Long lasting rubber tree resistance to Microcyclus ulei characterized by reduced conidial emission and absence of teleomorph

The resistance of the MDF 180 Hevea brasiliensis cultivar to South American leaf blight caused by Microcyclus ulei has been studied under both controlled conditions of inoculation, and under natural infestation in the Brazilian state of Bahia. Inoculated isolates on this cultivar in most cases developed sporulating lesions and produced conidiospores, but at a moderate level, characteristic of a race non-specific, partial resistance. The teleomorph of M. ulei has never been reported on this cultivar, either in controlled conditions or in natural infestation, whereas it is commonly observed on other susceptible cultivars. This type of resistance has seldom been described for other pathosystems. MDF 180 resistance having also endured for more than 30 years in areas very conducive to the disease can, therefore, be described as a durable resistance. Rubber productivity of this cultivar is not sufficient to allow planting on industrial scale, but its resistance characteristics make it a good progenitor candidate for rubber tree resistance breeding programs.     

不同花生品种的抗旱性比较鉴定

通过研究花生种子在盛花期与抗旱性密切相关的形态指标与生理指标，对9个不同的花生品种（系）进行了抗旱性鉴定，并用隶属函数法对花生品种的抗旱性进行了综合评价。结果表明，同一花生品种在干旱与正常供水条件下相比较，其株高、单株叶面积、根冠比、比叶重、根茎叶干重及叶绿素含量差异显著，因此，它们可以作为鉴定花生抗旱性的简易指标。不同花生品种的抗旱性有明显差异，并鉴定出高抗旱品种丰花1号，抗旱品种海花1号、农大142、鲁花14号，不抗旱品种农大818、鲁花5号与79266。     

国际马铃薯中心种质资源在内蒙古西部干旱地区的评价

1990～1991年,在内蒙古阴山北部丘陵区干旱条件下,对国际马铃薯中心引入的17份品种资源和7份国内品种进行了抗旱性、适应性评价。紫花白、乌盟851、B71-240·2、晋薯1号和坝薯10号抗旱性强,田间感病轻,并获得较高产量,适应在干旱地区栽培种植;TM-1、G一1、CIP385373·1等品种表现较强的短日照特性,植株生长繁茂,分枝多,块茎产量低,不适应长日照地区种植;CIP24-16、380584·3在干旱条件下表现较好,有待于进一步鉴定其利用价值。     

大豆抗旱性鉴定指标评价的研究

选用10个不同生态类型的大豆品种,采用盆栽播种,分别在正常供水与水分胁迫条件下,测定并分析了花荚期与品种抗旱性有关的多项生理生化指标,并结合大田试验对材料进行抗旱性综合评价.结果表明:株高、单株荚数、单株粒数、单株粒重、分枝数、株重、地上干物重和根干重等生态形态指标及相对电导率、RWC、光合速率、各种保护酶的活性等生理生化指标都可作为抗旱性综合评定的指标性状.生理生化和形态多个指标相结合进行品种的评价和选择是较好的抗旱育种方法.     

2011年杂交晚稻新品种引进对比试验

2011年对引进的3个优质、抗病水稻新品种在晋江市进行丰产性、稳定性、品质及其它重要品种特性的研究与鉴定,筛选出适合该地区大面积推广或示范的优良品种。试验结果表明：玉优一号和D奇宝优5号在同等栽培、气候条件下表现出产量高、抗性强、适应性好、品质较优的特点,在该地区有良好的推广前景。     

反复干旱法在甘蔗抗旱性研究中的应用

选取2个甘蔗品种4种下种方式在反复干旱区和非干旱区进行试验。研究结果表明:非干旱区以双芽种较好,而在反复干旱区经反复干旱法处理后种茎仍有较高的根系活跃吸收面积,萌芽率和出苗率都高,叶片气体交换特性较强的品种或处理,在大田试验中表现出较强的耐旱性,在干旱条件下栽培仍能达到较高的蔗茎产量和糖产量。4种下种方式中以剥叶不砍种处理综合表现最好,桂糖11号耐旱力比新台糖16号强。     

