Wheat cellular thermotolerance is related to yield under heat stress

Cellular thermotolerance in terms of cellular membrane thermostability is often implied as an indication of crop heat tolerance and it is therefore considered as a possible selection criterion for heat tolerance. While there is ample genetic variability for cellular thermotolerance in wheat and other crop plants its relations to yield under heat stress is not sufficiently established. This study was performed to assess the genetic relations in wheat between cellular thermotolerance and yield under heat stress. In one study the co-segregation among cellular membrane thermostability (CMS), yield under chronic heat stress and yield under non-stress conditions was evaluated in a random inbred line (RIL) population of a cross between heat resistant (Danbata) and heat susceptible (Nacozari) cultivars. In a second study the same association was evaluated for yield under heat stress in 49 F₇ breeding lines randomly selected from a breeding program. CMS was assayed in growth chamber grown and heat-hardened seedlings. Yield was evaluated under Mediterranean summer irrigated conditions where chronic heat stress caused a reduction in mean yield of the RIL population by 47% as compared with the normal winter growing conditions (non-stress). The RILs varied significantly (p<0.05) for CMS, biomass and yield under stress and non-stress conditions. The two parent cultivars did not differ in biomass or yield under non-stress (winter) conditions but they widely differed for both traits under heat stress. Yield of RILs under heat stress was well distributed between the extreme values of the parent cultivars. There was a significant RIL by season interaction for biomass (F = 9.74; p<0.0001) and yield (F = 10.08; p<0.0001), indicating specific adaptation to heat stress of certain lines in terms of their productivity. Broad-sense heritability for yield was high and nearly the same in the winter (h ²=0.71)and the summer (h ²=0.67). Broad-sense heritability for CMS was high (h ²=0.74). CMS was positively and significantly (p<0.01) correlated across 98 RILs with biomass (r = 0.60* *) and yield (r = 0.53^**) under stress but rot with biomass or yield under non-stress conditions. The 49 breeding lines varied significantly (p<0.01) for CMS and yield under chronic heat stress in the summer season. CMS and yield were significantly correlated (r = 0.56^**) across lines. Overall the associations between CMS and yield under heat stress were reasonably strong and significant but not perfect. Other factors besides cellular thermostability may support yield under heat stress. CMS alone cannot be used as the exclusive selection criterion for heat tolerance in wheat breeding. lt may be valuable as a supplemental criterion in the final breeding stages or as a rough selection tool to reduce a large population into the most likely heat tolerant core at the early stages of the breeding program.     

Partial resistance of barley to leaf rust,Puccinia hordei. IV. Effect of cultivar and development stage on infection frequency

Summary The cultivar effect on infection frequency (IF) was studied in the seedling and adult plant stages of 15 spring barley cultivars. In both stages the cultivar effects were highly significant. The cultivars L94 and Vada represented the extremes. Vada having about 2 1/2 times fewer uredosori than L94. Between cultivars and development stage clear interactions occurred. Pauline f.i. had the same low IF as Vada in the seedling stage, but in the adult plant stage its IF was about 70% higher. Also other effects could influence the cultivar effects. Increasing leaf age appears to increase IF. The cultivar effect also seemed to depend on the level of IF. At high levels the cultivars differed far less than at low levels of IF. The cultivar effect on IF appeared correlated with partial resistance in the field (r=0.7) through a high correlation with the cultivar effect on latent period (r=0.8).     

基于图像处理的冬小麦植被覆盖率测定及其遗传解析

植被覆盖率是反映植株生长势的重要生理性状,在旱作地区尤为重要。图像处理技术能够快速有效地对苗期和孕穗期植被覆盖率进行量化分析。以28份山东小麦主栽品种和品系为材料,在240株 m^-2和360株 m^-2密度下,连续2年测定了孕穗前不同发育阶段的植被覆盖率,并利用921个DArT标记和83个SSR标记分析了与植被覆盖率相关的遗传区段。结果表明。不同密度下,冬小麦植被覆盖率在越冬期、返青期和孕穗期存在显著差异,而起身期基本一致。起身期植被覆盖率与春季最高分蘖数、抽穗后群体叶面积指数、单位面积穗数和籽粒产量均呈显著正相关,r = 0.73~0.76 (P<0.01),表明起身期植被覆盖率可用于预测上述性状。共检测出12个遗传区段与植被覆盖率相关联,大部分区段直接参与调控苗期和孕穗期的生长势。10个遗传区段与已报道的苗期性状、产量性状及抗病位点一致,其中5BL、6AS和6BL染色体上携带的植被覆盖率相关遗传区段与已报道的苗期比叶面积和生物量等位点完全相同。建议将植被覆盖率作为生长势量化指标,用于育种选择和遗传研究。     

