共查询到20条相似文献，搜索用时 31 毫秒
1.
The radial growth rate and sclerotial density ofColletotrichum coccodes isolates representing four major vegetative compatibility groups (VCGs) were determined at three temperatures (21,25, and 30 C) and three pH levels (pH 5, 6, and 7). This is the first report indicating thatC. coccodes isolates characterized to the same VCG share common physiological traits. The optimal temperature for growth of isolates from all four VCGs was 25 C, except for VCG1 isolates, for which growth at 21 and 25 C was equivalent. The growth rate of all isolates, of all VCG groups was decreased at 30 C, whereas sclerotia development was enhanced. The optimal pH level for growth of all isolates was pH 6 and pH 7. Interactions between VCGs and temperature or pH were observed in relation to radial growth rate and sclerotia density. At 25 C, isolates from VCG1 and 2 demonstrated the most rapid growth rate. At 21 and 30 C, VCG1 isolates demonstrated the fastest growth compared with all other VCGs. In response to pH, VCG1 and 2 demonstrated the fastest growth rates at all pH levels. VCG3 and 4 demonstrated the highest sclerotial density at 25 C and at pH 6; and VCG2 and 4 demonstrated the highest sclerotial density at 30 C. 相似文献
2.
Khoshnoud H Ghiyasi M Amirnia R Fard SS Tajbakhsh M Salehzadeh H Alahyary P 《Pakistan journal of biological sciences: PJBS》2008,11(10):1380-1384
In this study, botanicals extracted from two the species of family Scrophulariaceae, Verbascum cheiranthifolium Boiss and Verbascum speciosum Schard, were examined for their effect on mortality and progeny production against adults of Sitophilus oryzae (L.). The plant extracts were applied at five dose rates, which 0.25, 0.5, 1.0, 2.0 and 3% (w/v). Adults of S. oryzae was exposed to the treated wheat at 25 degrees C and 65% RH and mortality was assessed after 24 h, 48 h, 7 day, 14 day and 21 day of exposure. Then all adults were removed and the treated substrate remained at the same conditions for an additional 45 day after this interval, the commodity was checked for progeny production. In use two extracts the mortality of adults increased with the increase of dose and exposure interval so that; mortality was 100% after 21 days of exposure at the highest dose rate. Results indicated that applied of V. cheiranthifolium extract was more effective than V. speciosum against adult insects. Interestingly, in two cases complete suppression (100% reduction) of the progeny production (F1) was observed in the treated wheat than in control even in the lowest dose rate. Therefore, our results indicate that these medicinal plants can be used for protection of stored grain from infestations of stored-product insect pests. 相似文献
3.
Khoshnoud H Nemati N Amirnia R Ghiyasi M Ghourttapeh AH Tajbakhsh M Talati F Salehzadeh H 《Pakistan journal of biological sciences: PJBS》2008,11(5):783-787
Tissues of higher plants contain novel natural substances that can be used to develop environmental safe methods for insect control. In this study, ethanol extract from flowers of Verbascum cheiranthifolium Boiss. (Scrophulariaceae) was examined for their effect on mortality and progeny production against adults of Rhyzopertha dominica (F.) on two commodities, wheat and barley. The botanical extract was applied at five dose rates, which 0.25, 0.5, 1.0, 2.0 and 3% (w/v). Adults of R. dominica were exposed to the treated wheat and peeled barley at 25 degrees C and 65% RH and mortality was assessed after 24 h, 48 h, 7 day, 14 day and 21 day of exposure. Then all adults were removed and the treated substrate remained at the same conditions for an additional 45 day after this interval, the commodities were checked for progeny production. In two commodities mortality increased with the increase of dose and exposure interval. Results indicated that on wheat, mortality was 100% after 14 days of exposure at the highest dose rate. Whereas, in the same conditions mortality of adults on barley was 63%. Thus plant extract was more effective against adults of R. dominica on wheat than application of barley. Interestingly in two diets, complete suppression (100%) of the progeny production was observed in the treated wheat and barley than in control even in the lowest dose rate. 相似文献
4.
