Download or read book Evaluation of Elite Exotic Maize Inbreds for Use in Long term Temperate Breeding written by Paul Thomas Nelson and published by . This book was released on 2006 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: gray leaf spot, topcross, exotic inbreds, tropical inbreds, germplasm, maize breeding.
Download or read book Evaluation of Elite Exotic Maize Inbreds for Use in Long term Temperate Breeding written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. maize (Zea mays L.) germplasm base is narrow. While maize is a very diverse species, that diversity is not represented in U.S. maize production acreage. Most elite U.S. maize inbreds can be traced back to a small pool of inbreds that were developed decades ago. Increased genetic diversity can be obtained through breeding with exotic germplasm, especially tropical-exotic sources. However, setbacks are often encountered when working with tropical germplasm due to adaptation barriers. Furthermore, the pool of available tropical germplasm is large and diverse, making choices of tropical parents difficult. The maize breeding program at North Carolina State University has begun a large-scale screening effort to evaluate elite exotic maize inbreds, most of which are tropical-exotic in origin. The purpose of this research was to: 1) generate comparative yield-trial data for over 100 elite exotic maize inbreds, 2) determine the relative effectiveness of various testcross regimes, 3) identify sources of gray leaf spot (GLS) resistance among these elite exotic inbreds, and 4) promote the use of exotic maize germplasm to broaden the genetic base of U.S. maize. Over 100 elite exotic maize inbreds were obtained from various international breeding programs. They were tested in replicated yield trials in North Carolina as 50%-exotic testcrosses by crossing them to a broad-base U.S. tester of Stiff Stalk (SS) x non-Stiff Stalk (NSS) origin. The more promising lines additionally entered 25%-tropical testcrosses with SS and NSS testers and were further evaluated in yield-trials. A dozen tropical inbred lines performed well overall--CML10, CML108, CML157Q, CML258, CML264, CML274, CML277, CML341, CML343, CML373, Tzi8, and Tzi9. Inbred lines CML157Q, CML343, CML373, and Tzi9 did not show significant line x tester interaction. Furthermore, it was determined that testcrossing to a single broad-based tester will suffice for initial screening purposes, allowing for elimination.
Download or read book Plant Breeding Reviews written by Jules Janick and published by John Wiley & Sons. This book was released on 2010-05-05 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plant Breeding Reviews presents state-of-the-art reviews on plant genetics and the breeding of all types of crops by both traditional means and molecular methods. Many of the crops widely grown today stem from a very narrow genetic base; understanding and preserving crop genetic resources is vital to the security of food systems worldwide. The emphasis of the series is on methodology, a fundamental understanding of crop genetics, and applications to major crops.
Download or read book Quantitative Genetics in Maize Breeding written by Arnel R. Hallauer and published by Springer Science & Business Media. This book was released on 2010-09-28 with total page 669 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize is used in an endless list of products that are directly or indirectly related to human nutrition and food security. Maize is grown in producer farms, farmers depend on genetically improved cultivars, and maize breeders develop improved maize cultivars for farmers. Nikolai I. Vavilov defined plant breeding as plant evolution directed by man. Among crops, maize is one of the most successful examples for breeder-directed evolution. Maize is a cross-pollinated species with unique and separate male and female organs allowing techniques from both self and cross-pollinated crops to be utilized. As a consequence, a diverse set of breeding methods can be utilized for the development of various maize cultivar types for all economic conditions (e.g., improved populations, inbred lines, and their hybrids for different types of markets). Maize breeding is the science of maize cultivar development. Public investment in maize breeding from 1865 to 1996 was $3 billion (Crosbie et al., 2004) and the return on investment was $260 billion as a consequence of applied maize breeding, even without full understanding of the genetic basis of heterosis. The principles of quantitative genetics have been successfully applied by maize breeders worldwide to adapt and improve germplasm sources of cultivars for very simple traits (e.g. maize flowering) and very complex ones (e.g., grain yield). For instance, genomic efforts have isolated early-maturing genes and QTL for potential MAS but very simple and low cost phenotypic efforts have caused significant and fast genetic progress across genotypes moving elite tropical and late temperate maize northward with minimal investment. Quantitative genetics has allowed the integration of pre-breeding with cultivar development by characterizing populations