棉铃虫对辛硫磷抗性的选育、交互抗性及增效剂增效作用研究

1 991年采自河南偃师棉田的棉铃虫种群(简称 YS种群 )与敏感品系相比有 2 .7倍的抗性。该种群在室内经功夫菊酯 +辛硫磷 (1∶ 2 5 )筛选了 2 7代后 ,对辛硫磷的抗性达到 9.4倍 ,再单用辛硫磷对该种群筛选 2 1代 ,获得 6 3 .0倍的抗性。交互抗性测定结果表明 ,棉铃虫对辛硫磷产生高水平抗性后对灭多威具有比较明显的交互抗性 ,对久效磷具有一定程度交互抗性 ,对甲基对硫磷和丙溴磷只有较低水平的交互抗性。 3种增效剂 TPP、DEF和 PBO对辛硫磷的增效比分别为1 .4、2 4 .8和 1 .0 ,DEF的增效作用明显 ,使辛硫磷的抗性由 6 3倍降至 2 .5倍 ,初步证明酯酶是引起棉铃虫对辛硫磷产生抗性的重要原因。本文的研究结果对于在棉铃虫抗药性治理措施中选择辛硫磷的轮换或替代品种具有重要参考价值     

棉铃虫对丙溴磷抗性风险评估、预报及交互抗性研究

分别用高浓度和低浓度丙溴磷对室内连续饲养29代的江苏东台棉铃虫连续筛选12代,平均存活率分别为27.5%和46.5%,抗性分别上升了7.1倍和3.7倍,抗性现实遗传力分别为0.1372和0.1171。用高浓度丙溴磷筛选的种群对氟氯氰菊酯、辛硫磷、久效磷及溴氰菊酯具有明显交互抗性(6.3～10.4倍);用Bt生物制剂Dipel和转Bt棉筛选的种群对丙溴磷无交互抗性,但用Bt棉筛选的高抗品系(>1000倍)对辛硫磷具低水平交互抗性(8.0倍)。     

甜菜夜蛾对虫酰肼的抗药性监测及抗性风险评估

用浸叶法监测了江苏丰县、大丰、射阳、阜宁、南京江宁及河南新野6个地区甜菜夜蛾初孵幼虫对虫酰肼的抗性,结果表明:各种群对虫酰肼的抗性倍数为2.1~4.2,属敏感至敏感性下降阶段。用虫酰肼筛选甜菜夜蛾广东深圳种群34代后,与起始种群相比,抗性为17.0倍。筛选前17代,甜菜夜蛾对虫酰肼的抗性现实遗传力为0.1021,筛选后17代,现实遗传力为0.1519,前半段现实遗传力小于后半段的现实遗传力。整个34代筛选期间,现实遗传力为0.1695。当抗性现实遗传力为0.1021,杀死率为80%~90%时,抗性上升10倍,需要14~18代。试验结果证明甜菜夜蛾对虫酰肼产生抗性的风险较低。并对甜菜夜蛾的抗性治理进行了讨论。     

甜菜夜蛾对几类新型杀虫剂的早期抗性监测

 用浸叶法测定了江苏和河南等地甜菜夜蛾种群对几种作用方式新颖的新型杀虫剂甲维盐、阿维菌素、茚虫威、溴虫腈、虫酰肼、甲氧虫酰肼及呋喃虫酰肼的敏感性,尽管大多数种群对这些杀虫剂处于敏感阶段,但首次监测到江宁和射阳两个种群已对阿维菌素产生了中等水平的抗性（10.4和14.2倍）,另一个丰县种群对茚虫威也具有低水平的抗性（6.8倍）。测定结果可以为甜菜夜蛾的抗性治理策略的制定提供理论依据。     