为了解小麦吸浆虫幼虫在麦穗上的危害特点及在麦田的空间分布型,在春季越冬幼虫出土期选择小麦吸浆虫越冬基数不等的麦田4块,在籽粒乳熟期调查小麦吸浆虫危害程度的基础上,运用扩散系数、聚集度指标、聚集指数、平均拥挤度、聚块性指标、负二项分布参数等聚集指标及Iwao的x*x回归法和Taylor 幂函数法,综合分析小麦吸浆虫幼虫在麦穗上的空间分布型。结果表明,小麦吸浆虫的危害程度在田块间差异很大,且危害程度与春季的幼虫越冬基数无关;在麦穗不同部位,总体趋势是上、中部受害程度大于下部,但不同田块之间有差异。以麦穗为单位时,幼虫在麦田的空间分布型属于聚集分布;以麦穗不同部位为单位时,幼虫在麦田的空间分布型也属于聚集分布,且与密度有关。聚集均数λ值的测定结果表明,小麦吸浆虫幼虫的聚集成因主要由自身的生物学特性和环境因素所决定。 相似文献
5.
本文介绍了意大利近年来小麦主要推广品种（80个硬粒小麦品种和7 3个面包小麦品种）1992－1996年在田间对白粉病的成株抗性情况，和13个意大利硬粒小麦和20个面包小麦品种及11个中国小麦品种（系）用意大利10个主要菌系进行的苗期抗性鉴定情况。在田间成株抗性监测中，12．2％和58．9％的硬粒小麦品种和面包小麦器分别表现抗病或中抗；在苗期抗性鉴定中，参试的很多中国品种（系）对大部分意大利菌株表现免疫、近免疫或高抗。由于意大利小麦品种或含有其亲本血缘的中国品种曾经在我国小麦育种和生产中起过比较重要的作用，因此希望这些信息对育种和植病工作者有所帮助。 相似文献
6.
Thermal requirements per developmental stage, offspring production, and percent survival of three isolates of the green peach aphid,Myzus persicae (Sulz.), were determined over a range of constant temperatures from 12.4°–29.4°C. Isolates were collected from Pennsylvania, Maine, and Washington State potato producing regions. Offspring produced, survival, and thermal requirements were not different for all three isolates. Offspring production increased from 12.4°–15.6°C and then decreased as temperature increased. Percent survival averaged 78.2% except at 29.4°C where only 26.7% survived to reproduce. Thermal requirements, with 4°C as the lower developmental threshold, were 25.2, 27.1, 30.9, 30.7, 20.4, 74.2, 201.6 and 135.7 degree days, respectively, for instars 1–4, prereproductive adults, reproductive adults, longevity, and generation time. Data were used as the basis for a computer forecast system to predict aphid population development in potato fields. 相似文献
7.
《Crop Protection》1988,7(3):207-209
Fungal diseases of spring wheat (Triticum aestivum L.) in Central Saudi Arabia (AlGassim region) were surveyed in 1984 and 1985. Over 95% of the wheat fields were planted to the Yecora Rojo cultivar. Root and crown rots (Fusarium spp. and Helminthosporium spp.); brown root rot (Pythium spp.); leaf and head blotches (Helminthosporium spp.) and take-all (Gaeumannomyces sp.) were the most serious fungal diseases observed in the fields. Several H. sativum isolates were pathogenic to seedling leaves of most or all local and imported wheat cultivars (22 cultivars). Numerous soil-borne fungi were isolated from wheat roots and tested for pathogenicity to Yecora Rojo seedlings in the greenhouse. Alternaria sp., Helminthosporium spp. (two isolates), Fusarium spp. (three isolates), Pythium spp., Stemphylium spp. (two isolates) and Gaeumannomyces sp. were pathogenic to the inoculated wheat plants in the greenhouse. 相似文献
8.
为给江苏淮北麦区不同肥力土壤上小麦高产施氮提供理论依据,以该麦区主推中筋小麦淮麦19和强筋小麦烟农19为材料,研究了高、中、低肥力稻茬田上施氮量对小麦籽粒产量和物质生产的影响。结果表明,产量与施氮量在高、中土壤肥力条件下呈二次曲线关系,在低肥力条件下呈线性关系;高、中肥力条件下获得最高产量所需施氮量淮麦19分别为246.7和286.1 kg·hm-2,烟农19分别为247.9和292.6 kg·hm-2;不同土壤肥力水平的高产处理在各个生育时期均有相应较高的群体质量性状。各土壤肥力条件下的不同施氮量处理,由于小麦物质生产多方面因素的综合作用,均出现了各自相对的最高产量,而最高产量随土壤肥力提高而显著上升,相反取得最高产量所需的施氮量却依次相应降低。因此,小麦生产中要因土壤肥力水平的高低来制定不同的目标产量以及相对应的精确施氮量。 相似文献
9.
