The influence of mechanical impact and storage conditions on subsurface hardening in pre-peeled potatoes (Solanum tuberosum L.)

Summary In investigating the effect of mechanical impact and storage conditions on subsurface hardening in boiled pre-peeled potatoes, potatoes (cv. Sava) were peeled using an industrial peeler, a laboratory knife peeler or a hand knife peeler, packed in polymer bags and stored at 4 to 18 °C for 6 days. Industrially peeled potatoes were significantly harder than potatoes peeled by hand or using a laboratory knife peeler. Potato hardening was not related to pectin methyl esterase activity (EC 3.1.1.11.). However, it was significantly correlated with mechanical impact from the peeler knives and by treatment in a damage barrel. Blunt knives resulted in harder potatoes than when sharp knives were used. An increase in storage temperature from 4 to 18 °C also increased subsurface hardening significantly. Maximum hardness was found below the wounded surface at a depth of 2–8 mm (average 4 mm).     

Effect of fertilisation, development stage, mechanical impact and heating during processing on subsurface hardening in pre-peeled potatoes (Solarium tuberosum L.)

Summary Studies of the effect of fertilisation stress, harvest time, machine sorting, storage time, peeling and blanching of potatoes (Solarium tuberosum L.) were carried out. Mechanical impact by sorting before storage did not have a significant effect on hardness of pre-peeled potatoes. Potato hardness decreased significantly with the storage time for raw potatoes following an exponential function. Treatment of potatoes in a damage drum for 5 minutes (36 drops from 35 cm) increased the subsurface hardening, production of brick-like cells and deposition of suberin. Potato hardness throughout the whole potatoes increased with blanching time by blanching at 85 and 95 °C. It was concluded that development of potato hardiness occur because of two mechanisms. That is: 1) wound healing by periderm formation with deposition of suberin and: 2) activation of methyl esterase activity by blanching and subsequent crosslinking of demethoxylated pectin by calcium ions, respectively.     

PCR analysis of bisulfite-modified DNA to investigate developmental variation in micropropagated potatoes (Solanum tuberosum L.)

Summary Bisulfite modification of DNA from potato leaves showing juvenile and mature leaf morphologies and from leaves of autotrophic and heterotrophic microplants showing different morphologies was carried out to deaminate cytosine residues while leaving 5-methylcytosine residues intact. RAPD analysis of the DNA was then performed using selective primers; firstly, with a 50–70% GC content and subsequently with a 50–70% AT content which contained CG or CA 3' ends. Three of the 4 primers used detected band polymorphisms in the juvenile versus mature leaves and all four primers detected band polymorphisms in the autotrophic·versus heterotrophic in vitro leaf samples. These results indicate differences in methylation in the different paired DNA samples. The hypothesised increase in band numbers in the relatively less mature samples was confirmed for both the in vivo and in vitro leaf samples; a higher number of bands was amplified from the DNA of the leaves from heterotrophic cultures compared with those from autotrophic culture when the results for all primer sets were grouped. however, this trend did not apply to the results from all the individual primers. The application of this approach to the evaluation of in vitro protocols for potato micropropagation is discussed.     

The effect of water salinity on potatoes (Solanum tuberosum L.): Physiological indices and yielding capacity

Summary The response of several potato cultivars to salinity levels of 20.5, 34.2 and 51.3 mM NaCl was investigated. Salinity tended to lower the water and the osmotic potentials of leaves and tubers while increasing the content of total soluble solids and of proline; it also increased the content of dry matter in the tubers and reduced tuber yields. Susceptibility to salinity was described by the relative loss of tuber dry weight. ‘Blanka’ tolerated the lowest NaCl level (20.5 mM) and exhibited moderate tolerance to higher levels when exposed to salinity stress for 37 days.before harvest, but was susceptible when exposed to the higher levels for 63 days. Cv. Alpha showed moderate tolerance, loosing up to 15% of tuber dry weight when exposed to salinity levels of 20.5 and 34.2 mM NaCl. Mechnisms involved in the adaptation of potatoes to salinity stress are discussed. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 2206-E, 1987 series.     

Cell and nuclear degradation in root meristems following exposure of potatoes (Solanum tuberosum L.) to salinity

Summary In many plant species, it has been demonstrated at the whole plant level that supplemental Ca²⁺ alleviates the effects of salinity stress. These effects have been attributed to physiological processes, but there are no reports of the effects of supplemental Ca²⁺ on preventing nuclear damage to the root meristematic cells following exposure to NaCl salinity. Two in vitro cultured potato (Solanum tuberosum L.) cultivars, analysed by fluorescent microscopy and flow cytometry, showed a similar pattern of salinity-induced changes to the nuclei of root meristematic cells. Damage occurring after only a few hours was followed by nuclear degradation at 24 h. Flow cytometry histograms showed a reduction in G1 and G2 nuclei and an increase in degraded nuclei, in NaCl-stressed roots. Salinity-induced nuclear degradation was alleviated by the addition of CaCl₂.     

