水、旱条件下稻米品质相关性状的QTL定位及其与环境互作分析

为探究干旱胁迫环境条件下水稻(Oryza sativa)碾米品质和外观品质相关性状的变化规律,挖掘干旱条件下稳定存在的控制稻米品质性状的QTL,同时分析QTL与环境的互作效应,本研究以陆稻小白粳子和水稻空育131杂交构建的207个重组自交系(recombinant inbred line,RIL)群体及2个亲本为实验材料,在干旱胁迫和正常灌溉2个环境条件下进行重复实验,对糙米率(brown rice rate,BRR)、精米率(milled rice rate,MRR)、整精米率(head rice rate,HMRR)及垩白粒率(chalky rice rate,CG)4个品质性状进行QTL定位.结果表明,在2个环境下BRR、MRR、HMRR三者之间均呈极显著正相关,MRR、HMRR与CG分别呈显著和极显著负相关.各性状在2个环境下均呈现出连续分布,表现为数量性状的遗传特点.4个性状两年共检测到24个加性QTL和9对上位性互作QTL,分布于除第10和第12染色体的其余10条染色体上.在所有检测结果当中,5个加性QTL(qBRR1a,qMRR11a,qHMRR6a,qCG6a和qCG6c)均在2年干旱胁迫环境下同时检测到,3个加性QTL和4对上位性互作QTL检测到显著的环境互作效应,但各性状均以加性遗传效应为主,受水分环境影响较小.对干旱胁迫具有特异性QTL的挖掘和发现,在一定程度上为干旱胁迫下稻米品质的遗传改良提供了基础资料.     

水稻苗期耐高Cu2+胁迫的QTL定位和上位性分析

用珍汕97B/密阳46构建RIL群体及其遗传图谱,对其种子采用沙培法育苗和培养,试验设置2个高浓度(100.mg/L和200.mg/L)Cu2+胁迫处理,以处理20.d后的幼苗相对根长(%)和相对苗高(%)作为苗期耐Cu2+胁迫指标,并用于QTL定位分析。结果表明,试验共检测到苗期耐Cu2+胁迫的主效应QTL.4个,以相对根长为指标,检测到qRCC(r)6(100.mg/L)和qRCC(r)9(200.mg/L),以相对苗高为指标,也检测到qRCC(s)1-2(100.mg/L和200mg/L)和qRCC(r)6-1(200.mg/L),有效基因分散于双亲中。试验还检测到苗期耐Cu2+胁迫的上位性互作8对,以相对根长为指标时,检测到2对互作;以相对苗高为指标时,检测到6对上位性互作。表明水稻苗期耐高浓度Cu2+胁迫,其上位性互作也起到较为重要作用。     

不同营养水平水培条件下幼苗期大豆下胚轴性状QTL定位与上位互作分析

为探究不同氮磷钾水平对大豆幼苗期下胚轴性状的影响,发掘其基因资源,了解其遗传机制,本试验以栽培大豆晋豆23为母本,以山西农家品种灰布支黑豆为父本及其所衍生的447个重组自交系(RIL)为材料,设置3个处理:CK(模拟种植不施肥)、T1(模拟大田正常配施氮磷钾肥)和T2(模拟高肥田块,含量为大田常规配施氮磷钾肥的1.5倍),研究不同营养水平水培条件下幼苗期大豆QTL间的上位性和环境互作效应。结果表明,基于复合区间作图(CIM)共检测到20个影响下胚轴长和下胚轴重的QTL,分布于第2、第6、第7、第8、第9、第10、第13、第16、第20共9条染色体上,单个QTL的贡献率介于3.65%~18.13%之间。基于混合线性模型(MCIM)检测到3对下胚轴长上位互作QTL,2对下胚轴重上位互作QTL,5对QTL均发生在2个非主效QTL之间。第9和第10染色体分别在3种处理中同时检测到下胚轴长和下胚轴重QTL,表明加性效应、加性与环境互作效应和加性×加性上位性互作效应在下胚轴长和下胚轴重的形成和遗传中起重要作用。本研究为大豆幼苗期下胚轴性状的QTL定位、图位克隆和分子标记辅助选择以及为实际生产中苗期施肥时间的选择和氮磷钾高效利用提供了一定的理论参考。     

