Unsprouted potato tubers treated with gibberellic acid (GA3)

Summary Tubers (still unsprouted after an eight months' storage period) of the late varietyLibertas with slow growth in youth and few stems were treated with gibberellic acid (GA₃) in 1958 and 1959. Two sprayings gave similar results as dipping for 15 minutes. 25 ppm probably had more effect than 12,5 ppm. During both years the treatment resulted in more and longer sprouts and more stems, although the number of stems is usually less than the number of sprouts. Emergence was not accelerated and in both years yields tended to be lower. In 1958 all yields reached a high level, treatment gave a non-significant lower yield, but there was a greater number of tubers especially in the 25–40 mm seed-class. In 1959 the size and the number of tubers were affected by second growth owing to the unusually dry summer with short spells of rainy weather. In this year presprouted tubers emerged 10 days earlier than treated and non treated, unsprouted seed, which for a long period gave the crop a lead in haulm growth and even a permanent lead in tuber yield.

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Zusammenfassung Von der sp?ten SorteLibertas, die in ihrer Jugend ein langsames Wachstum zeigt und wenig Stengel entwickelt, wurden ungekeimte Knollen (nach 8-monatiger Lagerung) in den Jahren 1958 und 1959 mit Gibberellins?ure (GA₃) behandelt. Eine zweimalige Spritzung ergab zumindest ?hnliche Ergebnisse wie das Eintauchen w?hrend 15 Minuten. 25 ppm hat wahrscheinlich eine bessere Wirkung, wie 12,5 ppm. In beiden Jahren ergab die Behandlung mehr und l?ngere Keime sowie mehr Stengel, obzwar die Anzahl der Stengel gew?hnlich nicht so hoch ist, wie die Anzahl der Keime. Es zeigte sich keine Beschleunigung des Auflaufens, jedoch eine Tendenz für einen geringeren Ertrag in beiden Jahren. In 1958 waren alle Ertr?ge hoch und die Behandlung ergab eine nicht signifikante Ertragsverminderung, jedoch eine gr?ssere Knollenzahl (insbesondere in der Saat-Gr?ssenklasse, 25–40 mm). In 1959 war die Gr?sse und die Anzahl der Knollen infolge des ungew?hnlich trockenen Sommers mit kurzen Regenperioden durch Mehrwüchsigkeit beeintr?chtigt. In diesem Jahr sind die vorgekeimten Knollen um 10 Tage früher aufgelaufen, was den Pflanzen im Vergleich zu den behandelten und nicht behandelten ungekeimten Pflanzgut einen l?ngeren Vorsprung im Krautwuchs und einen dauerhaften Vorsprung in der Knollenbildung gab.

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Résumé Des tubercules non germés (après stockage pendant huit mois) de la variété tardiveLibertas, à lente croissance de début et à petit nombre de tiges, ont été traités à l'acide gibberellique (GA₃) en 1958 et en 1959. Deux pulvérisations donnaient des résultats au moins égaux à ceux d'une immersion de 15 minutes. La concentration de 25 millionièmes est probablement plus efficace que celle de 12,5 millionièmes. L'une et l'autre année, les tubercules traités avaient des germes plus nombreux et plus longs et un plus grand nombre de tiges, bien que le nombre de tiges ne soit généralement pas aussi grand que le nombre de germes. La levée ne fut pas accélérée et il se manifesta une tendance de diminution du rendement. En 1958, toutes les récoltes furent bonnes, le traitement entra?nant une diminution non significante de la récolte mais faisant augmenter le nombre de tubercules (particulièrement dans la catégorie de semenceaux de 25–40 mm). En 1959, la grosseur et le nombre des tubercules furent influencés par croissance secondaire (excroissance) par suite de l'été exceptionnellement sec avec de courtes périodes de pluie. Cette année-là, les tubercules prégermés levèrent 10 jours plus t?t que les plants non prégermés, traités et non traités, de sorte que le développement du feuillage fut supérieur pendant une longue période et que celui des tubercules fut supérieur jusqu'à la récolte.

