Study on Optimization of Hydroponic Technology of Virus-free Potato Plantlets in Winter in Chengdu Plain

The effects of different heating measures on breeding virus-free potato plantlets with hydroponic technology were studied in this paper. The virus-free tube plantlets of potato （Favorita） were used as test material. A total of 3 treatments were designed, including traditional hydroponics （CK）, installing heaters （T1） and in- stalling heaters and thermal insulation device （T2）. The results showed in the Chengdu Plain in low-temperature winter, the installing of heaters and covering of thermal insulation device could maintain the hydroponic water temperature at 15-22 ~C. The potato seedlings grown in heaters and thermal insulation device-installed seedbed rooted 6.4 d earlier and emerged 13 d earlier compared to that in tradi- tional seedbed. The growth of potato seedlings grown in heaters and thermal insu- lation device-installed seedbed was more robust. Their root length, stem diameter, plant height, leaf number and fresh weight were all higher than that of traditional potato seedlings. The tuber number per plant in T1 group reached 1.7 and in T2 group reached 3.57 42 d after the cutting of hydroponic seedlings, while then the plantlets in CK group just turned into the aeroponics stage. Therefore, heating hy- droponics is conducive to advancing the cutting of virus-free seedlings and breeding robust water-cultured seedlings. Moreover, the fruiting of aeroponics seedlings is al- so advanced. The heating hydroponics plays an important role in actual production.

Design and experiment of conical diversion virus-free potato minituber precision seed-metering device

In order to accelerate the development of sowing mechanization of virus-free potato minituber,a conical diversion virus-free potato minituber precision seed-metering Device was designed according to the structural characteristics and agronomic requirements of virus-free potato minituber.The device is mainly composed of conical turntable,transmission shaft,outer baffle of seed-metering Device,baffle,seed outlet,seed cleaning device,type hole,etc.The working principle of conical diversion precision seed-metering device for virus-free potato minituber was expounded,and the stress analysis of virus-free potato minituber in each region was carried out.By EDEM discrete element simulation software,the structure of the type hole is optimized to determine the optimal structure of the type hole and according to the physical characteristics of virus-free potato minituber,the single factor experiments of the effects of length of type hole,cone disc speed and cone disc angle on seed filling performance were completed.The orthogonal regression test was carried out with the length of type hole,cone disc speed,and cone disc angle as the test objects,and the leakage rate and qualified rate as the response indexes.The regression models of leakage rate,replay rate,and qualified rate were established,and the parameters of the regression model were optimized.The optimal parameter combination is that the length of type hole is 33.61 mm,the cone disc speed is 6.35 r/min,and the cone disc angle is 26.59°.Bench test was carried out under the optimal conditions,the leakage rate was 3.80%,the replay rate was 0.80%,and the qualified rate was 95.40%,which was basically consistent with the prediction results of the regression model,and met the requirements of precision sowing of virus-free potato minituber.

Standardized Production Technology of Virus-free Seed Potato

The research reviewed standardized production technology of virus-free seed potato, including stem tip isolation, tissue culture seedling production, breeder＇s seed and protospecies production, and standard potato tubers＇ production, and concluded a set of standardized production technology for virus-free seed potato, in order to provide theoretical references for improving potato yield.

Evaluation of the Characteristics of Virus-free Sweetpotato and Its Use in Hybridization

Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% - 91. 61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.

Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. III. Influence of viral infection on field plants and new technology of clone selection of virus-free planting potato

At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount of stems, plants’ height and assimilation area surface, yield, acceleration of plants development and their early die-off. The differences of DF pa-rameters and yields between strongly and weakly infected plants increase in case of a combined virus infection. In industrial test of the selection of virus-free planting potato by the use of DF parameter, a rise in the yield and de-crease degree of viral infection of crops was obtained.

Study on Virus-free Breeding Technology of Potato Microtuber

It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. Microtuber is featured by small volume,no pathogen,convenient storage and transportation,which can be induced in summer with high temperature and humidity,and overcome a series of problems such as poor survival rate of transplanted test-tube plantlets,and easy pollution of cutting tips. Therefore,it can replace conventional test-tube plantlets directly for reproduction. Meantime,if minitubers are sown ahead of time using cold frame,the growth stage of potato minituber will avoid the occurrence period of aphids. The use of gauze cover for insect prevention has good effect on maintaining the excellent characters of microtuber. The yield and quality of virus-free potato are greatly improved by means of virus-free culture of shoot tip seedlings,subculture propagation of virus-free seedlings,induction of microtubers by dark culture,cultivation of breeder’s seeds in greenhouse and screenhouse to preserve the characters of potato.

