不同生态条件对玉米郑单22生长发育及产量的影响

通过播种期试验,研究了不同生态条件对玉米品种郑单22的生长发育和产量的影响。结果表明,在河南夏播条件下,随着播种期的推迟,郑单22的产量逐渐下降,穗行数、行粒数和千粒重均逐渐降低,生育进程加快,叶面积指数最大值、干物质积累量逐渐减小,但6月15日以前播种的差异不大。适宜生态条件为：全生育期积温2835.1~3038.2℃,至2560.4℃产量严重下降;全生育期日均温度为25.3~25.7℃,至25.1℃产量严重下降;全生育期光照484.2~630.4h,至420.7h产量严重下降;全生育期日均光照为4.3~5.3h;至4.1h产量严重下降     

高淀粉玉米新品种郑单21生态适应性研究

通过播种期试验，研究了不同生态条件对高淀粉玉米品种郑单21的生长发育和产量的影响。结果表明，在河南夏播条件下，随着播种期的推迟，郑单21的产量逐渐下降，穗行数、行粒数、千粒重逐渐降低，叶面积系数最大值、干物质积累量逐渐减小，生育进程加快，但6月15日以前播种差异不大；适宜生态条件为：全生育期积温2596．2—2764．5℃，至2307．7℃产量严重下降；全生育期日均温度为23．2～24．0℃，至22．6℃产量严重下降；全生育期光照514．9～603．2h，至425．3h产量严重下降；全生育期日均光照为4．6～5．3h；至4．3h产量严重下降。     

不同生态条件对玉米郑单23生长发育及产量的影响

摘 要：通过播种期试验,研究了不同生态条件对玉米品种郑单23的生长发育和产量的影响。结果表明,在河南夏播条件下,随着播种期的推迟,郑单23的产量逐渐下降,穗长、穗粗、百粒重均逐渐降低,生育进程加快,叶面积指数最大值、干物质积累量逐渐减小,但6月15日以前播种的差异不大。适宜生态条件为：全生育期积温2835.1~3038.2℃,至2560.4℃产量严重下降;全生育期日均温度为25.3~25.7℃,至25.1℃产量严重下降;全生育期光照484.2~630.4h,至420.7h产量严重下降;全生育期日均光照为4.3~5.3h;至4.1h产量严重下降。中图分类号：S513 文献标识码： A     

不同生态条件对高淀粉玉米品种郑单18生长发育及产量的影响

通过不同生态条件对郑单18号生长发育及产量的影响研究，在河南夏播条件下，随着播种期的推迟，郑单18号的产量逐渐下降，穗行数、行粒数、千粒重逐渐降低，叶面积系数最大值变小，生育进程加快，生育期缩短；适宜生态条件为：全生育期积温2674.9—2860.8℃，至2496.0℃产量严重下降，全生育期日平均温度24.8—25.8℃，至24.5℃产量严重下降，对光照条件要求不严格。     

高产高淀粉玉米新品种郑单21生态适应性研究

通过播期试验,研究了不同生态条件对高淀粉玉米品种郑单21的生长发育和产量的影响。结果表明,在河南夏播条件下,随着播期的推迟,郑单21的产量逐渐下降,穗行数、行粒数和千粒重均逐渐降低,生育进程加快,叶面积系数最大值、干物质积累量逐渐减小,但6月15日以前播种的差异不大。适宜生态条件为：全生育期积温2596.2~2764.5℃,至2311.7℃产量严重下降;全生育期日均温度为23.2~24.0℃,至22.7℃产量严重下降;全生育期光照514.9~603.2h,至436.7h产量严重下降;全生育期日均光照为4.6~5.2h;至4.3h产量严重下降。     

张家口坝下地区夏播小麦病害问题考察

张家口坝下地区,在冬麦不能越冬和春麦因干旱产量低而不稳的情况下,在高海拔1400~1800米的山区或丘陵地带进行春麦夏播,或进行春小麦加代繁殖。小麦生长情况有些与川地比较不相上下,是个一举多得的……     

丘陵旱地夏播小麦高产品种性状分析及选育目标的探讨

一、试验研究方法为了筛选适宜夏播的小麦品种,我们自1981—1983三年先后从各地广泛征集了国内外春小麦品种资源723个。在夏播小麦适宜栽培地区,海拔为1000公尺的丘陵旱地,选择了太原市北郊区丈子头公社丈子头大队进行引种观察试验。当地因春旱比较严重,冬、春小麦产量极不稳定,丰收年亩产仅百斤左右。夏播小麦可以躲过春旱,充分利用夏秋降雨。太原7月上旬     

四川盆地丘陵区小麦-玉米模式夏玉米适宜播期研究

以仲玉3号、蠡玉16、成单30为试验材料,研究不同播期对小麦-玉米模式夏玉米产量和生育进程的影响。结果表明:夏玉米吐丝期和成熟期随播种期推迟而延迟,生育期总天数随播种期推迟而减少;在四川盆地丘陵区的生态条件下,小麦-玉米模式夏玉米适宜的播种期为5月上旬和中旬,5月上旬和中旬播种的产量差异不显著,随着播种期的延后,5月下旬播种的产量下降,6月上旬和中旬播种产量下降明显。     

夏播小麦品种选育目标

我们在1981~1983年从各地征集了国内外春小麦品种,在太原市北郊海拔1,000米的丘陵旱地进行夏播引种试验,初步筛选出一些适于夏播的小麦品种。 一、选生育期较长的品种 太原地区,一般6月下旬至7月初进入雨季,10月上中旬出现早霜,夏播小麦的最长生长日期不超过100天。从筛选的结果看,高产品种为生育期较长(90天左右)的     

绿豆新品种冀绿7号产量影响因素的研究

在绿色标准化生产条件下,研究了播种期、密度和施肥量三因素对绿豆新品种冀绿7号产量和品质的影响.研究结果表明:播种期对冀绿7号夏播绿豆产量的影响最大,其次是密度,最后是施肥量;冀中南地区夏播绿豆产量和品质影响因素的最优组合是6月20日播种、密度1.2万株/667m2、施肥量10kg/667m2.     

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.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

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.     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.