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Based on the climatic and geographical condition, cropping system and season sowing types and maturity group (MG) types of 256 varieties in test from total cultivating regions of soybean in China, six ecological regions of soybean were suggested. Those are: Northern single cropping, spring planting eco-region(I), Huanghuaihai double cropping, spring and summer planting eco-region(II), Middle and lower Changjiang valley double cropping, spring and summer planting eco-region(III), Central south multiple cropping, spring, summer and autumn planting eco-region(IV), Southwest plateau double cropping, spring and summer planting eco-region(V), and South China tropical multiple cropping, all season planting eco-region(VI). The cultivating environmental condition and representative varieties were shown, and the characteristics of all ecological regions of soybean in China were also discussed in this paper.

A high-density genetic map was constructed with a RILs population (NJRIKY) from a cross of two cultivated soybean Kefeng 1 and Nannong 1138-2, using RFLP, SSR, RAPD and AFLP markers. The map consists of 24 linkage groups, which include 792 genetic markers, and covers 2,320.7 cM with an average genetic distance of 2.9 cM. The higher polymorphsims between two parents were identified with SSR markers. Due to its simplicity and stability, they could be used as anchored marker to integrate different maps constructed with different genetic markers. AFLP marker system is efficient for map construction while it easily form clusters to cause big gaps in the map. A total of 21.7% of markers was found with distorted segregation in the RILs population. The high-density molecular linkage map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.

Inheritance of erucic acid content in the cross of HSTC14 x Ningyou 7 (Brassica napus L.) was investigated by applying the major gene plus poly-gene model of quantitative traits to a joint analysis of multi-generations (P1, F1, P2, B1:2 B2:2 and F2:3). The results showed that erucic acid content in the cross of HSTC14 x Ningyou 7 was controlled by two major genes with additive-dominance-epistatic effects plus polygenes with additive-dominance effects (the E-1 model). Heritability values of the major genes of B1:2, B2:2 and F2:3 population were estimated as 69.47%, 28.25% and 51.33% respectively, while those of polygene were 29.81%, 70.39% and 47.86%. This results demonstrated that erucic acid content level in the cross was mainly controlled by two major genes mixed with the effect of polygenes. The estimated additive effects of the two major genes, da and db, were -12.1712 and -6.5423 respectively. The dominant effect of the first major gene was 9.1011, much higher than that of the second one. The interaction effect of the first major gene's additive effect and the second major gene's dominance effect was 22.4400, while that between the second major gene's additive effect and the first major gene's dominance effect was only 1.0317. There were obvious differences in genetic effects between the two major genes. The effect of db was only about 53.75% that of da, indicating that the contributions to erucic acid level of the two major genes was not equal in the cross. The possible reasons resulting in the difference was discussed in this paper.

Cotton worm [Prodenia litura(Fabricius)] was one of the major leaf-feeders for soybeans in Southern China. Resistance to leaf-feeders has been recognized as one of the major breeding target traits in the National Soybean Breeding Program. This paper deals with the study of inheritance of resistance of soybeans to cotton worm [Prodenia litura(Fabricius)]. P1, P2, F1, F2, F2:3 of four susceptible x resistant crosses, i.e. N21297 x N1178-2-2, N21266 x N23860, N119-1 x N1178-2-2 and N21266 x N3039, were used in the study. The materials were planted in net room under artificial infestation in 1996-1998. The data of defoliation percentage of successive development stages, during cotton worm damage period were obtained and collected for genetic analysis. The segregation analysis methods for major genes plus polygene mixed inheritance model developed by Gai et al. were used to identify the genetic system of resistance. The results from joint analyses of multiple segregating generations as well as from analyses of single F2 or F2:3 generations of the four crosses showed a two major genes plus polygene mixed inheritance model at fully developed stages of resistance while one or two major genes with or without polygene were observed at other stages. Between the two major genes, the additive effect of one locus was from 1.56 to 9.89(%, defoliation), another from -3.79 to 3.75(%, defoliation). The heritability values of major genes were estimated as 70.40%-99.21%, greater than those of polygene which were only 0.00%-22.29%. Therefore, in the improvement of resistance to cotton worm, major gene resistance should be considered at first.

The prerequisite of genomic research such as genetic mapping is construction of a suitable segregating population and its reasonable evaluation before use. A recombinant inbred line (RILs), NJRIKY, was constructed through a cross between Kefeng 1 and Nannong 1138-2. The present study was focused on evaluation of genetic structure of the RILs through the simple sequence repeats (SSRs) analysis. A total number of 138 pairs of SSRs primers covering the whole soybean genome were randomly selected for polymorphic analysis between two parents. 86 pairs of which were polymorphic and polymorphic rate is up to 62.32%. 90 polymorphic loci were found. Further analysis with polymorphic SSRs loci on the sampled lines indicated that not only segregation of most SSRs loci conformed to the ratio of 1:1, but also almost each sampled line tended to homozyge. The distribution of genotypic composition was normal. The population is ideal for genetic mapping and other genomic research.

A recombinant inbred population of soybean was developed from a intraspecies cross of Kefeng1 and Nannong 1138-2. A genetic linkage group of soybean genome was constructed, which composed of 22 linkage groups, included 302 loci, covered 2,363.8 cM. The interval mapping was used to identify quantitative trait loci (QLTs) associated with ten important agronomic traits in the RIL population. The results indicated that thirty-four QTLs were detected for the ten traits associated with yield and seed quality. We conclude that QTL analysis offers a useful tool for the genetic improvement of soybean cultivars.

