小麦种子萌发期抗早衰鉴定指标的初步研究

为了探索小麦抗早衰性的早期鉴定指标,采用种子萌发试验比较了不同抗早衰类型的33个小麦(Triticum aestivum L.)品种(系)萌发种子的芽长、胚芽鞘长、主胚根长、种子根数、根系活力、种子贮藏物质转运率、总鲜重、总干重、根芽干重、干物质含量等指标与抗早衰性之间的关系。结果表明,萌发种子的芽长、胚芽鞘长、主胚根长、种子根数、根系活力、总鲜重及根芽干重等7项指标均与小麦抗早衰性无明显相关性;萌发种子的总干重、干物质含量与小麦抗早衰性有部分相关性,但不能准确区分抗早衰型和典型早衰型品种(系);种子贮藏物质转运率能较好区分不同抗早衰类型的小麦品种,可作为小麦种子萌发期抗早衰性的鉴定指标。     

肥床旱育稀植水稻单株生产力研究

研究汕优６３不同带蘖秧苗的结实性状及相互关系，表明旱育稀植水稻的结实性状与单株带蘖数呈二次曲线关系，与单株成穗数亦呈二次曲线关系，以单株带蘖２～３个、成穗８～９个秧苗综合性状好，产量高     

A Varietal Difference in Coleoptile Growth is Correlated with Seedling Establishment of Direct Seeded Rice in Submerged Field under Low-Temperature Conditions

Abstract

To elucidate the physiological characteristics relating to better seedling establishment in submerged field under low-temperature conditions, we compared the time required to reach various growth stages after seed imbibition among rice {Oryza sativa L.) varieties differing in the performance of seedling establishment. Two experiments were conducted. In the field experiment, the percentage of seedlings with expanded second leaf at 30 days after sowing (PSSL) was measured and regarded as the index of establishment rate for each variety. In agar-bed experiment, the number of germinated seeds, the seedlings with the coleoptile elongated to the medium surface, and the seedlings with the 1st leaf apparent were counted daily under a 16°G condition. A sigmoid model was applied to the above values to evaluate the time requirements. There was a significant correlation between the duration from 50% germination to 50% emergence in the agar-bed experiment and PSSL in the field experiments. However, the duration from imbibition to 50% germination, and that from 50% emergence to 50% appearance of the first leaf were not significantly correlated with PSSL. We found that fast growth of the coleoptile is an important characteristic for the varieties that can provide stable and excellent seedling establishment at low temperature.     

基因型和环境对小麦种子活力的影响

为了明确环境、基因型及其互作对小麦种子活力的影响,以湖北省小麦区域试验三个试点的16个小麦新品种(系)为材料,对收获后的种子进行发芽率、幼苗干重及简易活力指数的计算并进行了统计分析,结果表明:(1)发芽率、幼苗干重及其简易活力指数在地点间、品种(系)间差异均达到了极显著水平,且品种(系)间的差异均比地点间的差异大,发芽率和简易活力指数的地点×品种(系)互作(GEI)间差异也达到了极显著水平。(2)发芽率和简易活力指数以武汉最高,且与其他地点的差异达极显著水平;而幼苗干重则以荆州最高,与武汉差异不显著。(3)鄂麦27和楚0805的发芽率较高,襄麦27和河科大9612的幼苗干重最高,而鄂麦27的简易活力指数最高。(4)简易活力指数与发芽率呈极显著正相关,与幼苗干重呈不显著的正相关,而发芽率与幼苗干重呈不显著的负相关。     

秧苗密度和施氮量对超高产杂交籼稻秧苗素质的影响

 2007年在云南省永胜县涛源乡水稻特殊高产生态区,利用杂交籼稻组合协优107,设计了氮肥处理（10.3、207、31.0和41.4 g/m2N）和秧苗密度处理（353、706、1059和1412苗/m2）双因子试验,旨在探讨施氮水平、秧苗密度和秧龄对超高产杂交籼稻秧苗素质的影响。结果表明：1)秧苗密度降低或施氮量增加,均降低出叶所需的有效积温,加快秧苗的出叶,且秧苗密度的效应更显著;2)高密度或低氮条件下,秧苗单株带蘖数随着秧龄的增加有减少的趋势;而在高氮或低密度条件下,秧苗单株带蘖数在播种后27 d（7叶期）内呈增加趋势,之后进入分蘖衰减期;3)施氮对秧苗新分蘖的发生和大分蘖保持、苗床叶面积指数的增大、单株干质量的增加以及植株含氮量的提高均有正效应;4)秧苗密度对秧苗新分蘖的发生和大分蘖保持、单株干质量的增加均有负效应,并比氮效应明显;对植株含氮量的提高也有一定的负效应;对苗床叶面积指数的增大有正效应。     

