Mutation breeding for yield andPhytophthora infestans (Mont.) de Bary foliar resistance in potato (Solanum tuberosum L. cv. Golden Wonder) using computerized image analysis in selection

Summary Using visual selection for off-types and image analysis to select against maturation mutants, a line combining improved late blight resistance and yield was isolated in an in vitro mutagenesis programme from a population of 2101 putative mutants. The adventitious regenerants from mutagenesis treatment, including spontaneous mutants (somaclonal variants), were subjected to serial subculture of the apical bud in vitro and two cycles of apical cuttings in vivo to breakdown chimeras. The selected line was stable in trials over five years; others were unstable or failed to combine improvement in late blight resistance with high yield. Leaf and tuber image analysis was used to characterize selected lines. Lines that differed most from cv. Golden Wonder in yield and late blight resistance were more easily distinguished from the control by image analysis. The role of image analysis in negative selection and in determination of the relatedness of mutants to the control is discussed.     

毛白杨优良无性系选育研究

通过苗期选择,测定及区域化栽培试验,从３７１个无性系中选育出５个速生,抗商,适宜培育工业用材的优良无性系,其生长速度,抗病能力,主效值,生产力指数等主要经济性状均明显超过对照;其树高、胸径遗传力,选择增益均高,效果显著,经环境互作及稳定性分析稳定性好,适应范围广泛,具有较大的推广价值。     

离体筛选油菜耐草酸变异体研究

用ＮａＮ３对甘蓝型油菜（Ｂｒａｓｓｉｃａｎａｐｕｓ）茎尖进行诱变处理,以草酸作为筛选压力,采用多步正筛选系统,获是的变异体及其再生植株在培养物水平上,对草酸的耐性比野生型明显提高,过氧化物酶,多酚氧化酶活性均与野生型有明显差异,说明经过诱变处理后,基因及其表达产物发生了变化。     

大青杨、香杨种间及种源间的交配

对大青杨、香杨种源选择和种源间交配进行了研究。通过苗期测定、成树评比、冻害、虫害、形质指标PCA和聚类分析,综合选出了30＃（大带×大奋）、94＃（香虎×香奋）、60＃（香奋×香带）等优良组合,材积生长超过对照种131．61％～107．87％,选出60-1、61-1、60-2、60-4、94-1、30-1、30-2、30－4、30-5、30-6等无性系．生长量与对照差异达显著水平。该项研究对大青杨、香杨遗传改良提供了一条新的途径。     

杉木配合力第1轮回选择的研究 Ⅰ.遗传参数估计及配合力效应分析

对７５个参试杉木亲本进行巢式交配设计,１４年生时,测定其树高、胸径等生长性状,分析了它们的一般配合力、特殊配合力效应及其遗传差异;估计了调查性状的加性遗传方差,显性遗传方差、组间环境方差、组内环境方差、半同胞表型协方差、全同胞表型协方差、半同胞相关系数、全同胞相关系数、雄亲遗传力、雌亲遗传力和雄亲＋雌亲遗传力等遗传参数．     

油松无性系种子园疏伐研究

去劣疏伐是提高种子园产量和品质的主要措施之一,而无性系再选择则能科学地确定出疏伐对象.通过子代测定和对无性系开花结实及产种量的观测, 综合评定出优、中、劣无性系,从而制定出疏伐强度、疏伐时间等疏伐方案.同时,向其它油松基地推广评选出的油松优良无性系.     