苗期及灌浆期抗Bipolaris sorokiniana叶枯病小麦品种（系）鉴定及相关性分析

叶枯病对小麦生产危害严重,麦根腐平脐蠕孢菌（Bipolaris sorokiniana）是小麦叶枯病的主要致病菌。为筛选抗B. sorokiniana叶枯病小麦种质,采用“孢子液喷洒、套袋（罩）保湿”接菌鉴定的方法,于2019-2020年对130个小麦品种（系）进行苗期及灌浆期叶枯病抗性鉴定,同时分析了小麦苗期与灌浆期对B. sorokiniana叶枯病抗性的相关性。结果表明,130个小麦品种（系）中,苗期抗病材料占32.3%,其中高抗与中抗材料分别为1.5%与30.8%,无免疫材料;感病材料占67.7%,其中中感与高感材料分别为20.8%与46.9%;灌浆期抗、感叶枯病材料分别占11.5%与88.5%,无高抗材料;小麦苗期与灌浆期对B. sorokiniana叶枯病抗性呈显著正相关关系（r = 0.72）。此结果为抗B. sorokiniana叶枯病的遗传育种与抗病机理研究提供了优异的种质资源;基于苗期抗性与灌浆期抗性的显著相关性,可以通过室内快速准确的苗期叶枯病抗性鉴定预测大田条件下小麦灌浆期的抗性,节省时间,减轻大田鉴定繁重的工作量,并降低环境因素对鉴定结果的影响。     

Heat Shock Protein in Developing Grains in Relation to Thermotolerance for Grain Growth in Wheat

Wheat ( Triticum aestivum L.) cvs DL 153-2 and HD 2285 (relatively tolerant), HD 2329 and WH 542 (relatively susceptible), were grown under normal (27 November) and late (28 December) sown conditions. In another experiment, these cultivars were grown under normal sowing and at anthesis stage, they were transferred to control (C) and heated (H) open top chambers (OTCs). Under late sowing, wheat cultivars were exposed to a mean maximum temperature of up to 3.6 °C higher than normal sowing and in H-OTCs, mean maximum temperature was 3.2 °C higher than C-OTCs during grain growth period. Heat susceptibility index (S) for grain growth and grain yield was determined at maturity in both the experiments. The level of heat shock protein (HSP 18) in the developing grains was determined in C- and H-OTC grown plants and in normal and late sown plants by Western blot analysis. The moderately high temperature exposure increased the accumulation of HSP 18 in the developing grains. The relatively tolerant cultivars, as also revealed from S , showed a greater increase in HSP 18 compared with susceptible types in response to moderate heat stress. An association of HSP 18 with thermotolerance for grain growth in wheat was indicated.     

Effect of Temperature Hardening on Growth, Carbohydrate and Protein Levels in Three Grain Crops

The effect of seedling pretreatment at different temperature levels and periods of exposure on growth, pigments, carbohydrates and proteins was studied in three grain crops; sorghum, wheat and barley at different stages of growth. Greater shoot-dry weights were obtained in sorghum with exposure for 15 hrs at 40 °C in the flowering, in wheat for 2 hrs at 10 and 40 °C in the fruiting and in barley for 15 hrs at 0 °C in the flowering stage. Increased root-dry weights were achieved by wheat with exposure for 4 and 15 hrs at all levels even at 0 °C in the flowering and for 15 hrs at 40 °C in the fruiting stage. Chl_a and Chl_b were more responsive in sorghum to higher temperature pretreatments than either wheat or barley. In sorghum the temperature extremes (0 and 50 °C) had resulted in a substantial reduction of Chl_a, and Chl_b in the fruiting stage. Lower and higher temperature-pretreatments had resulted in total available carbohydrate reduction in shoot and root of sorghum and wheat at the early stage, but the reverse was true later in flowering. In contrast, lower and higher temperature pretreatments had increased shoot-protein in sorghum and wheat in the vegetative and in sorghum in the flowering stage. Root-protein was more responsive to low temperature-pretreatments in sorghum and barley during the fruiting stage.     

