薏苡种质资源成株期抗旱性鉴定及抗旱指标筛选

以50份薏苡种质为材料,设置正常灌水和干旱胁迫2个处理,测定株高、茎粗、分枝数、主茎节数、分蘖数、单株粒数、单株粒重、千粒重和产量,采用抗旱性度量值(D值)、综合抗旱系数(CDC值)、加权抗旱系数(WDC)、相关分析、频次分析、主成分分析、灰色关联度分析、隶属函数分析、聚类分析和逐步回归分析相结合的方法,对其进行成株期抗旱性鉴定及抗旱指标筛选。结果表明,各指标对干旱胁迫的反应及关联程度各异。6个公因子可代表薏苡抗旱性90.80%的原始数据信息量。基于D值、CDC值和WDC值的供试薏苡种质抗旱性排序相近。供试薏苡种质产量抗旱系数(Y值)与D值、CDC值和WDC值均呈极显著正相关。筛选出成株期抗旱性强的薏苡种质有yy18-1、yy03-8和粱丰薏14-2。分蘖数、单株粒重和千粒重可作为薏苡种质资源成株期抗旱性评价的直观指标。     

青稞种质资源成株期抗旱性鉴定及抗旱指标筛选

干旱是影响青藏高原青稞生产的主要因素之一,鉴定青稞种质资源成株期抗旱性,筛选可靠的抗旱指标,可对抗旱青稞品种培育提供依据。本研究以238份青稞种质为材料,于2019和2020年在甘肃省张掖市设置正常灌水和干旱胁迫2个处理,测定青稞株高、单株穗数、单株生物量、单穗粒重、穗长、千粒重和产量,结果表明:采用抗旱性度量值(D值)、综合抗旱系数(CDC值)、加权抗旱系数(WDC值)分别进行成株期抗旱性综合评价。相关性分析表明,干旱胁迫对各指标的影响均达到极显著水平,产量与株高、千粒重呈极显著正相关,与单穗粒重呈显著正相关。频次分析表明,各指标对干旱胁迫的敏感程度依次为株高、产量、单株生物量、单穗粒重、单株穗数、穗长和千粒重。基于D值、CDC值及WDC值的种质排序基本一致。灰色关联度分析表明,各指标DC值与D值之间的关联度大小依次为产量、单株生物量、单穗粒重、株高、单株穗数、穗长和千粒重,这与各指标DC值与WDC值的密切程度基本一致。逐步回归分析表明,产量、株高、单株穗数、千粒重及单株生物量可作为青稞成株期抗旱鉴定的可靠指标, D值为适宜的抗旱评价方法。以D值为依据将供试青稞种质划分为5个抗旱等级...     

绿豆种质资源成株期抗旱性鉴定

作物种质资源抗旱性鉴定是获得抗旱资源和挖掘抗旱基因的前提。本研究以21份绿豆种质资源为材料,采用温室内盆栽控水旱胁迫,考察不同品种单株产量、单株荚重、单株粒数、单株地上部生物量、单株生物量、根冠比等12项指标,计算各指标在旱胁迫与对照条件下的比值,运用相关性分析、隶属函数、抗旱系数和抗旱指数方法,评价绿豆成株期抗旱性,筛选抗旱优异种质。结果表明,抗旱系数与单株地上部生物量、单株总生物量、单株荚重、单株粒数、单株有效荚数在旱胁迫与对照条件下的比值呈极显著正相关,与根冠比呈极显著负相关,从而遴选出这7项指标作为绿豆成株期抗旱性鉴定的评价指标;基于隶属函数、抗旱系数和抗旱指数三者呈极显著正相关,且3种评价抗旱分级结果一致性较高,故认为抗旱指数法适宜于大规模绿豆成株期抗旱性鉴定;筛选获得高抗种质3份、抗旱种质6份、中抗种质4份、敏感种质5份和极敏感种质3份。     

