超高产两系杂交稻不同施氮水平剑叶光合特性研究

研究了超高产两系杂交稻两优培九、金两优36在不同施氮水平下剑叶的光合特性,结果表明,两优培九、金两优36在每公顷施氮120kg、165kg、210kg 3种水平下,剑叶比叶重、叶绿素含量、光合速率均比对照汕优63高,这可能是两优培九、金两优36高产的生理基础之一。在每公顷施氮120~210kg的范围内,两优培九剑叶光合速率及产量均随施氮水平的增加而提高,金两优36剑叶光合速率及产量在公顷施氮165kg最高,增加到210kg时反而下降。     

施氮量对双季稻产量及其群体光合特性的影响

以早稻株两优4024、金优402和晚稻H优159、金优207为试材分析了不同施氮水平对双季稻(早稻、晚稻)产量及群体特性的影响。施氮水平设置为120,150,180,225 kg/hm2(分别记作N1、N2、N3、N4),考察各处理的产量及其形成和分蘖动态、剑叶SPAD值、剑叶光合速率以及干物质积累等变化指标。结果表明:早稻株两优4024、金优402和晚稻H优159、金优207各处理产量均呈N1、N4、N2、N3依次增加的变化趋势;4个供试组合在分蘖盛期的总生物量呈N1、N2、N3、N4依次增大的变化趋势,在齐穗后13 d、成熟期4个组合的总生物量均呈N1、N4、N2、N3依次增大的变化趋势;相关分析发现,齐穗后13 d、成熟期的叶干质量、茎鞘干质量、穗干质量、根系干质量、地上部干质量、生物总量和剑叶光合速率与产量之间均呈显著或极显著正相关。试验结果说明,在120~180 kg/hm2,增加施氮量有利于双季稻取得高产;增加施氮量可促进分蘖盛期干物质的积累,但过量施氮会影响生长后期干物质的积累;齐穗后较大的生物总量和较高的剑叶光合速率有利于双季稻取得高产。     

水稻强化栽培体系(SRI)优化配套技术探讨

以两优培九为试验材料,采用正交试验设计方法,研究了水稻强化栽培体系（SRI）秧龄、密度、施氮量等三因素三水平对两优培九产量及其构成因素的影响,建立高产的水稻强化栽培农艺措施的优化方案。试验结果表明,密度、施氮量、秧龄三因素对产量影响均达极显著水平。水稻强化栽培体系（SRI）农艺优化措施是：15d秧龄移栽,密度为每公顷栽150000丛、施氮量为每公顷在30000kg绿肥作基肥的基础上,加化肥纯氮150kg。     

直播种植模式下水稻剑叶光合、强弱势籽粒灌浆特性及产量的氮素调控

为探讨不同施氮水平对水稻剑叶光合、籽粒灌浆特性和产量的影响。以生育期较短的‘新稻567’、‘新稻568’和‘新科稻31’为试验材料,在直播种植模式下,设置3个施氮水平0、255、300 kg/hm²,分别测定抽穗后剑叶光合速率、强弱势籽粒灌浆速率和产量等指标,研究氮肥调控水稻产量的生理机制。结果表明,随着施氮量的增加,3个品种产量均呈先增加后降低的趋势;高效叶面积率和粒叶比表现为中氮水平较高,高氮水平较低。灌浆期剑叶光合速率呈先增加后降低趋势,不同氮肥处理间基本表现为中氮处理高于高氮处理;强弱势籽粒灌浆速率在整个灌浆期内呈开口向下的抛物线趋势,不同氮肥处理间的差异在灌浆盛期至灌浆中后期较大,表现为无氮和中氮处理高于高氮处理,灌浆末期处理间差异较小。产量与灌浆期剑叶光合速率呈正相关关系,与强弱势籽粒灌浆速率在灌浆初期呈负相关在灌浆中后期呈正相关关系。适度的氮肥施用量有利于提高直播水稻高效叶面积率、粒叶比,增加剑叶光合速率、强弱势籽粒灌浆速率,从而促进水稻高产。     

氮素水平对不同基因型小麦旗叶光合特性和子粒灌浆进程的影响

在池栽条件下，研究了不同施氮水平对强筋小麦8901和弱筋小麦1391生育后期旗叶叶绿素含量、光合速率、灌浆速率和产量的影响。结果表明，两品种表现为随施氮量的增加，叶绿素含量、光合速率都有增加的趋势，但是过量氮肥又使它们降低。在本试验条件下，两品种均以中氮处理(240kg／hm^2)光合速率大，灌浆进程合理，产量水平高。研究发现，强筋和弱筋小麦生育后期叶光合特性和子粒灌浆进程差异显著；旗叶光合速率和叶绿素含量及子粒产量呈正相关。     