Yield response of rice (Oryza sativa L.) genotypes to drought under rainfed lowlands: 2. Selection of drought resistant genotypes

Drought frequently reduces grain yield of rainfed lowland rice. A series of experiments were conducted in drought-prone northeast Thailand to study the magnitude and consistency of yield responses of diverse, rainfed lowland rice genotypes to drought stress environments and to examine ways to identify genotypes that confer drought resistance. One hundred and twenty-eight genotypes were grown under non-stress and four different types of drought stress conditions. The relationship of genotypic variation in yield under drought conditions to genetic yield potential, flowering time and flowering delay, and to a drought response index (DRI) that removed the effect of potential yield and flowering time on yield under stress was examined.Drought stress that developed prior to flowering generally delayed the time of flowering of genotypes, and the delay in flowering was negatively associated with grain yield, fertile panicle percentage and filled grain percentage. Genotypes with a longer delay in flowering time had extracted more water during the early drought period, and as a consequence, had higher water deficits. They were consistently associated with a larger yield reduction under drought and in one experiment with a smaller DRI. Genotypes, however, responded differently to the different drought stress conditions and there was no consistency in the DRI estimates for the different genotypes across the drought stress experiments. The results indicate that with the use of irrigated-control and drought test environments, genotypes with drought resistance can be identified by using DRI or delay in flowering. However, selections will differ depending on the type of drought condition. The inconsistency of the estimates in DRI and flowering delay across different drought conditions reflects the nature of the large genotype-by-environment interactions observed for grain yield under various types of drought in rainfed lowland conditions.     

花生对根结线虫病抗性温室快速鉴定方法

为了通过对花生抗线虫鉴定方法的比较,确定更加快速有效的抗性鉴定技术,作者于2002～2003年在佐治亚大学的Tifton试验站进行了温室盆栽试验.结果表明侵然期幼虫(2000～4000条/株)与虫卵(8000～16000粒/株)均可以用于花生抗线性鉴定的温室接种,但与使用虫卵接种相比,以侵染期幼虫作为接种体需要多花3～5d的时间收集幼虫;接种后14d,可以依据0～5级的虫瘿分级标准将供试的4份花生种质区分开来;接种后6～10周依据卵块数量或每克根中的虫卵数可以进一步确认花生的抗性水平.虫瘿级数、虫瘿数量、卵块数量及每克根中的卵量之间存在着极显著(P＜0.01)的正相关关系.根据研究结果提出了温室中花生抗线虫鉴定的程序方法以8000粒卵/株为适宜接种量,接种后14d依据0～5级的虫瘿分级标准进行初筛,对初筛入选的材料再在接种后6周根据卵块数量或卵量验证其抗性.     

大豆抗食心虫性的遗传方式及其相关性研究概述

本文总结了大豆抗食心虫性的遗传方式,在一定条件下可能表现为数量性状,也可能表现为质量性状的不连续变异。在适宜的接虫强度下,抗食心虫性的选择可能会比选择其他数量性状更易奏效。同时,对大豆抗食心虫与生育期及其他性状的相关性进行了总结分析。     

亳萝一号品种选育和高产栽培技术

亳萝一号是通过综合考虑抗性、品质、产量等主要农艺性状提纯的新品系,广泛适合在外界条件适宜的情况下进行四季栽培,突破了一般萝卜品种一年只能种植一季的局限.对亳萝一号品种选育过程、栽培特征特性、适宜生产地区和高产栽培技术要点等内容进行介绍,有助于填补蔬菜供应缺口.     

