Effects of Leaf Age, Leaf Area, and Plant Growth Regulators on the Production of Potato (Solanum tuberosum L.) Minitubers Derived from Direct Shoot Cuttings

Shambhu P. Dhital,Seon Phil Choi,Chang Won Kang,Tae Joo Kim,Hak Tae Lim 한국원예학회 2004 Horticulture, Environment, and Biotechnology Vol.45 No.4

The study was carried out to investigate effects of leaf age and area of shoot cuttings, and planting media types on the rapid multiplication of potato seed tubers. Axillary buds and the basal portions of the petiole were buried in a moist medium, containing equal volume of commercial soil and vermiculite and then placed under continuous light and examined for the production of minitubers after 3 weeks. Young and fully expanded leaves on third to seventh node from the top showed significantly higher tuberization rate (100%) and bigger minituber size (average 1.51 g/node in ‘Superior’ and 1.25 g/node in ‘Winter Valley’) than the very young or very old and less expanded leaves in the single node cuttings. Defoliated stem with four nodes gave less tuberization and less average minituber weight than the stem with leaf and apex or without apex in both cultivars. Medium containing equal volume of commercial soil and vermiculite was the most effective for both higher tuberization (average 100%) and higher minituber yield (average 1.52 g/node in ‘Superior’ and 1.55 g/node in ‘Winter Valley’). For the application of plant growth regulators, 6-benzylaminopurine of 10 ㎎ㆍL?¹ produced significantly higher percentage of tuberization and bigger minituber size (average 1.35 g/node in ‘Superior’ and 1.31 g/node in ‘Winter Valley’) as compared to 50 ㎎ㆍL?¹ kinetin and the untreated control. Thus, minitubers produced by direct cuttings can provide an alternative method for the rapid production of potato seed tubers compared to that produced by conventional minituber production systems.

A study of wind effect on damping and frequency of a long span cable-stayed bridge from rational function approximation of self-excited forces

Shambhu Sharan Mishra,Krishen Kumar,Prem Krishna 한국풍공학회 2007 Wind and Structures, An International Journal (WAS Vol.10 No.3

This paper presents an aeroelastic analysis procedure to highlight the influence of wind velocity on the structural damping and frequency of a long span cable-stayed bridge. Frequency dependent self-excited forces in terms of flutter derivatives are expressed as continuous functions using rational function approximation technique. The aeroelastically modified structural equation of motion is expressed in terms of frequency independent modal state-space parameters. The modal logarithmic dampings and frequencies corresponding to a particular wind speed are then determined from the eigen solution of the state matrix.

A High Yield and Processing Potato Cultivar "Taedong Valley"

Shambhu P. Dhital,Yu J. Lian,Won N. Hwang,Hak T. Lim 한국육종학회 2010 한국육종학회지 Vol.42 No.3

‘Taedong Valley’ is a high yielding and processing potato cultivar, which is a clonal selection resulting from a cross between ‘W870’ and ‘A88431-1’. It is a medium maturating cultivar with medium plant height and light green foliage. ‘Taedong Valley’ has profuse flowering habit and light purple flowers. Tubers are smooth, round, and with yellow skin, light yellow flesh, medium eye depth. Tubers have medium dormancy and good keeping quality. ‘Taedong Valley’ has stable yield under wide range of climatic conditions. It is resistant to common scab and potato virus Y, but moderately susceptible to late blight. It is also resistant to most of the disorders, particularly dehiscence, hollow heart and internal brown spots. This cultivar has high level of tuber uniformity and capable of yielding 43.6 t/ha which is about 9.0% higher than the control potato cultivar ‘Atlantic’ under optimum agronomical practices.

Ability of Biochemical Parameters to Distinguish between Bile Duct Cancer and Gall Bladder Stones

( Shambhu Kumar Yadav ),( Brijesh Sathian ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: The present study was designed to comparatively assess alteration of biochemical parameters in bile duct cancer and gall stone disease. Methods: A hospital based case-control study was carried out in the Department of Biochemistry of Manipal Teaching Hospital, Pokhara, Nepal between 1st January 2013 and 31st December 2015. The variables collected were age, gender, serum total cholesterol, total bilirubin, AST, ALT, serum alkaline phosphatase, albumin and hemoglobin. One way ANOVA was used to examine the statistical significance of differences between groups. A post-hoc LSD test was applied for the comparison of means of control versus case groups. A p-value of <0.05 (two-tailed) was considered significant. Results: The mean age of cases and controls was 53.2±21.2 years. The levels of serum cholesterol were higher in cases of cancer 192.5±21.5 mg/dl in comparison to stone cases 168.7±16.1 mg/dl (p value: 0.0001). The total bilirubin showed the marked difference in cases of cancer 7.6±3.2 mg/dl in comparison to stone cases 2.5±0.8 mg/dl of bile duct. There was discernible divergence in values of alkaline phosphatase in cases of cancer 251.5±20.1 IU/l when compared to stone cases 173.2±12.6 IU/l of bile duct. In contrast, there was no apparent deviation in values of aspartate transaminases and alanine transaminases in cases of cancer 59.1±8.9 IU/l and 105.5±26.5 IU/l when compared to stone cases 56.9±7.9 IU/l and 84.5±13.5 IU/l respectively. Conclusions: LFT analysis for pre-operative assessment was a good predictive marker in setting apart bile duct cancer and gall bladder stone.

