The use of image analysis to study developmental variation in micropropagated potato (Solanum tuberosum L.) plants

Summary Potato leaf morphology changes during plant development with the phase shift from vegetative growth to flowering. Image analysis can detect differences in leaf morphology and has been used here to distinguish differences in leaf morphology between potato crops derived from seed tubers and minitubers and between crops derived from different micropropagation protocols. Further, leaf shape parameters can be used to determine the relative maturity of crops. This finding is of economic importance since differences in plant development, for example delayed flowering, are associated with yield parameters. It is hypothesised that image analysis of established microplants can be used as an early evaluation of micropropagation protocols for potato.     

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.     

Microstructural and chemical investigation of subsurface hardened potatoes (Solanum tuberosum L.)

Summary Microstructural changes related to subsurface hardening of pre-peeled potatoes were investigated using cv. Sava potatoes peeled using an industrial peeler, a laboratory knife peeler or a hand knife peeler. The pre-peeled potatoes were packed in polymer bags and stored at 18°C for six days until cooking. Potato hardness and microstructure of the tissue was investigated. Cellulose and suberin in hard potato tissue increased linearly with increase in mechanical impact in a damage barrel. The area of cell walls and especially cell corners of mechanically damaged potatoes showed white autofluorescence in blue light. The number of layers of bricklike and autofluorescent parenchyma increased significantly with increasing hardness. Subsurface hardening was related to percentage cells with fluorescent gelatinised cell mass and curly cell walls in a depth of the potato tissue corresponding to the depth of maximum hardness.     

利用RAPD技术鉴定花生种质资源的差异

利用RAPD技术对 7个不同植物学类型的花生种质资源进行了分析 ,在所用的 83个随机引物中 ,1 3个引物的扩增产物显示出不同品种间的多态性 ,能显示花生品种间DNA多态性的引物占1 5 .7%。这 1 3个引物共扩增出 1 2 1条DNA带 ,其中具多态性的片段 2 6条 ,占 2 1 .48%。根据本实验结果 ,利用RAPD技术鉴定花生种质资源的多态性是有效的     

马铃薯RAPD标记的PCR技术影响因素的探讨

试验采用不同的马铃薯材料进行ＰＣＲ 技术体系的研究, 建立和完善了马铃薯少量材料的ＤＮＡ提取方法, 研究了ＰＣＲ扩增中Ｍｇ２ ＋ 浓度、引物和底物浓度对ＰＣＲ产物的影响。试验结果表明, 在以引物为１０ ｍｅｒ 的ＰＣＲ反应体系中, 适当提高Ｍｇ２ ＋ 浓度（１－５ ～２－７ ｍＭ） 有利于ＰＣＲ反应的进行, 而引物与底物只有在一个相对适当浓度范围内才能获得理想的结果, 过低会使扩增产物达不到可检测的水平, 过高则会影响扩增产物的特异性。本试验中引物的适宜浓度为０－８ μＭ, 底物为８０ ～１８０ μＭ。所建立的优化马铃薯ＰＣＲ 体系同样适用于水稻、玉米、番茄和油菜等作物。     

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.     

马铃薯青枯病抗性鉴定新方法

采用传统方法和改进方法(取名为茎枝菌液浸泡法)对马铃薯的青枯病抗性进行了鉴定和评价,其结果是一致的,但茎枝菌液浸泡法更加简便快速、经济有效、可操作性和可重复性更好,并且在番茄的青枯病抗性鉴定上也得到了验证。该方法对于茄科作物的种质资源抗病性评价和筛选,特别是对于病菌诱导产生抗性的抗(感)病植株的快速鉴定及其幼苗的先期快速筛选具有重要意义,可望成为一种理想的茄科作物室内抗病鉴定方法。     

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.     

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.     

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).     

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.     

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.     

Mutation breeding for yield andPhytophthora infestans (Mont.) de Bary foliar resistance in potato (Solanum tuberosum L. cv. Golden Wonder) using computerized image analysis in selection

Summary Using visual selection for off-types and image analysis to select against maturation mutants, a line combining improved late blight resistance and yield was isolated in an in vitro mutagenesis programme from a population of 2101 putative mutants. The adventitious regenerants from mutagenesis treatment, including spontaneous mutants (somaclonal variants), were subjected to serial subculture of the apical bud in vitro and two cycles of apical cuttings in vivo to breakdown chimeras. The selected line was stable in trials over five years; others were unstable or failed to combine improvement in late blight resistance with high yield. Leaf and tuber image analysis was used to characterize selected lines. Lines that differed most from cv. Golden Wonder in yield and late blight resistance were more easily distinguished from the control by image analysis. The role of image analysis in negative selection and in determination of the relatedness of mutants to the control is discussed.     

