共查询到20条相似文献,搜索用时 15 毫秒
1.
J. M. J. De Wet 《Economic botany》1986,40(3):365-365
2.
Cassava genetic transformation and its application in breeding 总被引:1,自引:0,他引:1
As a major source of food, cassava (Manihot esculenta Crantz) is an important root crop in the tropics and subtropics of Africa and Latin America, and serves as raw material for the production of starches and bioethanol in tropical Asia. Cassava improvement through genetic engineering not only overcomes the high heterozygosity and serious trait separation that occurs in its traditional breeding, but also quickly achieves improved target traits. Since the first report on genetic transformation in cassava in 1996, the technology has gradually matured over almost 15 years of development and has overcome cassava genotype constraints, changing from mode cultivars to farmer-preferred ones. Significant progress has been made in terms of an increased resistance to pests and diseases, biofortification, and improved starch quality, building on the fundamental knowledge and technologies related to planting, nutrition, and the processing of this important food crop that has often been neglected. Therefore, cassava has great potential in food security and bioenergy development worldwide. 相似文献
3.
4.
5.
The polyploidy and its key role in plant breeding 总被引:5,自引:0,他引:5
Mariana Cansian Sattler Carlos Roberto Carvalho Wellington Ronildo Clarindo 《Planta》2016,243(2):281-296
6.
原生质体融合又称细胞融合,具有遗传信息传递量大,不受亲缘关系的影响,可以集双亲优良遗传性状为一体,并定向筛选表现双亲遗传性状的融合子,操作简便等优点,具有广阔的应用前景。本文就原生质体融合的程序以及该技术在微生物育种中的应用作一综述。 相似文献
7.
J. R. McWilliam B. D. H. Latter 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1970,40(2):63-72
Summary The genetic variation for a number of important agronomic characters within a widely based breeding population of Phalaris tuberosa has been analysed, and the interrelationships among the variables characterized.Estimates of heritability for flowering date, seed retention and seed weight were higher than those for cool season growth measured in spaced plants or swards, but all characters showed appreciable additive genetic variation, which offers considerable scope for further selection. There was no evidence of any general loss of adaptation in the widely based population, though flowering date and seed weight tended to show increased environmental variability by comparison with the adapted Australian cultivar.One of the most important changes in the genetic relationship between characters in the breeding population has been the elimination of undesirable ecotypic correlations which were present in the parental material prior to hybridization and recombination.In the advanced breeding population significant intra-population correlations existed between the various estimates of growth made on single plants, but in general, estimates of growth made under these conditions were not significantly correlated with the performance of the same families in swards. Of particular interest, however, were the significant genetic correlations between seedling growth of full-sib families measured in controlled environments, and the growth of the same families as spaced plants and in swards.The predicted response to either direct or indirect selection indicates considerable potential for improvement in a number of important characters including seedling growth, seed retention, and winter growth in swards. Of particular interest is the possibility of increasing sward production as a correlated response to intensive selection for seedling growth.A selection procedure is described involving simultaneous selection in full-sib families grown as swards and spaced plants. This technique provides a useful compromise when progress is desired in a number of characters which are best assessed under one or the other regime.
Zusammenfassung An einer Zuchtpopulation von Phalaris tuberosa, die aus Kreuzungen von 30 Ökotypen mediterraner Herkunft mit einer australischen und einer türkischen Sorte stammte, wurden die genetische Variation einer Anzahl agronomisch wichtiger Merkmale untersucht und die Beziehung zwischen den Variablen charak-terisiert.Die an Einzelpflanzen wie im geschlossenen Bestand ermittelten Schätzungen der Heritabilität für den Blühtermin, die Verringerung des Samenausfalls und das Samengewichtwaren höher als für das Wachstum während der kühlen Jahreszeit; alle Merkmale wiesen aber eine beachtliche additive genetische Variation auf, die Aussichten für eine weitere Selektion eröffnet. Ein allgemeinen Adaptationsverlust war in der umfangreichen Population nicht festzustellen, wenn auch die Merkmale Blütezeit und Samengewicht im Vergleich mit der adaptierten australischen Sorte zu einer erhöhten umweltbedingten Variabilität neigten.Eine der bedeutendsten Veränderungen in den genetischen Beziehungen zwischen Merkmalen der Zuchtpopulation war die Elimination unerwünschter, für die genannten Ökotypen zutreffender Korre-lationen, wie sie im Eltermaterial vor der Hybridi-sierung und Rekombination vorhanden waren. Es gab in der vorgeschrittenen Zuchtpopulation signifikante Intrapopulations-Korrelationen zwischen den ver-schiedenen an Einzelpflanzen ermittelten Wachs-tums-Schätzungen, im allgemeinen waren die unter diesen Bedingungen gemachten Schätzungen aber nicht signifikant mit der Leistung der gleichen Familien im geschlossenen Bestand korreliert. Von besonderem Interesse waren jedoch die signifikanten genetischen Korrelationen zwischen dem Keimlingswachstum von Vollgeschwisterfamilien, die unter kontrollierten Umweltbedingungen gemessen wurden, und dem Wachstum der gleichen Familien als Einzel-pflanzen und im geschlossenen Bestand.Die vorausgesagte Reaktion auf direkte oder indirekte Selektion läßt beträchtliche Möglichkeiten zur Verbesserung einer Anzahl wichtiger Merkmale einschl. des Keimlingswachstums, der Verringerung des Samenausfalls und des winterlichen Wachstums im geschlossenen Bestand erwarten.Die Möglichkeit der Steigerung des Bestandsertrages als Folge einer intensiven Selektion auf Keim-lingswachstum ist von besonderer Bedeutung.Es wird ein Selektionsverfahren beschrieben, das eine gleichzeitige Selektion in Vollgeschwisterfamilien ermöglicht, die sowohl im Bestand wie als Einzel-pflanzen angezogen wurden. Diese Technik bietet einen nützlichen Kompromiß, wenn eine Verbesserung einiger Merkmale erzielt werden soll, die sich entweder beim Anbau in der einen oder in der anderen Form am besten abschätzen lassen.相似文献
8.
9.
10.
11.
12.
13.
14.
We tracked eight adult northern lapwings Vanellus vanellus (six females and two males) from a Dutch breeding colony by light‐level geolocation year‐round, three of them for multiple years. We show that birds breeding virtually next to each other may choose widely separated wintering grounds, stretching from nearby the colony west towards the UK and Ireland, and southwest through France into Iberia and Morocco. However, individual lapwings appeared relatively faithful to a chosen wintering area, and timing of outward and homeward migration can be highly consistent between years. Movements of migratory individuals were usually direct and fast, with some birds covering distances of approximately 2000 km within 2 to 4 days of travel. The two males wintered closest and returned earliest to the breeding colony. The female lapwings returned well before the onset of breeding, spending a pre‐laying period of 19 to 54 days in the wider breeding area. Despite the potential for high migration speeds, the duration that birds were absent from the breeding area increased with distance to wintering areas, a pattern which was mainly driven by an earlier outward migration of birds heading for more distant wintering grounds. Moreover, females that overwintered closer to colony bred earlier. A large variation in migration strategies found even within a single breeding colony has likely supported the species’ responsiveness to recent climate change as evidenced by a shortened migration distance and an advanced timing of reproduction in Dutch lapwings since the middle of the 20th century. 相似文献
15.
SRAP标记是基于选择性扩增开放性阅读框的新型分子标记,具有简便、高效、重复性好、高共显性等优点,在植物育种中已经得到广泛应用.本文介绍了SRAP标记基本原理和特点,对SRAP标记在遗传多样性研究、遗传连锁图谱构建、比较基因组以及分子标记辅助选择育种等方面的应用进行了综述. 相似文献
16.
Hexaploid wheat is a species that has been subjected to most extensive cytogenetic studies. This has contributed to understanding the mechanism of the evolution of polyploids involving diploidization through genetic restriction of chromosome pairing to only homologous chromosomes. The availability of a variety of aneuploids and the ph mutants (Ph1 and Ph2) in bread wheat also allowed chromosome manipulations leading to the development of alien addition/substitution lines and the introgression of alien chromosome segments into the wheat genome. More recently in the genomics era, molecular tools have been used extensively not only for the construction of molecular maps, but also for identification/isolation of genes/QTLs (including epistatic QTLs, eQTLs and PQLs) for several agronomic traits. It has also been possible to identify gene-rich regions and recombination hot spots in the wheat genome, which are now being subjected to sequencing at the genome level, through development of BAC libraries. In the EST database also, among all plants wheat ESTs are the highest in number, and are only next to those for human, mouse, Ciona intestinalis (a chordate), rat and zebrafish genomes. These ESTs and sequences of several genomic regions have been subjected to a variety of applications including development of perfect markers and establishment of microcollinearity. The technique of in situ hybridization (including FISH, GISH and McFISH) and the development of deletion stocks also facilitated the preparation of physical maps. Molecular markers are also used for marker-assisted selection in wheat breeding programs in several countries. Construction of a wheat DNA chip, which will also become available soon, may further facilitate wheat genomics research. These enormous resources, knowledge base and the fast development of additional molecular tools and high throughput approaches for genotyping will prove extremely useful in future wheat research and will lead to development of improved wheat cultivars. 相似文献
17.
N W Moore 《Australian journal of biological sciences》1988,41(1):15-22
The ovariectomized ewe has been used to establish principles and procedures which have proved invaluable in controlled breeding in entire animals. Bioassays in the ovariectomized ewe, the end-point of oestrous behaviour, have been used to identify potent and rapidly metabolized progestagens which were subsequently used to control the time of oestrus and ovulation in cyclic ewes effectively, and to induce oestrus and ovulation in anoestrous ewes. Steroid hormone treatment of the ovariectomized ewe has been used to study relationships between the ovary and the pituitary-hypothalamic axis, to examine transport of embryos within the female tract and to establish the steroid hormone requirements of early pregnancy. 相似文献
18.
19.
JIN-WON LEE BYOUNG-SOON JANG† DEBORAH A. DAWSON TERRY BURKE BEN J. HATCHWELL 《Molecular ecology》2009,18(12):2728-2739
The pattern of fine-scale genetic structure in a population may reflect current biological processes of the species, such as natal dispersal, the breeding system and demography. We investigated the spatial distribution of nests and fine-scale genetic structure during two breeding seasons in a population of a weakly territorial, flock-living passerine bird, the vinous-throated parrotbill, Paradoxornis webbianus . Nest distribution was clustered. There were two peaks of egg laying within each breeding season, and spatial clustering of nests was more extreme during the second peak after controlling for breeding density. The patterns of genetic structure during the breeding season varied with parental sex and season. Genetic structure occurred during the second laying peak: males breeding within 200 m of one another at this time were significantly more closely related than males breeding farther apart. However, no apparent genetic structure was detected in males during the first laying peak or among females in either laying peak. These results reveal male-oriented kin affiliation during part of the breeding season in this species. Furthermore, juvenile recruitment into the winter flocks was positively related to this increased relatedness among males via kin affiliation. This study implies that fine-scale genetic structure during the breeding season could be a factor determining individual fitness and may play an important role in our understanding of the evolution of social systems. 相似文献
20.
东方白鹳繁殖期行为时间分配及日节律 总被引:1,自引:0,他引:1
2009年3—6月,采用扫描取样法对在黄河三角洲国家级自然保护区内繁殖成功的4对东方白鹳的行为活动进行了观察,同时对东方白鹳在繁殖期的行为时间分配和日节律进行了研究。结果表明:繁殖期各行为时间所占比例依次是繁殖22.17%±21.69%(其中孵化19.75%±20.71%,晾卵1.31%±2.16%,育幼1.00%±1.01%,交配0.11%±0.32%),静栖19.09%±13.94%,修巢6.40%±5.92%,警戒3.94%±4.88%,理羽3.11%±2.31%,其他行为45.27%±11.08%;在繁殖不同时期各行为差异显著(P0.01)。东方白鹳在繁殖期不同阶段行为活动存在一定节律,并且不同阶段日节律明显不同。此外,温度与晾卵(r=0.810,P0.01)、孵化(r=-0.518,P0.01)行为显著相关;车辆数与警戒(r=0.745,P0.01)、静栖(r=0.612,P0.01)行为显著相关。 相似文献