干旱胁迫下不同中间砧对苹果苗生理特性及MdPIP1-1基因表达的影响

为探讨不同中间砧对‘天红2号’红富士苹果苗抗旱性的影响，以2 a生‘天红2号/黄6/平邑甜茶’、‘天红2号/SH40/平邑甜茶’、‘天红2号/GM256/平邑甜茶’盆栽苗为试材，研究了干旱胁迫下不同中间砧对苹果苗旱害指数、相关生理指标及水通道蛋白基因MdPIP1-1相对表达量的影响。结果表明，随着干旱胁迫时间延长，土壤含水量降低，3种中间砧苗旱害指数、O^-₂产生速率升高，F_v/F_m值降低，SOD、POD活性呈现先升高再降低的趋势，但3个砧穗组合各指标的变化幅度不同。干旱9 d时3个砧穗组合以‘天红2号/GM256/平邑甜茶’的旱害指数最高，为91.67%，其F_v/F_m值与正常供水相比显著下降11.47%；‘天红2号/黄6/平邑甜茶’旱害指数仅为29.55%，F_v/F_m值下降幅度最小。干旱胁迫期间，3种中间砧苗的MdPIP1-1基因表达量均呈现先升高再降低的趋势，黄6中间砧苗的表达量峰值出现在第7 d，GM256和SH40中间砧苗出现在第5 d。综合认为，3个砧穗组合抗旱性强弱依次为‘天红2号/黄6/平邑甜茶’＞‘天红2号/SH40/平邑甜茶’＞‘天红2号/ GM256/平邑甜茶’。     

小麦条锈病不同病级损失率测定及其应用

测定了小麦条锈病不同病级所造成的小麦产量损失率 ,探讨了损失率以及田间产量损失程度的简便测算方法。小麦条锈病病级与小麦穗粒数、千粒重、穗重关系密切 ,其回归方程式分别为:Y₁=62.29-3.11X±1.16(r=-0.9920);Y₂=44.79-2.74X±1.98(r=-0.9708);Y₃=2.68-0.235X±0.08(r=0.9937)。小麦中后期功能叶受害损失较大 ,最终集中表现在穗重降低上 ,损失率回归方程为:Y₃′=9.27X-5.76±3.07(r=0.9937)。上穗危害损失率回归方程为:YY₃ ′=3.00X+0.64±0.58(r=0.9958) ,经测验相关系数均为极显著。中后期叶片受害病级 1级时损失率为3.5% ,以后每增加1个级别穗重降低0.235g ,损失率增加9.27% ;上穗危害穗部病级增加 1级穗重降低0.1g ,损失率增加3%     

马铃薯气孔密度表皮模式因子StSTOMAGEN的克隆和功能分析

为了研究马铃薯EPFL9/StSTOMAGEN基因在气孔发育过程中的功能,从马铃薯品种大西洋中克隆得到气孔密度表皮模式因子StSTOMAGEN,将其通过农杆菌介导的遗传转化方法,在拟南芥中异位表达,对该基因的表达特性及功能进行分析。结果显示：StSTOMAGEN主要定位于细胞间隙和细胞核,并且它在顶端未展开叶中表达最多,表达量在1 d中呈现周期性变化,长日照条件下（16 h/8 h,光/暗）,在授时因子为20 h时表达量最高;聚乙二醇（PEG）模拟干旱胁迫处理4 h后其表达量达到最高,而脱落酸（ABA）和NaCl胁迫处理后,其表达水平呈现出持续降低的趋势。功能鉴定表明,过表达StSTOMAGEN基因的拟南芥（ST）相对于野生型（WT）气孔密度增大63%~83%,光合速率增大36%~42%。此外,ST植株离体叶片的水分散失速率增大24%~55%,离体叶片H₂O₂含量也显著升高,约为野生型的50%~100%。干旱胁迫下,ST株系的光合速率、F_v/F_m和瞬时水分利用效率都显著低于野生型,其中光合速率降低55%~66%,F_v/F_m降低22%~50%,瞬时水分利用效率降低11%~12%。综上结果可知,表皮模式因子StSTOMAGEN通过正调控气孔密度而降低植物的抗旱性,该结果为后期通过基因编辑技术降低StSTOMAGEN基因的表达,培育抗旱节水型马铃薯新品种奠定理论基础。     