Analysis on Factors Affecting Seedling Establishment in Rice

Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production.Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl(long,medium and short)were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions.The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations,and two semi-dwarf varieties(G140,Zhong 96-21)with good seedling establishments and optimum mesocotyl lengths were found.The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted lognormal distribution. Analysis of the relationships among mesocotyl,coleoptile,seeding depth,flooding duration,and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl,coleoptile,mesocotyl×coleoptile, seeding depth,flooding duration and mesocotyl×sowing depth in the experiment for seedling establishment.     

中国双季稻栽培技术研究进展

结合双季稻品种的变更,介绍了中国双季稻栽培技术的3个发展阶段,重点介绍了双季稻"三高一稳"栽培技术、"旺壮重"栽培技术、以抛秧和机插稻为主导的轻型栽培技术及"三定"栽培技术的原理、技术要点、研究进展,并根据当前中国水稻生产中存在的问题,提出了发展双季稻生产的建议。     

春性和半冬性小麦氮效率差异的群体特征比较

为了解小麦群体结构特征与氮利用效率的相关性,以江苏省推介使用的6个半冬性小麦品种和9个春性小麦品种为材料,研究两类型小麦间群体特征及氮利用效率的差异。结果表明,在施氮量相同时,半冬性小麦群体植株平均干物质积累量、叶面积指数在生育前期低于春性小麦,生育后期高于春性小麦,茎蘖数在全生育期均高于春性小麦,平均花后干物质积累量、总结实粒数、粒叶比均高于春性小麦。同一类型小麦中不同品种间群体干物质积累量、总结实粒数也存在显著差异;同一类型小麦各品种花后干物质积累量、茎蘖成穗率、总结实粒数、粒叶比与产量均呈显著或极显著线性正相关,叶面积指数下降速率与产量呈线性负相关。半冬性和春性小麦花后干物质积累量、总结实粒数与氮肥生产效率(NGPE)呈显著或极显著正相关;春性小麦的粒叶比与NGPE呈显著或极显著正相关,叶面积指数下降速率与NGPE呈显著或极显著负相关,茎蘖成穗率与氮肥吸收效率(NUEa)呈显著或极显著正相关;半冬性小麦粒叶比与氮肥农学效率(NAE)呈显著正相关。花后干物质积累量、总结实粒数是两种类型小麦群体NGPE的共性调控特征表现,粒叶比可作为春性小麦NGPE、半冬性小麦NAE差异的评价指标,茎蘖成穗率可作为春性小麦NUEa的调控指标。     

不同小麦种质资源耐深播能力的差异

为筛选耐深播小麦种质资源,以国内部分育成品种、地方种质及引进种质共100份小麦材料为对象,测定了7和15cm两种播种深度下小麦出苗率、胚芽鞘长、地中茎长和苗高,研究了小麦耐深播相关性状之间的关系,对100份小麦种质的耐深播能力进行了聚类分析和等级划分。结果表明,播种深度从7cm增加到15cm,小麦出苗率显著降低,而胚芽鞘长、地中茎长及苗高却显著增加。在7cm播种深度下,小麦出苗率与苗高以及胚芽鞘长与地中茎总长之和呈正相关;在15cm播种深度下,小麦出苗率与胚芽鞘长、地中茎长、苗高以及胚芽鞘长与地中茎长之和均呈极显著正相关。100份小麦种质可划分为强耐深播、中等耐深播及弱耐深播3种类型,其中富尔纳尼、红春麦、红齐麦、青芒麦、陕地535、三道塘(有芒)、陇春31号等29份材料为强耐深播小麦种质。     