Molecular examination and genotype diversity of vernalization sensitivity and photoperiod response in old and modern bread wheat cultivars grown in Iran

Understanding the genetic factors governing developmental patterns and flowering time in breeding materials is required for the development of new wheat varieties for a specific environment. Iran is among the largest wheat producers in the arid and semi-arid regions of the Middle East and North Africa. The wheat germplasm grown in Iran is either developed nationally or is introduced from the CIMMYT global wheat program. For decades, the wheat breeding program in Iran focused on generating new varieties better able to grow in the predominant Iranian climatic conditions such as humidity at the reproductive stage, high temperature during reproductive stages (terminal heat stress), moderate temperature during the cropping season, and high probability of frost damage during early stages of growth. There have also been sub-programs aimed at developing drought and salinity-tolerant wheat cultivars in Iran. Knowledge of cultivars’ growth habits in Iran is currently limited to flowering in spring-sown nurseries. We identified allelic diversity in loci involved in vernalization response (Vrn) and photoperiod sensitivity (Ppd) in 60 bread wheat cultivars developed in Iran, CIMMYT, or ICARDA. This study revealed that the spring growth habit observed in most of the cultivars is conferred by a combination of recessive vrn-A1 and dominant Vrn-D1, Vrn-B1, and/or Vrn-B3 loci. This implies that most of the cultivars have minimal vernalization requirements for overwintering. Perhaps cold winters, even in the southern regions of Iran, provide sufficient vernalization conditions for cultivars possessing the recessive vrn-A1 allele. The germplasm investigated in this study revealed no evidence indicating selection for or against any specific Vrn and Ppd allele in our wheat breeding program.     

节水条件下不同播期密度设计对不同品种冬小麦群体生长特性和产量的影响

明确适应本地区气候变化和节水需要的小麦晚播适期范围,了解不同品种特性并确定其合理的播种期和种植密度,对充分挖掘小麦品种的产量潜力是非常重要的。利用随机区组试验研究‘泰山23’和‘泰山9818’在只浇底墒水和灌浆水的情况下,在4个播期、密度组合时的产量构成变化及群体发育动态变化。结果表明：适宜的晚播期限内通过增加播量来达到高产的同时,重要的是稳定其较高的千粒重。花期、灌浆期叶面积指数和产量存在正相关关系。‘泰山23’各播期的产量顺序为B1>B2>B3>B4,第四播期产量最低,且与其他播期产量有显著差异,在当前设计密度下,宜适期早播。‘泰山9818’产量顺序为B2>B1>B3>B4,且各播期产量无显著差异,各播期均可播种。     

不同品种羽衣甘蓝生长期色素含量变化规律研究

基于对彩叶植物羽衣甘蓝彩色形成机理的探索,以12个羽衣甘蓝品种为研究对象,分析了生长发育过程中其内叶（变色叶）、外叶（非变色叶）的叶绿素、类胡萝卜素和花青苷含量变化。试验结果表明,各品种外叶的叶绿素a、b及总量,类胡萝卜素含量在整个生长期内均呈现由高到低的变化规律。观赏期外叶叶绿素含量显著降低,至抽薹期‘名古屋红’叶绿素总量仅占幼苗期的65.7%。内叶叶绿素总量下降幅度大于外叶,降幅最大的是‘名古屋白’,观赏期含量比幼苗期降低了96.1%。内叶类胡萝卜素含量呈上升的变化趋势。内叶的叶绿素a/b比值和类胡萝卜素与叶绿素比值均高于外叶。品种间色素含量也存在较大差异。在幼苗期和观赏期,‘名古屋红’的外叶叶绿素总量、叶绿素a和类胡萝卜素含量最高,‘粉鹤’最低。幼苗期品种间类胡萝卜素含量差异不大,而其他时期则存在显著差异。所有羽衣甘蓝品种在幼苗期均未检测到花青苷,观赏期和抽薹期只有紫色品种的内叶检测到花青苷。花青苷含量由高到低依次是‘红鹤’、‘大阪红’、‘桃鹤’、‘名古屋红’、‘红寿’、‘红鸥’、‘粉鹤’。     