F1代法检测棉铃虫种群对Bt棉的抗性等位基因频率变化

 在具有室内高抗Bt棉棉铃虫品系的前提下,F₁代法是检测棉铃虫对Bt棉抗性等位基因频率的最简捷、快速的生物测定方法。2010－2012年采用F₁代法检测了河北省邱县棉铃虫田间种群对Bt棉的抗性等位基因频率变化。结果表明,2010－2012年采集的122、141及124头田间雄虫中,分别有32、22及43头携带抗性基因,抗性等位基因频率分别为0.131(95%置信限CI:0.101～0.162)、0.078(95% CI:0.034～0.122)及0.199(95% CI:0.124～0.274)。2012年采用带毒饲料法测定河北邱县等4个地区Bt棉田间棉铃虫对Cry1Ac的抗性。结果表明,河北邱县棉铃虫种群的抗性最高(抗性倍数RR为19.2倍）,明显高于湖北荆州、湖北枣阳和安徽萧县种群的抗性（RR为4.9～9.3倍)。该地区长期大面积种植转单价Bt棉导致田间棉铃虫抗性进化,需要尽快采取有效的抗性治理措施。     

黄河流域田间棉铃虫对转Bt基因棉抗性监测

利用改进的单雌系F1/F2代法,对黄河流域主要棉区河南安阳县、河北威县、山东武城县的棉铃虫种群进行了系统监测。在2007-2009年,连续3年保守地估计了以上3个主要植棉县棉铃虫种群对Cry1Ac的抗性基因频率。结果表明,山东武城棉铃虫种群3年的抗性等位基因频率分别为0.00086、0.00097和0.00052;安阳田间棉铃虫种群2008和2009年抗性等位基因频率分别为0.00090和0.00103;河北威县的田间棉铃虫种群抗性等位基因频率为0。所有家系F1代和F2代的相对平均发育级别均值比较结果显示,山东武城县棉铃虫种群耐受性高于其它2个地区,其次为安阳县种群,威县种群敏感度最高。总之,我国黄河流域这3个主要棉区田间棉铃虫种群对Cry1Ac毒素还没有产生明显的抗性,抗性基因频率仍处于正常水平,但是棉铃虫对Cry1Ac毒素的耐受性有升高趋势,需要进一步加强全国性的监测工作。     

有机磷/拟除虫菊酯混剂筛选棉铃虫品系的交互抗性和生化机理

 用辛硫磷/氟氯氰菊酯(25：1, 有效成分)混剂对棉铃虫田间种群(HN)进行33代筛选获得抗性品系(HN-R)。筛选获得的HN R抗性品系对辛硫磷和氟氯氰菊酯的抗性分别达17.4倍和144.7倍。HN-R品系对两种拟除虫菊酯产生了高水平交互抗性(对氯氰菊酯和氰戊菊酯分别为86.2和23.4倍),对久效磷产生了中等水平交互抗性(5.2倍),对甲基对硫磷(1.6倍)、丙溴磷(1.8倍)和灭多威(2.4倍)产生了低水平交互抗性。酯酶抑制剂DEF能有效抑制HN-R品系对辛硫磷的抗性(增效比为15.3倍),而多功能氧化酶抑制剂PBO则对辛硫磷没有任何增效作用;PBO则使HN-R品系对3种拟除虫菊酯的抗性显著降低(对氟氯氰菊酯、溴氰菊酯和氰戊菊酯的增效比分别为21.9、19.1和21.4倍)。DEF和PBO都能使HN-R对久效磷的抗性下降一半(增效比分别为2.2和2.5倍)。HN-R抗性品系多功能氧化酶活性(以pNA为底物)和酯酶活性(以a-NA为底物)分别为HN品系的6.5倍和1.6倍。因此,在HN-R抗性品系中至少存在2种代谢抗性机理,即增强的酯酶解毒代谢(对辛硫磷、久效磷)和多功能氧化酶介导的氧化解毒代谢(对3种拟除虫菊酯、久效磷)。本研究表明,在田间使用有机磷/拟除虫菊酯混剂可能同时选择出多种代谢抗性机理,从而导致广谱的交互抗性。     

西花蓟马对新烟碱类杀虫剂存在高抗风险

正为明确使用新烟碱类杀虫剂烯啶虫胺、噻虫胺和噻虫嗪防治入侵害虫西花蓟马的抗性风险及抗性稳定性,浙江农林大学农业与食品科学学院等单位研究人员采用芸豆浸药法,对西花蓟马敏感种群初羽化雌成虫进行连续筛选获得抗性种群,根据抗性现实遗传力计算公式分析西花蓟马对上述3种杀虫剂的抗性风险,预测了其抗性发展速度,并测定抗性稳定性。结果表明,经过30代抗性筛     