Key Technology for Virus-free Seed Potatoes Pre-elite Breeding

[Objectives]To establish a breeding system for pre-elite seed potatoes.[Methods]Shoot-tip seedlings were cultured with different medium,and then transplanted in different substrates.They were sprayed with nutrient solutions of different formulas.Potato minitubers were induced.[Results]The medium of MS+2.0 mg/L 6-BA,1.0 mg/L NAA+3%sugar was preferable for potato shoot tip culture.After virus detection,the virus-free potato seedlings were propagated.The medium composed of vermiculite,peat and perlite(1∶3∶1)was recommended for transplanting potato tissue culture seedlings in greenhouse.The three-dimensional spray method was used to produce pre-elite seed potatoes.The full-amount MS nutrient solution could increase the tuber number per plant to 55.Induction of minitubers is a better breeding technology for pre-elite seed potatoes.The optimal medium screened for induction of potato minitubers was MS+(5-7)mg/L 6-BA,with a dark culture duration of about 20 d.[Conclusions]The breeding technology established is suitable for the two-season cultivation areas in Zaozhuang.

Establishment of Three Breeding System of Virus-free Strawberry Plantlet in Infantry Regiment of the Twelve Division

Shoot-tip culture of strawberry is the most important way to get virus-free plants.Moreover,detoxification and rapid propagation are the key techniques for producing high-quality seeds and seedlings massively and rapidly and achieving the high-quality,high-yield and high-efficiency development of strawberry industry.We have recently produced virus-free strawberry seedlings by combing tissue culture technology and stolon-reproduction method and this technology has been widely used.In addition,a relatively perfect three breeding system of virus-free strawberry seedlings was established after production practices,guaranteeing the supply of high-quality seeds and seedlings and technical support for strawberry industry in corps.

Detection of Ratoon Stunting Disease in Virus-free Seedcane via Real-time Fluorescence Quantitative PCR

This study was to develop the real-time fluorescence quantitative PCR technique for detecting the ratoon stunting disease （RSD） in virus-free seedcane seedlings. Healthy tissue culture seedlings were obtained from six plants of sugarcane ROC22, which had been confirmed RSD-positive by detecting the sugarcane juice, by employing the sugarcane seedlings production protocol. Real-time fluorescence quantitative PCR was used to detect RSD pathogens in tissue culture sam- pies. The results showed that target fragment of RSD pathogens was not found in all 10 samples in real-time fluorescence quantitative PCR, with the Ct values of 37 - 39. The healthy tissue culture sugarcane seedlings do not carry RSD pathogens, indicating that adopting healthy seedcane seedlings production technique could thoroughly get rid of RSD pathogens.

Effect of Heat Treatment Combined with Shoot Tip Culture on the Virus-Free of Arena Strawberry

With Arena strawberry as experimental materials, heat treatments combined with shoot tip culture were used to explore their detoxification effects. The results indicated that if not heated, splitting shoot tips directly could not completely remove viruses. On the other hand, it will be obviously improved after shoot tips are heated. Incubators heat treatment （inconstant temperature） with shoot tip culture, constant temperature water bath incubation process with meristem-tip culture, hot air treatment （constant temperature） with apical meristem culture were three methods tested in searching for virus-free of Arena strawberry in this experiment. And their virus-free rates were 78.9%, 86.0% and 50.0% respectively. Of the three methods, the second, constant temperature water bath process with shoot tip culture, with 78.7% survival, is the best. Thus, it can be inferred that constant temperature water bath treatment combined with shoot tip culture might be the most appropriate method to remove viruses of Arena strawberry.

Rapid Propagation of Virus-free Sugarcane Plantlets via Temporary Immersion Bioreactor System

By employing temporary immersion bioreactor system(TIBs),we studied virus-free culture of seedlings from sugarcane varieties ROC16 and ROC22,from medium recipe,inoculation amount,sucrose concentration,and variety difference. The results showed,using this method,that proliferation rate of ROC16 improved by 40 times,per flask generated about 800 plantlets; of ROC22 improved by 30 times,per flask generated about 400-600 plantlets. The results provided basis for using TIBs in rapid propagation of plantlets via tissue culture.

A Preliminary Study on Tissue Culture and Rapid Propagation of Virus-free Plantlets of Benihoppe Strawberry

[ Objective] This study aimed to investigate the tissue culture and rapid propagation techniques of Benihoppe strawberry. [ Method] Shoot tips of new stolons of Benihoppe strawberry were used as experimental materials to analyze the effects of media type, cytokinin type and concentration, carbon source type and concentration, and light intensity on tissue culture and propagation of Benihoppe strawberry. [ Result] MS was the optimal media for plantlet propagation. In the media containing 1.2 ing/L BA （with addition of 0.1 mg/L NAA）, fresh weight, dry weight and propagation coefficient of strawberry plantlets reached the maxi- mum, which were 2.259 g, 0. 221 g and 12.4, respectively. The optimal carbon source was 30 g/L sucrose, and the optimal light intensity was 1 600 lx. [ Conclu- sion] The best media for tissue culture and rapid propagation of Benihoppe strawberry was MS ＋ BA 1.2 mg/L ＋ NAA 0. 1 mg/L ＋ sucrose 30 g/L ＋ agar 8 g/L. This study provided scientific basis for large-scale production of Benihoppe strawberry.