Identification of 18 flutter derivatives by covariance driven stochastic subspace method

Shambhu Sharan Mishra,Krishen Kumar,Prem Krishna 한국풍공학회 2006 Wind and Structures, An International Journal (WAS Vol.9 No.2

Response of Planting Material and Seed Size on the Production of Minituber of Potato in Glasshouse and Plastichouse Conditions

Shambhu P. Dhital,Hak T. Lim,Won N. Hwang,Woo J. Lee,Hwang S. Mo 한국원예학회 2008 Horticulture, Environment, and Biotechnology Vol.49 No.5

The experiment was conducted to investigate the effect of different in vitro planting materials and seed size on the production of minitubers under glasshouse and plastic house conditions. Three different types of in vitro planting materials for minituber production were used; microtubers, non-hardened and hardened in vitro plantlets of potato cultivars “Gogu Valley”, “Juice Valley”, “Early Valley”, “Purple Valley”, “Golden Valley” and “Superior”. Microtuber showed better performance in plant height, the number of main stem/plant and the number of tuber/plant than the direct planting and indirect planting of in vitro plantlets under glasshouse condition. Tuber yield was significantly higher from the microtuber than the direct planting and indirect planting of in vitro plantlets in all six potato cultivars. The highest yield was 46.2 g/plant in “Early Valley” from microtuber and the lowest yield was 15.4 g/plant in “Juice Valley” from direct planting of in vitro plantlets. In the case of seed size, four different seed size minitubers (0.5-2 g, >2-4 g, >4-6 g and >6-8 g) from first generation of in vitro plantlets of potato cultivars “Superior”, “Purple Valley”, and “Golden Valley” were used. Results showed that bigger seed size resulted in higher emergence rate while higher number of main stem resulted in higher number of tuber per plant. The largest sized seed produced the highest tuber yield (301.6 g/plant) in “Superior” with the highest percentage of medium sized tubers in all evaluated potato cultivars and the lowest yield (105 g/plant) was in “Golden Valley” from the second smallest seed sized tubers. These results demonstrated that microtubers have high potential for better production of minituber among the in vitro planting materials under glasshouse condition and seed sizes are also one of the responsible factors for the production of potato with optimum seed size of minituber in subsequent generation.

Elimination of Potato Viruses (PLRV and PVY) by Cryopreservation of In Vitro Grown Shoot Tips of Potato (Solanum tuberosum L.)

Shambhu Prasad Dhital,Hak Tae Lim,Hira Kaji Manandhar 한국원예학회 2009 Horticulture, Environment, and Biotechnology Vol.50 No.3

Cryopreservation has been recognized as a practical and efficient tool for long-term storage of vegetatively propagated plants. This study was conducted to investigate the effect of sucrose concentration and hardening temperature on the survival of cryopreserved shoot tips and virus elimination through cryo-therapy. Virus-free in vitro plantlets of potato cultivars ‘Atlantic’ and ‘Superior’ were used for survival studies whereas naturally infected in vitro plantlets of potato genotype ‘F9-99’ by potato leaf roll virus (PLRV) and potato virus Y (PVY) were used for virus elimination by cryopreservation. Excised shoot tips were cryopreserved by vitrification using plant vitrification solution-2 (PVS-2). Nine-percentage sucrose concentration gave the highest survival of 41.7% in ‘Atlantic’ and 33.3% in ‘Superior’. The most optimum hardening temperature for the highest survival of ‘Atlantic’ (43.3%) and ‘Superior’ (32.3%) was 10℃. The virus status of the regenerated in vitro plantlets before and after treatment was tested by employing double antibody sandwich-enzymelinked immunosorbent assay (DAS-ELISA) and reverse transcription polymerase chain reaction (RT-PCR). Virus status was subsequently detected following greenhouse acclimatization by both methods. In the case of virus elimination using different steps of cryopreservation, none of the steps were found effective before freezing. The conventional meristem tip culture resulted in 13.6% PLRV and 11.4% PVY free plantlets, while the cryoprotective treatment resulted in 36.8% PLRV free plantlets and 42.1% PVY free plantlets. Cryopreservation steps were not affected for virus elimination, whereas in the case of cryopreservation procedures, vitrification and cryopreservation were more effective than the encapsulation-vitrification and cryopreservation for elimination of PLRV and PVY from the in vitro plantlets. Leaf and tuber morphology of potato plants regenerated after cryopreservation (cryo-therapy) was similar to that of the control. Thus, this study demonstrated that PLRV and PVY can be successfully eliminated from the infected in vitro shoot tips of potato by cryo-therapy.