不同水肥管理模式下糯玉米水氮利用及熵权TOPSIS综合评价

为探究施肥与灌水方式对糯玉米各生育期株高、叶面积指数、产量品质及水氮利用率的影响,以晋糯41号为材料进行田间试验,设置I₀（播种期75%θ_f~85%θ_f,苗期~拔节前期65%θ_f~75%θ_f,拔节后期~孕穗期70%θ_f~80%θ_f,孕穗期~开花期70%θ_f~80%θ_f）、I₁（播种期75%θ_f~85%θ_f,拔节后期~孕穗期75%θ_f~85%θ_f）2种灌水方式,F₀（N、P、K肥全部基施）、F₁（N、K肥基施30%+拔节期30%追施+大喇叭口期追施40%,P肥全部基施）和F₂（N、K肥基施30%+大喇叭口期追施70%,P肥全部基施）3种施肥方式。结果表明：不同施肥水平F₁、F₂相比F₀可增加株高2.86%~4.29%,增加叶面积指数6.47%~11.61%,增加鲜穗产量0.63%~8.42%,提高水分利用效率6.41%~21.34%,提高灌溉水利用率1.94%~21.88%,提高氮肥农学效率10.02%~19.80%,I₁水平效果更加显著,I₀相比I₁在F₀、F₁、F₂施肥方式下分别可增加鲜穗产量13.57%、5.54%、8.59%,增加籽粒产量16.14%、2.77%、6.49%,I₁水平相比I₀水平可减少灌水量29.55%、37.02%、25.20%,减少土壤耗水量20.82%、22.01%、13.44%,增加灌溉水利用率11.50%、33.31%、17.57%,增加水分利用效率4.09%、18.69%、6.51%。研究表明F₁I₀处理为最优水肥管理方案。     

施氮水平和干旱锻炼后复水程度对小麦水分利用效率的影响

以‘XR4347’冬小麦品种为供试作物,在温室内开展盆栽试验。设置低氮（N0.5,74 mg ·kg^-1）,中氮（N1.5,223 mg·kg^-1）和高氮（N3,446 mg·kg^-1）3个氮素水平,各氮素水平下设置3种水分处理,分别为W85:干旱锻炼（40%土壤持水量（SWHC））后复水至85% SWHC;W60:干旱锻炼后复水至60% SWHC;W40:干旱锻炼后复旱至40% SWHC,研究氮素水平及干旱锻炼后复水程度对小麦生理特性及水分利用效率的影响。结果表明：干旱锻炼后复水能够改善植株水分状况,但中氮和低氮处理时,复水程度过高降低小麦根水势（RWP）。叶片气孔导度（g_s）受水力信号和脱落酸（ABA）信号的调控,叶片内在水分利用效率（WUE_int）与g_s呈显著负相关关系,因此降低复水程度或增施氮肥通过调控g_s提高WUE_int。干旱锻炼后复水程度高增加小麦叶面积（LA）、地上部干物质量（SDB）和植株耗水量（PWU）,促进氮素吸收,但降低根系生长。与复水程度相比,氮素水平对植株水分利用效率（WUE_p）的影响更显著,高氮处理在保证SDB积累的同时使PWU降低9.1%,WUE_p提高10.1%。植株叶片的碳同位素组成（δ¹³C）随着氮素水平的提高而增加,WUE_p与叶片δ¹³C呈显著正相关关系,表明叶片δ¹³C可以用来表征干旱锻炼条件下WUE_p的高低,增施氮肥通过增强叶片的光合能力或优化调控叶片的气孔开度提高WUE_p。在所有处理中,N3W85和N3W60处理在保证SDB积累的同时提高WUE_p,但N3W60处理的PWU显著降低10.4%且根冠比较高,相比之下更有利于小麦植株的生长且节约灌溉用水,为本试验的最优处理。因此,在干旱缺水地区,增加施氮量或干旱锻炼后适当复水,不仅可以显著降低PWU、节约灌溉用水、维持作物生长和养分吸收,还可以提高叶片和植株的WUE。     

