【Objective】 It is of great importance to construct a shareable high-quality crop variety standard DNA fingerprint database for effectively managing the huge number of known varieties.【Method】 Based on fluorescence capillary electrophoresis detection platforms and the plant variety DNA fingerprint database management system, a database containing 3 998 maize authorized accessions was built with 40 SSR primer pairs. Multi-laboratories and multi-detecting platforms were used to conduct the quality evaluation of the database.【Result】 Allele frequency distribution graphs of the 40 corn primers were plotted as characteristic spectrums of each primer, which played the role of the similarity of reference samples in the database construction. A decuplet fluorescent capillary electrophoresis combination was formed and a set of system default PANEL was established in the SSR analyzer. Statistics were conducted on the experimental conditions of the database construction. Of the total samples, 61% of them were subjected to two group independent trials and 33% of them were subjected to three group independent trials. Each sample had 2-5 sets of original experimental data and the corresponding fingerprint maps. The accumulated loss and variable sites of the final built standard fingerprint database accounted for only 0.2%, the data integrity reached 99.8%. The assessment results in different laboratories and different electrophoresis platforms showed that the SSR fingerprint data obtained high agreement on the same electrophoresis fluorescence detection platform, but showed a certain bias in different electrophoretic detection platforms. In order to realize the sharing of SSR fingerprint data in different laboratories, a unified fluorescent primer, analysis software and electrophoresis detection platform were needed. Overall pairwise comparisons were conducted on all the fingerprint data, the results showed that there existed a relative big overall difference among the certification varieties of corn in China. Percentage of different sites among the authorized varieties was mainly concentrated between 80% and 95% (accounted for 78.28%), the percentage of different sites with more than 50% reached 99.21%, and less than 20% of only 0.09%. The average hybrid rate of the authorized varieties reached 64% and mainly concentrated between 50% and 80% (accounted for 89%). By using the corn variety standard fingerprint matching service platform (URL: http: //www.maizedna.org/), a shared fingerprint database is realized. 【Conclusion】 A standard procedure in constructing crop variety SSR fingerprint database was formed in this study and the SSR fingerprint database was constructed with a scale of nearly 4 000 corn authorized varieties. Through joint multi-laboratory comparison tests, the accuracy of database building and the sharing property of database were ensured. A service platform website for corn variety standard fingerprint matching was established in this study, thus achieving sharing of corn authorized variety fingerprint database in national seed identification system, and providing an important reference for other crop species in building high-quality SSR fingerprint database.
【Objective】Understanding of the genetic variations in response to drought conditions of four physiological indexes, namely stomatal conductance (Gs), original light energy transformation efficiency of PSII (Fv/Fm), leaf elongation (LE) and leaf relative water content (RWC) could help their adaption to the current breeding program.【Method】The genetic variation (sg2), broad sense heritability (hb2) under rainfed and irrigated conditions for four physiological indexes, namely Gs, Fv/Fm, LE and RWC were measured for 13, 18, 15 and 10 times, respectively, from two sets of field trials in 22 and 18 genotypes which were consistently conducted at two locations in Kaiyuan and Yuanjiang counties of Yunnan province in the crop growing periods of 2013 and 2014. In the trials, rainfed and irrigated treatments were set as the main plot, and genotype was used as the sub-plot. The sg2 and error variation (se2) for each index at each measurement was determined using software GenStat, and hb2 was calculated. Paired t tests for the differences of sg2 and hb2 between drought and irrigated treatments were processed using software SAS9.1.【Result】The mean differences between drought and irrigated treatments were all significant (P<0.01) in 13, 18, 15 and 10 measurements of Gs Fv/Fm, LE and RWC, respectively. Under drought and irrigated treatments, the differences in Gs among the genotypes was significant in 10 and 11 out of 13 measurements with the ranges of hb2 at 0.19-0.68 and 0.19-0.82, and grand means of 0.49 and 0.53, respectively, overall significantly higher sg2 and hb2 were found under the irrigated treatment. The differences in Fv/Fm, among the genotypes were significant in 17 and 16 out of 18 measurements with the ranges of hb2 at 0.26-0.83 and 0.16-0.85, and grand means of 0.64 and 0.58, respectively, overall higher sg2 and hb2 were found under the drought treatment. The differences in LE among the genotypes were significant in 14 and 10 out of 15 measurements with the ranges of hb2 at 0.09-0.89 and 0.09-0.81, and grand means of 0.58 and 0.50, respectively, overall higher sg2 and hb2 were found under the drought treatment. The differences in RWC among the genotypes were significant in 8 and 6 out of 10 measurements with the ranges of hb2 at 0.10-0.76 and 0.16-0.77, and grand means of 0.57 and 0.47, respectively, overall higher sg2 and hb2 were found under the drought treatment. 【Conclusion】The sg2 and hb2 of Gs, Fv/Fm, LE and RWC were impacted by water stress, in general, much higher sg2 and hb2 of Gs could be obtained under irrigated conditions and that of Fv/Fm, LE and RWC under drought conditions. However, higher hb2 could be obtained under irrigated conditions for all the four physiological indexes.
【Objective】 The progenies of Sesamum indicum and wild species were obtained by interspecific hybridization in order to improve charcoal rot disease (Macrophomina phaseolina) resistance of sesame cultivars. 【Method】 No.3 wild sesame (S. indicatum) (P3), Zhongzhi 14 (P1) and autotetraploid of Zhongzhi 14 (P2) were used as reciprocal cross parents, the F1 plants of interspecific hybrids were obtained using the immature embryo culture technique. First, the authenticity of F1 progenies were confirmed by using phenotypic, cytological and SSR marker methods in order to screen out the true hybrids . Then the three parents of the interspecific hybrids (No.3 wild sesame, Zhongzhi 14 and autotetraploid of Zhongzhi 14 )and hybrids of F1 lines resistance to Macrophomina phaseolina was identified by artificial inoculations. 【Result】The seedling ratios of immature embryos between reciprocal combinations existed significant difference. The 773 immature embryos were inoculated of which 155 embryos developed into seedlings and the average seedling rate was 20.05%. The seedling ratios of combinations (P3×P1 32.75%, P3×P2 21.11%) were higher than those of reciprocal combinations (P1×P3 8.84%, P2×P3 13.41%). This indicates that the genotype of the parent affects the seedling rate of distant hybridization to a large extent. The number of chromosomes in the F1 plants of (P3 × P1, P1 × P3) was 42 and in the F1 plants of (P3 × P2, P2 × P3) was 55. The majority of the pollen grains of the F1 hybrids were regular but no inclusions, all of which were highly sterile. HS142 primer with a better polymorphism could be clearly amplified two specific types in Zhongzhi14 (about 460 bp and 500 bp) and the one in No.3 wild sesame(about 380 bp) .Then, it could be used to identify twelve hybrid progenies and their parents. There are ten of F1 progenies with three male and female-specific markers of the parents, the other two plants only appeared in the female parent or male parent type which was the fake hybrids. The infected lesion length of progenies from interspecific hybridization P3×P1, P3×P2, using No.3 wild sesame with high charcoal rot resistance as female parent, was 9.35 cm and 6.65 cm, respectively, while 9.90 cm and 8.90 cm from reciprocal combinations. The resistance to Macrophomina phaseolina of progenies from all combinations was higher than their cultivated parents (P1 14.30 cm and P2 11.46 cm), but weaker than wild relative (P3 4.80 cm). 【Conclusion】 New germplasms with high charcoal rot resistance can be created through interspecific hybridization combined with immature embryo culture, which provides important materials for genetic improvement of sesame with charcoal rot resistance.