Performance of potato (Solanum tuberosum L.) in three tropical soil families as influenced by their temperature regimes

Potato experiments (cv. Kennebec) were conducted in three tropical soil families as part of a program to determine crop production potential and land capabilities of a network of tropical soil families. Good tuber yields resulted from matching the requirements of the potato crop to land characteristics. An average yield of 32,000 kg/ha was obtained in the thixotropic, isothermic soil family of Hydric Dystrandepts in Hawaii. The results of this study indicate that with optimum plant protection year-round potato production is possible in this family of Hydric Dystrandepts under rainfed conditions. Yields of irrigated plots in the clayey, kaolinitic, isohyperthermic soil family of Tropeptic Eutrustox were 36,000 kg/ha in the winter and 25,000 kg/ ha in the summer. The results indicate that winter temperatures are nearly isothermic, and are thus suitable for potato production, in an isohyperthermic Tropeptic Eutrustox of Hawaii. No yields were obtained from plantings in the clayey, kaolinitic, isohyperthermic soil family of Typic Paleudults in Indonesia and the Philippines. Tuberization did not occur in the warm and moist environment of the Typic Paleudults. Mismatch between the temperature requirements of the potato crop and the soil temperature regime of Typic Paleudults resulted in no potatoes.     

Growth and yield of potato (Solanum tuberosum L.) cultivars Atlantic and Monona as influenced by seed type and size

Growth and yield of potato plants grown from several weight classes of whole “B” seed, unsorted “B” seed, and 56 g cut seed pieces were compared in Ohio in 1988 and 1989. Whole “B” seed classes were 8 g ranges with means of 35 g, 43 g, 51 g, and 58 g. Unsorted “B” seed was used as an experimental control. Treatment responses were inconsistent. Few significant differences were evident at bloom in leaf area, number of main stems, and total plant dry weight (without tubers) per hill. However, the number of tubers greater than 1 cm in diameter per hill at bloom was less for cut seed as compared with several whole seed treatments. Percent stand at four weeks was also less for cut seed compared with 51 g and 58 g whole tuber treatments. Significant differences in total and U.S. No. 1 yields were absent despite differences in several plant growth variables early in the 1988 and 1989 growing seasons.     

Stomatal conductance and gross photosynthesis of potato (Solanum tuberosum L.) as influenced by irradiance,temperature, and growth stage

Summary Stomatal conductance (SC) and gross photosynthesis (P_G) of two potato clones were measured simultaneously with a dual-isotope porometer. Maximum P_G rates by Russet Burbank in the field were at intermediate levels early in the season, nearly doubled during mid-season, and declined during August. Maximum SC and P_G rates by Russet Burbank in the field occurred about 11h00, although leaf temperature did not reach its maximum unit¹ about 16h00. P_G rates by Russet Burbank in the glasshouse were maximum at about 24–30°C; SC was maximum by about 24°C and remained relatively constant at higher temperatures even though P_G declined. Clone A6948-4 had higher P_G rates in the field than Russet Burbank under all conditions and did not reach maximum levels until 1350 μE. The P_G response by Russet Burbank to varied irradiance in the glasshouse was similar to its response in the field.

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Zusammenfassung Die stomatale Leitf?higkeit (SC) und die Bruttophotosynthese (P_G) von zwei Kartoffelklonen (Solanum tuberosum L. — Russet Burbank und A6948-4) wurden gleichzeitig mit einem Dual-Isotop-Porometer gemessen. Die maximalen P_G-Raten von Russet Burbank im Feld waren anfangs Saison mittleren Grades, w?hrend der Saisonmitte fast doppelt und im Lauf des Augustes nahmen sie ab (Abb. 1). Die maximalen SC- und P_G-Raten von Russet Burbank im Feld wurden um etwa 11 Uhr vormittags erreicht, obwohl die Blattemperatur ihr Maximum erst ungef?hr um 4 Uhr nachmittags erzielte (Tabelle 1). Die P_G-Raten von Russet Burbank im Glashaus waren bei ca. 24–30°C maximal; das Maximum von SC war ungef?hr bei 24°C und blieb bei h?heren Temperaturen relativ konstant, selbst wenn P_G abnahm (Abb. 2). Offenbar kann die Abnahme von P_G nicht Aenderungen in SC zugeschrieben werden, sondern muss auf eine direkte Temperaturhemmung von P_G zurückgeführt werden. Die P_G-Reaktion von Russet Burbank auf unterschiedliche Einstrahlung im Glashaus war gleich wie ihre Reaktion im Feld. Im Gegensatz zu manchen C₃-Spezies nahm die SC von Russet Burbank mit steigender Einstrahlung von 400 auf 1700 μE m² s¹ zu (Abb. 3). Vergleichende SC-Messungen mit Kartoffeln müssen offenbar bei konstanten und bekannten Lichtstufen vorgenommen werden. Die SC- und P_G-Reaktionen auf die Einstrahlungsstufen (Abb. 3) deuten darauf hin, dass Russet-Burbank-Pflanzen einen überm?ssigen stomatalen Wasserverlust haben und dass SC unter Feldbedingungen vielleicht ohne jede Reduktion in P_G reduziert werden k?nnte. Der Klon A6948-4 hatte h?here P_G-Raten im Feld als Russet Burbank unter allen Bedingungen und erreichte die maximalen Grade nicht bis 1,350 μE (Abb. 4). Diese Vergleiche illustrieren die natürliche Variabilit?t, die in Kartoffelzüchtungsprogrammen vorhanden ist, und best?tigen den Wert des Screenings, um jene auszulesen, die als Elternmaterial für Kreuzungen am nützlichsten sind.