四川干旱情况下灌水对土壤和小麦产量的影响

为减少粮食损失,探讨四川在干旱气候条件小麦有效节水栽培,通过在四川绵阳丘陵区设置田间试验,大田生产条件下,分析比较了完全依靠自然降水和人工浇灌以及进行1 次渗灌、2 次渗灌,小麦生长重要时期土壤物理特性的变化及小麦主要农艺性状和产量状况。结果表明：不同灌溉处理在小麦各生长阶段对土壤物理特性和小麦农艺性状影响不同。苗期和拔节期,不同处理间土壤紧实度、土壤容重、土壤含水量差异较小。开花期和成熟期,不同灌溉处理对土壤紧实度、土壤容重、土壤含水量以及小麦性状影响较大。在四川丘陵干旱和半干旱地区,对冬小麦在拔节期进行渗灌1 次为宜,此次灌溉比完全依靠自然降水每公顷增加小麦产量2113.46 kg,增产极显著。     

Phosphorus Accumulation and Translocation in Wheat as Affected by Cultivar and Nitrogen Fertilization

To improve nutrient management strategies in wheat more information is needed about the interaction effects among nutrients in their uptake and redistribution in the plants, in relation to different genotypes. Therefore, two bread ( T. aestivum L.) and two durum ( T. durum Desf.) winter wheat cultivars were grown in the field for 2 years (1986, 1987) in a silty-clay soil under different nitrogen (N) levels, in Northern Greece. Nitrogen at a rate of 150 kg ha⁻¹ was applied before planting or 100 kg ha⁻¹ before planting and then 50 kg ha⁻¹ at early boot stage. Cultivar differences in phosphorus (p) concentration were observed only in vegetative parts but not in the grain. Maximum p accumulation was observed either at anthesis or at maturity. During grain filling dry matter and p accumulation in the grain followed almost the same pattern. Phosphorus translocation efficiency of the cultivars at the 2 years ranged from 70.7 to 84.3 % and the amount of p in the grain derived from translocation 52 to 100 %. Phosphorus translocation efficiency was weakly correlated with p content in grain only in 1986, while phosphorus harvest index (PHI) was positively correlated with harvest indst (HI) both years (r = 0.82** in 1986 and 0.75** in 1987). Nitrogen application mainly affected p accumulation of the cultivars via its effect on biomass production. The split N application promoted slightly the p uptake in 1987 and this resulted in the reduction of both the contribution of the translocated p to the grain and the efficiency of p utilization for total biomass. Results indicated that p accumulation and translocation and the efficiency of p utilization in wheat were mainly determined by the genotype in relation to environmental condition of growth.     

干旱胁迫对春大豆超氧化物歧化酶活性和丙二醛含量的影响

大豆是一种对水分最敏感的豆类作物,明确干旱对大豆叶片主要生理特性的影响,对于进行更好的水分管理具有重要的理论和实践意义。本试验选用耐旱型品种黑农44和敏感型品种黑农65为材料,测定了不同生育时期干旱及复水后大豆叶片SOD活性和MDA含量。结果表明：在干旱条件下,SOD活性随干旱程度增加呈先增加后降低的趋势,活性增加幅度花期>苗期>鼓粒期,且黑农44的SOD活性明显大于黑农65;MDA含量随干旱程度增加呈逐渐上升趋势,苗期>开花期>鼓粒期,且黑农44明显小于黑农65。复水后,SOD活性和MDA含量均逐渐降低;苗期干旱复水后MDA含量恢复较快,开花期干旱复水后恢复时间较长,鼓粒期干旱复水后不能恢复。     

