Analysis of reproductive isolation between pearl millet (Pennisetum glaucum (L.) R.Br.) and P. ramosum, P. schweinfurthii, P. squamulatum, Cenchrus ciliaris

Crosses between pearl millet lines and Pennisetum ramosum, P. schweinfurthii, P. squamulatum or Cenchrus ciliaris were observed for the frequency and development of zygotes, the possibility of embryo rescue, and the fertility of F1 hybrids obtained. Eight per cent of the ovules from diploid millet × P. ramosum crosses showed small embryos which could not be rescued. However, 59% of the ovules from tetraploid millet × P. ramosum crosses showed well-developed embryos that were easy to rescue 14 days after pollination. F1 hybrids were male sterile but female fertile when pollinated by diploid millet. Both diploid and tetraploid millet ovules showed the presence of hybrid zygotes after pollination with P. schweinfurthii at rates ranging from 25% to 45%. The diploid millet× P. schweinfurthii hybrid zygotes often developed almost normal seeds giving, without embryo rescue, totally sterile plants. The tetraploid millet × P. schweinfurthii hybrid embryos were normal but the endosperm was severely defective. A hybrid obtained by embryo rescue was totally sterile. A diploid millet-P. schweinfurthii amphidiploid was obtained by somatic embryogenesis associated with colchicine treatment during callogenesis. This amphiploid plant was male sterile, but gave many seeds when pollinated by a tetraploid millet and few seeds when pollinated by a diploid millet. P. squamulatum pollinating diploid millets produced proembryos with large undifferentiated endosperms in 73% of the ovules. A normal seed set was observed on tetraploid millets pollinated by P. squamulatum and the resulting F1 hybrids were partially male and female fertile. Backcrosses of these hybrids were much more fertile when pollination was from a tetraploid millet rather than from a diploid millet. C. ciliaris pollinating a diploid millet showed, in 60% of the ovules, proembryos and endosperms similar to those observed with P. squamulatum and no hybrid could be rescued. Crosses with a tetraploid millet could not be attempted due to the pistil-pollen incompatibility of tetraploid millets available with C. ciliaris. Ploidy levels of mating partners do not seem to influence pistil-pollen compatibility, but play a major role in post-zygotic abortion. With adequate ploidy levels of parents, and embryo rescue, it seems that the pearl millet gene pool can be considerably enlarged by germplasm from many other species.     

Is the European plum,Prunus domestica L., a P. cerasifera EHRH. x P. spinosa L. allo-polyploid?

Summary The mode of origin of the hexaploid (6x=48) European plum Prunus domestica has been re-examined. It is argued that the evidence in support of an allo-polyploid origin and the participation of 4x P. spinosa in the formation of this fruit tree is far from being satisfactory. Instead, the morphological affinities between P. domestica, P. spinosa and P. cerasifera (= P. divaricata) and the available cytogenetic evidence seem to implicate 2x, 4x, 6x P. cerasifera as the sole wild stock from which the cultivated 6x European plum could have evolved.     

Relationship changes between lowlander and hill tribes in Xishuangbanna,P.R. China

Xishuangbanna, which is well known for its ethnic diversity, is located in the upper reaches of the Mekong River. Dai lowlanders make up one third of the total population, 13 other indigenous highland groups make up another third and the balance are Han Chinese. The research on which this paper is based was conducted in three villages, Dai, Hani and Jinuo communities and designed to explore the changing relationships between lowlanders and highlanders. It was found that over the past five decades two critical events triggered profound changes. One was liberation by the Chinese Communist Party in 1950, and the other the land and economic reform policies introduced at the beginning of the 1980s.     

远志对氮磷钾需求特性的研究

为研究栽培远志对氮、磷、钾的需求特性，指导产区大田生产，采用三因素三水平正交试验设计。结果是氮、磷、钾在不同施用条件下，远志单产有显著性差异。结果发现栽培远志氮、磷、钾的合理施肥比例为1:1.04:1.34，每公顷年平均施肥量为尿素390kg，重过磷酸钙405kg，硫酸钾480kg。     

关于《中华人民共和国种子法》及其配套规章实施中存在的主要缺失与修改建议

<中华人民共和同种子法>(以下简称<种子法>)颁布实施9年来,对规范品种选育和种子生产、经营、使用行为,维护种子"四者"的合法权益,提高种子质量水平,推动种子产业化,促进农业发展发挥了重要作用.<种子法>前瞻性较强,罚责具体,在农业法律体系中是一部良法,但是,由于它是在我国市场经济发展不是很成熟的背景下出台的第一部专门的种子法律,因立法经验和体制机制等原因,本身不可避免地存在一定的局限性,特别是在实施过程中,也暴露出一些不容忽视的问题.     