Powders prepared from sweetflag Acorus calamus rhizomes collected at both high (1700 m) and low (900 m) altitude in Eastern Nepal were admixed with wheat at concentrations in the range 0.05–2% w/w and the wheat infested with Sitophilus oryzae or S. granarius adults. Following a 7 day incubation, the mortality of both species was significantly lower at 20 °C than at 30 °C, and the material collected from high altitude was slightly less toxic than that from low altitude. The moisture content of the wheat (14 or 17%) and the part of the rhizome used to prepare the powder (young or mature growth) had no apparent effect on the toxicity of the preparation. Sitophilus granarius (L.) adults were more tolerant of the material than S. oryzae (L.), while the converse was true for larvae developing in treated grain. An admixture rate of approximately 2% w/w admixed rhizome powder was required to give complete kill of adults of both species following 7 days exposure at 20 °C, while a concentration of 1% w/w either prevented the emergence of adults or killed them rapidly following emergence when wheat containing eggs of either species was incubated for 7–8 weeks at 30 °C.
The β-asarone content of the rhizome powders was determined by GC-MS as 6.4 and 4.7% w/w (mature section of rhizomes collected at high and low altitudes, respectively) and 3.6 and 4.0% w/w (young sections of rhizomes collected at high and low altitudes, respectively). It is anticipated that, under field conditions and in the temperature range 20–30 °C, the initial residue of approximately 1300 mg/kg β-asarone required to disinfest wheat containing these weevil species would decline rapidly due to evaporation. 相似文献
10.
江浙麦区灰飞虱春季种群的发生消长和迁飞动态 总被引：1，自引：0，他引：1
对灰飞虱进行越冬调查、田间调查、卵巢解剖、逐时扑灯行为观察、迁飞轨迹和虫源地分析发现：1）灰飞虱以3~5龄若虫越冬,并以4龄为主;2）江苏北部麦田灰飞虱若虫于3月越冬结束,3-4月陆续发育羽化为越冬代成虫,4-5月在麦田繁殖为第1代若虫;3）浙江海宁春季第1代灯诱灰飞虱具有本地迁出和外地迁入两种性质与时期,并可依卵巢发育级别加以区分;4）春夏季浙江海宁灰飞虱可由本地越冬虫源繁衍而来,或由江苏、安徽、浙江、江西、福建等省迁入。无论从越冬寄主小麦向夏寄主水稻扩散转移,或6月初大量外地迁入,杂草充当了极其重要的中间寄主;5）逐时灯诱观察结果表明,迁出期灰飞虱起飞呈晨暮双峰型,迁入期在19:00至次日凌晨5:00,每1 h均有上灯,以上半夜居多; 6）利用美国NOAA的HYSPLIT轨迹模拟平台对主要迁入期进行数值模拟和虫源地分析,结果表明,2009年5月底至6月初迁入浙江海宁的灰飞虱虫源地来自江苏北部和中部、皖南、浙南、赣东北和闽西北等地区。 相似文献
11.
The biocontrol activity of three isolates of Pseudomonas fluorescens against gray mold of apple fruit caused by Botrytis mali and their ability to induce biochemical defense response in apple tissue were investigated. Apple fruit (Malus domestica) wounds were inoculated with 20 microL bacterial suspension (10(8) CFU mL(-1)) of Pseudomonas fluorescens followed 24 h later by 20 microL of conidial suspension of B. mali (10(5) conidia mL(-1)). The apples were then incubated at 20 degrees C for 11 days. Lesion diameters were evaluated 6 and 10 days after pathogen inoculation. In addition to controlling gray mold, these three isolates of P. fluorescens caused increase in peroxidase activities that reached maximum levels 2-6 days after pathogen inoculation. Phenolic accumulation was increased in apple fruit treated with antagonists and inoculated with B. mali and exhibited the highest level 6-8 days after treatment. The ability of P. fluorescens to increase activities of peroxidase and levels of phenol compounds maybe one of mechanism responsible its biocontrol activity. 相似文献
12.
分属於三个株系群的SMV119、245、86—9、87—02、87—44及173毒株,接种到大豆不同品种上,於接种后48小时、10、15、20、25、30、35、40、50、60天用酶联检测植株体内的病毒浓度。结果证明:条件适宜时,接种后48小时各毒株都能在部分顶芽内测出病毒。接种后25天及50为植株体内病毒浓度含量的两个高峰。一个植株内以第一复叶的浓度最高。各毒株以87—02浓度最高,119次之,245最低。病株的病毒浓度并不和外观症状严重程度成正相关。 相似文献
13.
稻茬晚播小麦不同品种产量及群体特征和氮效应比较研究 总被引：1，自引：0，他引：1
为筛选出适合苏中地区稻茬晚播条件下种植的小麦品种,以苏中地区生产上大面积推广应用的宁麦14、宁麦19、苏麦188、扬麦16、扬麦22、扬辐麦4号、扬麦23和扬麦25为试验材料,比较了不同品种在晚播条件下生育进程、产量、群体结构特征、氮效率及抗倒性的差异。结果表明,晚播条件下,扬麦16、扬麦23、宁麦14以及宁麦19的生育进程略快于苏麦188及扬麦22,扬麦16和扬麦23较其他品种早熟1~2 d。两年度均以扬麦23产量最高(8 168.82 kg·hm-2),其次为扬辐麦4号(8 124.06 kg·hm-2),这两个品种生育前期干物质积累量高, LAI较大,花后旗叶叶绿素含量较高。扬麦16虽然越冬期有较大的生长量及分蘖发生量,熟期较早,但晚播条件下穗数不足,限制了其产量潜力的发挥。成熟期扬麦16和扬麦23的氮素积累量显著高于宁麦14和扬麦25,花后氮素积累量扬麦23最高。扬辐麦4号和扬麦23氮效率指标优于其他参试品种。扬辐麦4号抗倒伏指数最高,其次为扬麦23和扬麦25,抗倒性能均较好;扬麦22株高与重心高度低于其他品种,但茎秆质量较差。综合考虑,扬麦23和扬辐麦4号生育前期分蘖发生较快,中期群体结构协调,花后旗叶叶绿素含量较高,同时具有较好的抗倒性能,稻茬晚播条件下推荐选用。 相似文献
14.
为明确不同土壤肥力下小麦干物质生产和产量的差异,于2019-2020年小麦生长季,选择了产量潜力分别为10 500 kg·hm-2和9 000 kg·hm-2的超高产土壤肥力和高产土壤肥力两种麦田,以济麦22为材料,比较分析了不同土壤肥力麦田小麦的群体动态、干物质生产、籽粒灌浆特性、穗部特征和产量构成的差异。结果表明,与高产土壤肥力相比,超高产土壤肥力增加了小麦拔节至成熟期的干物质积累量及成熟期干物质在籽粒中的分配量,促进了小麦开花前营养器官储存同化物在开花后向籽粒的转运量和开花后的光合物质同化量,提高了收获指数;超高产土壤肥力使籽粒在灌浆中后期维持较高的灌浆速率,延长了活跃灌浆期,提高了粒重。超高产土壤肥力通过增加单位面积的穗数和千粒重,实现小麦高产。 相似文献
15.
Z. Basky 《Crop Protection》1993,12(8):605-609
A yellow water pan trap was used to collect Diuraphis noxia (Mordvilko) in Central Hungary in 1989. In 1990 a Rothamsted-type suction trap collected 31 individuals. A D. noxia infestation was found in an autumn-sown wheat field in October 1990. The D. noxia population that overwintered was holocyclic. The life-span of fundatrices was 43.2 days at 18–22°C. The number of nymphs produced per fundatrix was 46.6. Average progeny numbers of first-generation apterae and alatae were 29.4 and 21.4, respectively. Second-generation apterae produced an average of 48.8 nymphs; 35.9% of nymphs were alatiform. The D. noxia population reached its peak on 3 July in the field, at which time the mean number of individuals per wheat plant was 3953.6. By 20 July, the wheat plants had matured and the D. noxia colonies had disappeared from the wheat. 相似文献
16.
Information on gas exchange of crop stands grown in controlled environments is limited, but is vital for assessing the use of crops for human life-support in closed habitats envisioned for space. Two studies were conducted to measure gas exchange of wheat stands (Triticum aestivum L. cv. Yecora Rojo) grown from planting to maturity in a large (20 m2 canopy area), closed growth chamber. Daily rates of dark-period respiration and net photosynthesis of the stand were calculated from rates of CO2 build-up during dark cycles and subsequent CO2 drawdown in the light (i.e., a closed-system approach). Lighting was provided as a 20-h photoperiod by high-pressure sodium lamps, with canopy-level photosynthetic photon flux density (PPFD) ranging from 500 to 800 micromoles m-2 s-1 as canopy height increased. Net photosynthesis rates peaked near 27 micromoles CO2 m-2 s-1 at 25 d after planting, which corresponded closely with stand closure, and then declined slowly with age. Similarly, dark-period respiration rates peaked near 14 micromoles CO2 m-2 s-1 at 25 d and then gradually declined with age. Responses to short-term changes in irradiance after canopy closure indicated the stand light compensation point for photosynthesis to be near 200 micromoles m-2 s-1 PPFD. Tests in which CO2 concentration was raised to approximately 2000 micromoles mol-1 and then allowed to draw down to a compensation point showed that net photosynthesis was nearly saturated at > 1000 micromoles mol-1; below approximately 500 micromoles mol-1, net photosynthesis rates dropped sharply with decreasing CO2. The CO2 compensation point for photosynthesis occurred near 50 micromoles mol-1. Short-term (24 h) temperature tests showed net photosynthesis at 20 degrees C > or = 16 degrees C > 24 degrees C, while dark-period respiration at 24 degrees C > 20 degrees C > 16 degrees C. Rates of stand evapotranspiration peaked near Day 25 and remained relatively constant until about Day 75, after which rates declined slowly. Results from these tests will be used to model the use of plants for CO2 removal, O2 production, and water evaporation for controlled ecological life support systems proposed for extraterrestrial environments. 相似文献
17.
播期、密度和行距对BNS型杂交小麦光合及产量的影响 总被引：3，自引：0，他引：3
为筛选BNS型杂交小麦的适宜播期、密度和行距配置,设置了3个播期[10月5号(A1)、10月15号(A2)、10月25号(A3)]、3个密度[基本苗150×104株·hm~(-2)(B1)、225×104株·hm~(-2)(B2)、300×104株·hm~(-2)(B3)]和3个行距[18.3cm(C1)、23cm(C2)、宽窄行13.3/23cm(C3)],研究了播期、密度和行距配置对小麦光合特性及产量的影响。结果表明,杂交小麦旗叶净光合速率在所有测定时期均以A2B1C2处理最高,A2B3C1处理次之;通过极差分析可知,旗叶叶绿素a和叶绿素b含量的最佳处理为A2B3C2;三因素对小麦冠层透光率的影响程度因时期和部位而不同;A2B3C1和A3B3C2处理的产量显著高于其余处理。因此,在本试验条件下,杂交小麦适宜的播期、基本苗和行距分别为10月15号、300×104株·hm~(-2)和18.3cm。 相似文献
18.
四川盆地弱光照生态区小麦超高产技术途径分析 总被引：1，自引：0，他引：1
为提升四川盆地弱光照生态区小麦产量潜力,基于2005-2012年系列控制性试验和农民高产跟踪田数据,系统分析了该区域限制小麦高产的关键因子及实现超高产(9t·hm-2以上)的技术途径.结果表明,小麦籽粒产量与单位面积穗数呈极显著正相关关系,但相关程度随产量水平的提升而下降(y=-0.151x+1.453,R2 =0.329,P＜0.05),9 t·hm 2以上时穗粒数和千粒重成为产量高低的决定性因素.籽粒产量普遍与生物产量、收获指数、生物生产率、籽粒生产率呈显著正相关,与抽穗期、全生育期呈显著负相关,与最高茎数、分蘖力和成穗率的相关程度则因试验不同而存在较大差异.籽粒产量与群体干重、叶面积指数等群体指标的相关程度:开花期＞拔节期＞苗期.高产田分蘖、拔节期的群体干重与中高产田相当甚至略低,但在开花期,高产田的干物质积累量显著高于中高产田,且个体质量也更高,着重反映在单茎绿叶数、旗叶SPAD值、单茎叶面积等指标上.根据上述结果和四川盆地生态条件,提出了在弱光照生态条件下小麦实现超高产的技术途径、阶段指标和关键技术. 相似文献
19.