Resistance toErwinia carotovora subsp.atroseptica in second backcross populations of somatic hybrids betweenSolanum tuberosum andS. brevidens

Summary Eleven clones obtained from a cross between cv. Katahdin and fusion products betweenSolanum tuberosum and the non tuber-bearing speciesS. brevidens, were backcrossed again withS. tuberosum (clone AR80-127-5). Small tubers harvested from 583 seedlings of these second backcross (BC2) populations were screened for tuber tissue resistance toErwinia carotovora subsp.atroseptica under aerobic conditions. After multiplication in the field. BC2 clones again were screened for soft rot resistance under aerobic as well as anaerobic conditions. In general, the resistance of the BC2 populations was reduced in comparison with the BC1. Variation for resistance was found within the BC2 populations, but there was no correlation between the results of the three tests performed. Four BC2 populations were also screenned for resistance to blackleg in the field. Significant differences were found between populations for mean percentage of diseased plants, but these differences could not be explained by the resistance of the parental clones.     

Identification of resistance to Uromyces pisi (Pers.) Wint. in Pisum spp. germplasm

A germplasm collection of 2759 pea accessions was screened for resistance against Uromyces pisi (Pers.) Wint. All accessions displayed a compatible interaction (high infection type) both in adult plants under field conditions and in seedlings under growth chamber conditions, but with varying levels of disease reduction. The identified resistance was based on reduction of disease severity with no associated host cell necrosis, which fits the definition of Partial Resistance. No complete resistance or incomplete resistance based on hypersensitivity was observed.     

周8425B衍生品种抗倒伏特性分析

为从遗传和种植密度两个角度探讨黄淮麦区南片骨干亲本周8425B及其后代的抗倒伏特性,以周8425B及其衍生品种共计69份材料为研究对象,采用两种密度处理（225万和450万株·hm^-2）,连续2年分别种植在河南郑州和周口,分析了其抗倒伏相关性状的遗传变异及其与种植密度的关系。结果表明,小麦株高和穗下节长主要受品种控制,茎基部第二节间长主要受品种、品种与环境互作及品种、环境和密度三者互作的影响;茎基部第二节间粗和截面面积主要受环境、品种与环境互作及品种、环境和密度三者互作的影响,其次为品种及品种与密度互作的影响;茎基部第二节间强度和抗倒指数主要受密度及品种与环境互作的影响。聚类分析表明,冠麦1号、理生828、04中36、郑农21、郑麦7698、周8425B和周麦18等品种的抗倒指数在两种密度条件下均显著高于其他品种,可用作抗倒伏亲本。两种密度条件下,茎基部第二节间茎秆强度与抗倒指数呈显著正相关（r分别为0.919和0.894,P值均小于0.001）。这说明,亲本选择对小麦抗倒伏育种非常重要,茎基部第二节间茎秆强度依然是反映茎秆抗倒伏能力的较好指标。     

Development of drought-resistant cultivars using physiomorphological traits in rice

Drought is a major problem for rice grown under rainfed lowland and upland conditions, but progress in breeding to improve drought resistance has been slow. This paper describes patterns of water-stress development in rice fields, reviews genetic variation in physio-morphological traits for drought resistance in rice, and suggests how knowledge of stress physiology can contribute to plant breeding programmes that aim to increase yield in water-limiting environments. To provide a basis for integrating physiological research with plant-breeding objectives we define drought resistance in terms of relative yield of genotypes. Therefore, a drought-resistant genotype will be one which has a higher grain yield than others when all genotypes are exposed to the same level of water stress.A major reason for the slow progress in breeding for drought resistance in rice is the complexity of the drought environment, which often results in the lack of clear identification of the target environment(s). There is a need to identify the relative importance of the three common drought types; early-season drought which often causes delay in transplanting, mild intermittent stress which can have a severe cumulative effect, and late stress which affects particularly late-maturing genotypes. In addition, in rainfed lowland rice, flooded and non-flooded soil conditions may alternate during the growing season, and affect nutrient availability or cause toxicity.Several drought-resistance mechanisms, and putative traits which contribute to them, have been identified for rice; important among these being drought escape via appropriate phenology, root characteristics, specific dehydration avoidance and tolerance mechanisms, and drought recovery. Some of these mechanisms/traits have been shown to confer drought resistance and others show potential to do so in rice. The most important is the appropriate phenology which matches crop growth and development with the water environment. A deep root system, with high root length density at depth is useful in extracting water thoroughly in upland conditions, but does not appear to offer much scope for improving drought resistance in rainfed lowland rice where the development of a hard pan may prevent deep root penetration. Under water-limiting environments, genotypes which maintain the highest leaf water potential generally grow best, but it is not known if genotypic variation in leaf water potential is solely caused by root factors. Osmotic adjustment is promising, because it can potentially counteract the effects of a rapid decline in leaf water potential and there is large genetic variation for this trait. There is genotypic variation in expression of green leaf retention which appears to be a useful character for prolonged droughts, but it is affected by plant size which complicates its use as a selection criterion for drought resistance.There is a general lack of drought related research for rice in rainfed lowland conditions. This needs to be rectified, particularly considering their importance relative to upland conditions in Asian countries. We suggest that focussing physiological-genetic research efforts onto clearly defined, major target environments should provide a basis for increasing the relevance of stress physiology and the efficiency of breeding programmes for development of drought-resistant genotypes.     