低温胁迫下转ICE1基因水稻养分变化的研究

采用盆栽试验,选用转ICE1基因水稻T_4-8株系和T_4-9株系及未转基因水稻（Oryza sativa L.）品种垦鉴稻10号为试验材料,研究苗期低温胁迫对转基因水稻氮、磷、钾养分吸收的影响。结果表明,低温胁迫期间,转基因水稻幼苗丙二醛含量维持在较低水平,SOD活性维持在较高水平;地上部分氮、磷、钾含量变化不大,一直维持在较高水平;地下部分氮、磷、钾含量呈缓慢下降趋势,但降幅比非转基因水稻小,在胁迫第10天,T_4-8株系和T_4-9株系氮含量均高出对照13.86%,磷含量分别高出42.31%和50.00%,钾含量均高出85.71%。说明在低温胁迫条件下,ICE1基因过量表达可以增强水稻的抗寒性,减轻低温对水稻的伤害,保持根系较强的吸收养分能力。     

小麦品种C591的抗条锈性遗传分析

C591是原产于印度的普通小麦品种,苗期和成株期均对中国小麦生产上流行的条锈菌(Puccinia striiformis f.sp.tritici)主要生理小种表现良好抗性。本文以感病品种Taichung29作母本、C591作父本通过杂交制备了F₁代、F₂代和BC₁代种子,用人工接种方法研究了C591及其杂交后代对小麦条锈菌不同生理小种的苗期抗性并进行了遗传分析。结果显示,C591与Taichung29杂交F₁代植株对小麦条锈菌条中19号、条中29号和条中32号小种均表现出与C591相似的高抗,说明C591中的抗条锈基因主要为显性表达。根据杂交F₂代、BC₁代植株的抗性分离情况和F1代植株及亲本的抗性表现,说明C591中至少具有3对抗条锈基因,针对条锈菌不同的生理小种其有效性是不同的。对条中32号小种的抗性受1对显性基因控制,对条中29号小种的抗性受1对显性基因和2对隐性基因的独立控制,对条中19号小种的抗性受2对显性基因独立控制。结果表明,C591作为抗源在我国小麦抗锈育种中具有较大应用价值。     