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Résumé La conductance des stomates (SC) et la photosynthèse brute (P_G) de deux clones de pommes de terre (Solanum tuberosum L. —Russet Burbank et A6948-4) ont été mesurées simultanément en utilisant un poromètre à isotope dual. Les intensités maxima de P_G pour Russet Burbank, au champ, se situaient à des niveaux intermédiaires en début de saison, étaient pratiquement doubles en milieu de saison, puis déclinaient en ao?t (fig. 1). SC et P_G atteignaient leur maxima au champ vers 11 heures du matin, alors que la température des feuilles ne parvenait à son maximum que vers 4 heures de l’après-midi (tableau 1). En serre, pour Russet Burbank, P_G était maximum vers 24–30°C; SC était maximum vers 24°C puis restait constant aux températures supérieures, tandis que P_G diminuait (fig. 2). Apparemment, la diminution de P_G ne pouvait être attribuée à des variations de SC mais devait être d?e à une inhibition directe de P_G par la température. Pour Russet Burbank, la réponse de PG en serre à une variation de l’irradiation était identique à la réponse au champ. Contrastant avec de nombreuses espèces C₃, chez Russet Burbank, SC a augmenté avec l’irradiation de 400 à 1700 μEm² sec¹ (fig. 3). Pour les pommes de terre, les mesures comparatives de SC doivent de toute évidence être effectuées à des niveaux constants et connus d’éclairement. Les réponses de SC et P_G aux différents niveaux d’irradiation (fig. 3). suggèrent que les plantes de Russet Burbank perdraient trop d’eau par les stomates et que l’on pourrait peut être réduire SC dans les conditions du champ sans réduire P_G d’aucune fa?on. Quelles que soient les conditions, le cone A6948-4 avait des niveaux de P_G plus élevés au champ que Russet Burbank et n’atteignait un maximum que pour 1,350 μE (fig. 4). Ces comparaisons illustrent la variabilité naturelle que l’on rencontre dans les programmes d’hybridation des pommes de terre, et qui établit la valeur discriminante pour choisir quels seront les matériels parentaux les plus utiles pour les croisements.

     

Optimizing the propagation of potato (Solanum tuberosum L.) by stem cuttings

Stem cuttings from potato plants are frequently used in multiplication programs for disease-free cultivars. The survival of these leafy cuttings is often very poor, and thus various techniques were investigated which were designed to increase rooting and cutting survival. Stock plants of cultivars “Caribe,” “Jemseg,” “Keswick,” “Russet Burbank,” “Sable,” “Sebago” and “Shepody” were grown in the greenhouse under long days. Promoting growth of the axillary shoots was successfully achieved by shading the shoot apex with aluminum foil. Trimming the outer leaves of the cuttings was deleterious to both survival and rooting. A rooting hormone improved root initiation and development, and the use of shade cloth or intermittent mist increased survival by reducing wilting. A rooting substrate of vermiculite: perlite (1:1) provided sufficient aeration, support and drainage for the cuttings. Antitranspirants sprayed on the stock plants prior to the excision of cuttings and also on the excised cuttings did not improve rooting or survival. The addition of activated charcoal (1% w:w) increased rooting of the cuttings and improved vigor of potted plants obtained from the cuttings.     

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.     

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.     

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.     

Effects of auxin and calcium on phosphate partitioning in induced potato (Solanum tuberosum L.) cuttings

Summary Single-node leaf cuttings, from plants originated from apical cuttings on sprouted potato tubers (Solanum tuberosum L.), were used to study phosphate transport following hormone (IAA) and calcium treatments. Phosphate accumulation in tubers was significantly enhanced by axillary bud pretreatment with calcium followed by a subsequent treatment of the tuber formed with IAA. The results suggest that calcium may be necessary for the regulatory action of auxin on phosphate transport into the tuber.     

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.     