Responses of potatoes (Solanum tuberosum L.) to irrigation and nitrogen in a hot,dry climate: I. Water use

The effects of differential irrigation and fertiliser treatments on the water use of potatoes (Solanum tuberosum L. cv. Desirée) were studied over 2 years in the hot dry climate of northeast Portugal. Total actual evapotranspiration (ET_c) ranged from 150 to 320 mm in 1988, and from 190 to 550 mm in 1989 depending mainly on irrigation treatment, potential evaporation rates (ET_p) and duration of the growing season. By comparison, the effects of nitrogen fertiliser on total water use were relatively small. Although nitrogen increased transpiration (larger leaf canopy), it reduced evaporation from the soil surface, in frequently irrigated plots, by similar amounts. As a result, in well-irrigated crops, the ET_c/ET_p ratio averaged 0.85 over the season, regardless of nitrogen level. Evaporation from the soil surface represented 15–25% of total water use by well-fertilised plants, but as much as 30–50% from the sparse stands of unfertilised crops. The proportion of water extracted from each depth increment of the silt-loam soil declined logarithmically, from the surface to 1.1 m depth, the maximum measured, for irrigated crops, and linearly when rain-fed. The ET_c/ET_p ratio fell below unity when 25–30% of the available water in the top metre had been depleted, equivalent to soil water deficits (SWDs) of 45–50 mm. By comparison, ET_c declined to zero when 75–90% of the available water had been extracted, corresponding to actual deficits of 135–150 mm. Peak ET_c rates reached 12–13 mm per day on days immediately following irrigation, nearly twice ET_p (possibly due to the influence of advection) but then declined logarithmically with time to about 3 mm per day within 5 days. Using the same data, a companion paper reports the influence of climatic conditions on the yield responses to water of potato crops grown in the region.     

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.     

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.     

栽培稻和普通野生稻基因组的随机扩增多态性DNA（RAPD）初步分析

 用35个随机引物对5个籼稻品种、5个粳稻品种和27份中国普通野生稻进行了RAPD分析。60%以上的引物能在籼稻和粳稻基因组间显示差异；中国普通野生稻与栽培稻的差异主要表现在与籼稻的不同，绝大部分供试野生稻的RAPD带型与粳稻的相同。这说明多数中国普通野生稻偏粳，但也存在偏籼的普通野生稻。     

Cryopreservation of in vitro-grown meristems of potato (Solanum tuberosum L.) by encapsulation-vitrification

Summary Alginate coated meristems from in vitro-grown axillary buds of potato (Solanum tuberosum L.) were successfully cryopreserved by vitrification. Excised meristems were precultured on sucrose-enriched MS medium and then encapsulated. To induce dehydration tolerance (osmotolerance), encapsulated meristems were treated with a mixture of 2 M glycerol plus 0.6 M sucrose for 90 min. These encapsulated meristems were dehydrated with a highly concentrated vitrification solution (PVS2 solution) for 3 hr at 0°C prior to a plunge into liquid nitrogen. Successfully vitrified meristems developed shoots within 3 weeks after plating without intermediary callus formation. The average rate of shoot formation amounted to nearly 70%. No difference was observed in RAPD analysis using 17 primers between cryopreserved and non-treated plantlets. The cryogenic protocol was successfully applied to 14 cultivars. It was also confirmed that the encapsulated vitrified meristems produced much greater shoot formation than the encapsulated dried meristems. Thus, the encapsulation vitrification protocol appears promising for cryopreservation of potato germplasm.     

栽培稻和普通野生稻基因组的随机扩增多态性DNA（RAPD）初步分析

用35个随机引物对5个籼稻品种、5个粳稻品种和27份中国普通野生稻进行了RAPD分析。60%以上的引物能在籼稻和粳稻基因组间显示差异;中国普通野生稻与栽培稻的差异主要表现在与籼稻的不同,绝大部分供试野生稻的RAPD带型与粳稻的相同。这说明多数中国普通野生稻偏粳,但也存在偏籼的普通野生稻。