Effects of drying potatoes (Solanum tuberosum L.) after harvest on the incidence of disease after storage

Summary Drying potatoes for 2 weeks after harvest decreased the severity of skin spot, silver scurf, black dot and black scurf after 20–26 weeks' storage at 5°C. Diseases were decreased more after early than late harvest.     

Genotypic variation in the response of potatoes (Solanum tuberosum L.) to high ambient temperatures and water deficit

The response of potatoes to the major environmental stresses which prevail in a hot-dry climate, i.e., high temperature and water deficit, was studied. Nine potato cultivars and one unnamed clone of contrasting maturity classification were tested in the field under favorable climatological conditions in the spring and under high temperature conditions in the summer. In both seasons the plants were subjected to moderate and severe water deficits. In the spring, yield losses of 0 – 44% and 0 – 47% of fresh and dry weights, respectively, were obtained under moderate water stress, and losses of 16 – 55% and 2 – 52% of fresh and dry weights, respectively, under severe water stress. Under high ambient temperatures in the summer season and with adequate water supply, yield losses ranged from 0 – 96% compared with the spring crop yields, indicating the extreme susceptibility of some genotypes to heat stress. In all cultivars yield losses due to drought were much greater in the summer than in the spring. The early cultivars ‘Blanka’ and ‘Monalisa’ were less sensitive to changes in the environment, while the later maturing cultivars ‘Cara’ and ‘Desiree’ were very sensitive, being the highest yielding cultivars under the most favorable conditions. Early maturation was closely correlated with smaller yield losses in the summer, pointing to the possible involvement of an escape mechanism in the tolerance to heat stress. The differential response of the various genotypes to drought indicates the possible improvement of tolerance to drought in the potato. The possibility of improving adaptation to high temperatures is discussed.     

Shoot development and flowering in potato (Solanum tuberosum L.)

Summary The shoot system of potato is a configuration of stems with terminal inflorescences. In this review, shoot development is quantified in terms of stem production, while stem development is quantified in terms of leaf and flower primordia production per stem, which are functions of the rates and the durations of primordia initiation. The effect of the position of the stem in the shoot system on number of leaves and flowers per stem is also evaluated. Flowering of individual stems is described by the ‘time to flower primordia initiation’ (expressed in number of leaves produced) and ‘flower production’ (a function of the number and the development of flower primordia). At warmer temperatures and longer daylengths the number of leaves and flower primordia per stem, and the number of stems per shoot increase by prolonging stem production and primordia development. Temperature and photoperiod also affect flower primordia survival by altering assimilate production and partitioning. The photothermal response of the number of leaves per stem is small compared to the response of stem production; at higher temperatures, flower primordia survival becomes the principal factor determining flower production. The similarity of the signals leading to flower primordia initiation and tuberization, and the relation between shoot and tuber growth are discussed.     

Genetic Diversity and Yield Stability of Potato(Solanum tuberosum L.)

The present study was under taken to investigate the genetic distance and the performance of thirty one potato genotypes in diverse environments.Multivariate and canonical analysis were used to study genetic diversity among the genotypes and stability parameters were estimated according to Eberhart and Russell,Parkinge and Jinks and Freeman and Perkins models for plant height,branch number per plant,tuber number and tuber weight.Thirty one genotypes were grouped in to six clusters with the help of Mahalonobis distance and canonical analysis.The stability analysis revealed that yield was greatly influenced by the environments.Most of the studied genotypes were sensitive for yield with the environment.For over-all performance 'Hera','Chamak','Patnai','Lala pakri','TPS-7','TPS-364','Somerset' and 'Superior' were the best genotypes for tuber yield and breeding material for potato breeding.     

马铃薯花粉的离体萌发

选出普遍适合马铃薯花粉萌发的液体培养基 :10 %蔗糖 + 0 0 2 %CaCl2 + 0 0 2 %H3BO3+ 0 0 2 %MgSO4 ·7H2 O + 0 0 1%KNO3,在此培养基上花粉的最高萌发率达 78 1%。培养基中加入0 4 %的NaCl能显著提高萌发速度但并无促进萌发的作用 ;5～ 7d的低温预处理能显著提高花粉萌发率和萌发的同步性     

Genotype X environment interactions in potato (Solanum tuberosum L.)

Genotype X environment interactions were estimated for several traits in potato from a combined analysis of 11 genotypes grown at 3 locations for 2 years. Genotype X location X year and Genotype X location interactions were significant for the majority of the traits studied. Yield, reducing sugar content, dry matter content, leaf area, plant height and starch content should be tested over multiple locations and years in order to separate the genotype × environment interaction components from the total genotypic variance.     

