杂交水稻制种建立母本最佳穗层结构的探讨

将制种田中喷施“九二０”后的母本穗层划分为高层穗、表层穗、平颈穗、包颈穗４个层次。对各种类型穗层的受粉原理、自然受粉状态，与结实率的关系进行了研究分析，提出了母本最佳穗层结构模式，以及在实践中可以采取稀播壮秧、密植等６项农艺措施和配套措施，来建立起母本最佳穗层结构     

Hermetically Sealed Storage of Cereal Seeds and its Influence on Vigour and Germination

Investigations of the influence of hermetic cereal seed storage on germination were carried out in the laboratory of the Faculty of Agriculture in Osijek (Croatia) over 5 years (1992–96). Seeds of four species (winter wheat, winter barley, spring oat, and maize) were stored in hermetic glass containers at an air temperature of 20 °C and a relative humidity of 65 %. The moisture level in stored seeds was 13 %. After 5 years, statistically highly significant associations (P < 0.01) were found between storage longevity (five researched years) and seed germination of the four cereals. Germination of all investigated cereals was high (between 97.25 % for maize and 93 % for winter wheat) after harvest. The germination level decreased for all cereals, on average by 38 %, over the 5 years of storage. The highest germination values were found for wheat seeds (84.75 %) and the lowest germination values for maize seeds (36.0 %). The results showed that germination of all investigated cereals seeds was negatively correlated with storage longevity. The differences in germination found amongst the cereals were statistically highly significant (P < 0.01).     

施肥放养紫胶对马鹿花结籽的影响

对马鹿花植株施肥，放养紫胶与结籽关系的试验研究结果表明；只要控制好紫胶虫的固虫率（20%左右），放胶与否对马鹿花植株的结实量没有明显影响；马鹿花植株是否施肥对其生产紫胶量无明显影响；马鹿花植株施肥与否对其产种量无明显影响。故生产中以生产紫胶或种子为目的时，马鹿花植株不必追肥，并且可以同时放养紫胶和生产种子。     

Family Outcrossing Rates of Pinus caribaea Morelet var. caribaea in Seed Orchard and Natural Populations

Family outcrossing rates of Pinus caribaea var. caribaea populations that differed in origin and management were estimated by using isozyme markers. The family outcrossing rates were estimated by (1)fixing the probability of pollen gene frequency (p); (2) allowing pollen gene frequency to vary among families. The estimates of family outcrossing rates for all the populations varied widely among families (clones of the seed orchard), ranging from 0.39 to 2.0. The average family outcrossing rates of both methods were greater than the     

大豆对紫斑病抗性鉴定方法的研究

本研究通过自然发病和人工接种鉴定了不同大豆品种对紫斑病的抗性，旨在建立大豆对紫斑病抗性鉴定方法，为大豆品种资源抗性筛选创造条件。对不同成熟期的37个大豆品种在自然条件下对紫斑病的抗性调查结果表明，大豆紫斑病的发生受气候条件、大豆成熟期和品种抗性的影响，由于避免了病害发生的有利时期，晚熟大豆品种紫斑病发生很轻或不发病。1998年和1999年，分别在防虫网室和温室人工接种鉴定45份大豆种质，两次的鉴定结果均表明大豆品种间对紫斑病的抗病性存在显著差异，但在温室条件下大豆紫斑病平均病情指数显著低于网室条件下的试验结果。为提高大豆对紫斑病抗性鉴定的准确性，建议不同成熟期的品种同期鉴定时可对早熟品种进行摘花，保证接种时接种荚荚龄一致；对接种荚进行标记；设立高感对照；鉴定为抗病的材料进行重复鉴定。     

湿地松种子园无性系间开花结实差异分析

湿地松种子园内无性系间的生长，开花和结实等性状存在着显著差异，无性素水平和单株水平上的性状相关分析结果基本一致，雌花量与结实量，球果长与宽有较密切的相关关系，而无性素的雌花量与雌花量存在负相关关系。     

Integration of transgenes into sexual polyploidization schemes for potato (Solanum tuberosum L.)