小麦株高发育动态QTL定位及其与水分环境互作遗传分析

株高是影响小麦产量的重要农艺性状,对生境水分极为敏感。为探讨小麦不同发育时期株高数量性状遗传与水分环境互作,本研究利用抗旱性强的冬小麦(Triticum aestivum L.)品种陇鉴19与水地高产品种Q9086杂交,重组近交系(RIL)群体120个株系为供试材料,测定两试验环境(甘肃镇远和兰州)雨养(干旱胁迫,DS)和灌溉条件下不同发育时期株高,采用条件复合区间作图法进行株高发育动态数量遗传位点(quantitative trait loci,QTL)分析。共检测到26个条件加性QTL(A-QTL)和56对上位性QTL(AA-QTL)。在A-QTL中,Qph.acs-1A-1、Qph.acs-4B-2、Qph.acs-5A-1、Qph.acs-5D-1、Qph.acs-6B-2和Qph.acs-7D-1在开花期前能重复表达,且有相对较高的贡献率(H2(A))(7.39%~31.04%)。AA-QTL主要由非显著加性效应的位点间互作形成,贡献率(H2(AA))在1.38~24.27%之间,这些AA-QTL效应对后期株高有显著影响。有61.54%的A-QTL和58.93%的AA-QTL分别参与了水分环境互作,在雨养条件下普遍具有降低株高的效应。条件A-QTL的加性效应在拔节期最大,随后逐渐降低,更多的体现出上位性效应。说明控制小麦株高发育的数量性状基因易与水分环境发生互作,且在小麦不同发育阶段有不同的时空表达模式。本研究结果可为小麦抗旱遗传研究与分子改良提供基础资料。     

基于三重测交群体解析玉米株高与穗位高杂种优势QTL

为检测玉米株高、穗位高杂种优势QTL,以121株intermated B73×Mo17(IBM)个体为基础群体,按照三重测交交配设计构建了三重测交群体,通过完备区间作图法对株高、穗位高杂种优势的主效QTL及互作位点进行了分析。在第9染色体上的2个紧密连锁的区段分别定位到了一个株高、穗位高杂种优势加性QTL位点,单个QTL的表型贡献率为14.3%和18.6%。该QTL可能同时对株高、穗位高杂种优势起作用。在第1、第3染色体上检测到2个株高杂种优势超显性QTL,可解释表型变异的9.0%~11.4%;在第1、第6、第8染色体上检测到5个穗位高杂种优势超显性QTL,可解释表型变异的6.6%~16.8%。进一步分析发现,2对加加上位性互作区段及2对显显上位性互作区段对穗位高杂种优势存在上位性贡献,加加互作效应及显显互作效应可共同解释表型变异的40.7%和26.8%。由此可知,加性、显性及两位点互作上位性共同对株高、穗位高杂种优势存在贡献。本研究检测到的主效QTL位点有助于株高、穗位高在杂种优势育种中的进一步应用。     

利用三重测交群体剖析玉米苗期性状杂种优势的遗传学基础

为了探讨玉米苗期性状及其杂种优势形成的遗传学基础,以强优势玉米(Zea maysL.)杂交种组合豫玉22及其重组近交系为基础材料,采用三重测交(triple testcross,TTC)遗传交配设计,组配了包含312个测交后代的TTC群体,通过复合区间作图法检测到了30个控制发芽后第4天的最长根长、苗高、初生根数、根干重及叶干重的QTLs,并且在第2、3和7染色体上存在4个同时控制不同苗期性状的QTL区域。分析发现,在利用Z1和Z2数据定位出的22个QTLs中,以超显性位点最多(11个),加性(5个)和部分显性较少(5个),而显性最少(1个)。另外,还检测到8个QTLs与遗传背景之间的互作和16对不同标记间的互作。据此,我们提出超显性和上位性是玉米苗期性状及其杂种优势形成的主要遗传学基础。关键词玉米,苗期性状,三重测交,杂种优势,QTL定位     

利用旱稻导入系定位水、旱田外观品质的QTL及土壤水分效应分析

以271份具有优质水稻(Oryza sativa L.)越富遗传背景及旱稻IRAT109导入片段的导入系群体为材料,在北京、海南两地水、旱田环境下调查精米粒长、粒宽、粒厚、长宽比和垩白率5个性状,研究旱田栽培对外观品质的影响,进行QTL定位及QTL与水分环境的互作分析.结果表明,粒长、粒宽、长宽比和垩白率易受土壤水分的影响,粒厚比较稳定.水分胁迫使稻米粒长、粒宽变小,长宽比增大,垩白率减少.利用QTLNetwork软件,5个性状共检测到30个加性QTL和4对上位性QTL.6个加性QTL(qGL7、qGT2、qGT4、qLWR2、qC2和qC8)和2对上位QTL(qGL3-qGL7和qGL7-qGL10)的贡献率大于10%.21个QTL与前人研究结果相一致.外观品质性状QTL在染色体上多呈成簇分布,第2染色体RM492～RM1211、第3染色体RM6832～RM3166和第6染色体RM587-RM1163区段是外观品质QTL相对集中分布区域.41%的QTL存在水分环境互作.根据不同性状对干旱胁迫的反应特点,选择水、旱田贡献率大且稳定的QTL,或具有旱田特异性的QTL,进行标记辅助聚合育种是培育抗旱、优质稻的一个有效途径.     

