for higher rates of grain filling if negative associations between earliness and grain yield are to be avoided.

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 A Comparison of Two Methods of Divergent Mass Selection for Heading Date in Two Winter Wheat Triticum Aestivum L Em Thell Crosses written by Leslie John Frederickson and published by . This book was released on 1982 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Responses to two cycles of mass selection for heading date, followed by selfing or intermating, were studied in two diverse winter wheat (Triticum aestivum L. em. Thell) crosses. Selection was bidirectional, resulting in early and late populations for each mating system, cycle, and cross. The influence of mass selection for heading date on the expressions of eight other agronomic traits was also studied. Concurrent with selection for heading date, generation means and variances within crosses were used to obtain genetic information about each of the nine traits. Additive effects of genes were an important source of variation among Cross I generation means for most traits. Predicted response to selection for heading date was 7.1 and 9.1 days/cycle for 1981 and 1982, respectively. Most traits by which the parents differed in Cross II generations were primarily affected by non-additive genetic effects. Progress from selection for heading date was predicted to be 6.9 days/cycle in 1981, and 1.4 day/cycle in 1982. Observed response to selection for heading date in Cross I showed gains of -4.8 and 5.5 days/cycle with selfing and -4.2 and 5.1 days/cycle with intermating. Further progress from selection for heading date could be achieved through additional cycles of selection and intermating in this cross. Response to selection for heading date with intermating in Cross II was superior to selfing in the early direction (6.0 vs. 5.0 days/cycle) and inferior to selfing in the late direction (0.9 vs. 1.9 days/cycle). These results were ascribed to an accumulation of minor genes via intermating and rapid fixation of recessive genes via selfing, for early and late selection, respectively. Few large correlated responses in the eight unselected traits with selection for heading date were noted in either cross. In Cross I, intermating was more successful than selfing in retaining 'genetic variation' in most of the unselected traits. In Cross II, intermating showed a slight advantage in maintaining 'genetic variation' in unselected traits, probably due to the low levels of additive genetic variation present in this cross.

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 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 Meldinger Fra Norges Landbruksh gskole written by Norges landbrukshøgskole and published by . This book was released on 1974 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimates of Heterosis for Five Agronomic Traits in Selected Winter X Spring and Winter X Winter Wheat Crosses Triticum Aestivum L Em Thell written by P. Brajcich and published by . This book was released on 1980 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concern regarding the lack of genetic variability and the apparent yield plateau reached in wheat breeding have prompted this investigation. The systematic crossing of spring and winter wheat types which have evolved to form somewhat different gene pools, may provide a source of additional usable genetic variability for future yield increases. Five winter and five spring wheat cultivars with different degrees of genetic similarities in their pedigrees were crossed to obtain F1's and F2's. The parents plus winter x spring F1's were planted in two growing seasons at Hyslop Agronomy Farm near Corvallis, Oregon. During the second season the winter x spring F2 and winter x winter F1 crosses were also included. Agronomic traits were measured on an individual plant basis. These traits were plant height, number of tillers per plant, 100 kernel weight, number of kernels per spike and grain yield. Analyses of variance were conducted for each trait. Estimates of the amount of usable genetic variation were determined by heterosis values, inbreeding depression and parent-progeny standard regressions. Possible interactions between years and the above five characters were determined for the winter x spring F1's. Evidence of non-additive gene action was found in the expression of heterosis and subsequent inbreeding depression which depended on the specific trait measured and the parents involved in the cross. The greatest heterosis values were noted for grain yield per plant. Crosses with the winter parent, Weique Red Mace, resulted in the highest estimates for grain yield. This was due to the late maturity of these hybrids and to the diverse genetic background of this winter parent compared to the five spring parents. Parent-progeny regressions indicated that a large amount of additive genetic variance was present for plant height, 100 kernel weight and grain yield an intermediate amount for kernels per spike and tillers per plant. Winter x spring F1 crosses resulted in higher heterosis estimates and a wider range of values between crosses than winter x winter F1 crosses. Parent-progeny regression estimates were similar in value for the two types of F1 populations. Thus, these results indicate that the systematic crossing between winter and spring wheats will produce greater total genetic variability for further wheat improvement. This is true for the development of hybrid wheat (non-additive) and may also be promising for conventional breeding programs when only the additive portion of the total genetic variance can be used. The data support the general conclusion that the amount of heterosis is a function of genetic diversity between the two parents. Those breeders working on hybrid wheat may wish to look at winter x spring crosses as a means of maximizing heterosis. However, since a significant interaction between years x F1's was noted for the traits measured, more than one year of evaluation will be necessary if winter x spring crosses are employed.