PEG胁迫下甘蓝型油菜品种（系）种子发芽耐旱性鉴定

以10%（w/v）PEG6000做渗透介质模拟干旱条件,对不同来源的甘蓝型油菜(Brassica napus L.)品种（系）进行干旱胁迫下种子发芽鉴定,分析油菜种子发芽耐旱性的遗传多样性。结果表明：干旱胁迫下,部分材料处理与对照的发芽性状有显著性差异,81个甘蓝型油菜材料的平均苗高处理比对照低36.5％,平均鲜重处理比对照低31％,成苗率降低11.1％。甘蓝型油菜品种（系）耐旱性有较大遗传差异,幼苗活力指数的变异幅度为19％－81%,平均活力指数为55％。相关分析表明,活力指数与胁迫下的发芽性状达极显著正相关,可以作为油菜种子发芽耐旱的综合指标。根据活力指数,将81个油菜资源划分为强,中,弱三个耐旱等级,并筛选到30295,30253,中双6号,30703,30296,30290,30704,中油杂9号,德油4号等一批耐旱遗传资源。     

不同水旱地小麦品种聚类分析及其利用模式研究

为了合理利用小麦种质资源,减少组配小麦杂交组合的盲目性,选取34份在中国大面积推广种植的具有一定代表性的旱薄地、旱肥地、水肥地及水旱兼用型小麦材料,以株高、穗长、有效分蘖数、单穗小穗数、单穗粒数、单株粒重、单株生物学产量、千粒重为指标进行系统聚类分析.结果表明,参试品种可以分为3组,第Ⅰ组是节水高产型品种,可作为高产型亲本;第Ⅱ组耐旱性强的旱薄地品种,可作为改良耐旱性状的亲本材料;第Ⅲ组在旱作条件下综合表现较好,主要表现为有效分蘖多,株高适中,单株粒重、千粒重大,是较为理想的节水高产育种的亲本材料.研究表明,中国小麦育种已经从耐旱潜力的挖掘转向了节水高产潜力的挖掘,选育抗旱节水高产品种是现代育种模式发展的重要方向之一.     

播种模式对新疆小麦干物质积累和产量及水分利用效率的影响

为确定北疆小麦适宜的播种模式,以北疆主栽冬小麦品种新冬18号和新冬41号及春小麦品种新春44号和新春48号为材料,设置晚播冬小麦(10月8日播种,用B₁表示)、极晚播冬小麦和冬播春小麦(10月28日播种,用B₂表示)以及春播春小麦(4月4日播种,用B₃表示)三种播种模式,比较分析了播种模式间小麦的生育进程、总茎数、叶面积指数、光合势、干物质积累量、经济系数、产量及水分利用效率的差异。结果表明,B₂处理的冬小麦较B₁处理晚熟约7 d,生育期缩短162 d,出苗率、最高总茎数、LAI、总光合势、干物质积累量及总耗水量分别降低27.6个百分点、17.1%、11.5%、9.6%、3.7%和15.9%,而水分利用效率提高15.7%,平均经济系数和产量与B₁处理无显著差异;B₂处理的春小麦较B₃处理早熟7 d,生育期延长约4 d,出苗率、最高总茎数、LAI和总耗水量分别降低28.1个百分点、7.6%、5.2%和12.3%,总...     

α-Amylase Activity and Soluble Sugar Supply from Endosperm in Relation to Varietal Differences in Seedling Establishment under Low-Temperature Conditions in Rice (Oryza sativa L.)

Abstract

We examined 𰂱-amylase(EC 3.2.1.1) activity in endosperm in 6 varieties of rice (Oryza sativa L.), which showed different seedling establishment traits in field experiments, using seedlings grown in sterilized agar-bed at 16ºC. At the coleoptile elongation stage and the first leaf elongation stage, there were significant differences in 𰂱-amylase activity among the varieties investigated. However, the varietal difference in 𰂱-amylase activity at the coleoptile elongation stage did not correspond with that in coleoptile growth. Maltose, the immediate product of 𰂱 -amylase activity, accumulated in the endosperm at the coleoptile elongation stage in a greater amount in Fukuhibiki, which has a poor seedling establishment trait, than in Arroz da Terra, which has a superior seedling establishment trait. The concentration of glucose detected in the exudate from the endosperm adjacent to the scutellum at the coleoptile elongation stage was also higher in Fukuhibiki than in Arroz da Terra. The results obtained in sterileagar-bed conditions clearly demonstrated that neither deficiency in 𰂱-amylase activity nor glucose production in the endosperm were responsible for coleoptile growth retardation at 16ºC. Therefore, neither 𰂱-amylase activity nor sugar supply from the endosperm were responsible for the varietal differences seen in the rate of seedling establishment in paddy fields at around 16ºC.     