山西省通报2012年农业有害生物抗性风险评估结果

<正>山西省植保植检总站近期通报了2012年全省农业有害生物抗性风险评估结果。结果表明,该省运城地区麦长管蚜对抗蚜威的抗性为1.11倍,对氧乐果的抗性为0.92倍,对吡虫啉的抗性为0.25倍,对啶虫脒的抗性为0.04倍,对灭多威的抗性为2.68倍,对高效氯氰菊酯的抗性为0.33倍,对溴氰菊酯的抗性为0.25倍,对毒死蜱的抗性为0.17倍;棉铃虫对甲维盐的抗性为1.8倍,对高效氯氟氰菊酯的抗性为27.4倍,对辛硫磷的抗性为0.7倍;棉蚜对氟氯氰菊酯的抗性高达13636.36倍,对高效氯氰菊酯的抗性高达3991倍,对吡虫啉的抗性高达1179.84     

华北地区棉铃虫对Bt杀虫蛋白的抗性监测

采用Bt可湿性粉剂标样和含单一Bt杀虫蛋白CryⅠA(c)的MVPⅡ水剂,研究改进了棉铃虫对Bt杀虫蛋白的抗性测定方法.1996～1998年进行华北地区棉铃虫对Bt制剂的抗性监测,结果表明,河北省邱县、冀州市、山东省高密市、河南省西华县棉铃虫与敏感种群相比的抗性指数(RR)为1.3～5.3倍;用诊断剂量法测定,只在1998年检测到山东高密棉铃虫的抗性个体频率为0.9%,其余均为0.1998年测定棉铃虫对CryⅠA(c)敏感性,与室内种群相比,河北邱县、冀州和山东高密棉铃虫种群对CryⅠA(c)的相对RR值分别为4.9、3.9和3.8倍,对Bt粉剂的相对抗性指数(RR)分别为1.1、1.4和1.6倍;用转Bt基因棉叶直接测定,田间棉铃虫的死亡率降低,表明用CryⅠA(c)进行测定与用转Bt基因棉叶直接测定结果相关性较大.     

Number of involved genes and heritability of clover rot (Sclerotinia trifoliorum) resistance in red clover (Trifolium pratense)

European red clover (Trifolium pratense) crops are challenged by clover rot, a devastating disease caused by Sclerotinia trifoliorum or, in some cases by S. sclerotiorum. No completely resistant cultivars are available and resistance breeding is hampered by the lack of knowledge on the number of involved resistance genes and the heritability of clover rot resistance. In this study, we estimated the number of major genes contributing to clover rot resistance by analysing 15 F₁ progeny populations from pair crosses between ramets of resistant and susceptible genotypes. Parent plants were chosen from diverse, diploid populations, including wild material, landraces and cultivars. Young progeny plants were inoculated with ascospores, evaluated phenotypically and the segregation of disease scores was studied. Our results indicated that clover rot resistance may be conferred by three major effect genes, although segregation patterns suggested that there may be numerous minor effect genes involved as well. No proof was found for a maternal inheritance of clover rot resistance. To get insight in the heritability of clover rot resistance, we applied divergent selection by our high-throughput bio-test on an experimental diploid population: the original population (70.5 %), the first generation after selection for susceptibility (79.2 %) and the first generation after selection for resistance (62.3 %) differed significantly in susceptibility (p < 0.001). The second generation after selection for resistance (60.0 %) was not more resistant than the first generation after selection for resistance. In the first generation of selection the heritability (h²) was on average 0.34. In the second generation of selection h² was 0.07. These findings have important implications for resistance breeding.     

Genetic analysis of resistance to tomato late blight in Solanum pimpinellifolium accession PI 163245

Late blight (LB), caused by Phytophthora infestans, is one of the most devastating diseases of tomato (Solanum lycopersicum) worldwide. Due to the emergence of new and aggressive P. infestans isolates, identifying new genetic resistance to LB is a priority in tomato breeding. Recently, we reported the identification of several Solanum pimpinellifolium accessions with strong LB resistance. In this study, we investigated the utility of resistant accession PI 163245 for tomato breeding by examining heritability (h²) of resistance and the response to selection for resistance. Estimates of h² based on F₂ : F₃ and F₃ : F₄ parent : offspring correlation analyses averaged 0.79 and 0.94, respectively, suggesting the heritable nature of LB resistance in PI 163245. Analysis of response to selection for resistance from F₂ to F₄ generations indicated a realized h² of 0.63, confirming the utility of this resistance in tomato breeding. Two methods of estimating the minimum number of loci involved indicated the presence of one major resistance locus. Currently, genetic mapping and breeding efforts are underway to further confirm the viability of this accession for improving tomato LB resistance.     

