品种退化

玉米在重金属污染条件下的生态分化与品种退化

Ecological differentiation and variety degeneration of maize under heavy metal contamination

对马铃薯晚疫病的危害症状、病菌特性、侵染机理、传播途径、品种退化、气候条件、人为感染、栽培管理，以及马铃薯晚疫病防治方法等方面的研究进展进行了较为全面的综述。

The paper summarizes the harmfulness symptom , fungus character , infection mechanism and way of potato late blight , variety degeneration , climate condition , man-made infection and cultivation management , and reviews the different ways to control potato late blight in detail .

本实验就是用微卫星DNA技术对核心群中的个体进行亲缘关系分析，为建立合理的选配制度提供参考，防止近亲繁殖引起的品种退化，加快品种选育进程。

This study analyzed the relation of the goats in nuclear group using microsatellite DNA technology and it could be referred in establishing of a rational breeding system to avoid trait degeneration caused by inbreeding and to quicken the process of breeding .

中国狐狸养殖品种退化原因及改良措施探讨

The Approach of Fox Species Devolution and Measures for Development in China

针对湟源县绵羊品种退化，生产性能低下，制约着养羊业的发展。

Sheep breed degraded and productivity was low , developing of sheep multiplication was restricted .

油桐选优去劣是防止品种退化、实现油桐良种化的主要途径。

To select the improved varieties of Tung trees is a main approach to prevent the breed from degenerating .

近十几年来，坛紫菜品种退化、产量降低、质量下降，本实验通过诱变处理，筛选和培育优质高产的坛紫菜新品系。

The blades were guided to variation in order to select and cultivate new strains of Porphyra haitanensis that were high quality and high yield .

力克斯兔自引入我国后，由于品种退化、粗放的饲养管理以及不合理的繁殖，使其皮、肉性能出现了下降趋势。

Since Rex rabbits were introduced , the qualities of pelt and meat have been reduced because of degeneration of variety and extensive management and so on .

针对品种退化，从生产与管理两方面提出了相应的防止品种退化，改善大丽花生长发育条件的有利措施。

Aim at deterioration of breed , put forward the relative and favorableness measures of preventing deteriorating and improve growth condition of Dahlia in aspect of yield and manage .

而对海带种质的鉴定仍然主要依靠技术人员的经验判断，就更进一步加重了苗种混杂、品种退化等影响海带养殖品种使用寿命的情况。

The identification of germplasm of Laminaria still rely on the experience of technical staff to determine , to further increase the impact of the hybrid Seed and variety degradation in useful life of farming varieties .

概述了家蚕品种退化的遗传实质及原因，简要介绍了防止品种退化的措施和方法，这对家蚕品种的种性保持和复壮更新，具有较为重要的现实意义。

The paper introduced briefly the hereditary essence and reason of variety degeneration of silkworm , it also discussed many kinds of measure and method of preventing the variety degeneration , the studies had a practical significance for the properties keeping and renovation to silkworm variety .

但迄今为止，对延胡索的生长发育和栽培技术缺乏系统的研究，再加上产地连年种植，品种退化，病虫危害，致使延胡索产量降低，品质下降。

But so far , there was no intact study on the development and planting technique of yanhusuo . Due to the field often was planted consecutively , variety degeneration and plant diseases and insect pests , all these made the yield of yanhusuo reduced and quality declined .

但广大农村仍然存在品种退化，饲养周期长，饲养管理水平低，科学养猪和防疫治病意识淡薄等问题，从而导致了养猪经济效益不明显，严重地制约着农村养猪业的发展。

However , in the vast rural areas , there are still varieties degradation , long keeping cycle , low levels of feeding and management , awareness of scientific cultivation and quarantine . These results in obvious economic benefits Reduction , and seriously restricts pig-raising industry development in the rural .

然而，在其发展过程中，存在着技术方面、安全方面、生物学方面和环境方面的问题，造成渔业水域环境恶化、养殖自身污染加剧和养殖品种种质退化。

However , in its developing process , the problem in technical aspect , security aspect , biology aspect , and environment aspect causes the fishery aquatic environment to become worsen , cultivate pollution to intensify , and cultivate variety to degeneration .

因长期无性繁殖，品种老化和退化严重，但有性世代退化而缺乏有效的育种途径。

But variety has been aged and degenerated severely for long time because of asexually propagation and lack of effective breeding route .

主产于河南省封丘县的金银花是我国著名的道地中药材，但在生产中，其品种单一、退化严重且繁殖速度较慢，无法满足大田规模化种植和市场的需求。

Is a famous authentic Chinese herbal medicine , which is major in Fengqiu city of Henan province . Because of the single species , serious degradation and the low speed of propagation , there is no ways to satisfy the need of large scale planting and market .

而当前我国花生主产区花生品种老化、退化、杂化现象突出，生产的标准化程度较低，严重影响花生单产水平的提高、良种配套技术的推广和品种自身优势的发挥。

However , the peanut varieties aging , degradation and hybridization phenomenon in current main domestic peanut producing areas is significant . The production standardization degree is very low . The problems above seriously affect the peanut yield improvement , fine breeds supporting technology promotion and breeds advantages performance .

这样可以将快繁、脱毒、复壮、嫁接集为一体，快速建立人工三倍体嘉陵20号的母本圃，解决生产上该品种接穗的供应，防止品种退化等。

Thus , this procedure help to integrate rapid propagation , virus elimination , rejuvenation and grafting , to rapidly build a maternal parent seminary for the artificial triploid variety Jialing 20 , to guarantee the adequate supply the scion of the variety and to prevent variety degradation .

种性退化是农业生产中的普遍现象，采用适当的技术手段对农作物品种进行改良，可有效延缓品种退化、延长优良品种的生产寿命。

Variety retrogression is a universal phenomenon in agricultural production , so improving crop varieties by using proper technical means could delay the degradation of its species and prolong productive life of excellent varieties effectively .

多年来新疆辣椒主栽品种一直以当地农家品种为主，品种退化严重，且不适合设施栽培。

The main varieties of the pepper planted in Sinkiang have always been the local varieties for many years , being degenerated seriously and unsuitable for protected cultivation .

通过对烤烟品种重复繁殖性状变化研究，研究品种的退化情况。

Investigation of the changes of the traits of tobacco varieties in repeated multiplication to understand their degeneration .

长期无性繁殖的良种，由于受品种机械混杂等诸多因素的影响，常导致品种退化。

To the elite by clone propagation at long-term , varietal deterioration result from mechanical complexity in variety and other affecting factors .