140个冬小麦品种(系)对UV-B辐射的响应

为深入了解不同小麦基因型对UV-B辐射响应的差异,以中国黄淮地区140个冬小麦育成品种(系)为材料,在苗期施加4.3kJ·m~(-2)·d~(-1)的UV-B辐射,培养15d后,测定相关的生物量(株高、鲜重、干重)、色素相对含量(花青素、叶绿素、类胡萝卜素)及光化学植被指数(PRI)等指标,计算UV-B辐射下的响应指数,并根据冬小麦幼苗干重响应指数对140个品种(系)进行了UV-B耐性分类。结果表明,140个冬小麦幼苗的7个被检测指标对UV-B辐射的响应不尽相同。对7个被测指标响应指数的相关性分析发现,反映植物生物量指标的响应指数与色素指标的响应指数之间没有显著相关性。有39个品种(系)的幼苗对UV-B辐射敏感,其中,9305031-2的干重降低幅度最大(34.8%);抗UV-B辐射的品种(系)有36个,其中,京10531干重增加幅度最大(71.0%);其他65个品种(系)对UV-B辐射不敏感。     

中国长江流域冬麦区小麦品种试验精确度回溯分析

为全面评价长江流域小麦品种区域试验精确度的发展水平,分析了2011—2021年度中国长江流域冬麦区单年单点和一年多点小麦区域试验的试验精确度和品种比较精确度,对产量、穗数、穗粒数、千粒重、生育期、株高、基本苗和最高茎数等性状的试验精确度差异进行了比较。结果表明,长江流域冬麦区单年单点品种试验精确度较好,试验误差变异系数(CEV)在5%和10%以下的试点数占比分别在60%和95%以上,但品种比较精确度(RLSD_0.05)在3%以下的试验比例不到10%,长江上游和中下游单点品种试验RLSD_0.05在10%以下的试点数分别占比约60%和90%。一年多点区域试验精确度和品种比较精确度显著优于单年单点试验,上游和中下游试验平均CEV分别在8%和5%以下。采用试点固定模型时,长江上游和中下游试验平均RLSD_0.05分别为2.19%和1.49%,符合国家小麦品种审定标准对品种比较精确度的要求;但采用试点随机模型时,小麦品种试验尚无法鉴别出品种间3%的产量差异。试验对生育期、株高、基本苗、千粒重和穗数的RLSD_0.05优于产量性状,而最高茎数和穗粒数的RLSD_0.05较低。     

小麦种质资源耐深播性评价体系研究

为建立准确、简单易行的种质资源耐深播评价体系,以15份耐深播能力存在不同程度差异的小麦种质为材料,在大田环境下,研究6个播种深度(5 cm、7 cm、9 cm、11 cm、13 cm、15 cm)下小麦出苗率、出苗时间、苗高、地中茎长、胚芽鞘长、胚芽鞘横截面积及初生根长的差异,筛选小麦耐深播评价的最佳播种深度及其密切相...     

Studies on Agronomic Traits of African Rice (Oryza glaberrima Steud.): IV. Changes in growth,dry matter productivity and yielding ability related to domestication from wild to cultivated form

Abstract

The changes in growth, dry matter productivity and yielding ability in the course of domestication from O. breviligulata to African rice (O. glaberrima) were examined. Between the two rice species, differences were hardly detected in plant height, culm length and final leaf number, although O. breviligulata had a wider variation of these characteristics as compared with African rice. The shorter strains tended to produce more tillers at the maximum tiller number stage, and the high tillering capacity was correlated with a low percentage of productive tillers, although the strains having a small number of grains per head showed a high percentage of productive tillers, in both species. No significant difference was detected between the two species in straw weight at maturity, and the differences in straw weight among strains were attributed to the differences in days required from transplanting to heading and to plant height. No significant difference between the two species was observed in top and total weights. The grain number per head was conversely related with panicle number in both species. Although the percentage of ripened grain tended to be slightly lower in O. breviligulata than in African rice, this may be attributed partly to the difference in grain number per hill. Single grain weight in O. breviligulata was nearly equal to that in African rice. These results suggest that agronomic traits such as growth, dry matter productivity and yielding ability have been changed only slightly in the course of domestication from O. breviligulata to African rice.     