苹果MdGH3-2/12在盐胁迫下的功能分析

于2020年5月—2021年2月以苹果野生型WT植株和MdGH3-2/12的RNA干扰转基因植株（RNAi）为材料，采用水培试验方法测定了盐胁迫条件下苹果植株的表型、生长量、光合参数、叶绿素含量、抗氧化酶及活性氧（ROS）含量变化，初步解析了MdGH3-2/12在苹果响应盐胁迫中的功能。研究结果表明：（1）与WT植株相比，RNAi植株叶表面出现更多的褐斑和坏死，且根系活力显著降低，其3个株系（GR-1,GR-9,GR-10）根系活力分别为WT植株的93.8%、77.5%和90.0%；植株的生长和光合作用受到更大影响，P_n、C_i和G_s都显著降低，其中P_n值分别下降至WT植株的62.9%、77.41%和83.6%。最大光化学效率（F_v/F_m）也显著下降，3个株系分别为WT植株的97.0%、96.4%和97.5%；叶绿素含量分别显著下降至WT植株的90.7%、86.2%和81.9%，MDA含量分别为WT植株的1.15、1.25倍和1.16倍；REL含量分别为WT植株的1.23、1.39倍和1.48倍；叶片气孔开度在盐胁迫下也分别缩小了35.0%、39.0%、55.0%和46.2%。（2）与WT植株相比，RNAi植株株系体内Pro含量显著增加，3个株系分别为WT植株的7.1、10.3倍和6.3倍；叶片中ROS积累显著高于WT植株，H₂O₂含量分别为WT植株的1.6、1.8倍和1.8倍，而抗氧化酶活性显著下降，各材料（WT,GR-1,GR-9,GR-10）盐胁迫组的SOD酶活性分别为对照组的2.4、1.2、1.7倍和1.9倍，这表明与WT植株相比，盐胁迫下RNAi植株各株系不能有效清除ROS，对植株造成了更大伤害。（3）盐胁迫后各材料植株的Na⁺/K⁺比值分别为0.497、0.558、0.525和0.577，RNAi植株株系显著高于WT植株，但是相关离子转运基因的表达量显著低于WT植株，致使Na⁺不能及时外排，植株受到钠离子毒害，从而导致其耐盐性降低。以上结果表明，MdGH3-2/12在苹果植株应对盐胁迫方面发挥着重要的作用，将MdGH3-2/12[STBZ]基因干扰后苹果植株在盐胁迫下受到的伤害更大，植株对盐胁迫的抗性下降。     

转ATCIPK23基因烟草植株钾素营养效率研究

通过考察转ATCIPK23基因烟草植株在不同钾浓度下钾及干物质积累的能力，研究了外源基因的导入对转基因烟草植株钾吸收能力的影响。结果表明，在低钾环境下，转基因株系具有明显的生长优势，烟株发育较快、根系发达、生物量较大、植株的含钾率也有明显提高，随着供钾量的减少，这种差异幅度逐渐增大。当供钾浓度为0.1 mmol·L^-1时，对照品种K326植株的平均钾含量为17.7 g·kg^-1，而转基因品系KA12为23.3 g·kg^-1，KA16为24.6 g·kg^-1，KA21为22.1 g·kg^-1，分别较对照品种增加了31.6%、39.0%和27.7%。钾吸收动力学研究表明，转基因植株与对照品种植株的最大吸收效率（V_max）差别不大，而最低浓度（C_min）与米氏常数（K_M）的差别较为明显。     

基于基因混池测序技术的小麦条锈菌对三唑酮抗性位点相关分析

为探究小麦条锈菌Puccinia striiformis f. sp. tritici对三唑类杀菌剂产生抗药性的相关机理,以小麦条锈菌抗药性菌株YQ324与敏感性菌株贵1-2在转主寄主堆花小檗Berberis aggregata上构建的有性遗传群体为材料,通过离体叶段法对F₁代杂交及F₂代自交后代的夏孢子群体进行三唑酮敏感性生物学测定,并在F₂代夏孢子群体中筛选20株抗药性菌株和20株敏感性菌株分别构建DNA抗、感池。在对抗、感混池进行高通量测序之后,通过质量检测和数据分析得到2个极端混池中的变异信息。根据ΔIndex为1的筛选标准在小麦条锈菌中鉴定出67个与三唑酮抗性显著相关的单核苷酸多态性（single nucleotide polymorphism,SNP）位点;利用SNPEff软件对这些SNP位点引起氨基酸非同义突变所在的基因序列进行功能注释,最终在pcontig_030上筛选到Pst104E_09436和Pst104E_09437这2个基因作为小麦条锈菌对三唑酮抗性相关的候选基因。     

An avirulence gene to rice cultivar K60 is located on the 1.6-Mb chromosome in <Emphasis Type="Italic">Magnaporthe oryzae</Emphasis> isolate 84R-62B

A Japanese differential rice cultivar K60 was tested with 114 F₁ cultures of Magnaporthe oryzae from a cross between isolates 84R-62B and Y93-245c-2. Segregation patterns of avirulence and virulence in the progeny suggested that avirulence on cv. K60 was controlled by a single gene derived from 84R-62B and tentatively named AvrK60. In the F₁ population, AvrK60 cosegregated with avirulence gene AvrPik on a small 1.6-Mb chromosome of 84R-62B and with the 1.6-Mb chromosome itself. Therefore, we suggest that, along with AvrPik, AvrK60 is also located on the 1.6-Mb chromosome of 84R-62B.     

