Population genetic structure was studied using fluorescent-AFLP markers on 45 apricot (Armeniaca Mill.) accessions collected from the Dzhungar-Zailij group, Xinjiang cultivated apricot sub-group and Liguang apricot sub-group in the Central Asian group, the European group, and the Northern China group. A. mume, A. sibirica, and A.mandshurica were used as outgroup of fluorescent-AFLP markers. The purpose of this study was to determine the genetic structure and genotypic diversity amongst the different eco-geographical populations. The results showed that the average number of polymorphic loci (A) was 130.86, the percentage of polymorphic loci (P) was 60.58% by 7 pairs of EcoRI/MseI (Mse I-a FAM fluorescent marked primer) primers in common apricot of four groups. Analysis for the average number of polymorphic loci (A) and the percentage of polymorphic loci (P) in four common apricot groups indicated that the Dzhungar-Zailij group (P = 43.59%)> the Xinjiang cultivated apricot sub-group in the Central Asian group (P = 41.27%)> the Northern China group (P = 39.42%)> the European group (P = 39.42%) > the Liguang apricot sub-group in the Central Asian group (P = 37.57%). Nei's gene diversity (H = 0.143) and Shannon information index (I = 0.226) at species level were higher than ones at group level with significant or highly significant differences. At group level, Nei's gene diversity and Shannon information index (H = 0.131; I = 0.202) in the Dzhungar-Zailij group were higher than that in the Xinjiang cultivated apricot sub-group in the Central Asian group (H = 0.127; I = 0.195), or in the European group (H = 0.124; I = 0.189), or in the Northern China group (H = 0.116; I = 0.180) with no significant differences, respectively, but were significant higher than that in the Liguang apricot sub-group in the Central Asian group (H = 0.113; I = 0.173). Genetic differentiation coefficient (GST = 0.147) for four apricot groups showed that apricot genetic variation was mainly within the groups and accounted for 85.3% of total variations. The gene flow Nm = 2.901, according to the genetic differentiation coefficient between groups (GST = 0.147), indicated that there were partly gene exchanges among four apricot groups. Occasional seedling introduced by human beings could be the main way of gene exchanges and geographical barriers could be the main factor of hindering gene exchanges. The analysis of genetic diversity and genetic structure from four geo-ecological groups suggested that common apricot originated in the Dzhungar-Zailij geo-ecological group, then diffused to central Asia and formed cultivated apricot center in central Asia by domestication. It was further disseminated by human introduction to the East forming the Northern China group, and to the West forming the European group.
SSR technique was used to develop fingerprinting key and study the genetic diversity on sweet cherry. Eighteen pairs of primers cloned from cherry, peach and apricot amplified a total of 83 alleles among the 19 cultivars of sweet cherry ( Prunus avium ) and 2 cultivars of ground cherry ( P. fruticosa). The number of alleles amplified per primer pair ranged from 2 to 8, with a mean of 416. The polymorphic information content values ( PIC) ranged from 0.38 to 0.80, with a mean of 0.64. Seven sweet cherry cultivars showed unique bands or banding patterns. A fingerp rinting key developed by 4 pairs of p rimers: UDP98-414, UDP98-406, UDP96-001 and PMS40 could discriminate 18 sweet cherry cultivars. UPGMA cluster analysis of genetic distance separated the 19 cultivars of sweet cherry into two group s. The phylogeny of sweet cherry cultivars revealed the closed relationships among cultivars tested.
This paper was conducted to evaluate the salt tolerance of pepper cultivars by multiple statistics analysis according to agronomic character indexes at seed germination and seedling stage. The twelve character indexes from different pepper cultivars, such as relative trend of germination, relative radicle length, relative germination index, salt injury index and relative plant height etc. showed significant difference by using multiple variance analysis. Factor analysis indicated the twelve character indexes could be synthesized into four main factors, keeping 95.35% of information of primitive variables. Based on the score vectors of the factors, ten cultivars were classified into three categories by using cluster analysis. Zhongjiao No.4, No.8, No.7 and No.12 were salt sensitive cultivars, whereas Zhongjiao No.5 and No.11 were moderately salt sensitive cultivars, but Zhongjiao No.6, No.13, No.16 and No.10 were salt tolerant cultivars. These results indicated the multiple statistics analysis could be used to early evaluate the salt tolerance of pepper cultivars by investigation of agronomic character indexes at seed germination and seedling stage.
