Abstract:Soybean （Glycine max （L.） Merr.） is a self-pollinating crop， and producing hybrids through artificial emasculation is time-consuming and expensive. Unlocking the function of the male sterility gene is a prerequisite for harnessing heterosis in soybean. Up to now， only a few loci of male sterility had been reported in soybean， and progress in molecular cloning and functional characterization of related genes lagged behind. Advances in biotechnology and soybean genetic transformation system enabled the possibility to employ reverse genetics methodology for studying the male sterility genes. The transcriptomic data indicated that the small G protein encoding gene GmARFA1a was regulated simultaneously by the male sterility gene MS1 （Male Sterile 1） and MS2. Data from the public library indicated that GmARFA1a expression was the highest in unopened soybean flowers， qRT-PCR data demonstrated that GmARFA1a was preferentially expressed in stamen before flowering. The pollen germination experiment and seed setting statistics found that the decrease of pollen viability of Gmarfa1a mutant resulted in the significant inhibition of seed setting Collectively， this study identified the GmARFA1a gene and uncovered its function on male fertility. It will not only enhance our understanding of the GmARFA1a and ARF gene families but also lay the foundation for further study the function of GmARFA1a genes and the utilization of heterosis in soybean.

Abstract:Vegetables of the genus Allium L. with high diversity are very important in the vegetable production. The viability ofthe short-lived seed of Allium is easily reduced or even lost during storage. A total of 610 accessions of 6 species of allium vegetablesin the National Medium-term Genebank of Vegetable Germplasm Resources, including 267 accessions of A. tuberosum Rottler ex Spreng., 226 accessions of A. fistulosum L., 40 accessions of A. ascalonicum L., 67 accessions of A. cepa L., 8 accessions of A. porrumL., and 2 accessions of A. ampeloprasum L. were evaluated for seed germination. The results indicated that the seed viability of the 6species of allium vegetable resources declined significantly after 21-30 years storage, with A. ascalonicum and A. cepa the most seriously, that the initial germination percentage of the seeds put in storage heavily affected the viability of the seeds during storage, and that the different genotypes of the same species of allium vegetables also showed difference in longevity.

Abstract:In order to produce the elite germplasm resource for tea breeding, we deployed the artificial hybridization approach to generate the F1 hybrids by crossing six elite tea varieties including Fuding Dabaicha (mother) with another variety Baojing Huangjincha 1, which showed a specific phenotype golden rhyme but weak adaptation ability. We found that Baojing Huangjincha 1 pollen exhibited a strong living force whose fresh pollen life force reached to 94.22% by taking researching on Baojing Huangjincha 1 pollen life force, different hybrid combination strong rate, hybrid F1 generation seedling rate, F1 generation excellent single plant selection rate, etc.. Under room temperature, 4℃ and -20℃ conditions, its pollen was able to survive up to 7d, 30d and 40d, respectively. The seed setting rates of six hybrid combinations were variable from 15.25% (Bixiangzao) to 31.32% (Fuding Dabaicha) with the average of 21.88%, while the seedling rates were arranged from 50.77% (Bxiangzao) to 66.65% (Tieguanyin) with a mean value of 59.62%. No significant difference was observed in seed setting rate and seedling rate among different treatments (combinations and years). By taking use of three rounds of selecting excellent strains and identifying asexual reproduction ability, a total of 60 strains were finally accepted with a selection rate of 2.35%. The rate of elite hybrids was much higher than that of naturally-occurring hybridization offspring (0.04%). Furthermore, we conducted a comprehensive evaluation of biochemical composition, yield and quality related traits in selected hybrids. Three new strains, which were subjected for the regional test, showed the growth potential and excellent sensory quality (especially with aroma prominent), much better than the father Baojing Huangjincha 1.