沙埋对毛乌素沙地沙芥和斧形沙芥幼苗生长的影响

为探讨沙生植物幼苗对沙埋逆境的适应机理,以中国特有种沙芥(Pugionium cornutum L.)和濒危种斧形沙芥(Pugionium dolabratum Maxim)为研究材料,取自然生境的沙土,采用人工模拟试验,研究沙埋对沙芥、斧形沙芥幼苗生长的影响。结果表明：遭受沙埋后,沙芥和斧形沙芥幼苗节间伸长的顺序均为T2/3>T1/2>T1/3>T0。沙埋深度在沙芥与斧形沙芥幼苗高度的1/3、1/2时,幼苗存活率100%,地上干重、总生物量、叶面积增长百分率、每天净增加的生物量和每天单位面积所固定的净光合产物均明显高于对照,根冠比显著低于对照;沙埋深度在幼苗高度2/3时,沙芥和斧形沙芥存活率分别为80%、60%,以上各指标均明显低于对照,根冠比显著高于对照;全部沙埋时,均不能成活。本研究说明,沙芥、斧形沙芥幼苗对沙埋具有较强的适应性,当幼苗遭受到沙埋后,沙芥、斧形沙芥延长了节间伸长和分配较多的生物量用于地上部分的生长,这种生长方式和分配模式可能是沙芥和斧形沙芥幼苗对沙埋环境的重要适应对策。     

The importance of wild potato species resistant to the potato cyst nematode,Globodera pallida,pathotypes P4A and P5A,in potato breeding. I. Resistance studies

Summary Seven wild diploid potato species, Series Tuberosa, representing 1023 clones were screened for resistance to the potato cyst nematode, Globodera pallida. Over 25% of the clones were resistant to pathotype P₄A and almost 30% were resistant to pathotype P₅A. The resistance in hybrid progenies of these and other resistant species with cultivated potatoes was evaluated, and over 2200 seedlings were screened. High frequencies of resistance (>50%) to P₄A were found in progenies with Solanum leptophyes, S. vernei, S. gourlayi and S. capsicibaccatum, whereas resistance to P₅A was found in these species as well as S. sparsipilum. The importance of nematode resistant wild species for potato breeding is discussed.     

Genetics of isozyme variants in Populus tremula,P. tremuloides and their hybrids

Summary Eight Populus tremula and six P. tremuloides clones as well as 49 full-sib families were studied in GOT, LAP, 6-PGDH, and SKDH by horizontal starch gel electrophoresis. For GOT one polymorphic zone was found and segregation of seven full-sib families suggests Mendelian inheritance. For LAP and 6-PGDH two zones each were clearly scored. For LAP two polymorphic loci were proposed based on the phenotypic segregation of isozyme variants in six and 34 full-sib families, respectively. In 24 full-sibs families the presence of null alleles was inferred for both loci. The genetic control of the upper zone of 6-PGDH was demonstrated by a segregation analysis of 17 full-sib families. SKDH also demonstrated a Mendelian inheritance pattern in 12 of the full-sib families analysed. The electrophoretic patterns of pollen were similar to those of buds, but migration rates of the supposed corresponding isozymes were slightly modified (Lap-B, Skdh, 6Pgdh-A). Lap-A was not present in pollen extracts and hybrid bands were not found when gels were stained for dimeric enzymes (6-PGDH, GOT).     

Environmental Impact Modeling of Urban Sprawl in Beijing, P. R. China

City expansion is a major driving force altering local and regional hydrology and increasing non point source (NPS) pollution. To explore these environmental consequences of urbanization, long term runoff and NPS pollution were assessed in Beijing, P. R. China. The assessment was based on land use types, soil hydrology, and long term precipitation data. The environmental impact model L THIA was used. The outcomes indicate that the area likely would be subjected to impacts from urbanization on runoff and some types of NPS pollution. Urban sprawl will increase runoff volume considerably and significantly increase losses of COD and certain heavy metals such as Pb, Zn in runoff. The results of this study have significant implications for urban planning and decision making efforts to protect and remediate water and habitat quality in the Beijing area. The techniques described herein can be used in other areas.     

Genetic Control of Abnormal Seedling Development in Phaseolus vulgaris L. and P. vulgaris×P. acutifolius A. Gray Hybrids

Abnormal hybrid seedling development hinders attempts to introgress diverse germplasm in common bean (Phaseolus vulgaris L.) breeding programs. In this study, the hypothesis that DL₁ and DL₂ loci control abnormal seedling development both in Phaseolus vulgaris L. intraspecific hybrids and in P. vulgaris×P. acutifolius A. Gray interspecific hybrids was tested. Hybrids from crosses between six P. vulgaris lines (two Andean dl₁ d₁, DL₂DL₂, two Mesoamerican DL₁DL₁ dl₂ dl₂, and two facilitators dl₁dl₁, dl₂dl₂) and P. vulgaris cultivar Ex Rico 23 developed normally, indicating that Ex Rico 23 has the facilitator genotype dl₁, dl₁, dl₂dl₂. Previous studies have shown that Ex Rico 23 ×P. acutifolius results in abnormal seedlings, but ‘ICA Pijao’, also dl₁, dl₁ dl₂dl₂, ×P. acutifolius results in normal seedlings. Neither the Andean nor the Mesoamerican lines crossed successfully with P. acutifolius, but crosses between one of the two facilitators (G3807) and P. acutifolius resulted in normal seedlings. These results support the hypothesis that different loci control intra- and interspecific hybrid seedling development.     