Three alloploids with different ploidies from interspecific hybridization in Cucumis [interspecific hybrids F1 (2n = 2x = 19, HC), allotriploid (2n = 3x = 26,HCC), and allotetraploid C. hytivus (2n = 4x = 38,HHCC)] and their parents were used for the comparative studies on expression pattern of peroxidase (POD), glutamate dehydrogenase (GDH), and aspartate aminotransferase (AAT). The results showed that the zymograms in the alloploids were similar in band number and band distribution. The intensity of band in these allopolyploids, however, presents significant difference, which was caused by genome dosage. In AAT zymogram, the intensity of band was positively correlated with ploidy level. In POD and GDH zymogram, however, the intensity of band was negatively correlated with ploidy level. It was indicated that the coherence between genome dosage and isozyme expression pattern would be opposite in different enzyme systems. These data will be helpful to illuminate the morphological changes caused by the polyploid level.
A protocol for the induction of somatic embryogenesis via pseudobulbils from mature seeds of Rosa multiflora 'inermis 3' was established. The results showed that the primary pseudobulbils were obtained by using a two-stage procedure where excised seed cotyledons were incubated 30 days on the 1/2 Murashige and Skoog (MS) medium supplemented with 2, 4-D at 0.5~2 mg·L-1 under the dark conditions for calli induction, and subsequently transferred to a 1/2 MS medium supplemented with TDZ at 5~20 mg·L-1 under the light conditions for 20 days for pseudobulbils induction. The pseudobulbils were incubated 20 days on the induction medium supplemented with TDZ at 10 mg·L-1 under the dark conditions and then transferred to the hormone-free medium supplemented with maltose instead of sucrose under light conditions for the secondary pseudobulbils and embryogenic calli induction. The pseudobulbils were maintained on the induction medium. The embryogenic calli developed into normal somatic embryos then plantlets. By this way, the pseudobulbils have been maintained for two years by far.
In order to provide genetically improved new germplasm resources and achieve the GNA transgenic plants of Euonymus japonicus 'Cu zhi', genetic transformation system was established based on the system of regeneration. Several factors affected genetic transformation of Euonymus japonicus 'Cu zhi' mediated by Agrobacterium tumefaciens (LBA4404) were studied. The results showed that preculture or not, bacterial concentrateions, the time of infection and co-cultivation had some effect on transformation frequency. The highest transformation frequency was obtained through the following transformation procedure after preculture for 0 d, the explants were infected for 40 min with the concentration of Agrobacterium tumefaciens OD600=0.6 , and then co-cultivated for 3 d. The PCR and PCR-Southern blotting analysis showed the snowdrop lection gene gene was integrated into the genome of Euonymus japonicus 'Cu zhi'. The system of genetic transformation of Euonymus japonicus 'Cu zhi' could provide new germplasm resource used in genetic improvement of Euonymus japonicus 'Cu zhi' and the other plants of Euonymus.
Zantedeschia Aethiopia was treated with colchicines at different concentration and time duration in vitro. The results showed: the best effect was obtained by the treatment of 0.05﹪ colchicines with 24 hours, and its induction rate was 52%. Chromosome observation found that the chromosome number of treated plants was 64, and the chromosome number of the control was 32, indicating the tetraploid (2n =4x=64) of coloured Zantedeschia aethiopica is induced successfully.
The world organic agriculture develops rapidly after entering to the 21st century. At present, China has become the third great country of organic farming area in the world. The organic horticulture, as an import part of the organic agriculture, is one new mode of horticultural production. There are the exceptional advantages and potential of labor force, plant resources, geographic condition, agricultural technology and thought in China to develop organic horticulture. In order to promote the development of organic horticulture, it is necessary to strengthen the support from government and to strengthen the research of theory and technology of organic agriculture. It is necessary to discover the hazard analysis and critical control point (HACCP) in horticultural production and establish the good agricultural practices (GAP) according with the principle of organic agriculture for horticulture in China. The development of general production for organic horticulture needs to be guided by GAP and led by theories and principle of ecology.