云南玉米资源成株期的抗旱性鉴定

１９９２～１９９４年，在云南元谋自然干旱条件下对１４６７份玉米资源进行了成株期的抗旱性鉴定。筛选出抗旱（１～２级）玉米种质３０份；抗旱玉米种质以黄、白粒，中间型及硬粒型居多，且抗旱性分布与生态地理条件有关，它们主要集中在镇雄、镇康、昌宁等地     

黑龙江省春大豆种质资源芽期抗旱鉴定与筛选

利用水分胁迫溶剂聚乙二醇(PEG-6000)20%浓度对黑龙江省主推品种抗线号、黑河号、黑农号、绥农号、合丰号、垦豆号、垦丰号等78份材料进行芽期抗旱鉴定,并调查和计算相对发芽率。结果表明:耐旱品种有黑河53、合丰45、合丰48、绥农22、绥农30;较耐旱品种有抗线7号、黑河46、黑河52、黑农53、黑农62、黑农65、龙小粒豆1号、龙小粒豆2号、合丰47、垦豆25、垦豆26、绥农10、绥农15、绥农28、垦丰10、垦丰11、垦丰13、垦丰17。     

小麦种质资源成株期抗根腐病鉴定技术探讨

由Drechlera sorokiniana引起的小麦根腐病广泛分布于世界各国和我国的东北、西北、华北等主要产麦区。它是小麦生产上重要病害之一,苗期可引起苗腐、茎基腐;成株期导致叶枯、穗腐和种子黑胚,叶枯和穗腐对小麦产量影响最大,常年减产10～15%,严重年可达25%以上,而且黑胚率还影响籽粒的品质。     

大豆成株期抗旱性鉴定评价方法研究

以我国不同地区育成的77个大豆品种(系)为供试材料、以晋豆21为对照, 在年降雨量不足40 mm的甘肃敦煌市, 设干旱胁迫和正常灌水2个处理, 考察与产量相关的8个农艺性状, 应用简单相关、等级相关等统计学方法, 筛选优异的抗旱种质资源, 旨在明确大豆成株期抗旱性鉴定指标和评价方法。9种抗旱性评价方法比较结果表明, 基于抗旱系数法、伤害指数和敏感指数对供试材料的抗旱性评价结果完全一致, 基于生物产量、单株粒数和单株荚数的综合评价方法与基于产量的直接评价方法比并无优势。经典的抗旱系数法适宜于筛选抗旱资源, 但不一定能筛选出正常条件下的丰产资源, 而本文提出的改进抗旱指数法可筛选到抗旱性和丰产性兼备的品种, 为抗旱育种和生产应用服务;通过划分不同品种熟期组, 筛选到不同熟期类型的抗旱、丰产品种。本研究为制订“大豆抗旱性鉴定评价技术规范”提供了理论依据, 对大豆资源的抗旱性鉴定和抗旱性育种具有重要的意义。     

小麦种质资源抗旱耐盐性评价及种质筛选

为了解16份小麦种质材料的苗期抗旱性和耐盐性,本研究分别以20％PEG-6000溶液和0.20 mol/L NaCl溶液模拟干旱胁迫和盐胁迫,对其抗氧化酶活性、叶绿素含量、细胞质膜透性、苗长、根系性状、生物量等指标进行测定,应用隶属函数、因子分析和聚类分析等方法综合评价小麦苗期抗旱性和耐盐性.结果表明,在胁迫处理下,小...     