     

Use of activated charcoal to enhance the germination of botanical seeds of potato

The effect of activated charcoal (AC) on the germination of botanical potato seeds was tested by applying AC to seeds in petri dishes which had been pretreated with gibberellic acid (GA). A diverse sample of accessions including cultivar and cultivated species germplasm, cultivated species hybrids, wild species, and wild species known for their slow germination was tested. The time required from hydration to75% germination was significantly less for all types of seeds tested when AC was present. Cultivated species hybrids reached75% germination an average of four days sooner, wild species two days sooner, and slow germinating wild species 18 days sooner when AC was present. Only slow germinating wild species’ seeds germinated with significantly more uniformity in the presence of AC.     

Dependence on exogenous gibberellin for seed germination inSolanum acaule Bitter and otherSolanum (potato) species

Certain seed populations of the wild potato speciesSolanum acaule Bitter were identified as having consistent qualitative dependence on 6A to germinate. This was true for both germination in petri plates and in greenhouse conditions. The effect could be transmitted across sexual generations. Progeny from crosses with GA-independent populations were intermediate, with no consistent reciprocal effect. A broad survey of 2,580 populations including 60 potato species indicated that significant dependence on GA also exists in other species. This trait may have physiological and evolutionary implications worth further investigation. Recognizing that populations of some species are highly dependent on GA allows genebank managers and other potato scientists to accurately assess seed viability and avoid inadvertent selection against useful traits which may be linked.     

GA3和6-BA对降香黄檀种子发芽的影响

用两种植物生长调节剂GA3和6-BA不同药剂浓度（0、20、40、80 mg/L）和不同浸种时间（3、6、12、24 h）处理带果荚和去果荚的降香黄檀种子,结果表明：去果荚的种子用GA340 mg/L溶液浸泡12 h的发芽率最高,达到78%,壮苗指数和根冠比最优,效果最好。     

Transmission and yield effects of a gibberellin mutant allele in potato

Summary A selected clone ofSolanum tuberosum Group Andigena PI 347773 (clone Adg 11.1) and the cultivar Superior had previously been shown to be heterozygous at a gibberellin related dwarfing locus, ga₁. Experiments were conducted to test for gametophytic selection for alleles at the ga₁ locus in reciprocal crosses and for the effect of genotype on tuber yield. The genotypes of individuals from superior-Adg 11.1 reciprocal F₁ families were determined by test crossing. Genotypic classes could be distinguished by the percentages of dwarf seedlings in their test cross progeny. No differences were found in the genotypic distributions of the reciprocal families, which indicates gametophytic selection at this locus is not the cause of reciprocal yield differences. Superior-Adg 11.1 individuals classified by ga₁ locus genotype were evaluated for tuber yield. Tuber yields were highly correlated with genotype in both reciprocal families. Yields followed the pattern of simplex>duplex>triplex, indicating that the recessive mutant ga₁ allele exhibited a dose effect stimulating yield.     

不同赤霉素浓度处理对野生山樱桃种子萌发的影响

[目的]研究不同浓度赤霉素处理下山樱桃种子的萌发率.[方法]以天津蓟州区发现的野生山樱桃种子为试验材料,研究不同赤霉素浓度浸泡24 h和48 h对野生山樱桃去壳种子萌发的影响.[结果]野生山樱桃带壳种子吸水性较差,种胚完好率高,500 mg/L赤霉素浸泡48 h后,野生山樱桃种子发芽率最高,适当增加赤霉素浓度和浸泡处理...     

Characterization of a new gibberellin related dwarfing locus in potato (Solanum tuberosum L.)

Gibberellins have been shown to be involved in such important processes as seed germination, flowering, maturation and tuberization in potato. Parents fromSolanum tuberosum Groups Andigena and Tuberosum were found to produce progeny containing dark green, rosette dwarf individuals which could be completely restored to normal appearance by exogenous GA₃. Test crosses indicated that this phenomenon can be explained by the action of a single locus, the dwarfing characteristic being conferred by the nulliplex condition. The gene symbol “ga₁” is proposed. Group Andigena dwarfs demonstrated much greater tuberization compared to their normal full sibs or dwarfs restored to normal phenotype by exogenous GA₃. The possibility that such gibberellin mutants may be involved in the long day adaptation of Gp. Tuberosum is discussed. This character may also be a useful tool for investigating various aspects of the gibberellin status of the potato.     