Expression of Invertase Genes in Virus-free Sugarcane

Virus-free sugarcane seedlings have improved biomass and sucrose content compared with ordinary seedlings, and sucrose invertases are key enzymes regulating sugarcane growth and sucrose accumulation. In this study, the differences in the expression levels of 3 invertase genes, CWI, SAI and NI, between virus- free and ordinary sugarcane seedlings were analyzed. Compared with ordinary sugarcane plants, the expression of CWI was mainly up-regulated in immature leaves and stems at elongation stage and leaves and immature internodes at maturation stage, and especially, greatly up-regulated in immature interuedes at maturation stage of virus-free plants. The expression of SAI and NI were mainly up-regnlated in leaves and immature internedes of virus-free plants at maturation stage, which might be beneficial to sugar accumulation and rapid utilization of monosaccharide in the stalks of virus-free plants. It is further indicated that virus-free treatment could significantly improve the expression of sucrose invertases at late growth period, and might facilitate the increase of plant biomass.

Detection of Ratoon Stunting Disease in Virus-free Seedcane of Saccharum officinarum by PCR

[Objective]The study was carried out for providing good method to detect ratoon stunting disease（RSD）in virus-free seedcane of Saccharum officinarum.[Method]PCR method was used for the detection of RSD in virus-free seedcane of sugarcane.[Result]During the different growth stages of healthy virus-free seedling including proliferation stage,rooting stage,sand culture stage and temporary planting stage,the RSD detection results were negative.PCR detection sensitivity in the present study showed that PCR could detect RSD pathogen in the solution with bacterium concentration 10-3.[Conclusion]PCR method showed a good specificity and higher sensitivity,so it was suitable for the batch detection in the production of healthy virus-free seedlings of sugarcane.

Effect of Inorganic and Organic Fertilizers on Growth and Yield of Two Industrial Potato Varieties (Asterix and Courage) in Bangladesh

Potato is one of the most important vegetable crops, which contributes more than half of the total vegetable production in Bangladesh. Four field experiments were conducted in two different locations in Bangladesh to develop integrated nutrient management practices to produce quality potato seed in industrial processing varieties Asterix and Courage. For the inorganic trial, Factorial Randomized Complete Block Design (RCBD) including 2 potato varieties, 5 treatments with 4 replications, and in the organic fertilizer trial, Factorial RCBD including 2 potato varieties, 6 treatments with 4 replications were used. In the inorganic fertilizer trail, the highest yield was obtained in the variety Asterix due to Nitrogen, Phosphorus, Potassium, and Sulfur (NPKS) plus Magnesium treated plot in Domar BADC farm and due to NPKS plus Boron, Zinc, and Magnesium treated plots in Kashimpur Farm. In the case of variety Courage, the highest yield was found in the treatment of NPKS plus Zinc in Domar BADC farm while in Kashimpur farm, NPKS plus Mg treated plots had the highest yield of potato variety-Courage. In the organic fertilizer trail, the highest tuber yield per hill was obtained by applying the government-approved commercial brand Northern organic fertilizer in variety Asterix and by organic fertilizer brand Chook Chook in variety Courage. Parameters such as days to tuber initiation, number of stems per hill, plant height, and number of tubers per hill were found statistically different among the treatments and between the two varieties. Treatments namely Northern organic fertilizer and Cowdung combined with mustard oil cake performed better considering standard grade tuber yield (grade A and B) compared to other treatments. Hence, the combination of NPKS MgZn and either Northern organic or Chook Chook or Cowdung plus mustard oil cake could be used to grow the varieties Asterix and Courage.

Metabolic profiles and morphological characteristics of leaf tips among different sweet potato(Ipomoea batatas Lam.)varieties

Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this study,a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties.Three varieties with distinct overall metabolic profiles(A01,A02,and A03),two varieties with distinct profiles of phenolic acids(A20 and A18),and three varieties with distinct profiles of flavonoids(A05,A12,and A16)were identified.In addition,a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips,respectively,were identified through morphological characterization.Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids.Also,the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips,with lobed leaf types having higher levels of polyphenols than the entire leaf types.The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.