施氮水平和栽插密度对天优华占生长和产量及产量构成因子影响

摘 要：天优华占由中国水稻研究所等多家科研单位选育而成新品种,米质优良,达到国家一级标准。因而,对于天优华占最佳氮肥用量和种植密度的研究及其高产机理的探讨,可为该品种在金华地区的大面积推广提供理论支持。以晚稻天优华占为材料,研究不同氮肥用量(0、120、165、210kg/hm2)和栽插密度(22.5万/hm2和16.5万/hm2)对水稻产量的影响,探索其最佳的栽培方式。结果表明：不同栽插密度下,不同施肥水平间天优华占产量水平差异较大。两种栽培密度下,天优华占的产量都随着氮肥用量的增加而增加。相同施氮水平,以高密度处理产量较高。高密度和低密度下,均以高肥区产量水平最高,分别达到7 464.3、6 534.8 kg/hm2。通过此研究发现,天优华占最佳栽插密度为22.5万/hm2,每1 hm2施用氮肥210 kg比较适宜。     

超级杂交稻“两优培九”剑叶叶鞘的光合功能

以超级杂交稻“两优培九”及其父本“9311”、母本“培矮64S”和三系杂交稻组合“汕优63”为研究材料,采用14C同位素示踪等技术,研究了“两优培九”剑叶叶鞘的光合能力与叶鞘光合产物的分配。结果表明,两优培九剑叶叶鞘的净光合速率均值比汕优63高0.10 µmol CO₂ m^-2 s^-1,尤以第3期,即灌浆关键时期,极显著高于汕优63,其他时期差异不显著;其叶鞘叶绿素含量的均值比汕优63高2.36 SPAD值,各期均高于汕优63,其中,第1、3期显著高于汕优63;其剑叶叶鞘的Rubisco初始活性和总活性与汕优63差异不显著,但Rubisco活化率均值比汕优63高1.52%,具有平均优势,其中第3期显著高于汕优63;其叶鞘光合产物输送到穗部的量即转化为经济产量的量比汕优63高;与父母本相比,其剑叶叶鞘光合能力的均值具有平均优势或超亲优势;水稻叶鞘完全具有同叶片一样的光合能力,只有值的大小差异;水稻叶鞘的光合产物对产量的贡献一般为10%~20%。两优培九叶鞘及叶片光合功能都较强是其具有超高产特性的一个重要原因。     

三熟制油菜秸秆还田条件下施氮量对早稻产量形成和氮肥利用率的影响

为明确油-稻-稻三熟制油菜秸秆还田条件下早稻的适宜施氮量,2017-2018年以超级常规早稻中嘉早17为材料,设置0、75、120、165、210kg/hm ²等5个施氮量,探究油菜秸秆还田条件下施氮量对早稻产量形成及氮素吸收利用的影响。结果表明：在油菜秸秆还田条件下,适宜施氮量有利于早稻分蘖成穗,灌浆期维持较高的叶面积指数、光合势和干物质积累量,同步增加单位面积有效穗数和保持较多的每穗粒数,从而扩大总库容量。在施氮量为165kg/hm ²时早稻即可达到较高产量,同时维持较高的氮肥吸收利用率。采用线性加平台模型拟合得出最佳施氮量,2017和2018两年分别为155.91、160.37kg/hm ²,产量潜力分别达8 241.17和8 387.32kg/hm ²。     

氮钾配施对强筋小麦济麦20产量和品质的影响

为了给强筋小麦品种济麦20优质高产配套栽培提供理论依据及技术支撑,在大田高产栽培条件下,研究了氮钾肥施用量及其配比对强筋小麦品种济麦20产量和品质的影响。结果表明,氮和钾及其互作对小麦籽粒产量及其构成因素的影响均达到显著或极显著水平,以每公顷施氮225kg、K2O150kg的处理产量最高。随着氮和钾肥的增加出粉率和容重均呈先增加后降低的变化趋势,籽粒蛋白质含量和湿面筋含量、沉降值均随施氮量增加而增加,籽粒蛋白质含量和湿面筋含量在每公顷施K2O 0-150Kg范围内随施钾量的增加而增多,到每公顷施K2O 210kg的处理反而降低,而沉降值随着钾肥的增加而降低。氮钾配比对籽粒蛋白质含量的影响未达到显著水平,但对湿面筋含量、沉降值的影响达到显著水平。氮肥能提高小麦面团的弹性,钾肥则提高了面团的延伸性,氮钾配比极显著提高了拉伸面积。     

拔节、抽穗期叶片SPAD值与杂交中籼稻产量及其构成因素的关系

以杂交中籼稻两优培九、丰优香占、汕优63为材料,研究不同施氮水平叶片SPAD值与产量及其构成因素的关系。结果表明:在试验条件下,随施氮量增加,初展时剑叶SPAD值先增加后降低;拔节期顶叶、抽穗期上部3张叶片SPAD值相应增加;而抽穗期剑叶SPAD值变化趋势品种间存在差异。各生育期叶片SPAD值品种间有差异。相关分析表明,拔节—抽穗期SPAD值与产量、结实率与千粒重的关系因品种而异,但剑叶SPAD值变化率与产量呈显著或极显著的负相关关系,与结实率、千粒重呈显著或极显著正相关关系。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Relation between wheat-rye crossability and seed set of common wheat after pollination with other species in the Hordeae

Summary Cultivars of common wheat (Triticum aestivum L. em. Thell.) of high wheat-rye (Secale cereale L.) crossability set more seed with pollen of other related species than did wheats of low wheat-rye crossability. This was found to be true for pollen parents from the genera Triticum, Aegilops, Secale, Agropyron and Elymus.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.