甘薯脱毒试管苗直繁种苗技术及生产应用研究

甘薯脱毒试管苗直繁种苗技术通过试管苗继代扩繁、日光温室暖棚扩繁、塑料大棚扩繁、大田扩繁等,1株试管苗可扩繁60000株生产用脱毒种苗,具有生产周期短、扩繁效率高、感染病毒率低,种苗质量稳定等优点,已在生产中获得推广、应用,是一种新的脱毒甘薯繁育技术。本文介绍了甘薯脱毒试管苗直繁种苗的生产流程,并对直繁种苗和种薯繁苗2种繁殖方式的成本、农艺性状及产量进行了对比,以期为我国脱毒甘薯繁育体系的更新提供参考。

甘薯脱毒试管苗直繁种苗生产技术体系的创建

推广应用甘薯脱毒苗是目前防治甘薯病毒病、提高甘薯产量和品质的唯一有效方法。详细介绍了甘薯脱毒试管苗直繁种苗生产技术体系的创建,主要包括茎尖脱毒培养、试管苗继代扩繁、日光温室扩繁、防虫网塑料大棚扩繁及大田扩繁等技术环节,阐明了河南省甘薯脱毒试管苗直繁种苗具体生产流程,并与常规薯块育苗技术体系进行了比较。甘薯脱毒试管苗直繁种苗生产技术体系中试管苗的扩繁完全在室内进行,全年可灵活安排生产;且种苗繁育过程不经历种薯生产环节,繁育周期大大缩短,减少了种苗感染病毒病的风险,提升了种苗质量。

Different Understory Cultivation Techniques of Paris polyphylla Smith

This study was conducted for the purposes of reducing consumption of wild resources of Paris polyphylla Smith, satisfying the market demand, saving the production cost, improving utilization rate of forest land, increasing income of foresters and protecting ecological environment. Three types of fores{ land, i.e., the evergreen forest land （China fir forest）, deciduous forest land （walnut forest） and shrub land （honey suckle forest.） were selected, and seeds and cut rhizomes of Paris polyphylla Smith produced in Bamian Mountain, Hunan, were used in the study on understory seedling raising and cultivation techniques. The results showed that： when using different propagation materials, seed propagation could be adopted to reduce the consumption of wild resources and provide a large number of seedlings, and was beneficial to large-scale planting; and when conducing seedling and plantlet raising followed by transplanting and direct seeding and planting using different propagation materials in large-scale understory cultivation, direct seeding/ planting was appropriate for saving save production cost with the advantage of early production. Among the 3 different types of forest land, the best choice was broad- leaved forest land, which could achieve better economic benefit because of con- forming with the ecological habit and growth and development law of Paris poly- phylla Smith.

Performance and Inheritance of Rice Starch RVA Profile Characteristics

The classification and inheritance of rice starch RVA profiles were studied by testing RVA profiles of F2 clonally propagated population and some varieties, including japonica, indica, and glutinous types. All the RVA profiles of accessions could be divided into six kinds based on the cluster analysis, that is A, B, C, D, E and F. Feature profile of sticky variety was type A. The profiles of indica varieties could be presented as B, C, D, E and F types and that of japonica varieties fell into D, E and F types.RVA profiles of the rice were mainly affected by apparent amylose content (AAC), but the difference of RVA profiles could also be detected in the varieties with similar AAC. The close relationship between RVA profile indices and sensory of low or middle AAC varieties suggested that the RVA profiles can be used as indirect index to evaluate eating and cooking quality. In four hybrid combinations, the component indices of RVA profiles of F1 were between those of its parents except peak viscosity and pasting temperature. Also, in F2 clonally propagated population, all the components of the RVA profiles showed continuous segregation,suggesting that all of them were controlled by a series of minor genes, although Wx gene may play an important role in determining the RVA profiles. These results may provide some new information useful for rice quality breeding program.

Oscillating Propagation of Kink in Nondissipative Frenkel-Kontorova Chain Due to External DC Force

We report the oscillating propagation of kink in a nondissipative Frenkel-Kontorova （FK） chain driven by external DC force, which is different from the usual propagation of localized modes with equal speed. When the kink moves in the opposite direction of the external DC force, the kink will be accelerated and the potential of the FK chain in the external force field is transformed to be the kinetic energy of the kink. If the kink reaches the boundary of the FK chain, the kink will be bounced back and moves in the opposite direction, then the kink will be decelerated gradually and the kinetic energy of the kink ＆ transformed to be the potential of the FK chain in the external force field. If the speed of the kink reaches zero, the kink will move in the opposite direction again driven by the external DC force, and a new oscillating cycle begins. Simulation result demonstrates exactly the transformation between the kinetic energy of the kink and the potential of the FK chain in the external force field. The interesting energy exchange is induced by the special topology of kinks, and other localized modes, such as breathers and envelope solitons, have no the interesting phenomenon.

Fecundity and Distribution of Oocyte Diameters of Horse Mackerel Trachurus trachurus from Algerian Western Coast （Oran Bay）

In the present paper, a study of the productivity of oocytes in 402 female individuals of the horse mackerel, Trachurus trachurus for an interval of fork length （LF） between 14 cm and 20 cm, in stage IV （pre-spawning） and V （spawning） was performed to estimate the fecundity rate in Oran Bay （Algerian western coast） since October 2008 to April 2009. Total fecundity （absolute and relative） were calculated using fish length, weight and eviscerated weight of gonads. Absolute fecundity by size class oscillates from 33,375 to 56,391 eggs with an average of 48,686 ±11,470. The relative fecundity ranges from 34,802 to 139,636 eggs per 100 g body weight with an average of 96,955 ± 33,814 and it is varying between 15,544 and 46,561 per gram of gonad with an average of 28,595 ±20,251. The distribution of oocytes shows that stages I and II are presented throughout the spawning season and they constitute a stockpile for subsequent clutches.