Abstract:Bretschneidera sinensis Hemsl., a monotypic species and Tertiary relict tree, is listed in the State First-Class Protection Tree Species of China. The natural population is decreasing nowadays with a sparse distribution ranged from south China to northern Vietnam. Within this study, we investigated the flowering behavior, pollen type, dynamic viability and storage method of pollen and receptivity of stigma. The elongation of the stigma at initial flowering stage was observed, which leads to the physical barrier compromising the self-pollination effectively. The receptivity of stigma developed form little bud to full-bloom stage, and mucilage was secreted by stigma only at full-bloom stage. Pollen grains were starchless which indicate a typical insect pollination. The viability of pollen was very low at bud stage, and then reached high at full-bloom stage. The optimal concentration of sucrose solution for in vitro germination was 20%. Pollen grains were observed to be sensitive responding to storage treatments. Pollen viability could be maintained up to 190 h under freeze storage (- 20 ℃), suggesting that low temperature is the key factor to reserve the pollen viability. The resistance of the wild population upon climate change was quite fragile because the time-frame on the flowering of natural populations of B. sinensis was short. Thus, collection and low-temperature storage of mature pollen in combination with artificial pollination are recommended in B. sinensis.

Abstract:To predict seed longevity and viability of Sorghun vulgare, Agopyrum escutentum, Lactuca sativa, and Amaranthus by survivor proportion and main storage condition factors, seeds of 8 seed lot of Sorghun vulgare and Amaranthus with 3 levels of water content were stored at 20℃, 30℃ and 40℃ for lasting 810 d. Data sets of germination percent and storage period of seed from storage experiments of Sorghun vulgare and Amaranthus seed lot and from literature reported for Fagopyrum escutentum and Lactuca sativa seed lot were used to estimate mean viability period (p50) and standard deviation of seeds death distribution in time (σ) for different seed lot using regression equations of probability and survivor proportion in linearity, and fitting of the equations were also synchronously compared. Moreover, p50 and σ by two equations estimated were used to analyze storage condition factors with stepwise regression method, including storage temperature(t℃)and its quadratic term（t2), water content of seed (m%)and its logarithm(logm), and interaction between storage temperature and water content of seeds (t×m and t×logm), respectively. The results showed that estimated p50 and σ with survivor proportion to estimate was feasible and had more statistical significance than probability estimated. Seed viability was quickly lost and its longevity was decreased by interaction between storage temperature and water content of seed (t×m). The mathematic model Gi/G0=A-P/10K-CWT (t×m) containing the interaction factor and survivor proportion had higher accuracy to predict initial germination percent of Lactuca sativa than the model Vi=Ki- p/10 K-CWT (t×m). Thus, the former and latter models were recommended to predict initial germination rate with longevity and viability of seed known and unknown, respectively.

Abstract:Seed viability loss at low temperature genebank and ambient storage received increasing concerns, but comparing with its importance, few publications dressed this question. In this paper, viability monitoring data of wheat (Triticum aestivum Linn.) seed from a midterm genebank, ambient storage, as well as an accelerated ageing experiment were quantified to get further understanding of seed ageing under these conditions. The results showed that seed longevity of all accessions followed normal distribution, and that seed survival curves showed inverse-S shape, which received no obvious effects from storage conditions. The rate of seed viability loss decreased, and the plateau phase and seed longevity increased as the storage temperature reduced. T-test was adapted to determine the turning point (Pt) between the plateau phase and viability sharp decline phase of the seed survival curve. The results showed that the Pt under different storage conditions were quite close, which varied between 82.2% and 83.6%. The possible role of Pt and some physiological indexes as indicators for seed viability loss during germplasm storage were discussed.