微量元素喷施对冬小麦籽粒产量和品质的影响

通过对不同生育期小麦叶面喷施不同浓度微量元素,探究冬小麦对微量元素的吸收和利用。采用大田试验,设置1倍(B1)、50倍(B2)、100倍(B3)和500倍(B4)四个浓度处理（等量水为对照）,喷施时期为苗期(A1)、苗期+拔节期(A2)、苗期+拔节期+扬花期(A3)、拔节期(A4)、拔节期+扬花期(A5)和扬花期(A6),测定成熟期产量及籽粒微量元素含量。不同处理下产量变化范围为3741~6204 kg/hm²,A4B4处理下产量最优,相对于对照产量增加了39.52%。锌(Zn)变化范围为31.07~44.68 mg/kg,A3B1处理下Zn含量最高。铜(Cu)变化范围为1.75~28.67 mg/kg,A1B1处理下Cu含量最高。铁(Fe)变化范围为73.62~203.99 mg/kg,A3B1处理下Fe含量最高。锰(Mn)变化范围为36.48~55.56 mg/kg,A6B4处理下Mn含量最高。相对于对照,Zn、Cu、Fe、Mn含量分别提高了37.86%、1650%、148%和26.82%。拔节期喷施高浓度微量元素对增产最有利,不同喷施时期和喷施浓度影响微量元素的利用效率。     

Growth Responses of Twelve Wheat Cultivars and their Phosphorus Utilization from Rock Phosphate

Growth responses of 12 wheat cultivars and their phosphorus utilization were studied in a greenhouse. They were grown for 18 days in a solution containing rock phosphate as the phosphorus (p) source. Biomass of 26 day old plants of all the cultivars varied significantly whereas their shoot to root ratio stayed constant. The dry matter yield of all the 12 cultivars was significantly correlated with the p uptake (r = 0.74). Whereas the higher p uptake by all the cultivars was significantly (P < 0.01) related to the drop in the root medium pH, which was presumably owing to the H⁺ efflux from their roots. The wheat cultivar Blue Silver proved to be the most efficient p user and therefore seems to have the highest potential of making best growth in soils with poor p availability among the 12 wheat cultivars under investigation.     

14个小麦品种(系)抗叶锈性分析

选用16个小麦叶锈菌菌系对14个小麦品种(系)进行抗叶锈性鉴定和苗期抗叶锈基因推导,初步分析这些品种(系)的抗性和携带的抗病基因;进一步利用21个与Lr基因紧密连锁或共分离的分子标记,对这14个品种(系)中可能含的抗叶锈基因进行鉴定。结果表明,s98351-2-2-2-1可能含Lr3a、Lr28和Lr50;9629-03A-4-1-1可能含Lr37;97167-1-2-1-1-2-1、919-20-2c2、9589、免中438、9916-8-6和9916-8-18含Lr26;96104-1-5-1c2可能含Lr28;00-55-3-1-1含Lr1;1R13可能含Lr24、Lr37和Lr38;1R17可能含Lr24和Lr38;1R35含Lr10和Lr34,还可能含Lr3a和Lr50;9524-1-2-2-1含未知抗叶锈基因或本试验使用的已知抗病基因以外的抗叶锈基因。所有品种(系)均不含Lr9、Lr19、Lr20、Lr21、Lr29、Lr35、Lr42和Lr47基因。测试的14个品种(系)中有比较丰富的抗叶锈病基因,可为育种提供丰富的抗源。     

Varietal Differences of Wheat and Triticale to Water Stress

Six wheat ( Triticurn aestivum L.) and ten triticale (x Triticosecale Wittmack) cultivars were screened for water stress tolerance during germination and seedling stages in the laboratory and growth chamber, respectively. Germinating seeds and hydroponically-grown seedlings were subjected to osmotic stresses of –0.3 and –0.6 MPa using polyethylene glycol M. W. 8000. Both species and cultivar differences were found among the tested genotypes for all the parameters analyzed in both germination and seedling tests. Germination stress index was lower for seed exposed to -0.6 MPa than for -0.3 MPa osmotic stress. A significant relationship was found among plant height, fresh weight and dry weight stress indices evaluated during the seedling test. The cultivars that grew taller under stress conditions had greater dry matter accumulation, as well as higher germination and water uptake stress indices indicating the reliability of height to predict cultivar performance under such conditions. The cultivars Stacy (wheat) and Eu 14/15 (triticale) had higher dry matter accumulation, higher water uptake and leaf water potential, greater height and better germination under stress conditions than the other cultivars tested. Conversely, the cultivars GA 781014 (wheat) and Am 4147 (triticale) performed poorly with respect to all the parameters analyzed. Based on results from germination and seedling tests, the cultivars Stacy and Eu 14/15 were selected for more stress studies in the greenhouse and field.     