冬小麦田大穗看麦娘种群动态及对小麦产量的影响

为明确麦田杂草大穗看麦娘Alopecurus myosuroides的田间种群发生动态规律,采用固定样方和随机样方取样方法于2013—2015年在山东省济南市研究了冬小麦田大穗看麦娘田间种群的萌发和生长动态,并分析了不同密度大穗看麦娘对小麦产量及其构成因素的影响。结果表明:在济南市小麦播后20~40 d为大穗看麦娘出苗高峰期,至11月下旬出苗量占全年出苗总量的97.1%。11月上旬,大穗看麦娘开始出现分蘖,至翌年4月上中旬结束,分蘖数平均每株为6.3个,比小麦多3.1个。3月下旬大穗看麦娘开始拔节,4月中旬平均株高超过小麦,5月下旬平均株高达到75.6 cm,高出小麦2.5 cm。5月上旬大穗看麦娘单茎平均鲜重达到最大为1.7 g,小麦为12.6 g。大穗看麦娘出苗、株高、分蘖和鲜重的变化与小麦变化趋势一致,与时间、温度密切相关。随着大穗看麦娘密度的增加,小麦产量急剧下降,当密度达到420株/m~2时,小麦产量损失率高达65.8%。大穗看麦娘对小麦产量构成因素中的穗密度影响最大,其次是穗粒数,对千粒重影响不显著,当密度为420株/m~2时,小麦穗密度减少55.2%,穗粒数减少26.4%。     

Ability of aLeptosphaeria maculans isolate to form stem cankers on Indian mustard (Brassica juncea) segregates as a single locus

Australian isolates of the blackleg fungusLeptosphaeria maculans, that form cankers on two Indian mustard (Brassica juncea) varieties (Stoke and Zaria) are described. This ability to form cankers on var. Stoke segregates as a single locus in both F₁ and backcross progeny from a cross between twoL. maculans isolates.     

Elucidating resistance in cotton genotypes to whitefly, <Emphasis Type="Italic">Bemisia tabaci,</Emphasis> by population buildup studies

Plant resistance has become an important component of integrated pest management (IPM) for management of whitefly, Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), an important pest of cotton in India. The present studies were undertaken to standardize the plant stage and identify resistant cotton genotypes against whitefly. Nine plant stages of F846, a susceptible cotton genotype, were exposed to whitefly for 25 days under no-choice conditions. The population buildup (eggs, nymphs, pupae and adults) was recorded. The 12-, 14- and 16-leaf stages were suitable for plant resistance studies against whitefly, and the 14-leaf stage was taken for further studies. Ten cotton genotypes of Gossypium hirsutum and two of G. arboreum were covered with split cages in which five pairs of B. tabaci (F₁) were released. The population buildup was recorded to categorize genotypes as resistant, moderately resistant, moderately susceptible or susceptible. The experiment was repeated with F₂ and F₃ generation whiteflies. Based on overall average score of three experiments, LD694 was rated as resistant; LK861, Supriya, RS2013, CNH911 and PA183 as moderately resistant; IS-376/4/1/20/72, NHH44, TxMaroon2-78, Bt 6304 and RS2098 as moderately susceptible; and F846 as susceptible. LD694 was found to be resistant in three consecutive generations of whitefly.     