棉花种质资源萌发期耐盐性鉴定及筛选

种子萌发期是对盐分较敏感的时期,测定不同盐浓度胁迫下的棉花种子发芽情况是筛选棉花耐盐种质的重要依据之一。本研究对629份棉花种质资源进行0、150mmolL^–1 NaCl处理,对鲜重、发芽势等6个性状的耐盐系数进行差异分析,结果显示盐胁迫下各个性状较对照均存在显著差异;使用主成分分析、隶属函数分析对棉花种质耐盐性进行综合评价;对综合评价值D值进行聚类分析,根据D值的大小将629份种质资源分成5类:188份耐盐中间型材料、376份耐盐型材料、36份高耐盐型材料、28份盐敏感型材料、1份高盐敏感型材料;通过逐步回归分析建立棉花萌发期耐盐性评价预测模型:D=0.277RFW+0.29RGP+0.189RPL+0.387RGR-0.32 (R²=0.992),筛选出鲜重、下胚轴长、发芽势和发芽率4个指标可作为棉花萌发期耐盐性鉴定的指标。本研究建立了一套精准、高效的耐盐性鉴定体系,筛选到36份高耐盐材料和1份高敏感材料,为棉花耐盐机制研究和培育耐盐新品种提供参考。     

Characterization of greenbug resistance in barley

The greenbug [Schizaphis graminum (Rondani)] is an extremely damaging pest of barley (Hordeum vulgare L.), particularly in the southern Great Plains of the USA. Winter barley targeted for production in this region should incorporate resistance to greenbug in the form of the resistance gene Rsg1a (in ‘Post 90′) or Rsg2b (in PI 426756). This study was conducted to fully characterize the resistance profile of these two genes against important greenbug biotypes, and to determine which of the two resistance genes is most effective in protecting barley from the greenbug. Eight barley and four wheat cultivars and germplasms were challenged with six greenbug biotypes and damage ratings were recorded for each combination. In five of the six tests, ‘Post 90’ was significantly more resistant than PI 426756 to greenbug feeding damage. Based on the results presented here, we conclude that the resistance gene, Rsg1a, in ‘Post 90’ is the better choice for use in breeding programmes and will provide better protection than Rsg2b against the greenbug.     

Selection of Barley Lines for Drought Tolerance in Low-Rainfall Areas

An experiment was conducted at five locations in Jordan (Khanasri, annual rainfall 150 mm; Ramtha, 225 mm; Muwaqar, 150 mm; Rabba, 350 mm; Ghweer, 250 mm) during the 1996/1997 growing season, to evaluate the yield performance and some agronomic traits of 84 barley breeding lines and three long‐term checks (Zanbaka, Arta and Klaxon) for drought tolerance. An α‐lattice design with two replications and six incomplete blocks for each replication was used. Genotype 6 (WI2291/Tadmor) was found to be superior in grain yield, especially compared to the best check (Arta) at the two wettest locations (Rabba and Ghweer). Genotype 21 (Mo.B1337/WI2291/5/Emir/Sb//CM67/3/F8‐HB‐854‐23/121//148‐221/4/CI 08887/CI05761) out‐yielded the best check (Arta) at the driest location (Khanasri), while genotype 61 (Salmas/Arabia Aswad) produced a higher grain yield than the best check (Zanbaka) at Ramtha. The correlations amongst grain yield, biological yield, straw yield, plant height and harvest index were always significant and positive regardless of the location. The correlations amongst days to heading, days to maturity and grain yield were significant at the two driest locations only. This suggests that different phonologies are required to maximize grain yield in wet and dry environments. Also, the relationship between grain yield and the length of grain‐filling period was positive in the wettest location (Rabba), negative in the driest (Khanasri) and not significant at the two intermediate locations. These results emphasize the importance of selection in the target environment and the need to develop early‐maturing genotypes as a way of withstanding drought and high temperatures during the grain‐filling period. A high and negative correlation coefficient was found between the drought susceptibility index and grain yield at the driest site, whereas at the wettest site the correlation coefficient was lower and in some cases positive, indicating the existence of traits that are desirable under drought and undesirable under favourable conditions.     