杂草稻幼苗期耐旱性的初步筛选与评价

采用盆栽试验,在人工设置干旱胁迫条件下,对不同地区杂草稻幼苗期的耐旱性进行了鉴定。杂草稻具有良好的抗逆能力,本文利用33份杂草稻种质资源,在苗期对其进行抗旱性筛选,调查了幼苗存活率,抗衰度等指标,计算了苗期抗旱性综合系数。结果表明,大部分杂草稻在苗期具有较强抗旱性,为下一步更深入的研究奠定基础。     

When and where a seed mix refuge makes sense for managing insect resistance to Bt plants

Planting of a separate structured refuge for Bt crops as part of an insect resistance management (IRM) strategy to delay resistance evolution is the most common method of refuge deployment but this strategy depends on growers planting a refuge. A seed mix refuge interspersed with a pyramided Bt product is an alternative strategy that addresses the risk of growers not planting a refuge. However, concerns exist regarding how larval movement between Bt and non-Bt plants might influence resistance evolution in a seed mix field. To understand when seed mixes are an appropriate IRM strategy, a deterministic model run probabilistically was used to examine the evolution of Bt resistance in seed mix and structured refuges under varying levels of Bt efficacy, pest fitness, refuge size, larval movement, movement penalty and grower compliance. Results from modeling simulations show that the addition of a second and third Bt toxin can delay resistance evolution longer than a single toxin, making a seed mix refuge strategy a viable option where refuge compliance is a concern. In seed mixes, resistance was shown to evolve faster compared to a responsibly implemented structured refuge and evolved fastest in seed mixes when larval movement rates were high. However, when mortality from larval movement was included in model simulations, the selection pressure from Bt was reduced and two or three Bt-pyramids with a 5% seed mix refuge were at least as durable as the same products with a 5% structured refuge, depending upon refuge compliance. These simulations show that, across a range of conditions, seed mix refugia provide an effective alternative IRM tactic for delaying resistance evolution. Under some conditions use of seed mix refugia may be a superior IRM tactic leading to longer delays to resistance, and greater durability, compared to structured refugia and is a risk adverse tactic in situations when no refuge is planted.     

应用隶属函数法鉴定水稻的抗旱性

采用隶属函数法对25个水稻材料进行了抗旱性综合评价,结果表明:在干旱处理的情况下,短生育期材料生育期缩短,长生育期材料则延长;有效穗、千粒重、株高、每穗实粒数及单株粒重则普遍下降,但抗旱性强的材料降幅较小.依据隶属函数值,筛选出了8份强抗旱材料,可作为水稻抗旱育种的抗旱资源.     

Genetic analysis and validation of quantitative trait loci associated with reproductive-growth traits and grain yield under drought stress in a doubled haploid line population of rice (Oryza sativa L.)