genetically, adapting them to places never thought of (e.g., tropical to short-seasons), improving them by all sorts of intra- and inter-population recurrent selection methods, extracting lines with more probability of success, and exploiting inbreeding and heterosis. Quantitative genetics in maize breeding has improved the odds of developing outstanding maize cultivars from genetically broad based improved populations such as B73. The inbred-hybrid concept in maize was a public sector invention 100 years ago and it is still considered one of the greatest achievements in plant breeding. Maize hybrids grown by farmers today are still produced following this methodology and there is still no limit to genetic improvement when most genes are targeted in the breeding process. Heterotic effects are unique for each hybrid and exotic genetic materials (e.g., tropical, early maturing) carry useful alleles for complex traits not present in the B73 genome just sequenced while increasing the genetic diversity of U.S. hybrids. Breeding programs based on classical quantitative genetics and selection methods will be the basis for proving theoretical approaches on breeding plans based on molecular markers. Mating designs still offer large sample sizes when compared to QTL approaches and there is still a need to successful integration of these methods. There is a need to increase the genetic diversity of maize hybrids available in the market (e.g., there is a need to increase the number of early maturing testers in the northern U.S.). Public programs can still develop new and genetically diverse products not available in industry. However, public U.S. maize breeding programs have either been discontinued or are eroding because of decreasing state and federal funding toward basic science. Future significant genetic gains in maize are dependent on the incorporation of useful and unique genetic diversity not available in industry (e.g., NDSU EarlyGEM lines). The integration of pre-breeding methods with cultivar development should enhance future breeding efforts to maintain active public breeding programs not only adapting and improving genetically broad-based germplasm but also developing unique products and training the next generation of maize breeders producing research dissertations directly linked to breeding programs. This is especially important in areas where commercial hybrids are not locally bred. More than ever public and private institutions are encouraged to cooperate in order to share breeding rights, research goals, winter nurseries, managed stress environments, and latest technology for the benefit of producing the best possible hybrids for farmers with the least cost. We have the opportunity to link both classical and modern technology for the benefit of breeding in close cooperation with industry without the need for investing in academic labs and time (e.g., industry labs take a week vs months/years in academic labs for the same work). This volume, as part of the Handbook of Plant Breeding series, aims to increase awareness of the relative value and impact of maize breeding for food, feed, and fuel security. Without breeding programs continuously developing improved germplasm, no technology can develop improved cultivars. Quantitative Genetics in Maize Breeding presents principles and data that can be applied to maximize genetic improvement of germplasm and develop superior genotypes in different crops. The topics included should be of interest of graduate students and breeders conducting research not only on breeding and selection methods but also developing pure lines and hybrid cultivars in crop species. This volume is a unique and permanent contribution to breeders, geneticists, students, policy makers, and land-grant institutions still promoting quality research in applied plant breeding as opposed to promoting grant monies and indirect costs at any short-term cost. The book is dedicated to those who envision the development of the next generation of cultivars with less need of water and inputs, with better nutrition; and with higher percentages of exotic germplasm as well as those that pursue independent research goals before searching for funding. Scientists are encouraged to use all possible breeding methodologies available (e.g., transgenics, classical breeding, MAS, and all possible combinations could be used with specific sound long and short-term goals on mind) once germplasm is chosen making wise decisions with proven and scientifically sound technologies for assisting current breeding efforts depending on the particular trait under selection. Arnel R. Hallauer is C. F. Curtiss Distinguished Professor in Agriculture (Emeritus) at Iowa State University (ISU). Dr. Hallauer has led maize-breeding research for mid-season maturity at ISU since 1958. His work has had a worldwide impact on plant-breeding programs, industry, and students and was named a member of the National Academy of Sciences. Hallauer is a native of Kansas, USA. José B. Miranda Filho is full-professor in the Department of Genetics, Escola Superior de Agricultura Luiz de Queiroz - University of São Paulo located at Piracicaba, Brazil. His research interests have emphasized development of quantitative genetic theory and its application to maize breeding. Miranda Filho is native of Pirassununga, São Paulo, Brazil. M.J. Carena is professor of plant sciences at North Dakota State University (NDSU). Dr. Carena has led maize-breeding research for short-season maturity at NDSU since 1999. This program is currently one the of the few public U.S. programs left integrating pre-breeding with cultivar development and training in applied maize breeding. He teaches Quantitative Genetics and Crop Breeding Techniques at NDSU. Carena is a native of Buenos Aires, Argentina. http://www.ag.ndsu.nodak.edu/plantsci/faculty/Carena.htm