红叶李与安哥诺李及其杂交子代的RAPD分析

利用随机扩增多态性DNA分子标记（RAPD）技术对红叶李与安哥诺李及其杂交子代中的10株植株进行遗传多样性分析。从100个随机引物中筛选出15个引物,然后对所有子代进行分析。利用PopGene3.2软件分析所得图谱的多态位点数、多态位点百分率、Shannon信息指数(I)、Nei's基因多样性指数(H)、遗传距离和遗传一致度。用DPSv2.0软件依据所得到的遗传距离,按照非加权平均距离法（UPGMA）构建树状图。结果表明：15个随机引物共扩增出多态条带89个,总的多态位点百分率为93.54%,平均Shannon信息指数为0.4298,平均Nei's基因多样性指数为0.3574,说明杂交后代具有较丰富的遗传多样性。从树状图可以看出杂交子代的遗传变异较丰富,其中1号植株与母本亲缘关系最近,最有可能稳定遗传母本的红叶性状。     

The importance of wild potato species resistant to the potato cyst nematode,Globodera pallida,pathotypes P4A and P5A,in potato breeding. II. The crossability of resistant species

Summary Over 2400 pollinations were made to investigate the crossability relationships between cultivated potatoes, and wild diploid species from Series Tuberosa and Circaeifolia, as well as wild polyploid species in Series Tuberosa and Longipedicellata resistant to potato cyst nematode, Globodera pallida pathotypes P₄A and P₅A. Wild diploids in Series Tuberosa crossed easily with cultivated diploid species, except with Solanum lignicaule where most pollinations failed, and seed set was extremely low (0.2 seeds per pollination or less). It is suggested that this species is 1EBN. S. capsicibaccatum is clearly isolated from Series Tuberosa, but can form hybrids with S. lignicaule, which can act as a bridging species to S. tuberosum haploids. S. gourlayi and S. oplocense can be crossed with both subspecies of S. tuberosum, but S. papita, Series Longipedicellata is reproductively isolated from the tetraploid cultigens. The crossability data are discussed in the light of germplasm utilisation for breeding potato varieties resistant to potato cyst nematode.     

Research on and Improvement Measures for Building Volume of Residential Quarters in Chongqing, P. R. China

Through research and analysis on residential quarters in five large core zones in the city of Chongqing,P.R.China,it is found there are higher building volumes,smaller exploiting scale,and monotonous building forms in completed residential quarters.This leads to a series of problems influencing the living environment quality,including a low green cover rate,small open spaces,short distances between buildings,and insufficient natural daylight and aeration.By analyzing the influence of high building volumes on social consciousness,economic benefits,environmental hygiene and safety,this paper brings forward some improvement measures aimed at the problems in residential quarter construction in Chongqing.     

Morphology,cytology and forage potential of Pennisetum americanum (L.) K. Schum. x P. Purpureum Schum. amphidiploids

Summary F₁ hybrids between short-day photoperiod- sensitive maiwa bulrush millet, Pennisetum americanum (2n=14), and elephant grass, P. purpureum (2n=28), are triploid (2n=21), sterile, and can only be propagated vegetatively. Fertile amphidiploids, (2n=42, with 21 bivalents) were produced by colchicine treatment. Good seed set was obtained upon selfing the amphidiploids and the progeny exhibited variable pollen fertility and bivalent univalent and multivalent formation.Reciprocal crosses between elephant grass and the colchicine-induced amphidiploid failed to produce seeds. The maiwa millet x amphidiploid cross resulted in poor seed set and the reciprocal failed. Maiwa x amphidiploid hybrids were pollen sterile with 2n=21, rather than the expected 2n=28, indicating chromosome elimination.Morphologically, the amphidiploids and maiwa x amphidiploid hybrids closely resembled elephant grass and the F₁ hybrid. The amphidiploids showed no superiority over the F₁ hybrid and elephant grass in either forage yield or quality but one maiwa x amphidiploid genotype surpassed a promising local elephant grass selection in forage dry matter yield and flowered for a relatively short period.     

五味子及其栽培技术

五味子,别名北五味子,是著名的药用植物.由于它是北温带森林的层间植物,因此,对森林环境有较强的依附性.在我国,五味子一直处于野生状态.论述了五味子的资源现状、栽培历史、生物特性、生态特性、栽培技术和采收贮藏.