Five crosses between resistance and susceptible were analyzed to study major-polygene effect using major-polygene mixed mode. The result showed that 3 of 5 crosses were controlled by both major gene and polygene. In addition, there were large variation of additive effect, variance as well as heredity of major gene polygene in 3 crosses. Major gene was predominant in resistant variation, but durability should be considered. We suggested that construct major-polygene system be constructed in the long run in breeding program to ensure a durable and high level of resistance to constrain fluctuation of races of Xanthomonas campestris pv. oryzae population.

The P1, P2, F1, F2 and F2:3 in plant generation of three crosses of Liuhexiaoyeqing x Xinyixiaohedou, Shangraoganbusi x Huaiyinqiuhedou and Liuhexiaoyeqing x Nannong 73-935 were used to study the inheritance of dried tofu output. The results of the joint analyses of multiple plant generations showed a consistant one major gene plus polygene mixed inheritance model. The heritability values for dried tofu output were as high as 87.84%-99.98%. In plant generation F2:3 of these crosses, the heritabilities of major gene were 51.80%-61.85%, and those of polygene were 36.12%-48.03%. Therefore, both major gene and polygene effects were important and should be utilized in breeding program.

The accuracy of the mixed inheritance analysis of quantitative traits with larger experimental error could be improved while using DH or RIL population. The segregation analysis method of identifying mixed major genes and polygenes inheritance model, including linkage inheritance model, of quantitative traits by using DH or RIL population was developed in this paper. The method may be applied to identify the mixed major gene and polygenes inheritance model of quantitative traits, estimate genetic effects and variances of major genes and polygenes, and the recombination value while there is linkage between two major genes. Finally, an example was used to illuminate the above procedure.

It has been proved by many field experiments and QTL mapping results that among genes affecting some quantitative traits there are some major genes with larger genetic effect and some polygenes with smaller genetic effect. For such traits, the distribution of segregating population demonstrates multimodality, and this is the characteristic of the mixture of more than one distributions. Mixture distribution models have been used extensively as models in a wide variety of practical situations where data can be viewed as arising from two or more populations mixed in certain proportions. Akaike's Information Criterion(AIC) has been used to identify the existence of major genes affecting quantitative traits. Under the existence of major genes, the genetic effects of these genes and their genetic variance were estimated through segregation analysis. The genotype of major gene of F2 individuals of were determined by clustering using Bayesian criterion. With P1, P2, F1 and F2 populations, the likelihood ratio test was used to test the existence of polygenes. In the end, the inheritance of soybean flowering date is analyzed. One major gene was found in F2 population derived from Guludou x Shanghaihongmangzao.

Soybean disease loss estimates were compiled for the 1994 harvested crop from the 10 countries with the greatest soybean production. The objective was to document the major soybean disease problems in these countries and any recent changes in the severity of individual soybean diseases. Total yield losses caused by Heterodera glycines in these 10 countries were greater than those caused by any other disease. Next in order of importance were stem canker, brown spot, and charcoal rot. The total yield loss due to disease during 1994 in these countries was 14.99 million metric tons, valued at $3.31 billion. Methods used to estimate soybean disease losses were field surveys, plant disease diagnostic clinic samples, variety trial data, information from field workers and university extension staff, research plots, grower demonstrations, and private crop consultant reports. Yield loss estimates due to a particular disease varied by country. For example, yield losses due to rust were reported from China and Indonesia, but no losses due to this disease were reported from any of the remaining eight countries. Soybean disease control research and extension efforts are needed to provide more effective preventive and therapeutic disease management strategies and systems to producers.

The effect of SR 59026A, a new selective 5-HT(1A) receptor agonist, was evaluated on sexual behaviour of male rats in different experimental conditions. SR 59026A (1-10mg/kg p.o.) stimulated the copulatory behaviour of sexually experienced rats, as evidenced by a decrease in the number of pre-ejaculatory mounts and intromissions and a shortening of the ejaculation latency. SR 59026A also facilitated the sexual behaviour of naive male rats characterized by a low level of sexual performance: over the same dose range, the percentage of naive males that copulated was significantly increased and the ejaculation latency reduced. In experiments designed to evaluate the onset of sexual satiation, SR 59026A (1 and 3mg/kg) increased significantly the number of ejaculations and delayed the time of sexual satiation. Finally, in agreement with studies on other 5-HT(1A) receptor agonists, SR 59026A did not modify the occurrence of spontaneous erections in isolated male rats. Therefore, the present study shows that SR 59026A improves the sexual performance of male rats in a number of different experimental models, and the compound may prove to be of interest for the treatment of certain states of human male sexual dysfunction.

Ten susceptible x resistant and resistant x resistant crosses were made among eight varieties, of which seven were previously identified as resistant to one to four SMV strains, in order to investigate the inheritance of resistance to the four strains (Sa, Sc, Sg, and Sh) and the linkage relationship among the resistant genes. Seeds from F2 individual plants were randomly divided and planted in two separated nurseries, in which the seedlings were inoculated with two different strains. The genotype of each F2 plant was detected from the reaction of its F3 progenies to the two strains. The results showed that the resistance to each of the four strains was conditioned by a dominant gene which was labelled here with Ra, Rc, Rg, and Rh, respectively. All the four loci appeared to be in a same linkage group with the order of Rg--Rh--Ra--Rc. The recombination value between Ra and Rc was estimated to be 25.4 +/- 7.7%, and those between Rg and Rh, Ra and Rh, Ra and Rg, and Rc and Rg to be 27.3 +/- 5.4%, 23.5 +/- 5.2%, 41.1 +/- 8.5%, and 46.5 +/- 7.5%, respectively. The genes resistance to Sa in Kwanggyo and "7222" were determined at the same locus, so were the resistant genes for Sc. In addition, this linkage group seemed to be not related with the first and eighth linkage group.