Movement and survival of corn rootworm in seed mixtures of SmartStax® insect-protected corn

SmartStax^® insect-protected corn (Zea mays L.) contains genes for six Bacillus thuringiensis (Bt) proteins controlling both lepidopteran pests and the corn rootworm complex (Diabrotica spp.). The properties of SmartStax, particularly the multiple effective modes of action (i.e., each Bt protein provides a high level of control of the target pests with a low probability of cross-resistance among the proteins), have provided the opportunity to add to previously approved structured refuge options by combining the non-Bt refuge seed with SmartStax seed in a seed mix. Seed mixes ensure that a refuge is present in every Bt field, remove concerns about grower compliance with refuge requirements, and provide grower convenience. However, seed mixes could increase the likelihood that larval insects move between Bt and non-Bt plants and vice versa. Assessing the insect resistance management (IRM) value of a seed mix refuge requires an assessment of the amount of larval movement, and the consequences of that movement, for the key target pests. The studies here present such data for control of corn rootworm by SmartStax corn, which contains the rootworm-active protein Cry3Bb1 and the binary protein Cry34Ab1/Cry35Ab1. In a growth chamber experiment, SmartStax was most effective against first instars and significantly effective against second instars, but did not control third instars. In a field study of movement from a heavily infested non-Bt plant onto surrounding plants, a larger percentage of insects successfully dispersed from the infested plant when the surrounding plants were non-Bt plants than when they were SmartStax plants. A paired-plant study showed that few larvae migrated from infested SmartStax plants and survived on nearby non-Bt plants; larvae that migrated from infested non-Bt plants had low survival if the adjacent plants were SmartStax. Replicated field studies of plant-to-plant movement indicated that the non-Bt plants in a 5% or 10% seed mix consistently supported large populations of susceptible insects and represented a productive refuge, whereas the SmartStax plants had few or no survivors. The timing of emergence from seed mix plots containing 5% or 10% non-Bt plants was more similar to that of the non-Bt plots than that of the SmartStax plots. Thus, the available growth chamber and field data indicate that a seed mix of 5% or more will provide an effective refuge for corn rootworm in SmartStax corn.     

莲藕斜纹夜蛾的为害及绿色防控技术

近年来,斜纹夜蛾在水生蔬菜莲藕上的为害日益猖獗,严重影响了莲藕的产业发展,但其化学防治受到限制．迫切需要建立新的防控技术体系。结合相关资料,分析了斜纹夜蛾在莲藕上的为害特点、发生动态及发生原因,探讨了可行的莲藕斜纹夜蛾绿色防控技术。     

观赏荷花新品种‘首领’

‘首领’是从观赏荷花‘钗头凤’芽变中选出的新品种,重台,小株型。立叶高20~30 cm,叶径13.5~26.5 cm×11~20 cm。花色为复色,花瓣外被18~22枚,内被122~140枚,花冠直径15.0~17.5 cm。着花密度较高,7~13朵·m~(-2)。     

不同贮藏处理对辣椒种子发芽的影响

调查不同贮藏处理下辣椒种子发芽情况,结果表明,在常温、相对低温或者在常温环境下贮藏后再进行相对低温贮藏,随着贮藏时间的延长,种子始发芽率和发芽率逐渐降低、始发芽时间和发芽持续时间延长、发芽集中程度变弱、种子活力下降,但低温环境贮藏较常温环境贮藏能明显延长种子的使用寿命.     

种子纯度研究现状与发展

种子纯度鉴定是评定种子等级和质量的重要参考标准,也是我国当前种子质量检验工作的重点和难点.随着现代生物技术的不断发展,种子纯度鉴定技术由传统的形态标记鉴定逐步发展到集形态标记鉴定、生化标记鉴定和DNA分子标记鉴定为一体的综合鉴定技术体系.对现阶段主要的种子纯度鉴定技术进行了简要的介绍,分析了各种技术的优缺点和应用情况,...     

Genetic variation among and within populations of <Emphasis Type="Italic">Cordia africana</Emphasis> in seed size and germination responses to constant temperatures

Cordia africana Lam. is a commercial timber species that grows naturally throughout sub-Saharan Africa and tropical Arabia. At present very little is known about genetic variation in this species and baseline information is needed to initiate improvement programs in Ethiopia. Thus, the objectives of the study were to quantify the inter- and intra-population variations in seed size traits and germination responses to different constant temperature regimes. Seeds were collected from 30 open-pollinated families within each of the five populations representing the natural distribution of the species in Ethiopia. To examine seed size variations, seed length, seed width, and 1,000-seed weight were quantified. Inter- and intra-population variations in seed germination were investigated under different constant temperature regimes from 20 to 35°C in climate chambers. Significant variations in seed length, width and weight were detected both at inter- and intra-population levels, and family heritabilities of 0.63–0.76 showed that much of the phenotypic variation in seed size traits were additive genetic variation. Significant variation in germination was also found among and within populations as well as between the different constant temperature regimes. Generally the variation in germination was considerably higher within population than between populations. The optimal temperature for germination of C. africana seeds was 25–30°C with family heritabilities for germination ranging between 0.20 and 0.33, depending on the germination temperature.     

粘果山羊草细胞质对小麦种子发芽率和出苗率的影响

本试验选用粘果山羊草（Ae.Kotschyi）细胞质不育系（简称K型）及相应的保持系、恢复系和杂交种研究了K型胞质材料和普通小麦胞质材料在种子发芽率、出苗率的差异。结果表明：K型胞质材料和普通小麦胞质材料的种子发芽率没有显著差异,浅播（3cm）条件下,K型胞质材料和普通小麦胞质材料种子出苗率没有显著差异,而深播（6cm）条件下,不同核基因材料表现出不一致现象,K型不育系豫麦3号及其杂种表现出偏高的出苗率,但不显著;K型不育系S43及其杂种表现出偏低的出苗率,且达到了极显著水平。     

不同化学试剂对丽江山慈菇种子发芽力影响

采用培养皿发芽法研究了2％NaOH、0．1％KMnO4、1％CuSO4、NAA、6-BA及GA对丽江山慈菇新陈种子的发芽力影响。结果表明：不同化学试剂处理的丽江山慈菇种子发芽率及发芽势均有不同程度的提高，其中对新种子的影响最显著。     

杂交水稻制种提高结实率的研究

杂交水稻制种不同于水稻栽培、其结实由柱头外露结实和非柱头外露结实两部分构成；空壳中90％以上是由于没有授粉受精造成的：90％以上的受精拉都能正常发育结实。柱头外露率和受精率与结实率呈显著正相关。后期施肥、父本大龄秧和机械授粉能有效地提高柱头外露率、花遇优度和结实率及制种产量。     

玉米不同基因型种子发芽及幼苗性状分析

对Ｓ２２、４７８、４８９自交系及其单交、回交、自交后代共１６个基因型的种子发芽和幼苗特性研究表明：①Ｓ２２（深色）、Ｓ２２（中色）、及（Ｓ２２×４８９）自交和回交后代各项指标均较差,且物质运转率低;Ｓ２２（浅色）与４７８相比,发芽率较高,但发芽较慢。②单交种的种子发芽和幼苗特性均随着杂种优势的产生而显著提高,自交、回交后代又随杂种优势的衰退而明显降低。③种子发芽及幼苗特性与粒色有关,受母本胞质基因的影响。④Ｓ２２的种子发芽和出苗特性可以通过后代选择予以改良。