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 checklist of academic theses produced with support from CIMMYT 1966 2000 written by John E. Woolston and published by CIMMYT. This book was released on 2000 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 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 O S U Theses and Dissertations 1978 1982 written by Oregon State University and published by . This book was released on 1983 with total page 64 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 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 Dissertation Abstracts International written by and published by . This book was released on 1984 with total page 524 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 1980 with total page 604 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 904 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 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 Agrindex written by and published by . This book was released on 1995 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1976 with total page 1732 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Association and Inheritance of Several Agronomic Characters in Four Wheat Crosses written by Mohammad M. El-Ajlouni and published by . This book was released on 1986 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Inheritance mechanisms for fifteen plant characters of wheat (Triticum durum) Desf. were studied in the F2, F3, and F4 generations in four crosses derived from four parents grown in Jubeiha, University of Jordan Campus during 1984 and 1985 seasons. The parents are Hourani, Mexicali 75, Yamuna, and Njoro 227. Phenotypic associations between grain yield and its components were high, while the morpho-physiological traits have poor positive association with grain yield and its components. Estimates of broad sense heritability indicated low to high values for all traits except number of spikelets/spike, spike length, and flag leaf area which showed low to medium values. High heritability coupled with high genetic advance for some characters such as total seed number/plant, plant height, and main spike seed number and weight indicated that selection for these traits will be valuable. Some characters showed high values for additive gene action in some crosses which mean that selection for these characters could be practiced in early generation. In Hourani x Mexicali 75 cross, heritability values were high in most of the characters. This cross also showed strong association between grain yield and other characters."--Page iv.
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1990 with total page 1842 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Agriculture with Subject Index written by and published by . This book was released on 1987 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guide to Bread Wheat Breeding at CIMMYT written by Maarten van Ginkel and published by CIMMYT. This book was released on 1998 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:
