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1.
Hybridisation between wheat and Aegilops geniculata was quantified in a 4‐year crossing experiment in the glasshouse, using three wheat cultivars as pollen donors and herbicide resistance as a phenotypic marker. Hybridisation rates ranged from 5% to 74%. Most of the hybrids were self‐sterile. However, seven F2 seeds were obtained from 165 A. geniculata–wheat hybrids. Hybrid seeds were found in all backcross (BC1) combinations at average rates of 4.2% (0–26.3%) and 5.88% (0–34%) under glasshouse and field experiments, respectively, with significant differences among years and cultivars. Wheat cultivars, F1 and BC1 plants, were resistant to herbicides while A. geniculata plants were susceptible. In the subsequent generations, although few plants were available, the BC1F1 had a certain degree of fertility and the fertility increased in the F2 plants, with one plant that reached 66.7%. The commercial growing of genetically modified herbicide‐tolerant wheat is expected to have the potential for the inserted gene to escape from the crop and become incorporated in a closely related wild species, conferring a competitive advantage to these conferring weeds. Determining the frequency of crop‐wild transgene flow and the fertility of the formed hybrids is a necessity for risk assessment. Data presented here provide new knowledge on the potential A. geniculata–wheat herbicide resistance transfer.  相似文献   

2.
Competition between wild oat (Avena fatua L.) and wheat (Triticum aestivum L.) was studied in two experiments; a replacement series model and a technique for separation of root and shoot systems. Wild oat and wheat in association resulted in a relative yield total very close to unity showing that the two species were‘crowding for the same space’(or competing for the same resources) and were‘mutually exclusive'. Wild oat was more competitive than wheat, as shown by its aggressivity relative to wheat, relative yields, shoot dry weights and other plant attributes. The greater competitive ability of wild oat was predominantly due to its greater root competitive ability, while the two species had similar shoot competitive ability. Root competition had a much greater effect on the relative performance of the two species than did shoot competition. The effects of root and shoot competition were additive.  相似文献   

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The frequency of hybridization through pollen flow from the cultivated soybean to the wild soybean was evaluated for the purpose of assessment of the ecological risk of genetically modified crops. The flowering habits of three soybean cultivars and one wild soybean accession were monitored on an experimental farm. A cultivar and a wild accession, both of which flowered at a similar period, were then planted alternately in 5 12 arrays with 50 cm spacing on the farm. The seedlings of progeny seeds gathered from individual plants of the wild accession were used for an isozyme analysis to identify whether they were hybrid or not. In 23 plants of the wild accession, four plants produced hybrids (the incidence of hybridization = 17.4%). There was no directionality in hybridization. The hybridization rate per maternal plant varied from 0 to 5.89% with a mean of 0.73% for all maternal plants. The results indicate that natural hybrids are easily produced in a certain frequency by pollen flow from the cultivated soybean to the wild soybean under their simultaneous flowering with adequate pollinators.  相似文献   

5.
聚合成株期抗性基因和全生育期抗病基因是小麦条锈病菌源越夏区甘肃陇南小麦生产中重要的育种策略, 可以减轻致病性小种定向选择压力、兼顾苗期抗病性和成株抗病性及提高品种抗病持久性。本研究利用常规育种结合分子标记辅助选择, 以抗病品种‘兰天15号’‘兰天26号’和品系‘C69-17-13-14-15-6-1’作为抗病基因供体亲本, 聚合成株期抗性基因Yr30/Lr27/Sr2, 全生育期抗病基因Yr9、Yr37/Lr17/Sr38和YrZH84, 对杂交组合‘兰天26号’ב兰天15号’和‘C69-17-13-14-15-6-1’ב兰天26’的后代进行抗性鉴定与目标基因分子检测, 育成了适宜在条锈病越夏核心菌源区甘肃陇南山旱地推广种植的冬小麦新品种‘兰天132’(Yr9+Lr37/Yr17/Sr38+Yr30/Lr27/Sr2+YrZH84)和‘兰天196’(Yr9+Lr37/Yr17/Sr38+Yr30/Lr27/Sr2), 其苗期均对主要流行小种CYR33免疫, 对CYR34感病, 田间成株期对混合菌(CYR32、CYR33、CYR34、Gui22-1、ZS等重要流行小种)高抗至免疫, 并具有较好的抗旱性和丰产性。基因聚合新品种‘兰天132’和‘兰天196’有望成为我国条锈病西北越夏核心菌源区陇南小麦生产中持久抗性新品种。  相似文献   

6.
Field and greenhouse experiments were conducted in 2004 and 2005 to study weed control and the response of winter wheat to tank mixtures of 2,4-D plus MCPA with clodinafop propargyl. The field experiments were conducted at Yazd and Oroumieh, Iran, with factorial combinations of 2,4-D plus MCPA at 0, 975, and 1300 g ai ha−1 and with clodinafop propargyl at 0, 64, 80, 96, and 112 g ai ha−1 in four replications. The greenhouse experiments further evaluated the effect of these tank mixtures on weed control, where each herbicide mixture was considered as one treatment and the experiment was established in a randomized complete block design with four replications. In the field experiments, the herbicides were applied at wheat tillering, while in the greenhouse experiments they were applied at the beginning of the tillering stage and at the four-leaf stage of the grass and broadleaf weeds, respectively. The results indicated antagonistic effects between 2,4-D plus MCPA and clodinafop propargyl. The best tank mixture with regard to weed control efficacy was 2,4-D plus MCPA at 975 g ai ha−1 with clodinafop propargyl at 96 g ai ha−1. The wheat grain yield was also increased by the tank mixture of clodinafop propargyl with 2,4-D plus MCPA. Generally, to inhibit clodinafop propargyl efficacy reduction due to tank-mixing with 2,4-D plus MCPA, it is recommended that the application dose of 64 g ai ha−1 should be increased to 96 g ai ha−1.  相似文献   

7.
外来入侵物种三裂叶豚草(Ambrosia trifida L.)及其风险分析   总被引:8,自引:0,他引:8  
外来入侵物种严重威胁着农业生产、生态安全及人类健康,已成为世界各国广泛关注和研究的热点。本文对外来杂草三裂叶豚草(Ambrosia trifida L.)的起源和分布、生物生态学特性、经济和生态影响及其控制管理措施等进行了系统综述。根据生物生态学特性、潜在风险及管理控制的难度等指标,初步建立了外来杂草的风险评估体系。应用该体系对三裂叶豚草进行了风险评估,得出其风险值为83,属高度危险的检疫性有害生物。  相似文献   

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