Download or read book High Throughput Phenotyping for Crop Improvement and Breeding written by Ankush Prashar and published by Frontiers Media SA. This book was released on 2022-02-04 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Argentine Maize Hybrids and Exotic X Temperate Testcrosses Across Environments written by Brett A. Ochs and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize (Zea mays L.) is grown in a wide range of environments and altitudes worldwide. Maize has transitioned from open pollinated varieties to single cross hybrids over the last century. While maize production and genetic gain has increased, genetic diversity among U.S. maize hybrids has narrowed. Problems, such as insect pressure, diseases, and mycotoxins, present obstacles for breeders. One approach is to use exotic germplasm in breeding programs to provide useful, novel alleles for productivity, grain quality, and disease resistance. Little exotic germplasm has been used, because of lack of agronomic adaptation and problems with lodging, earliness, and tall plants in more temperate areas. Using exotic elite materials and evaluating them in targeted regions might increase success. Objectives of this research were: to characterize and evaluate agronomic adaptation and performance of Argentine commercial hybrids in the U.S., to evaluate semi-exotic testcrosses developed from semi adapted 100% tropical lines and elite U.S. inbred LH195, and to estimate response to aflatoxin contamination of Argentine hybrids and semi-exotic testcrosses under inoculation with Aspergillus flavus. Agronomic data was collected during 2004 in eleven Texas environments for Argentine hybrids, and eight Texas environments for semi-exotic testcrosses. Response to aflatoxin was measured in three southern Texas environments. U.S. commercial hybrids were used as checks. Significant differences among hybrids were observed for most environments and traits. In general, Argentine hybrids yielded lower, had lower 1000 kernel weights, and greater test weights than U.S. hybrids. Hybrids AX889, AX882MG, and AX890MG were competitive with U.S. hybrids for grain yield and were stable across environments. Semi-exotic testcrosses had similar lodging and grain moisture percentages, heavier test weights and competitive grain yields compared with U.S. hybrids. Hybrid TX-LAMA2002-9-2-B/lH195 had the highest overall grain yield mean for semi-exotic testcrosses and yielded better than two U.S. hybrids. Argentine hybrids had lower aflatoxin concentration than U.S. hybrids; several hybrids had less than 50 ng g−1 aflatoxin. Semi-exotic testcrosses had reduced aflatoxin compared to U.S. hybrids, with several hybrids under 35 ng g−1. These elite, exotic materials show promise for breeding programs, with competitiveness for grain yield, kernel traits, and reduced aflatoxin levels.
Download or read book Effects of Long term Selection on the Performance of a Semi exotic Population of Maize written by David Bryan Rubino and published by . This book was released on 1989 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Elite Maize Inbreds as Sources of Favourable Alleles for the Improvement of Quantitative Traits written by Terence Keith Stanger and published by . This book was released on 1989 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Maize Genome written by Jeffrey Bennetzen and published by Springer. This book was released on 2018-11-24 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses advances in our understanding of the structure and function of the maize genome since publication of the original B73 reference genome in 2009, and the progress in translating this knowledge into basic biology and trait improvement. Maize is an extremely important crop, providing a large proportion of the world’s human caloric intake and animal feed, and serving as a model species for basic and applied research. The exceptionally high level of genetic diversity within maize presents opportunities and challenges in all aspects of maize genetics, from sequencing and genotyping to linking genotypes to phenotypes. Topics covered in this timely book range from (i) genome sequencing and genotyping techniques, (ii) genome features such as centromeres and epigenetic regulation, (iii) tools and resources available for trait genomics, to (iv) applications of allele mining and genomics-assisted breeding. This book is a valuable resource for researchers and students interested in maize genetics and genomics.