EcoTILLING for the identification of allelic variation in the powdery mildew resistance genes mlo and Mla of barley

In this investigation the successful implementation of a CEL I‐based mutation detection technique for the discovery and detection of DNA polymorphism in the genes mlo and Mla of barley is described. The technique is called EcoTILLING, which is a high‐throughput method to detect and discover new point mutations and small insertions/deletions in DNA. That the method not only reveals polymorphism between different alleles but can also be used as a powerful genetic marker is demonstrated. The genes mlo and Mla are involved in the defence of barley against the fungal pathogen powdery mildew. The powdery mildew resistance gene mlo is a single copy gene, whereas multiple alleles exist at the Mla locus. With EcoTILLING it was possible to identify point mutations and deletions in each of the 11 mlo mutants tested. For Mla 25 natural barley variants were tested, and although the identification was complex due to the presence of highly similar paralogues of Mla, most of the recently identified alleles from Hordeum vulgare ssp. spontaneum were identified. This method offers the possibility to combine different mlo alleles with different Mla alleles from wild barley to obtain cultivars with more durable resistance.     

种植密度对2个青稞品种抗倒伏及秸秆饲用特性的影响

种植密度是影响青稞抗倒伏和秸秆饲用特性的重要因子。以抗倒伏品种昆仑14号和倒伏品种门源亮蓝为试验材料,比较研究种植密度对这2个品种生长发育、抗倒伏特性和秸秆饲用特性的影响。结果表明,种植密度对2个品种的抗倒伏和秸秆饲用特性的影响存在差异。随着种植密度的增加,昆仑14号根长、根体积、根数和根干重先增后降,茎粗和壁厚依次下降;门源亮蓝根系和茎秆相关指标则随种植密度增大而下降。昆仑14号抗倒伏相关指标先增后降,但整个生育期未发生倒伏;门源亮蓝各指标均显著降低,诱发倒伏现象提前发生,致使倒伏率增大、倒伏程度加剧。昆仑14号茎秆中性洗涤纤维、酸性洗涤纤维、半纤维素、纤维素和木质素等化学成分含量随密度增加先增后降,门源亮蓝各成分含量呈下降趋势,相对饲喂价值随密度增加呈现增高的趋势。综合抗倒伏特性与秸秆饲用特性,昆仑14号最佳种植密度为375×104株hm^-2,门源亮蓝粮饲兼用时适宜密度为300×104～375×104株hm^-2。     

Heterosis and mixing effects in barley under drought stress

Yield stability is one of the main breeding objectives in breeding for stress environments, such as the semi‐arid areas of Syria. The objectives of this study were to measure the effects of heterogeneity and heterozygosity on yield and yield stability by comparing doubled haploid lines (DHL) in mixed vs. pure stand (influence of heterogeneity) and F₂ populations vs. corresponding DHL mixtures (influence of heterozygosity). Six barley lines from two gene pools (LR = landraces, EL = experimental lines) were used to produce nine crosses (two LR × LR, three EL × EL, four LR × EL). The F₂ generation and eight DHL per cross were produced from each cross. The six parental DHL, nine F₂ populations, nine 8‐line mixtures and 72 DHL in pure stands were tested in five environments under drought stress in north Syria. The mean superiority of F₂ populations over DHL mixtures for yield traits across environments and cross combinations ranged between 7.5 and 10%. The effect of heterogeneity was small throughout. For grain yield, harvest index, 1000‐grain weight and plant height significant interactions between heterozygosity levels and environments were observed. The effect of heterozygosity for grain yield increased substantially from ‐1.2% in the highest‐yielding environment to 45.6% in the most stressful environment. Interactions between levels of heterozygosity and cross combinations were significant for most traits. F₂ populations were considerably more stable than DHL in pure stands, yet not as stable as DHL mixtures. It is concluded that heterozygosity is more important than heterogeneity in breeding for improved yield and yield stability under drought stress.     