Electrotherapy and Chemotherapy for Eliminating Double-Infected Potato Virus (PLRV and PVY) from In Vitro Plantlets of Potato (Solanum tuberosum L.)

Shambhu P. Dhital,Hak Tae Lim,Buddhi P. Sharma 한국원예학회 2008 Horticulture, Environment, and Biotechnology Vol.49 No.1

In vitro plantlets of potato genotype ‘F9-99’ infected with potato leaf roll virus (PLRV) and potato virus Y (PVY) were used for virus elimination studies using electric current and chemical treatments. Virus status of in vitro plantlets was determined by double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcription polymerase chain reaction (RT-PCR) before and after treatment. The highest (62.5%) and the lowest (21.9%) regeneration rates were observed from the shoot buds excised after electric treatments with 10 miliampers (mA) for 5 min and 15 mA for 10 min, respectively; also, there were no significant effect on plant growth after electric treatment, except for very high mA for long time. As for virus elimination, current supplied at 10 mA for 5 min resulted in the highest rate of PLRV (46.7%) and PVY (40%) elimination, whereas the lowest virus elimination rate was from the lowest electric current applied for short duration in both of the potato viruses. Study also showed that the plantlets regenerated after electric treatments had higher percentages of virus-free from the shoot buds excision than the nodal cuttings. In the case of electric and chemical treatment combination, the highest rates of PLRV (67.2%) and PVY (62.8%) free plantlets were obtained from shoot buds excised after electrotherapy and cultured on MS medium containing 3% sucrose, 0.7% agar and addition of ribavirin (20 ㎎ㆍℓ?¹) and acetylsalicylic acid (ASA) (10?? M). However, the virus concentration was highly reduced by the addition of ribavirin in the culture medium and the regeneration rates were the highest (72.7%) from the ASA added treatment. Leaf and tuber morphology of plant regenerated from electrotherapy and chemotherapy were similar to those from non-treated control plants. Similar results of virus elimination were obtained under in vitro and in vivo conditions after treatment. Therefore, this study confirmed that electrotherapy (10 mA for 5 min) with the addition of ribavirin (20 ㎎ㆍℓ?¹) and ASA (10?? M) into the cultural medium was the most effective for virus elimination from the virus infected plantlets under in vitro condition and acetylsalicylic acid (ASA).

Microtuberization Response in Several Genotypes of Potato (Solanum tuberosum L.) by Direct Addition of Liquid Medium to in vitro Plantlets

Shambhu P. Dhital,Hak Tae Lim 한국원예학회 2004 Horticulture, Environment, and Biotechnology Vol.45 No.6

In vitro plantlets of eight potato varieties ‘Superior’, ‘Gogu Valley’, ‘Juice Valley’, ‘Early Valley’, ‘Winter Valley’, ‘Taedong Valley’, ‘Purple Valley’, and ‘Golden Valley’ were used to investigate the effect of an additional Murashige and Skoog (MS) liquid medium supplemented with sucrose and plant growth substances (PGSs) on the production of large size microtubers. Plantlets were grown in MS solid medium containing 6% sucrose and incubated for the first 60 days under long day condition (16 h light/day), and then added with MS liquid medium with 8% sucrose. These plantlets produced the highest numbers (1.7 microtubers/plantlet) and yield (635 ㎎/plantlet) of microtuber. The lowest number and yield were obtained from the in vitro plantlets grown in the solid medium without adding MS liquid medium. As for the utilization of PGSs, it was shown that the higher the PGSs levels, earlier the tuberizations with higher yield and lower number of microtubers. The highest yield (591 ㎎/plantlet) was obtained from 200 ㎎ㆍL?¹ of succinic acid 2,2-dimethylhydrazide (B-9) and numbers (1.6 microtubers/plantlet) from 10 ㎎ㆍL?¹ of 6-benzylaminopurine (BAP) treatment. In the case of combinations of PGSs, treatments of 10 ㎎ㆍL?¹ BAP and 200 ㎎ㆍL?¹ B-9 produced significantly the highest numbers (1.5/plantlet) and the highest yield (766 ㎎/plantlet) of microtuber, but lowest from the control. Thus, an extra addition of MS liquid medium with sucrose and PGSs might have played a major role for the further induction and development of large size of microtubers on diverse genetic background of potatoes under in vitro conditions.