Download or read book Conversion of Elite Subtropical Maize Germplasm to Temperate Environments written by Homer Gene Caton and published by . This book was released on 1999 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semi-exotic BC1F1 testcrosses were evaluated in five Iowa environments during 1998, with average grain yields of 95.7 q ha7−1 (153.1 bu ac−1). Selected testcrosses had grain yields similar to or greater (p[Less than or equal to]0.05) than their checks. Grain moisture of selected LSC-exotic and RYD-exotic testerosses was similar to and greater, respectively, than the recurrent parent testerosses, and resistance to root and stalk lodging was similar to the checks. Results support backcross introgression to incorporate alleles from exotic sources, to maintain the agronomic traits of the recurrent parent, and to maintain or enhance the combining ability of the recurrent parent heterotic pool. Inbred lines developed in CIMMYT's hybrid program have been improved for agronomic traits, for tolerance to inbreeding, and heterotic alignment. Pre-selected exotic germplasm represents a valuable resource for widening the genetic base of temperate maize.
Download or read book Plant Genetic Resources written by B. S. Dhillon and published by Alpha Science Int'l Ltd.. This book was released on 2006 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Food is the basic need of human beings. The increasing population and enhanced standard of living are placing greater demands on food-related requirements in terms of quantity, quality and diversity. The Green Revolution which significantly enhanced productivity of important food crops, nevertheless, resulted in certain fallouts as genetic erosion, soil degradation, chemical pollution and aquifer depletion. Amongst these, decrease in plant genetic diversity is an irreversible loss. As the basic raw material for future plant breeding, plant genetic resources of foodgrains are the key to future food security. Though, plant breeding has attracted the attention of many authors, plant genetic resources remain somewhat neglected. This book gives an overall perspective current status of genetic resource of important foodgrain crops (wheat, rice, maize, barley, sorghum, millets, pulses and legumes and underutilized crops). It provides a comprehensive compilation on current status of information on origin, taxonomy, diversity, collection, exchange, evaluation, utilization, molecular characterization and conservation for food grain crops. Eminent scientists and crop specialists have critically analyzed the information in view of the present and future research priorities. In addition, management issue related to plant genetic resources are also discussed. At present such information on these crops is lacking and this book fills in the void. It shall serve as reference for genetic resource managers, researchers, teachers, students and policy makers in biology and agriculture.
Download or read book Cereals written by Marcelo J. Carena and published by Springer Science & Business Media. This book was released on 2009-04-21 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Agriculture depends on improved cultivars, and cultivars are developed through proper plant breeding. Unfortunately, applied plant breeding programs that are focused on cereal commodity crops are under serious erosion because of lack of funding. This loss of public support affects breeding continuity, objectivity, and, perhaps equally important, the training of future plant breeders and the utilization and improvement of plant genetic resources currently available. Breeding programs should focus not only on short-term research goals but also on long-term genetic improvement of germplasm. The research products of breeding programs are important not only for food security but also for commodity-oriented public and private programs, especially in the fringes of crop production. Breeding strategies used for long-term selection are often neglected but the reality is that long-term research is needed for the success of short-term products. An excellent example is that genetically broad-based public germplasm has significantly been utilized and recycled by industry, producing billions of dollars for industry and farmers before intellectual property rights were available. Successful examples of breeding continuity have served the sustainable cereal crop production that we currently have. The fact that farmers rely on public and private breeding institutions for solving long-term challenges should influence policy makers to reverse this trend of reduced funding. Joint cooperation between industry and public institutions would be a good example to follow. The objective of this volume is to increase the utilization of useful genetic resources and increase awareness of the relative value and impact of plant breeding and biotechnology. That should lead to a more sustainable crop production and ultimately food security. Applied plant breeding will continue to be the foundation to which molecular markers are applied. Focusing useful molecular techniques on the right traits will build a strong linkage between genomics and plant breeding and lead to new and better cultivars. Therefore, more than ever there is a need for better communication and cooperation among scientists in the plant breeding and biotechnology areas. We have an opportunity to greatly enhance agricultural production by applying the results of this research to meet the growing demands for food security and environmental conservation. Ensuring strong applied plant breeding programs with successful application of molecular markers will be essential in ensuring such sustainable use of plant genetic resources.