Abstract:Fast, accurate and non-destructive identification of seed viability is a critical factor in the safe preservation of germplasm resources. In this paper, we have used yellow soybeans of different preservation period as samples, and established a mathematical model of non-destructive determination for its viability by employing Fourier transform near-infrared spectroscopy (FT-NIRS) in combination with partial least squares (PLS). Simultaneously, we have compared and analyzed the prediction performance of the model by using different spectral-pretreatment methods and different band ranges. Results indicate that the model has higher prediction accuracy in 4000~10000nm full-band range. After preprocessing these spectra data with Savitzky Golay second derivative and standardized pretreatment, we’ve found that the PLS model is the best for viability non-destructive determination. The correlation coefficient of calibration set samples is 0.937, and the correlation coefficient of prediction set samples is 0.902. RMSEC and RMSEP are 2.190 and 2.684 respectively. Therefore, the prediction accuracy of the model is close to that of normal germination method, and can meet the requirement in rapid non-destructive identification of seed viability, which provides theoretical basis for rapid non-destructive determination of seed vigor in the future.

Abstract:Determination on pollen viability of 19 pear cultivars in different storage temperatures were carried out by testing method of pollens cultured in vitro, pollination characteristics of 6 cross combinations and inbred of 15 pear cultivars were also studied. The results showed that addition of boric acid and gibberellin in culture medium can enhance pollen viability. It was found that Daci pear,Bayuehong,Whangkeumbae pear pollen abortion assayed under microscope.In different storage conditions, the lower of the temperature, the more slowly of the pollen germination rate dropped, lower temperature was suitable for long storage. During process of storage, the appearance of “compelled dormancy of short-term” was exist, and with lower temperature forced dormancy recovery time backward outspread. The average of fruit setting rate of flower and inflorescence of 6 cross combinations were 82.54% and 94.82%, and had no significant differences with open pollination. Gold-Nijisseiki could be used as pollination tree for Ya pear and Xuehua pear, also Xuehua pear, Ya pear, Red D Anjou and Red clapps favorite could be used as pollination tree for Whangkeumbae.The self-fertile rate of 15 pear cultivars were low, and 8 cuitivars included Daci pear, Whangkeumbae, Qinfeng, Xiuyu, Sinsei, Xuehua pear and Housui had no self-fertile rate. In production, pollination tree were needed to achieve production demand.

Abstract:Germination percentage of 89 accessions wheat germplasm stored-4～0℃ packed in vacuum aluminum foil bag and non-vacuum aluminum box were tested.Disussed the effect of storage method form three levels：the difference of germination percentage of two package methods for seeds stored at low temperature and initial germination percentage before stores, the difference of germination percentage of two package methods for seeds between storage years and the difference of germination percentage between two package methods in the same year. The result showed：the viability of wheat germplasm stored at low temperature were tested, the 82 percent of materials of mean germination percentage was higher than initial germination percentage,but ten years later, germination percentages were obviously decreased than initial germination percentage,and the germination percentage of aluminum foil bag were reduced of less than aluminum box and the difference was significant, the method of sealing up in aluminum foil bag showed best effect.

Abstract:In the present study, the viability of 14 thousands seed accessions, belonging to 34 crops, were detected after being stored at the National Genebank of China for 20 to 23 years. Results showed that the viability of 92.9% of the accessions were higher than 85%. Significant viability decline was detected in 155 accessions from broad bean, red adzuki bean, jute, castor, sugar beet, watermelon, tobacco and forage. A total of 2078 seed accessions from 8 crops, including wheat, soybean, sorghum, millet, cotton, peanut, common bean and watermelon, were uesd for seedling emergence survey. The results showed that each surveyed accession succeeded in seedling emergence, but the emergence percentage of 8 accessions was lower than 10%. The seedling emergence percentage was lower than the mean initial germination percentage. Among the 8 crops, the seedling emergence percentage of common bean was the highest, with a mean value of 86.2% of 126 accessions, which was only 9.3% lower than the initial germination percentage. The lowest seedling emergence percentage was found in millet seeds, with a mean value of only 39.2%, which was 51.3% lower than the initial germination percentage. To sum up, most of the collections in the National Genenbank of China can be safely conserved for more than 20 years, especially the cereal seeds, but as for the seed accessions that had showed significant reduction in the mean monitored germination percentage, for example, broad bean, red adzuki bean, etc, the viability should be monitored more frequently in order to assure the long-term safe conservation of these germplasm.