抗机械损伤褐变马铃薯品种(系)的筛选

采用分光光度法研究了21个马铃薯新品种(系)在机械损伤条件下的褐变。筛选试验表明,4℃褐变24 h后,品种(系)云薯301、S03-259、S04-801和JS05-53-275的褐变度变化值为0.004~0.081,而且初始褐变度都很小,因此这4个品种(系)可作为抗机械损伤褐变品种(系)加以研究和开发利用。     

Differences among potato (Solanum tuberosum L.) cultivars in northern India in performance of diffuse light stored seed potatoes

Summary Diffuse light storage (DLS) of potato seed tubers was evaluated in the Punjab, India. Seed tubers of seven cultivars were stored in a nylon mesh covered thatch-roofed DLS and their behaviour in store and subsequent performance in the field was compared with that of tubers stored traditionally in a refrigerated cold store (RCS). DLS of seed from March to October resulted in 34–82% loss by weight due to high temperature and low humidity compared to 6–8% in RCS. When the DLS seeds were planted in replicated field trials, they showed reduced germination, germination rate index, plant height and final yield (up to 37%) compared to seeds from RCS. However, in cvs. Kufri Lalima and Phulwa yields were not significantly reduced following DLS.     

The History of Potato (Solanum tuberosum L.) Research in Spain

Principal activities of the NEIKER-Basque Institute of Agricultural Research contributing to potato research in Spain are described from its origin in 1933 to 2004. In the first period, the genetic crosses begun and the first Spanish variety called “Eminencia” was obtained. From the 1950s (second period) the Station was divided into four sections: virology, ecology, pre-basic potato production and genetics. In 1979 (third period) a new generation of scientists was brought in to reinvigorate activities like genetic breeding and to start new ones, such as tissue culture, nematology, pathology and serology. Since the 1980s, a total of 23 varieties have been registered, which have good industrial attributes or fresh consumption characteristics.     

氮素形态与马铃薯品质的关系

在田间条件下研究了不同形态氮素对马铃薯块茎硝酸盐含量、淀粉、蛋白质及还原糖含量的影响。结果表明,马铃薯块茎内硝酸盐含量从块茎形成期到成熟收获期是逐渐降低的。使用铵态氮肥并加硝化抑制剂双氰胺可以显著地抑制马铃薯块茎硝酸盐的积累;与硝酸盐含量变化相似,从块茎形成期到收获期蛋白质含量也逐渐降低,不同氮素形态处理对马铃薯块茎内蛋白质含量的影响无显著差异;铵态氮添加双氰胺处理可降低块茎还原糖含量。虽然马铃薯被认为是喜硝作物,但本研究表明,不同氮素形态处理不仅没有造成马铃薯产量的显著差异,而且块茎内淀粉含量也无显著差异。     

Potato (Solanum tuberosum L.) cultivar response to bentazon and crop oil

Bentazon [3-(l-methylethyl)-(1H)-2,l,3-benzothiadiazin-4(3H)-one 2,2-dioxide] was applied at two rates to nine potato cultivars in the field, with or without a crop oil, to plant foliage at two different heights. Seven days after application of bentazon, foliar injury ranged from 0 to 36 percent depending on rate, cultivar, and plant height at the time of application. Of nine cultivars tested, Russet Burbank was the most susceptible to injury and Red LaSoda the least susceptible. A bentazon application rate of 1.12 kg a.i./ha, compared to a rate of 0.84 Kg a.i./ha, resulted in a biologically insignificant increase in foliar injury of two to four percent and a significant increase in weed control. The addition of crop oil to bentazon did not result in an increase of foliar injury, but increased the percentage of weeds controlled approximately two-fold. With one exception, application of bentazon to plants 8–15 cm in height resulted in less foliar injury than application to plants 20–30 cm in height. Application of bentazon to larger plants resulted in lower yield and quality. For most cultivars, the application of bentazon (1.12 kg/ha a.i.) and crop oil (2.3 L/ha) to 8 to 15 cm-tall potato plants resulted in no appreciable loss in potato tuber yield, while controlling 74–85 percent of broadleaf weeds.     

Suppression of marker genes in sequentially transformed potato (Solanum tuberosum L.)

Transgenic potato lines were developed from the advanced selection, ND860-2, by sequential transformation usingAgrobacterium tumefaciens and two different constructs. Five doubly-transformed lines were utilized to study gene expression of the first construct. Three doubly-transformed lines had less NPT II antigen than the singly-transformed counterpart from which each was derived. GUS activity was reduced in all doubly-transformed lines compared to their singly-transformed original genotypes. Therefore, NPT II and GUS genes in the first construct were suppressed to varying degrees by a second construct. Further investigations into this important subject will be necessary to enable multiple transformations with genes of agronomic interest.     

Plant regeneration from cell suspension culture of potato (Solanum tuberosum L.)

In the present study, for callus production leaf and stem segments of potato cultivar White Desiree were cultured on MS medium supplemented with 2,4-D, NAA and Kinetin (callus production medium). Calli then were transferred in the same liquid medium for cell suspension production. In the next step cell suspensions were transferred back to the callus production medium. Finally, calli derived from cell suspension were cultured on 6 different shoot initiation media (S1-S6). However, on S6 medium with combination of GA3 and BAP more than 80% of the calli produced shoot buds and shoots. Fully grown shoots then were rooted and produced whole plants. Chromosome and morphological analysis showed no somaclonal variation among regenerated plants.