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Author: Homer Gene Caton
Publisher:
ISBN:
Category :
Languages : en
Pages : 242
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Book Description
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.
Author: Homer Gene Caton
Publisher:
ISBN:
Category :
Languages : en
Pages : 242
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Book Description
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.
Author: Marcelo J. Carena
Publisher: Springer Science & Business Media
ISBN: 0387722971
Category : Technology & Engineering
Languages : en
Pages : 432
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Book Description
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.
Author: Freeman Callaway Whitehead
Publisher:
ISBN:
Category :
Languages : en
Pages : 254
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Book Description
The use of exotic maize (Zea mays L.) germplasm, particularly of tropical and subtropical adaptation, has been suggested to increase genetic variability and grain yield of maize breeding material in temperate environments. Lack of adaptation to temperate areas and photoperiod sensitivity may mask desirable traits and reduce breeding progress. The objectives of this study included two-stage evaluation and selection of segregating families in the central U.S. Corn Belt derived from the backcross introgression of previously improved tropical CIMMYT germplasm into adapted, elite U.S. Corn Belt germplasm. The U.S. Corn Belt heterotic patterns of Stiff Stalk and non-Stiff Stalk were combined with germplasm of primarily Tuxpeno and non-Tuxpeño racial origin, respectively. Per se evaluation of 891 backcross (BClF1) families from 33 different backcrosses, component Fl crosses, and adapted recurrent populations were conducted in Iowa in 1997. Backcross populations displayed grain yields either similar to or greater than the respective Fl crosses but with significantly less grain moisture and days to mid-pollen, suggesting 25% tropical germplasm to be the preferred starting point to initiate selection. Stalk lodging of backcross populations was similar to and sometimes less than the respective adapted recurrent population check while yield was greater in more than 50% of the crosses. BC1F1 families were selected from within Stiff Stalk and non-Stiff Stalk oriented materials and testcrossed to an elite inbred of the opposite heterotic pool. Testcrosses of backcross families and testcrosses of adapted parental populations were evaluated at seven locations in Iowa and Nebraska in 1999. Grain yield, percent root and stalk lodging, and plant and ear heights of selected testcrosses were generally similar (p[Less than or equal to symbol]0.05) to their respective checks. Harvest grain moisture and days to mid-silk and mid-pollen were either similar to or greater than the checks, averaging early zone 8 for maturity. Results support backcrossing to introduce previously improved tropical germplasm to the central U.S. Corn Belt. The alignment of established U.S. Corn Belt heterotic pools with tropical racial or heterotic pools during introgression will serve to enhance genetic variation within and among pools. Previously selected tropical germplasm of known heterotic affinity may be considered a significant resource for introduction of tropical germplasm into temperate breeding programs.
Author: Michiel Christiaan Brooks Coetzee
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 424
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Book Description
Author: Richard N. Wedderburn
Publisher: CIMMYT
ISBN: 9789686127157
Category : Technology & Engineering
Languages : en
Pages : 174
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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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.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 712
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Author:
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 338
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Book Description
Journal devoted to maize and allied species.
Author:
Publisher:
ISBN:
Category : Corn
Languages : en
Pages : 704
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Author:
Publisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 1064
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