A laboratory assessment was made of cold tolerance in seven cultivars and one natural population of red fescue, overwintered at lowland (30 m a.s.I.) or an upland (300 m a.s.l.) site.
After 5 months overwintering, plants were exposed under laboratory conditions to seven freezing temperatures, –7, –9, – 10, – 11, – 12, – 13 and – 15°C and + 2°C as control. Thawed tillers were grown in soil in glasshouse, and tiller survival and growth recorded after 28 days. Cold tolerance was estimated using LT50 values.
Tiller mortality increased with decreasing freezing temperature, with almost all tillers surviving at – 7°C and almost all dying at – 15°C. Cold hardening at the overwintering site markedly affected survival, plants overwintered at the upland site having significantly greater survival than those overwintered at the lowland site. All samples were affected to similar extent by overwintering site. The samples Aber Valley, Hawk, Merlin, Polar, and Dawson were significantly more cold tolerant than Jupiter, S59, and Highlight. Tiller production data closely resembled those for tiller survival.
For upland situations, eultivars or natural populations other than the currently recommended S59 have better cold tolerance, and may provide useful genetic resources for breeding cultivars for uplands use. 相似文献
After 5 months overwintering, plants were exposed under laboratory conditions to seven freezing temperatures, –7, –9, – 10, – 11, – 12, – 13 and – 15°C and + 2°C as control. Thawed tillers were grown in soil in glasshouse, and tiller survival and growth recorded after 28 days. Cold tolerance was estimated using LT50 values.
Tiller mortality increased with decreasing freezing temperature, with almost all tillers surviving at – 7°C and almost all dying at – 15°C. Cold hardening at the overwintering site markedly affected survival, plants overwintered at the upland site having significantly greater survival than those overwintered at the lowland site. All samples were affected to similar extent by overwintering site. The samples Aber Valley, Hawk, Merlin, Polar, and Dawson were significantly more cold tolerant than Jupiter, S59, and Highlight. Tiller production data closely resembled those for tiller survival.
For upland situations, eultivars or natural populations other than the currently recommended S59 have better cold tolerance, and may provide useful genetic resources for breeding cultivars for uplands use. 相似文献
20.
减氮对不同氮效率小麦品种花后光合物质生产力和产量的影响 总被引：3，自引：0，他引：3
为明确不同氮效率小麦品种对减氮的响应特点,以前期筛选出的氮高效品种扬麦25、宁麦21和氮低效品种扬麦22、扬麦20为材料,研究减氮模式对产量、氮肥利用效率、光合生产能力和干物质积累量的影响。结果表明,氮高效品种扬麦25和宁麦21的籽粒产量和氮肥利用效率显著高于氮低效品种扬麦22和扬麦20,氮高效品种的平均籽粒产量和平均氮肥利用效率较氮低效品种分别高10.9%和23.9%。与常规施氮处理(CK)模式相比,减氮20%并采用基肥和拔节肥各施氮90 kg·hm~(-2)(M4)模式下,氮高效品种开花期LAI、旗叶SPAD值、净光合速率及乳熟期旗叶SPAD值和净光合速率均未显著降低,且乳熟期平均LAI提高16.0%,进而使花后干物质积累量增加,从而实现产量稳定和氮肥利用效率的提高;而氮低效品种花后光合生产能力、籽粒产量和氮肥利用效率随施氮量降低而出现不同程度的降低。这说明,氮高效品种较氮低效品种有着更多的减氮潜力,前者在适量减氮和合理施肥方式下,可通过延缓花后叶面积衰减、保持较强的花后光合能力和增加花后物质生产力,实现产量稳定和氮肥利用效率提高。 相似文献