Drought is a major constraint for rice production and yield stability in rainfed ecosystems, especially when it occurs during the reproductive stage. Combined genetic and physiological analysis of reproductive-growth traits and their effects on yield and yield components under drought stress is important for dissecting the biological bases of drought resistance and for rice yield improvement in water-limited environments. A subset of a doubled haploid (DH) line population of CT9993-5-10-1-M/IR62266-42-6-2 was evaluated for variation in plant water status, phenology, reproductive-growth traits, yield and yield components under reproductive-stage drought stress and irrigated (non-stress) conditions in the field. Since this DH line population was previously used in extensive quantitative trait loci (QTLs) mapping of various drought resistance component traits, we aimed at identifying QTLs for specific reproductive-growth and yield traits and also to validate the consensus QTLs identified earlier in these DH lines using meta-analysis. DH lines showed significant variation for plant water status, reproductive-growth traits, yield and yield components under drought stress. Total dry matter, number of panicles per plant, harvest index, panicle harvest index, panicle fertility, pollen fertility, spikelet fertility and hundred grain weight had significant positive correlations with grain yield under drought stress. A total of 46 QTLs were identified for the various traits under stress and non-stress conditions with phenotypic effect ranging from 9.5 to 35.6% in this study. QTLs for panicle exsertion, peduncle length and pollen fertility, identified for the first time in this study, could be useful in marker-assisted breeding (MAB) for drought resistance in rice. A total of 97 QTLs linked to plant growth, phenology, reproductive-growth traits, yield and its components under non-stress and drought stress, identified in this study as well as from earlier published information, were subjected to meta-analysis. Meta-analysis identified 23 MQTLs linked to plant phenology and production traits under stress conditions. Among them, four MQTLs viz., 1.3 for plant height, 3.1 for days to flowering, 8.1 for days to flowering or delay in flowering and 9.1 for days to flowering are true QTLs. Consensus QTLs for reproductive-growth traits and grain yield under drought stress have been identified on chromosomes 1 and 9 using meta-QTL analysis in these DH lines. These MQTLs associated with reproductive-growth, grain yield and its component traits under drought stress could be useful targets for drought resistance improvement in rice through MAB and/or map-based positional analysis of candidate genes.     

8份强筋小麦品种抗旱性评价

为给强筋冬小麦品种的抗旱性评价和抗旱指标筛选提供理论依据,以黄淮麦区种植的8个强筋小麦品种为材料,在水培条件下设置正常供水(对照)和20%聚乙二醇(PEG-6000)模拟干旱胁迫两个处理,测定了萌发期11个抗旱相关指标、幼苗期20个抗旱相关指标,计算各指标的抗旱系数,采用主成分分析法和隶属函数法求得综合抗旱能力评价值(D值),基于D值评价萌发期和幼苗期抗旱性;在旱棚池栽条件下,测定了2种水分处理下(适时一次灌溉、雨养)籽粒产量,基于产量抗旱系数评价全生育期抗旱性。结果表明：(1)干旱处理下,8个小麦品种萌发期发芽势、发芽率等10个抗旱指标显著低于对照,根冠比显著高于对照;幼苗期叶片净光合速率、气孔导度等13个抗旱指标不同程度地低于对照,胞间CO₂浓度、SOD活性等7个抗旱指标显著高于对照。(2)与适时一次灌溉相比,雨养条件下小麦籽粒产量显著降低,降幅18.70%～28.66%,产量抗旱系数为0.713～0.813。(3)8个强筋小麦品种在萌发期和幼苗期抗旱等级不尽相同。藁8901在2个生育时期均表现出抗旱性;科大1026、郑麦7698和丰德存麦5号在幼苗期表现出抗...     

覆膜滴灌条件下灌溉量和种植密度对玉米茎秆抗倒能力的影响

设置两年灌溉量和种植密度互作试验,研究不同密度下,随灌溉量增加,玉米茎秆抗折断力、植株高度、基部节间形态及机械强度等的变化趋势,明确覆膜滴灌条件下灌溉量对密植玉米茎秆抗倒伏能力的影响.结果表明,随密度增加,茎秆抗倒能力呈下降趋势.不同密度下,滴灌量变化对茎秆抗倒能力的影响不完全一致.密植条件下,适当增加灌量(480～5...