运用致病毒素筛选抗烟草黑胫病细胞突变体I抗毒素愈伤组织的有效筛选

以６０Ｃｏ－γ射线照射烟草优质感病品种的花药作为诱变手段,用烟草黑胫病疫霉菌粗毒素为筛选剂,对烟草花粉植株叶片的愈伤组织,进行抗病突变体细胞的筛选．试验表明：毒素对烟草愈伤组织的存活和增殖有明显的抑制作用,抑制程度随毒素浓度提高而加强,同一浓度对不同品种也存在着差异．综合毒素浓度对烟草愈伤组织抑制、增殖程度及筛选的有效性,初步认为：筛选红大和Ｋ３２６抗黑胫病突变体细胞的最适粗毒素浓度分别为３０％和４５％．所筛选出的抗病突变体细胞,其细胞水平的抗性与再生植株的抗病性鉴定相吻合．     

Oceanographic influences on the distribution of Baltic cod, Gadus morhua, during spawning in the Bornholm Basin of the Baltic Sea

The Baltic Sea is a stratified, semienclosed sea typified by a low-salinity surface layer and a deep saline layer of varying volume, salinity, temperature and oxygen concentration. The relationships between these oceanographic factors and the distribution of Baltic cod are presented, utilizing results from a survey carried out during the 1995 spawning period in the Bornholm Basin, at present the main spawning area of this stock. Cod distribution, abundance and population structure were estimated from hydroacoustic and trawl data and related to hydrographic parameters as well as to bottom depth. In the central basin, cod were aggregated in an intermediate layer about 15 m thick. This area of peak abundance was defined at its upper limit by the halocline and at the lower limit by oxygen content. The majority of individuals caught in the basin centre were in spawning or pre-spawning condition with a high proportion of males to females. On the basin slopes, aggregations of cod were found near the bottom. These individuals were mainly immature and maturing stages with an increasing proportion of females to males with size. Salinity and oxygen conditions were found to be the major factors influencing the vertical and horizontal distribution of adult cod. Abundance of immature cod was also positively related to decreasing bottom depths. The effect of temperature was minor. The observed size- and sex-dependent spawning aggregation patterns, in association with habitat volume and stock size, may influence cod catchability and thereby the assessment and exploitation patterns of this stock.     

微卫星分子标记指导镜鲤群体选育

本文用26个扩增效果好的微卫星分子标记分析了镜鲤（Cyprinus carpio L.）养殖亲本群体的遗传结构,指导其群体选育。本研究共检测到153个等位基因,片段大小为108~400 bp,平均等位基因数（A）5.8846个,平均有效等位基因数（Ne）2.8625个,平均观察杂合度（Ho）0.5063,平均期望杂合度...     

Effect of masking organoleptic properties of fat on diet self‐selection by the sparid Diplodus puntazzo

Fish are able to select a balanced diet according to their nutritional needs by choosing among incomplete feeds or even pure macronutrients. However, the relevance of both the organoleptic properties of diet and the postingestive signals that they produce remains unclear. Thus, sharpsnout seabream were allowed to select between diets containing different edible oils with their organoleptic properties masked by using gelatine capsules. Fish were fed capsules of two different colours so that they could associate the capsule colour with its corresponding postingestive effect. The longitudinal experiment included a first phase during which the fish were adapted to consuming the gelatine capsules. In a second phase, the fish were challenged with two different encapsulated diets: one comprising a complete diet containing fish oil and the other a fat‐free diet. Sharpsnout seabream showed a preference for the fish oil capsules (3.8 ± 1.1 g kg^?1 body weight (BW), 66.8% of total intake) over the fat‐free capsules, showing that they were able to associate the colour of the capsule with their nutritional content through postingestive signals. After that, the fish were challenged to select between the capsules containing the fish oil diet and capsules containing a vegetable oil (linseed or soybean), in which case they showed no preference between diets (2.4 ± 0.3: 2.1 ± 0.5 g kg^?1 BW of fish oil versus linseed oil capsules and 2.2 ± 0.2: 1.8 ± 0.6 g kg^?1 BW of fish oil versus soybean oil capsules), indicating that the fatty acid composition of the different oils was not sufficient to affect dietary selection through postingestive signals. So, in conclusion, when orosensorial information from food is absent, the fish are able to select between diets at a macronutrient level by using postingestive information. However, this information is not sufficient for distinguishing between diets that differ in the type of oil used.