Inheritance of fiber quality and lint yield in a chemically mutated population of cotton

The narrow germplasm base of the upland cotton (Gossypium hirsutum L.), grown on the Texas high plains historically, has limited improvement of fiber quality. Chemical mutagenesis and subsequent selection have helped the development of lines with improved fiber quality in cultivars adapted to this region. This study was conducted to determine the inheritance of improvements in fiber quality. M₃ lines with divergent fiber properties of micronaire, length, and strength were selected from a population of Paymaster HS 200 treated with 3% v/v ethyl methanesulfonate (EMS) for two hours. The 115 selected lines of M₄ and M₅ generation were evaluated for fiber quality and lint yield. Regression of the M₄ and M₅ on the M₃ generation, as well as the M₅ on the M₄ was used to generate narrow sense heritability coefficients. Significant variations were observed between the mutant lines in all generations except for lint yield in the M₅ (1997). The highest heritability estimates were found in fiber length (h ²= 0.29** to 0.46**). Micronaire and strength showed intermediate heritability estimates of h ²= 0.14 to 0.19, while lint yield had a very low heritability estimate of h ²= 0.03. Fiber length and strength were correlated (r= 0.58** to 0.46**) in all the three generations. The mutants identified in these studies have the potential to improve fiber quality of upland cotton without introducing alien genes that may reduce adaptation to short growing season production regions.     

An Improved Assessment Procedure for Breeding for Resistance to Septoria nodorum in Wheat

A yield-based assessment procedure for breeding for resistance to Septoria nodorum (SN) is presented. Artificially infected as well as fungicide-protected plots were analyzed for each genotype. Considerable increase in precision of disease scores was gained by using an assessment matrix for different plant organs and time intervals during disease development. This technique resulted in yield loss: disease attack correlations up to r = 0.85:** and raised coefficients of heritability (h²_b= broad sense heritability) with h²_b= 0.72 for % yield loss and h²_b= 0.86 for SN-attack, calculated for a 3-year replicated field experiment with 105 winter wheat cultivars.     

Selection response for carbon isotope discrimination in a Triticum polonicum×T. durum cross: Potential interest for improvement of water efficiency in durum wheat

This study has been conducted to evaluate the usefulness of carbon isotope discrimination (δ) in mature kernels as a criterion for the improvement of water-use efficiency and yield under drought in durum wheat. For this purpose, Triticum durum‘Om Rabi 5’ was crossed with T. polonicum pseudochrysospermum 9 (Tp9) which has been found to be more drought tolerant and to have a lower carbon isotope discrimination value of the grain. The F₂ population showed a wide segregation for carbon isotope discrimination. Further, divergent selections (selection of plants most different in carbon isotope discrimination) were made among individual F₂ plants, and for carbon isotope discrimination in F₃ progenies under field conditions. Selected F₃ and F₄ progenies were evaluated under field conditions for morphological and agronomical traits. Broad-sense heritability (h²_b), response to selection and realized heritability (h²_r) were high. The narrow-sense heritability (h²_n= 0.37 ± 0.047) indicated that additive and dominance effects were involved in the genetic control of carbon isotope discrimination. Negative correlations were noted between carbon isotope discrimination and grain yield and between carbon isotope discrimination and biomass yield within years and generations. An explanation of this result is attempted by analysing the relationships between carbon isotope discrimination and several phenological and morphological traits influencing the water-use efficiency. The divergent groups selected for low and high carbon isotope discrimination exhibited significant differences for days to heading, plant height, shape of the spike and number of spikelets per spike. Correlations were also found between carbon isotope discrimination and plant height, harvest index, shape of the spike, spike length, and number of spikes per plant. The potential use of carbon isotope discrimination as a criterion for the improvement of water-use efficiency in durum wheat is discussed by considering the genetics of this trait (variability, heritability, response to selection) and also the associations with phenological and morphological traits.     