Influence of Bromoethane, Ethanol and GA₃ on Dormancy Breaking and Subsequent Tuber Yield of Several Potato Cultivars

Shambhu Prasad Dhital(샴부디히탈),Won Nam Hwang(황원남),Hak Tae Lim(임학태) 한국원예학회 2010 원예과학기술지 Vol.28 No.1

감자 괴경의 휴면타파와 후대 생산성에 미치는 브롬에탄, 에탄올, 지베렐린 등의 영향을 구명하고자 실험을 실시하였으며, 감자 품종은 ‘고구밸리’, ‘퍼플밸리’, ‘보라밸리’ 와 ‘수미’ 등을 이용하였다. 각 화학약품을 단일 처리하였을 경우, 브롬에탄과 지베렐린은 처리농도가 높을수록 맹아가 더 빨리 시작되었으며 80% 맹아까지의 기간이 짧았다. 그러나 에탄올은 처리농도가 높을수록 발아가 지연되었다. 각 화학약품과 처리농도 중에서 브롬에탄 0.2-0.3mL · L?¹를 처리하였을 때 무처리보다 휴면이 두 배 가량 빨리 타파되어 휴면타파에 가장 뛰어난 효과를 나타냈다. 브롬에탄이 처리된 괴경들은 또한 짧고 튼튼한 싹을 내었고, 고구밸리와 퍼플밸리 두 품종 모두 가장 높은 맹아율을 나타내었다. 또 다른 실험에서는 24시간 간격으로 0.2mL · L?¹의 브롬에탄을 이중 처리한 괴경과 200mL · L?¹의 지베렐린과 0.2mL · L?¹의 브롬에탄을 함께 처리한 괴경의 경우 중간 길이의 많은 수의 싹을 내었으며 높은 맹아율을 보여 휴면타파에 뛰어난 효과를 보여주었다. 반면에, 지베렐린 단독처리의 경우 휴면기간이 중간 정도인 ‘수미’와 휴면기간이 긴 ‘보라밸리’에서 싹의 길이가 길고 수가 적었다. 0.2mL · L?¹ 브롬에탄 단독 처리 괴경과 200mL · L?¹ 지베렐린과 0.2mL · L?¹ 브롬에탄이 함께 처리된 괴경의 경우 포장 재배를 하였을 때 줄기 수가 제일 많았으며 높은 생산성을 보여주었고, 괴경과 줄기 특성에 있어서도 어떠한 형태적 변화를 보이지 않았다. 따라서, 0.2mL · L?¹의 브롬에탄을 이중처리 하거나 200mL · L?¹의 지베렐린과 0.2mL · L?¹의 브롬에탄을 함께 처리하는 것이 다양한 감자 품종에 있어 갓 수확된 괴경의 휴면타파에 가장 적합한 것으로 판단되었다. Effects of bromoethane (BE), ethanol (EtOH), and gibberellic acid (GA₃) applications were evaluated for dormancy breaking of potato (Solanum tuberosum L.) tubers under room condition. Seed size (30-50 g/tuber) tubers of potato cvs. Gogu Valley, Purple Valley, Bora Valley and Superior were used. In the case of single application of chemicals, higher concentrations of BE and GA₃ resulted in earlier days of sprouting and earlier days to 80% sprouting; in contrast, higher concentrations of EtOH delayed the sprouting. Among the evaluated chemicals and concentrations, BE (0.2-0.3 mL · L?¹) showed the most desirable effect in breaking the tuber dormancy, which was about two times earlier than the untreated control. BE treated tubers also produced short and strong sprouts with the highest percentage of sprouted eyes in both of the tested potato cvs. Gogu Valley and Purple Valley. In the other experiment, double application of BE (0.2 mL · L?¹) at 24 h interval, and combined application of GA₃ (200 ㎎ · L?¹) and BE (0.2 mL · L?¹) showed significant effect on breaking the tuber dormancy with high percentage of sprouted eyes and medium-length multi-sprouts; whereas, tubers treated with GA₃ alone produced long sprouts with few sprouted eyes in medium dormancy (Superior) and long dormancy (Bora Valley) potato cultivars. Tubers treated with BE (0.2 mL · L?¹) alone or combination of GA₃ (200 ㎎ · L?¹) and BE (0.2 mL · L?¹) treatment showed the most number of main stems and higher tuber yield in the subsequent cultivation under field condition without any morphological changes in tuber and plant characters. Thus, the double application of BE (0.2 mL · L?¹) or combined application of GA₃ (200 mL · L?¹) and BE (0.2 mL · L?¹) is recommended for breaking dormancy of freshly harvested potato tubers in diverse potato cultivars.