亚致死浓度阿维菌素对荔枝叶螨种群发育的影响

于室内条件下研究了亚致死浓度阿维菌素对荔枝叶螨种群发育的影响。采用Potter喷雾法测得阿维菌素对荔枝叶螨成螨的亚致死浓度（LC10和LC30）,并通过生命表方法研究了阿维菌素LC10和LC30浓度处理荔枝叶螨对其生长和繁殖的影响。结果表明:用阿维菌素LC10和LC30浓度处理荔枝叶螨后,与对照相比,其F0代产卵量分别减少79.16%和71.83%,雌成螨寿命亦均明显缩短。F1代幼螨期、产卵前期与对照相比均无显著差异,但卵孵化期、前若螨期、后若螨期均显著延长,其中LC30浓度处理后分别延长41.4%、39.4%和36.1%;F1代产卵量降低、产卵期缩短,其子代雌性比提高;F1代内禀增长率均降低,分别为0.127 3和0.075 8,而对照为0.132 3;世代平均历期缩短,种群倍增时间延长;净生殖率和周限增长率均降低。表明亚致死浓度阿维菌素对荔枝叶螨种群增长有一定的抑制作用。     

节节麦等三种禾本科杂草对不同性状土壤的适应性

为明确不同性状土壤对小麦田重要的禾本科杂草节节麦Aegilops tauschi、多花黑麦草Alopecurus myosuroides和大穗看麦娘Lolium multiflorum出苗及生长的影响,在盆栽条件下研究了3种禾本科杂草对采自山东省不同区域的24份不同性状土壤的适应性。结果表明,节节麦适应性最强,在所有供试土样中均能正常出苗和生长,出苗率在64.2%～80.8%之间;多花黑麦草也有很强的适应性,在供试24份土样中出苗基本正常,出苗率均在90.1%以上,但有2份土样影响其后期生长的株高、鲜重等生长指标;大穗看麦娘的适应性略差,有4份土样明显影响其出苗,出苗率在32.5%～50.8%之间,在其它20份土样中出苗率均为70.0%左右,有11份土壤影响其生长期株高、鲜重、穗数或结实量。土壤性状中pH是影响杂草出苗及生长的最主要因素,pH小于6.0的强酸土壤和pH大于8.0的强碱土壤均对杂草生长会产生一定影响,另外,黏性土壤质地和高盐分土壤也对杂草生长有影响,其它土壤性状如氮含量、磷含量、钾含量、有机质含量和土壤类型对这3种禾本科杂草出苗及生长无影响。     

河北省禾谷孢囊线虫种群密度和冬小麦产量损失的关系

为明确禾谷孢囊线虫Heterodera avenae对小麦的危害,于2011年10月—2012年6月在自然环境条件下采用定量接种方法测定了其在不同接种密度下对冬小麦产量和线虫繁殖的影响。结果表明,随着禾谷孢囊线虫接种密度的增加,小麦的株高、穗长、小穗数、分蘖数和籽粒重均呈下降趋势。小麦产量随着接种密度的增加损失率增加,在接种密度大于29个卵和2龄幼虫/g土时,小麦产量损失率均达50%以上,接种密度为465个卵和2龄幼虫/g土时损失率最大,达到77.7%;当接种密度小于116个卵和2龄幼虫/g土时,禾谷孢囊线虫的最终密度随着接种密度的增加而增加,但接种密度大于该值时,最终线虫密度则随着接种密度的增加而减少;且其繁殖系数随着接种密度的增加而降低。以小麦单株籽粒重为参数,利用Seinhorst模型拟合孢囊线虫密度与产量的关系,可知小麦对禾谷孢囊线虫的最低忍耐值为5个卵和2龄幼虫/g土,相对最低产量为0.23。     

杂草稻对水稻生长及产量的影响

通过室内试验和田间试验明确了杂草稻对水稻生长、产量构成因子和产量的影响。水稻营养生长期,不同杂草稻密度对水稻基本苗、株高、单株鲜重、分蘖、倒二叶长与宽均没有影响。而水稻株高、有效穗数、穗长、一次枝梗数、穗粒数、千粒重、结实率、实际产量等均随杂草稻密度的增加而呈现下降趋势。杂草稻密度为1株/m2可导致水稻产量损失9.15%,当杂草稻密度达7株/m2时可导致水稻产量损失50%以上,杂草稻密度达到12株/m2时水稻产量损失可高达72.29%。     