Quantitative trait loci for seedling vigor in rice under field conditions

Previous QTL studies on seedling vigor in rice (Oryza sativa L.) were conducted all based on laboratory germination tests. In the current study, a set of recombinant inbred lines derived from a rice cross were assessed for seedling vigor related traits in natural field environments including two treatments (drained soil and flooded soil). Composite interval mapping identified nine QTL for seedling vigor traits that correlated positively with each other. Individual QTL explained 4–14% of the total trait variation. Among the QTL, three and four were specific to the drained and flooded treatments, respectively, while two others were common between the two treatments. Four QTL (qFV-1-1, qFV-3-2, qFV-5-1 and qFV-10) each simultaneously showed effect on two or more traits with additive effects always in the same direction. The QTL qFV-5-1 could be further resolved into at least two linked loci, qFV-5-1a controlling seedling height and qFV-5-1b controlling seedling dry weight while the QTL qFV-10 could be a single locus with a pleiotropic effect on both seedling height and dry weight. The QTL qFV-1-1 and qFV-3-2 expressed specially under the flooded conditions, each pleiotropically controlling both coleoptile and seedling emergence. These two QTL were completely different from that affecting seedling emergence in the drained conditions. Comparison of the QTL indicated that the QTL mapping results based on field assessments could to some extent coincide with those based on lab tests but the discrepancy between the two kinds of experiments could not be overlooked.     

Influence of long photoperiods on the growth of timothy (Phleum pratense L.) varieties from different latitudes in northern Europe

Plants of three varieties of Phleum pratense L. from different latitudes (cv. Engmo, 69°N; cv. S48, 52°N; cv. Motim, 52°N) were grown from the five-leaf stage at 12°C under continuous illumination or 8-h days at essentially identical daily inputs of radiant energy. The responses to daylength extension (increase in plant dry weight, plant height and leaf dimensions and reduction in the number of tillers per plant and in tissue dry matter content) were common to all three varieties and although the enhancement in plant dry weight and in leaf size was greater in the Engmo plants, this was principally the result of poorer growth and smaller leaf size in 8-h days. Marked differences between Engmo and the other varieties in the partitioning of dry matter within the plant were the consequence of differences in the rate of reproductive development. For example, compared with S48 and Motim, first spike emergence and 50% anthesis in the Engmo plants were delayed by 22 and 14 days, respectively, and 40% of the Engmo plants did not become reproductive even after 110 days of long-day treatment. Furthermore, by the time that 50% anthesis of the mainstem spike had been reached by the long-day plants of each variety, significant differences in tiller numbers and tiller fertility had developed between the varieties from high and lower latitudes. These findings and the results of previous studies of Poa pratensis, Dactylis glomerata and Bromus inermis are discussed in relation to the adaptation of high-latitude grasses to the Scandinavian environment.     

播期对不同穗部特征小麦品种(系)生育期和农艺性状的影响

为了解播期对多小穗和寡小穗小麦生育期及农艺性状的影响,对13份不同来源的小麦品种(系)两年分期播种的生育期和6个农艺性状(株高、单株有效分蘖数、穗长、每穗小穗数、穗粒数和千粒重)进行了分析和评价。结果表明,播期的推迟导致材料间出苗期差异变大,抽穗期差异缩小,但开花期和成熟期差异变化不大,各农艺性状值减小。经方差分析,各农艺性状在不同播期和品种(系)间均存在极显著差异,其中单株有效分蘖数的变异系数最大,穗粒数次之,每穗小穗数最小。多小穗材料10-A和寡小穗材料BE89的穗长、每穗小穗数和穗粒数在播期间差异较小。经相关分析,播种至出苗和分蘖至抽穗天数与温度呈极显著负相关,出苗至分蘖和开花至成熟天数与平均日照时间呈显著负相关,抽穗至开花天数与温度和降水量呈显著负相关。经多元逐步回归分析,日最高温和日均温对多小穗和寡小穗材料的分蘖至抽穗天数有显著影响,平均日照时间在开花期、日最高温在成熟期分别对多小穗材料发育有显著影响。由此可见,小穗数特异性材料的每穗小穗数在不同播期下能保持稳定。