稻米外观和碾磨品质QTL定位及其与土壤水分环境互作分析

本文利用旱稻品种IRAT109和水稻品种越富的花培DH群体的116个株系为作图群体，采用混合线性模型QTL定位方法，在水、旱2个土壤水分环境下对粒长(GL)、粒宽(GB)、长宽比(LWR)和垩白率(C)4项外观品质性状和糙米率(BR)、精米率(MR)、整精米率(HR)3项碾磨品质性状进行QTL定位及QTL与环境互作分析。在水、旱2种条件下对DH群体差异显著性分析结果表明，糙米率、精米率和长宽比差异不显著,而整精米率、粒长、粒宽、垩白率差异极显著。外观品质性状在水、旱栽培条件下变化较大，即在旱种环境下稻米粒形变小（粒长、粒宽减小）、变细（长宽比增大）垩白率大幅度下降。碾磨品质性状在双亲间均有差异，其中整精米率差异较大；且在两种土壤水分环境条件下均有变化，即在旱栽条件下两亲本的糙米率和精米率均降低，IRAT109分别减少了5.8%和5.5%，越富分别减少了11.7%和11.5%。共检测到11个加性效应QTL与稻米外观和碾磨品质性状7项指标有关，分别位于第1、3、5、6、7、10、11染色体上，单个QTL对性状的贡献率在3.15～21.42%之间，位于第1、7 染色体上2个控制整精米率的QTL存在显著环境互作，单个QTL与环境互作效应的贡献率分别为9.59%和13.58%。在第1染色体RM295标记附近同时检测到5个QTL，Qgc1a 、Qgc1b 、Qlwr1、QMr1b和QHr1，分别控制粒长、长宽比、精米率和整精米率，且该QTLs簇在2个环境下能稳定地被检测到。同时，还检测到10对上位性QTLs，所有上位性QTL都发生在不同染色体之间，其中，控制整精米率的4对QTL与土壤水分环境显著互作，其环境互作贡献率分别为14.29%、12.28%、10.56%和13.47%。控制粒长、粒宽、长宽比的6个加性QTL（Qgc1a、Qgc1b、Qgc5、Qgw6、Qlwr1、Qlwr10）与环境之间互作较小，在品质育种中可利用分子标记对其进行辅助选择，提高育种效率；而对于基因型×环境互作效应大的整精米率、垩白率应在特定环境(如土壤缺水条件)下进行选择，在特定水分胁迫条件选择目标亲本，并将抗旱基因导入该亲本方可选到品质较优的抗旱品种。     

水稻分蘖最大角度的QTL分析

利用籼稻(Oryza sativa sp indica)协青早B/密阳46所构建的重组自交系(RIL)群体(XM-RIL)及其相应分子遗传图谱,在海南和杭州两地试验,测量分蘖最大角度,应用检测QTL加性效应、上位性效应和G×E互作效应遗传分析方法,对该性状2个环境下数据进行联合分析.共检测到2个加性效应显著的QTLs,其中,qTA8-2的LOD值为21.7,贡献率为23.2%;qTA9-2的LOD值为22.0,贡献率为19.5%;增加分蘖最大角度的基因前者来自母本、后者则来自父本;这2个QTLs均不存在显著的G×E互作.试验还检测到3对显著的加性×加性双基因互作效应,它们与环境间的G×E互作也均未达显著水平,对该性状表型变异的总贡献率仅为7.69%,显得较为次要.     

UV-B辐射增强下水稻苗期硅营养性状的QTL定位及其与环境互作效应分析

以"Lemont"和"Dular"杂交建立的包含123个家系的水稻重组自交系(RILs)群体为材料,选用水稻根系硅吸收能力和叶片硅利用率为指标,进行水稻硅营养遗传性状QTL定位,并分析其与UV-B辐射增强的互作效应。结果表明,控制水稻叶片硅利用率的4个加性QTL分别在第2、3、10染色体上,而控制根系硅吸收能力的1个加性QTL位于第11染色体上。QTL与UV-B辐射互作分析发现2对控制根系硅吸收能力和3对控制叶片硅利用率的基因×环境上位性QTL,其中只有1对控制根系硅吸收能力的QTL效应值较大。说明水稻这两种硅营养性状中,根系硅吸收能力较叶片硅利用率受UV-B辐射影响大,在抗UV-B辐射育种中以叶片硅利用率为水稻硅营养遗传选择的指标具有较高效率。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.