地下水位对油菜生长及产量的影响

长江流域油菜生产主要采用水稻油菜轮作种植模式,地下水位高,易产生湿害。本试验采用PVC筒,在油菜4个生育期分别进行0、30、60和90 cm的地下水位处理,然后恢复至60 cm水位,比较2个耐渍性不同的油菜品系在不同生育期、不同水位条件下的生长状况及产量,从而确定油菜各生育阶段的适宜地下水位,为南方稻茬油菜排水降湿管理提供依据。试验结果表明: (1)地下水位高低影响了油菜的根系发育、地上部生长及产量形成;(2)就产量而言,各生育期对水分的敏感性依次为蕾薹期、花期﹥苗期、角果发育成熟期;(3)油菜苗期适宜地下水位为30~90 cm,蕾薹期、花期为30~60 cm,角果发育成熟期为30~90 cm;(4)就全生育期而言,即使选用耐渍性较弱的品种,地下水位控制在30~60 cm时能满足油菜生长发育及产量形成需求。     

不同生育时期水分胁迫对花生生长发育和产量的影响

旨在明确花生水分敏感时期,为花生进行科学合理灌溉、提高产量提供理论依据和技术指导。以中早熟大果型‘豫花9326’和早熟小果型‘豫花9936’为材料,在全自动防雨干旱棚条件下,通过人工控水的方法研究了苗期、花针期、结荚期和成熟期干旱胁迫对花生营养生长、生殖生长、产量、水分利用效率等的影响。结果表明：不同生长发育时期干旱胁迫均导致花生生长发育受抑制、产量降低。其中花针期干旱,影响最大,花针期干旱主茎高、侧枝长分别降低了42.1%、37.5%,产量降低了22.2%。其次是结荚期干旱和苗期干旱,成熟期干旱影响最小。通过对各指标的分析,苗期干旱、花针期干旱主要是影响了单株结果数,从而降低了产量;结荚期干旱、成熟期干旱则是降低了饱果率、百仁重、出仁率,进而影响了产量。本研究明确了花针期是花生对水分胁迫最为敏感的时期,对提高花生水分利用效率和我国干旱半干旱地区花生单产具有重要意义。     

稻瘟病苗瘟叶瘟和穗颈瘟的相关性分析

采用温室人工接菌法探讨水稻稻瘟病苗瘟、叶瘟和穗颈瘟的相关性,研究结果表明,稻瘟病苗瘟、叶瘟和穗颈瘟三者之间存在着一定的正相关性,相关程度因水稻品种、稻瘟病菌生理小种的不同而有所差异。此外,对水稻品种温室苗瘟抗性率与田间叶瘟抗性率、穗颈瘟抗性率之间的相关性进行研究,结果表明温室苗瘟抗性率与自然病圃叶瘟抗性率表现正相关关系(r=0.5435),温室苗瘟抗性率与自然病圃穗颈瘟抗性率表现极显著正相关关系(r=0.7583**,p<0.01),自然病圃叶瘟抗性率与穗颈瘟抗性率呈显著正相关关系(r=0.6322*,p<0.05)。因此,认为利用可控温室代替田间进行水稻品种稻瘟病抗性鉴定是可行的,而且根据苗瘟、叶瘟的抗性鉴定结果推测穗颈瘟的抗性基本上也是可行的。     

渍水时间对油菜生长及产量的影响

长江流域油菜生产期间雨水偏多,加上主要采用水稻油菜轮作模式,地下水位高、土壤粘重,常发生渍害。为了研究油菜各生育期渍水对其生长及产量形成的影响,设计盆栽试验,在油菜4个生育期分别进行3个不同渍水时间处理后,然后恢复正常水分管理。其中,苗期、蕾薹期分别进行10、20和30 d渍水处理,花期、角果期分别进行10、15和20 d渍水处理,各处理4次重复,比较2个耐渍性不同的油菜品系在各生育期的生长状况及产量。结果表明: (1) 渍水影响油菜各生育期根系发育、地上部生长及最终产量的形成,并存在品种间差异;(2) 苗期渍水导致叶片叶绿素(Chl)含量下降、丙二醛(MDA)及脯氨酸(Pro)含量增加,其变化过程在指标间存在差异;(3) 以产量为指标,渍水的敏感性依次为蕾薹期、花期＞苗期、角果发育成熟期;(4) 研究不同渍水处理对产量的影响可为持续降雨对大面积油菜生产影响的估算提供依据。