Ultrastructural changes in tubers of potato (Solanum tuberosum L.) affected by rust spot

Summary The medullary tissues of potato tubers affected by rust spot were embedded in resin, sectioned and stained for optical and electron microscopy. Under the optical microscope, the damaged zones were seen to have thickened and suberized cell walls, with cells partially or totally lacking starch. These features were confirmed by electron microscopy which revealed in relief the cell wall deformation and the characteristic presence, in the vacuole, of osmiophilic granules with a spongy appearance attached to the tonoplast, probable catabolic products of a disturbed metabolism. Separation and degeneration of the plasmalemma and the death of the cells were observed in tissues in the final stages of damage.     

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.     

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.     

Prevention of berry formation in potato plants (Solanum tuberosum L.) by single foliar applications of herbicides or growth regulators

Summary Thre seed production in potato plants (Solanum tuberosum L.) may contribute to the persistence of potato cyst nematodes and of viruses, fungi and bacteria. In four experiments MCPA, ethephon, 2,4D-amine, naphtylacetamide, metoxuron and gibberellic acid were tested for their potential to reduce berry formation. MCPA (500 or 750 g a.i. ha⁻¹ and ethephon (144 or 192 g a.i. ha⁻¹) reduced or almost completely prevented berry set and their effect was strongly influenced by the crop growth stage at the time of application. For both chemicals application at early bud stage was the most effective and, whereas MCPA showed no adverse effects on tuber yield, size, dry matter content and fry colour, ethephon substantially reduced the percentage of large tubers over 50 mm.     

Unsaponifiable lipids from haulm and tuber sprouts of potato (Solanum tuberosum L.)

Summary Fractions containing Δ⁵- and Δ⁷-sterols, 4-methyl-sterols, triterpenic alcohols, tocopherols and hydrocarbons were isolated by TLC from petroleum ether extracts of the haulm and tuber sprouts of cv Désirée. Sterol and triterpenic alcohol fractions of unsaponifiable lipids of the haulm and tuber sprouts were found to contain twelve sterols and four triterpenic alcohols, respectively. 24R-4-stigmasten-3-on, Δ⁷, Δ⁷, lanosterol, cycloeucalenol and obtisufoliol have not been identified previously in unsaponifiable lipids from haulm and sprouts. In the hydrocarbon fractions of the haulm extract, C₂₃-to C₃₃-n-parafins, C₁₉-and C₃₁-cyclohexyl hydrocarbons, C₂₂-to C₃₈-olefins and squalene were identified, and in the hydrocarbon fractions of the tuber sprouts C₁₂-to C₂₆-olefins and squalene were identified.     

Water relations of the potato (Solanum tuberosum L.) cultivars Raritan and Shepody

Physiological responses to drought stress were evaluated in the potato cultivars Raritan and Shepody. Under well-watered conditions, Raritan exhibited a higher transpiration rate than Shepody. This higher rate could be related to a lower calculated stomatal resistance on abaxial leaf surfaces. Under drought stress conditions, Raritan consistently demonstrated superior performance over Shepody in the following areas: leaf water retention, epicuticular wax levels, desiccation tolerance and root growth. The estimated relative water content at a leaf water potential of-1.0 MPa was higher for Raritan than Shepody regardless of leaf age and may indicate a greater drought resistance in the former cultivar.     

A rapid screening technique for drought resistance in potato (Solanum tuberosum L.)

Summary The reduction in growth in the dark of leaf dises floated over polyethylene glycol 6000 solution of water potential −0.4 MPa, relative to the growth of similar leaf dises floated over water for the same period, varied in the range 10–87% in 28 genotypes. The growth reductions in the genotypes tested were in general agreement with what is known about their drought resistance. Publication No. 906, Central Potato Research Institute, Simla.     

Cell wall mediated bulkiness as related to the texture of potato (Solanum tuberosum L.) tuber tissue

Summary Potato tuber bulkiness was studied in an attempt to elucidate the role of the cell wall (CW) in the tissue texture. The volume of the tissue homogenate was measured before and after enzymatic degradation of insoluble pectic substances (PS) and cellulose. Enzymatic removal of PS resulted in disappearance of the middle lamella ultrastructure, leading to a slight volumetric reduction at most, and both were retained the inner CW and the starch grains in the lumen. Enzymatic degradation of cellulose resulted in the loss of the CW ultrastructure and of the homogenate bulkiness; starch and protoplasmic residues precipitated separately. Among the neutral sugars, starch-glucose was the predominant one (ca. 15% of the fresh weight), and the others were cellulose-glucose, rhamnose, arabinose, xylose, mannose and galactose. The microfibrillar lattice of the cellulose glucan provided the tissue bulkiness and texture. Other factors such as pectin and starch may affect texture through interactions with the microfibrillar lattice of cellulose. Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 1518-E, 1985 series.