Most potato transgenic research has focused on development of resistance to pathogens and modification of potato physiology. Many transgenes, particularly those conferring pathogen resistance, could substantially lower potato production costs in developing countries. However, transgenes have not been reported in sexually propagated 4x-2x potato hybrids commonly grown in developing countries. Two transgenes,the Bacillus thuringiensis cry3Aa endotoxin protein gene and the PVY°coat protein gene, were engineered intodiploid and tetraploid potato using Agrobacterium tumefaciens-mediated transformation. Cry3Aa was produced at high levels in several lines while the PVY° coat protein was not expressed. Diplandroid and tetraploid genotypes were crossed to produce transgenic 4x-2x hybrids. Genetic transformation had no discernable effect on fertility ofthe primary transformants, germination of4x-2x seed derived from the transformants and agronomic performance(tuber set, average tuber weight and total tuber yield) of the 4x-2xhybrids. The transgenic 4x-2xhybrids produced non-viable pollen and could only be crossed as female parents. Results suggest that transgenes, such ascry3Aa, could be expressed in 4x-2x hybrids to lower costs of production with no significant effect on plant phenotype. This revised version was published online in July 2006 with corrections to the Cover Date.     

Geographical distribution of the DL1 and DL2 genes causing hybrid dwarfism in Phaseolus vulgaris L., their association with seed size,and their significance to breeding

Summary Dwarlism in F₁ hybrids has been observed in over 100 crosses of dry beans (Phaseolus vulgaris L.) at the Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia. In each cross, one parent always had small seeds and the other parent either medium or la ge ones. This apparent incompatibility between the two groups of germplasm was controlled by two complementary, dominant genes: DL₁ and DL₂. Smallseeded bean lines carried gene DL₁ and originated in Brazil, Colombia, Guatemala, and Mexico; medium for large-seeded bean lines carried gene DL₂ and were from Bolivia, Brazil, Chile, Colombia, Turkey, The United States, and West Germany. Thes two genes have probably played an important role in the evolution of dry bean forms of different seed sizes by serving as a genetic barrier or isolating mechanism, thus limiting free genetic recombination between the two germplasm groups.Apparent differences in the adaptiveness and yielding ability of the two groups of bean germplasm, smallys, medium- and large-seeded, and some breeding implications for manipulation of the genes causing F₁ hybrid dwarfism were also discovered.     

北京地区流苏及鸡麻种子的休眠与萌发研究

按A.W.Crocker与L.V.Borton(1959)提出的概念,凡是在苗圃条件下,犹如在自然条件下成熟后的第2个春季来临之前不出苗的种子,通称为二年种子(two years seed)[9]。鸡麻和流苏属两年种子的范畴。实验表明,第1年秋(11月底)种子经处理后砂藏,第2年春(4月初)种子在砂藏中少量发芽,播入地里后第3年春出苗。相比之下经酸蚀处理加催芽剂的种子出苗率最高,其次为酸蚀种子,对照种子出苗率最低。     

How to maintain improved cultivars

Improved cultivars loose their identity and healthiness unless maintained properly. Contaminating and degrading forces, such as outcrossing, volunteer plants, mixing, natural selection, mutation and seed-borne diseases, are at the root of this. Maintenance selection can prevent this deterioration. How it is carried out depends on the reproduction system of the crop. Crops are therefore classified into four categories; typical cross-pollinating crops, self-pollinating crops with a substantial amount of outcrossing, typical self-pollinating crops with little outcrossing, and the vegetatively reproduced crops. Generally some of the “breeder seed” is used to plant a small plot with spaced plants. A fair number of healthy plants of the cultivar type is selected and the seed is harvested per plant. The progenies of the selected plants are grown in small plots. Non-uniform or deviating plots and plots with a seed-borne disease are removed. The seed of the progenies that are healthy, uniform and similar (and so of the cultivar type) are harvested per progeny to be tested next season on larger plots. The same selection is applied and only the seed of the progenies that are healthy, uniform and similar are harvested together to produce the “breeder seed”. The details of this maintenance selection vary with the reproduction system, the multiplication rate of the crop and the possibilities available to the breeder. Seven crops, potato, common bean, barley, wheat, faba bean, quinoa and maize are discussed here as they represent the different reproduction systems and multiplication rates, while being important Andean food crops.