Interaction of substerilizing Gamma radiation and thiodicarb treatment for management of the Tobacco caterpillarSpodoptera litura

The F₁ sterility technique (inherited sterility using substerile insects) has been proposed for reproductive suppression of lepidopteran pests. Management of lepidopteran pests using F₁ sterility may be greatly influenced by other possible strategies, including chemical control measures. Within this context, a laboratory investigation was undertaken of the tobacco caterpillarSpodoptera litura (Fabricius) (Lepidoptera: Noctuidae) to assess the bioefficacy of a substerilizing dose (70 Gy) of gamma radiation on bio-characteristics(viz., adult survival, fecundity, egg hatch, F₁ larval weight, F₁ pupation, F₁ sex ratio); to establish the median lethal dose (LD₅₀) of an oxime carbamate insecticide, thiodicarb (Larvin®75 WP), toS. litura; and determine the interaction of thiodicarb with the F₁ insects derived from a substerilizing gamma dose. A dose of 70 Gy administered to 7-day-old male pupae reduced the the eclosion by ~ 10%. When the eclosed males (derived from treated pupae) were mated with normal females, the fecundity and fertility were decreased as compared with control (0 Gy). Analysis of body weight of the F₁ larvae showed no significant influence of radiation,i.e., growth was comparable to that of normal progeny, which is a positive factor in the sterile-insect technique. Bioassay on newly molted 6th instar larvae with thiodicarb (Larvin®75 WP) showed that the LD₅₀ of the insecticide was 6.76µg g^-1 in the combined treatment (radiation to P₁ male pupae + thiodicarb to F₁ larvae), as compared with 28.67 µg g_-1 in the chemical treatment (thiodicarb), indicating that the toxicity of the insecticide to the F₁ progeny was increased 4.24 times by the radiation treatment, which is a markedly pronounced effect. Further studies of the combined effect of radiation and insecticide on pupation and sex ratio of F₁ progeny showed that pupation was affected more by the combined treatment than by the insecticide alone, whereas the sex ratio was skewed in favor of males in both the combined treatment and the chemical treatment, indicating that thiodicarb was selectively more toxic to females. The possible interaction and potential and the feasible approaches of integrating F₁ sterility and thiodicarb treatment are discussed for management of the lepidopteran pestS. litura.     

Development of Fusarium Wilt-resistant Genotypes in Safflower (Carthamus tinctorius)

Screening of 51 promising safflower germplasm lines in Fusarium wilt-infested plots resulted in identification of highly wilt-resistant selections viz., 86-93-36A, 237550, VI-92-4-2 and II-13-2A, with some moderate resistance in HUS-305. Progenies from crosses made using these resistant lines were tested for their reaction to wilt. F₁ progenies from 86-93-36A × 237550 and 86-93-36A × II-13-2A recorded zero wilt incidence, while 237550 × 86-93-36A was highly resistant to the Rajendranagar geographical isolate. The reaction for the three progenies showed stability for wilt resistance with no segregation until the F₇ generation. Geographical isolates of Fusarium oxysporum f. sp. carthami (Foc) were collected from different safflower growing regions and tested for their pathogenic variability on six host differentials under glasshouse conditions. Based on the reaction of the differentials, the Foc isolates were grouped into four biotypes. The three resistant progenies were tested for their reaction to the four biotypes. The progeny of cross 86-93-36A × 237550 showed an immune reaction to all the biotypes, except for a highly resistant reaction to biotype 3. The progenies of the two other crosses (86-93-36A × II-13-2A and 237550 × 86-93-36A) exhibited immune reactions to biotypes 2,3 and 1,3, respectively, and were highly to moderately resistant to biotypes 1,4 and 2,4, respectively.