Download or read book Comparison of Conventional Modified Single Seed Descent and Doubled Haploid Breeding Methods for Maize Inbred Line Development Using GEM Breeding Crosses written by McDonald Bright Jumbo and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Choice of germplasm combined with use of efficient breeding methods and careful evaluation are essential tools for maize inbred line and hybrid development. Breeding crosses from the G ermplasm E nhancement of M aize (GEM) project (www.public.iastate.edu/~usda-gem) between exotic accessions and elite Corn Belt inbreds provide a unique opportunity for broadening US Corn Belt Maize germplasm by selecting exotic alleles in an elite genetic background. Progress in GEM could be enhanced by identifying more efficient procedures for both developing inbreds and determining which of the several hundred GEM breeding crosses have the most potential for future improvement and gene discovery. The primary research objective was to compare four breeding methods for their effectiveness and efficiency for developing superior maize inbred lines and hybrids from GEM breeding crosses. In addition, the study also aimed at identifying breeding methods that could be useful for prioritizing GEM breeding crosses for further line development and trait identification. Furthermore, breeding methods were compared to determine the effectiveness of mass selection for producing more adapted genotypes from GEM breeding crosses. Four breeding methods; Conventional GEM (CG), Conventional Mass (CM), Modified Single Seed Descent (MSSD) and Doubled Haploid (DH) were compared using three GEM breeding crosses ANTIG01:N16DE4, AR16035:S0209, and DKXL212:S0943b. Results showed that more DH lines were recovered from the non-stiff stalk than from the stiff stalk breeding crosses in the DH method due to differences in chromosome doubling rather than the induction phase. Field observations showed more uniformity in the MSSD S 2 lines derived from the Stiff Stalk than the non-Stiff Stalk (ANTIG01:N16DE4) breeding cross. The testcross evaluations generally showed no method effects between breeding methods, but method effects were present in the per se agronomic evaluations. The MSSD and CM methods had a higher proportion of top five lines in the second year testcross evaluations (about one third each) based on both yield and yield/moisture performance compared to the CG and DH methods. Hybrids from MSSD lines tended to have higher grain moisture than hybrids from the CG, CM and DH methods, but MSSD hybrids with high yield/moisture could be selected. The MSSD method may be an effective and efficient alternative to both pedigree and DH methods for developing high performing lines from the GEM breeding crosses.
Download or read book The Genetic Architecture of Maize Photoperiod Sensitivity as Revealed by Recombinant Inbred Line Backcross and Heterogeneous Inbred Family Populations written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The genetic diversity of elite temperate maize germplasm is very narrow in comparison to the genetic diversity available across of the entire species. Tropical maize germplasm has frequently been cited as a potential source of enhanced genetic diversity that could be used to increase corn productivity. One obstacle to utilizing tropical maize germplasm in temperate breeding programs is photoperiod sensitivity, which is very common in tropical adapted maize lines. An investigation of the quantitative trait loci (QTL) contributing to maize photoperiod sensitivity may increase the facility and ability with which maize breeders can adapt tropical maize germplasm to temperate latitudes. The inductive phase of maize photoperiod sensitivity was studied in a diverse set of temperate and tropical lines. From a factorial mating of two temperate and two tropical inbreds, four populations of recombinant inbred lines (RIL) were developed for the purpose of mapping the QTL underlying photoperiod sensitivity in tropical maize. Plants were grown in both long- and short-day environments and a number of traits were measured in each environment. These traits include flowering time, plant height, leaf number, and ear structure traits. The trait differences between long- and short-day environments were reported as the photoperiodic responses of the RILs. Utilizing the data of both individual and combined mapping populations, QTL were identified using Iterative QTL Mapping (iQTLm). The positions and effects of these QTL were compared between populations and with flowering time and plant height QTL from other mapping studies. We detected four regions in the genome that produced large photoperiod effects and named these ZmPR1, ZmPR2, ZmPR3, and ZmPR4. These four QTL accounted for 75% of the phenotypic diversity for photoperiod measured by our analysis. Similar QTL positions have been detected by other researchers studying photoperiod sensitivity and flowering time in maize. In addition to.
Download or read book Maize Genetic Resources in Europe written by E. Lipman and published by Bioversity International. This book was released on 1997 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tropical Maize written by R. L. Paliwal and published by Fao. This book was released on 2000 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Maize is an important crop and the demand for as both food and animal feed is expected to grow by 235 million tonnes between now and 2030. In many countries it will be difficult to increase the area under cultivation, so gains will have to come from increased productivity and intensification of the cropping system. This book looks at all aspects of tropical maize production from physiology, growing environments, pest and diseases, plant breeding and crop management and it is a substantial information resource necessary for the development of the crop.