Highβ-sitosterol-D-glucoside content in sweet potato varieties and its anti-breast cancer potential through multiple metastasis-associated signals

β-Sitosterol-D-glucoside(β-SDG)is a phytosterol compound whose antitumor activity has been confirmed by previous studies.However,its suppression on breast cancer remains unclear.To that purpose,we isolatedβ-SDG from sweet potato and investigated the breast-cancer-inhibiting mechanism using proteomic analysis.The sweet potato species S6 with highβ-SDG content were chosen form 36 species andβ-SDG was isolated by HPLC.Afterwards,an in situ animal model of breast cancer was established,andβ-SDG significantly reduced the tumor volume of MCF-7 xenograft mice.Proteomic analysis of tumor tissues revealed that 127 of these proteins were upregulated and 80 were downregulated.Gene ontology and network analysis showed that regulatory proteins were mainly associated with epithelial-mesenchymal transition(EMT),myogenesis,cholesterol homeostasis,oxidative phosphorylation and reactive oxygen pathways,while Vimentin,NDUF,VDAC1,PPP2CA and SNx9 were the most significant 5 node degree genes.Meanwhile,in vitro and in vivo results showed that the protein expression of PPP2CA and Vimentin,which are markers of EMT,were involved in breast cancer cell metastasis and could be reversed byβ-SDG.This work highlightsβ-SDG as a bioactive compound in sweet potato and the potential therapeutic effect ofβ-SDG for the treatment of breast cancer by inhibiting metastasis.

Effect of Chicken Manure, Compost and Cow Dung on the Growth and Yield of Sweet Potato [Ipomoea batatas (L.) Lam.] under Guinea Savannah Agroecological Zone of Ghana

Twelve percent (12%) of Ghanaians are food insecure, and climate-smart crops like sweet potatoes are required to help end poverty. Small-scale farmers in Ghana who produce low-technology, subsistence crops, such as sweet potatoes, are more food secure than those who do not. This study was initiated to investigate the effect of chicken manure, compost, and cow dung on the growth and yield of “apomuden”, “SARI-Nyoriberigu”, “SARI-Nan” and “kufour” sweet potato under the Guinea Savannah agroecological zone of Ghana. Organic fertilizer increased leaf chlorophyll content and leaf area index. The application of cow dung, chicken manure and compost in 2015 significantly increased total storage root yield by 38%, 55% and 98%, 62%, 45% and 37%, 52%, 61% and 44%, and 33%, 36% and 28% for SARI-Nyoriberigu, Kufour, SARI-Nan and Apomuden, respectively, when compared to the untreated check. In 2016, and in comparison with the untreated check, the application of cow dung, chicken manure and compost increased total storage root yield by 42%, 61% and 93%, 69%, 49% and 41%, 57%, 67% and 48%, and 36%, 39% and 30% for SARI-Nyoriberigu, Kufour, SARI-Nan and Apomuden, respectively. Hence, the application of organic fertilizers will increase sweet potato yield, give higher returns to resource-poor smallholder farmers and contribute to enhancing food and nutrition security.

Steps To ward HIV Cure Two more HIV-infected patients appear to be virus-free after bone-marrow transplants

THIS year＇s International AIDS Society Conference on HIV Pathogenesis, Treatment and Preven-／tion, held in Kuala Lumpur, Malaysia, made major headlines when Timothy Hendch, an American doctor, announced that two more cancer patients may have been cured of HIV after receiving bone-marrow transplants to treat lymphoma. Both patients had been taking retroviral medication, and continued to do so after the transplants as their viral levels sank until doctors were unable to find any traces of HIV in the patients＇ blood.

Effect of Size and Initial Water Content on the Effective Diffusion Coefficient during Convective Drying of Sweet Potato Cut into Cubic and Cylindrical Shapes

In this article, we investigated the influence of size and initial water content on the effective diffusion coefficient of sweet potatoes samples cut into cubic and cylindrical shapes. The sizes of the cubic samples are 0.5, 1, 1.5, 1.75, 2, 2.5 and 3 cm edge with a respective initial water content of 2.7, 3.76, 3.48, 2.68, 3.28, 2.17 and 2.29 kg/kgms. For cylindrical samples, the radius is set at 0.5 cm and sample heights are 1, 1.5, 2, 2.5, 3, 3.5 and 4 cm with respective water contents of 2.2, 3.19, 2.85, 2.1, 2.17, 2.39 and 2.03 kg/kgms. The effective diffusion coefficients of cubic samples are of the order of 10−10 and 10−9 m2∙s−1 grew with sample edge. As for the cylindrical samples, the effective diffusion coefficients were of the order of 10−9 m2∙s−1 and there was no linear correlation between cylinder height and their effective diffusion coefficient. As for the examination of the initial water content on the effective diffusion coefficient, it turned out that the initial water content had no influence on the effective diffusion coefficient of the sweet potato samples.