Hybridizing <Emphasis Type="Italic">Brassica rapa</Emphasis> with wild crucifers <Emphasis Type="Italic">Diplotaxis erucoides</Emphasis> and <Emphasis Type="Italic">Brassica maurorum</Emphasis>

Two wide hybrids, Diplotaxis erucoides (2n = 14) × Brassica rapa (2n = 20) and B. maurorum (2n = 20) × B. rapa, were developed using the sequential ovary–ovule culture. Reciprocal crosses failed, possibly as a consequence of strong unilateral incompatibility. The F ₁ hybrids in each combination were completely male sterile and morphologically intermediate to the respective parents. DNA marker polymorphism and chromosome counts confirmed their hybrid nature. High frequency of bivalents in the F ₁ and the presence of trivalents/quadrivalents in the derived amphiploids suggested genomic duplications and homoeology of the parental genomes. Up to three homoeologous pairs between the D. erucoides (D^eD^e) and B. rapa (AA) genomes, and one between B. maurorum (B^mB^m) and B. rapa genomes were observed. Successful synthesis of the F ₁ hybrids and amphiploids of B. rapa with D. erucoides and B. maurorum, and allosyndetic chromosome pairing are expected to permit introgressions of desirable loci into the cultivated Brassica germplasm, especially for resistance to Alternaria brassicae and Albugo candida.     

Plants regenerated from embryo cultures of an apomictic clone of Kentucky bluegrass (Poa pratensis L. ‘Baron’) are not apomictic in origin

Plants were regenerated from tissue cultures of embryos dissected from seeds that were harvested from a self-pollinated clonal selection of Kentucky bluegrass (Poa pratensis L.) ‘Baron’, an apomictic cultivar. Plants were regenerated from 35 embryo-derived callus cultures of the 3280 embryos that were plated. Flow-cytometric (FCM) and RAPD-marker analyses were performed to determine if regenerants were or were not apomictic in origin. Fifteen regenerants with a 3c DNA content were classified as arising from 2n + n aberrant embryos, which was a higher frequency than expected, based on a chi-square analysis. Of the remaining 20 regenerants with a 2c DNA content, a chi-square test showed that all could have arisen from n + n sexually-derived embryos, based on the observed segregation of n + n regenerants, which fit the expected 3:1 ratio of dominant:recessive RAPD-marker phenotypes. The apparent lack of regenerants of apomictic origin, and implications for genetic transformation and breeding of Kentucky bluegrass are discussed.     

A Control Algorithm to Regulate the Active and Reactive Power and Simulation Research of Dual-frequency Dual-Buck Inverter

This paper deduceS the control algorithm ,which can both regulate the active and reactive power of the novel dual-frequency dual-Buck inverter, and the control function. The control function based on one cycle control can control the AC-side active and reactive power by simple circuit. The simulation is given and the results prove the validity of the theory analysis. This inverter is valuable for the research of grid-connected inverters.     

Inheritance and relationships of important agronomic traits in almond

The inheritance of 16 important agronomic traits and its relationship were studied for four years in a population of 167 almond [P. dulcis (Mill.) D.A. Webb] seedlings obtained from a cross between the French selection ‘R1000’ (‘Tardy Nonpareil’ × ‘Tuono’) and the Spanish cultivar ‘Desmayo Largueta’. For some traits (blooming and leafing date) descendants segregated between the value of both progenitors, meanwhile for others the mean of the offspring was lower (bloom density, productivity and ripening date) or higher (in-shell/kernel ratio and double kernels). As expected, kernel bitterness and self-incompatibility behaved as monogenic traits. Some important correlations between traits were detected. The implications of the transmission and the correlation of these traits in the breeding programmes are discussed.     

A Integrate-Reset-Controlled Single Phase Power Factor Correction with High Efficiency

A novel single phase boost type power factor correction circuit is introduced .The converter's efficiency is greatly improved by improving on the traditional boost type power factor correction circuit. Integrate Reset Control circuit is adopted to realize unity power factor. The Integrate Reset Control high efficiency single phase boost type power factor corrector has these characteristics as follows: It's constant frequency operation, which is of advantage of the design of filter. The control circuit is very simple and no need for multiplier. The result is quiet perfect, the input current follows the input voltage very well. The efficiency is very high. The result of simulation and experiment proves the correction of theory analysis.     

华北寒旱区开放型农作制度的创新与实践

华北寒旱区位于内蒙古高原南缘的冀、晋、蒙长城沿线,区域资源匮乏、生境恶劣。经过多年封闭的农牧业过度开发产生低产低效、经济贫困、环境退化演替等问题。区域通过发展冷凉蔬菜生产,发挥区域间互补优势引进外部资源,同时结合国家的退耕政策该区域成功开启了经济生态良性互动可持续发展。实现资源高效利用、增产增收、环境改善。     

国内蔓性长豇豆系列品种的抽测与综合评价

通过田间试验对国内31个蔓性长豇豆品种进行重复鉴定。结果表明,约有四分之一的品种质量不合格;约有十分之九的品种不早熟,产量与对照之豇28-2差异不显著,约有二分之一的品种抗病性比对照差。国内虽有众多品种育成,但由于遗传性状的局限性而不能取代老品种之豇28-2。长豇豆虽然是高度自花授粉作物,但忽视选择也极易混杂退化。黑子类品种和柱头外露品种在留种繁殖,更要注意品种间隔离,并要多次进行去杂去劣。     

水稻雄性不育突变体012S-3的遗传分析和基因定位

雄性不育是水稻杂种优势利用的重要资源,对雄性不育现象的研究具有重要理论意义和实践价值。本研究以自然突变的水稻雄性不育突变体012S-3为试验材料,对其表型特征和花粉育性等进行调查,并构建遗传群体,利用分子标记对目的基因进行初步定位,然后应用基因组重测序技术对其进行精细定位。结果表明,012S-3是一个典型的无花粉普通型雄性不育材料,其不育性状受1对隐性核基因控制。初步定位分析目的基因与SSR标记RM6081存在连锁关系,其遗传距离约为34.4 c M;进一步的精细定位分析,找到3个候选基因:LOC_Os07g35880、LOC_Os07g35920和LOC_Os07g35940,其中LOC_Os07g35880和LOC_Os07g35940编码β-淀粉酶,属于水稻中新发现的花粉致死基因。该不育基因的成功定位为其进一步的分离克隆及其在水稻分子设计育种中的应用奠定了基础。     

银鹊树种子萌发过程中的过氧化物酶和酯酶同工酶的变化

应用聚丙烯酰胺凝胶垂直平板电泳对珍稀濒危植物银鹊树种子萌发过程中过氧化物酶（POD）和酯酶（EST）同工酶动态变化进行了研究。结果表明：在种子萌发过程中POD同工酶在萌发初期出现新酶谱带，随着萌发的推进，一些原有的谱带加深；EST同工酶在萌发过程中没有新的谱带出现，但原有谱带颜色不断加深，表明酯酶代谢合成的增强。