Heritability estimates of field resistance to spot blotch in four spring wheat crosses

Spot blotch of wheat (Triticum aestivum L.), caused by Bipolaris sorokiniana (Sacc. in Sorok.) Shoem., is a major disease in South Asia. Popular commercial cultivars have low levels of resistance to spot blotch. Information on the inheritance of spot blotch resistance in wheat is lacking. Field studies were conducted in four wheat crosses, each involving a Chinese hexaploid parent with high levels of resistance and a commercial cultivar with low to intermediate levels of resistance to spot blotch. Data were recorded in the F₂, F₃ and F₄ generations to estimate heritability. Field studies were conducted in three years (1992–94) at Rampur. Nepal, involving 150 lines in each cross. The spot blotch score was recorded as the percentage necrosis and associated chlorosis of the two upper most leaf surface. In the F₂ generation three spot blotch readings on the flag leaf were taken whereas in the F₃ and F₄ generations four readings were recorded at 5-day intervals on the flag and the penultimate leaves. The highest disease score (HDS) and the area under disease progress curve (AUDPC) were analysed. Heritability (h²) estimates for spot blotch resistance were intermediate to high measured in terms of HDS (0.47 < h² < 0.67) and also AUDPC (0.58 < h² < 0.77) both in F₃ and F₄ generations in each of the four crosses. Heritability values were somewhat higher for AUDPC than HDS. There were significant negative correlations (r) of days to heading with HDS (-0.186 < r < -0.515) and AUDPC (-0.218 < r < -0.623). One-hundred kernel weight was significantly negatively correlated to AUDPC (-0.245 < r < -0.454) in all crosses in each generation. The results suggest that selection for resistance to spot blotch could be effective in the segregating populations generated from hexaploid wheat parents having different levels of resistance. Although AUDPC appeared to be a better measure to determine genetic differences for spot blotch in wheat, HDS would be adequate in screening trials for resistance to spot blotch.     

Heritability of late blight resistance in tomato conferred by Solanum pimpinellifolium accession PI 224710

Late blight (LB), caused by the oomycete Phytophthora infestans, is one of the most destructive diseases of tomato and potato worldwide. Identifying and characterizing new sources of resistance is essential given the emergence of new aggressive and fungicide‐resistant P. infestans isolates. Recently, we reported identification of several new sources of LB resistance within the tomato wild species, Solanum pimpinellifolium. In this study, we examined heritability (h²) of LB resistance conferred by the S. pimpinellifolium accession PI 224710 using a parent–offspring regression (correlation) analysis. F₂ and F₃ progeny populations, derived from crosses between PI 224710 and a LB‐susceptible tomato breeding line, were evaluated for response to LB infection. To obtain a better estimate of h², the F₃ progeny were evaluated for LB resistance in two separate replicated experiments. The h² estimates were similar in the two experiments and averaged ~0.87, suggesting that this resistance was highly heritable. Two different methods estimated involvement of one resistance locus. Breeding and mapping efforts are underway to further assess the viability of this newly reported LB resistance.     

Analyses of Interactions of Wheat Cultivars in Tests for Resistance to Pseudocercosporella herpotrichoides

A total of 20 cultivars of winter wheat were tested by ELISA for resistance to Pseudocercosporella herpotrichoides in six environments and three growth stages. In a three-factor statistical analysis, the contribution of the different factors to their respective interactions was studied. The genotype × environment interactions exerted a considerable influence which could be reduced by increasing the number of test locations. Environments with a high disease level were less suited to measuring resistance than those environments with a medium level. Estimates of heritability from 0.54 to 0.78 show that successful selection may be possible using ELISA. Significant correlations of quantitative resistance at different environments were only obtained under similar environmental conditions (the same location, the same year) and with P. herpotrichoides populations of similar composition (the same inoculum). The contributions of the individual cultivars to the genotype/ environment interactions were not significantly different, except for ‘Roazon’ and ‘Rendezvous’. Due to high environmental effects in growth stage H5, the determination of quantitative resistance was more reliable in younger stages (65, 75). Nevertheless, the use of the values from that late stage did not reduce the genetic parameters (σ², h₂) if they were combined with the earlier measurements.