Mature plant resistance of barley to barley leaf rust,another type of resistance

Summary Seedling and flag leaves of three barley cultivars were simultaneously inoculated with urediospores of barley leaf rust, race 1-2-1, and incubated at the same greenhouse bench. The inoculated leaves were harvested before urediospore formation was initiated. The volume of a large number of colonies was estimated by measuring colony area and colony depth by embedding the colony containing leaf segments into paraffin for microtome cutting. The colony volume was considerably smaller in flag leaves than in seedling leaves even in the extremely susceptible cultivar. On average the difference was about tenfold.     

Genetic variation for dry matter and nitrogen accumulation and translocation in two-rowed spring barley: I. Dry matter translocation

A 4-year field study was carried out to determine dry matter and nitrogen accumulation until anthesis and at grain filling period and dry matter translocation and utilization in grain filling of barley. Twenty two-rowed spring barley (Hordeum vulgare ssp. distichum L.) cultivars originated from different countries (Yugoslavia, Germany, Australia, the Czeck Republic, Netherlands, France and USA) were grown during 1995–1998 on a non-calcareous chernozem soil near Novi Sad (45° 20′N, 15° 51′E, 86 m asl). Dry matter and nitrogen accumulation depended on the cultivar and year. In a year with favorable weather conditions, 58% of dry matter was accumulated during pre-anthesis, while in a year with less favorable weather the amount was 48%. In the favorable year 91% and in unfavorable year 65% of nitrogen was accumulated until anthesis. The results indicated that the greater amount of dry matter and nitrogen accumulated before anthesis. Dry matter translocation efficiency depended on the cultivar and ranged from 3 to 16.4%, while the contribution of pre-anthesis assimilates to kernel varied from 4 to 24.2%. Cultivars that have been developed for the growing conditions of the area where the experimental site was located, i.e. adapted ones, did not use pre-anthesis dry matter for grain filling. High positive correlations (P<0.01) were found between biomass at anthesis and biological yield, dry matter translocation efficiency, contribution of translocated dry matter to grain yield, and total plant nitrogen at maturity. Accumulated nitrogen at anthesis was positively correlated (P<0.01) with growing degree–days until anthesis, dry matter at anthesis and dry matter translocation parameters. Heritability for the investigated characters was rather high, over 0.60.     

Virulence studies of Swedish net blotch isolates (Drechslera teres) and identification of resistant barley lines

Six Swedish and one Canadian single spore isolate of Drechslera teres f. teres were used to screen 109 barley lines for disease resistance and to select a differential set of barley lines for use in assessing pathogen virulence. A large variation for net blotch resistance was found among the 109 barley lines which were classified into four groups, those showing: 1) only resistant reactions; 2) differential reactions; 3) only intermediate reactions and 4) only susceptible reactions. The European commercial varieties included, showed susceptibility to all Swedish isolates, but a few were resistant to the Canadian isolate. The 18- member differential set separated 25 Swedish and two Canadian isolates of D. teres into 14 pathotypes, three of which made up 59% of the isolates. Only one barley differential (CI 9776) was resistant to all net form isolates. Host selection on the pathogen seems to be present as all six isolates obtained from cv. Golf belonged to the same pathotype and 4 of 5 isolates from cv. Karin shared the same virulence pattern. The net form of net blotch (D. teres f. teres) predominated in the sampled regions and only one of 26 Swedish isolates was of the spot form (D. teres f. maculata). This revised version was published online in July 2006 with corrections to the Cover Date.     

A study of grain dormancy and viability in spring barley

In field experiments carried out between 1989 and 1991, spring barley was sampled to observe changes in the grain viability and dormancy during grain filling. The weather during the grain filling periods of 1989 and 1990 was unusually warm and dry, and the crop in 1989 was affected by drought. Some grains were capable of germination shortly after anthesis, but were dormant. Dormancy declined with increasing maturity, but was prolonged by low temperatures and reduced by warm weather. Differences were found in the dormancy characteristics of the two cultivars tested. Apart from grains at the extremities of the ear, which were sometimes found to be small and with low viability and greater dormancy, though not significantly so, no consistent differences were found between the viability and dormancy of grains in different positions in the ear.