赤霉素对粤西香根草种子发芽动态的影响

采用100、200、300、400 mg/kg浓度的赤霉素（GA3）溶液,分别对7~12月采集的粤西香根草种子浸种处理8 h,研究不同浓度赤霉素处理对不同月份的粤西香根草种子发芽动态的影响。结果表明：7~10月采集的粤西香根草种子的发芽势、发芽率和发芽指数逐渐增加,而后11、12月的香根草种子则呈下降趋势;赤霉素浓度为100~400 mg/kg时均可促进香根草种子的萌发,其中100 mg/kg赤霉素处理10月的粤西香根草种子,其发芽势、发芽率和发芽指数最高,分别为12.00％、14.00％和15.51,但移栽成活率低。旨在为提高香根草种子的发芽率提供依据。     

A comparison of gibberellin and cytokinin levels in normal and ‘little potato’ tubers

Summary Extracts of both normal and ‘little potato’ tubers of three varieties were bioassayed for gibberellin and cytokinin activity. The levels of activity of both gibberellins and cytokinins were greater in extracts from ‘little potato’ tubers than in extracts from normal tubers.     

赤霉素(GA_3)与茉莉酸甲酯(MeJA)对雾培马铃薯内源激素与生长发育的影响

试验以品种为主区,激素处理为副区进行裂区设计,研究了赤霉素(GA3)与茉莉酸甲酯(MeJA)对雾培马铃薯内源激素与生长发育的影响。结果表明:外源GA3处理增加了3个马铃薯品种叶片内源IAA和JA的含量,降低了中晚熟品种高原7号的内源ABA含量。外源MeJA对马铃薯块茎均有一定诱导作用,但结合GA3处理其诱导结薯的能力会减弱。     

Spindle tuber virus in seeds and pollen of infected potato plants

The presence of potato spindle tuber virus (PSTV) in seed and pollen of diseased plants was demonstrated. Transmission through the seed from open-pollinated female parents to the seedlings occurred frequently (average 31%) but varied in individual collections from zero to 100%. The amount of transmission did not appear to be correlated with variety or with age of the seed. All PSTV infections encountered appeared to be caused by mild strains. It is suggested that only healthy parents should be used for breeding purposes.     

Gibberellin-deficient dwarfs in potato vary in exogenous GA3 response when thega 1 allele is in different genetic backgrounds

Gibberellins (GAs) are involved in internode elongation and other important processes such as seed germination, flowering, maturation, tuberization, and tuber dormancy. The discovery of GA-deficient mutants enabled further study of the role of these hormones in many plant processes. GA-deficient mutants lack the ability to produce adequate amounts of gibberellin for normal growth, resulting in a rosette type growth and short internodes. Thega ₁ mutant allele was introduced into various genetic backgrounds including differentSolanum species and ploidies. Diploid GA-deficient genotypes were obtained by crossing haploidSolanum tuberosum ssp.andigena withSolanum chacoense. The progeny was then bulked and intermated to produce F₂ individuals. Tetraploid GA-deficient genotypes were obtained by crossingS. tuberosum ssp.andigena withSolanum sucrense and withSolanum gourlayi. The two resulting progenies were then bulked and intermated. Diploid and tetraploid GA-deficient genotypes were grown on MS media containing different levels of gibberellin (GA₃). Plant height and visual observations were made as a way to assess the response of these genotypes to GA₃. Concentration of 0.1 µM GA₃ and lower failed to restore normal plant height in both diploid and tetraploid genotypes. Normal plant height was restored in most of the GA-deficient genotypes when concentrations between 0.8 and 1.2 µM GA₃ were used. We found some important differences between these genotypes: (1) the level of GA₃ to restore normal plant height varies among the GA-deficient genotypes, some needed more GA₃ than others to grow normally; (2) the time to respond to the presence of GA₃ in the media differs between the GA-deficient genotypes, (3) tetraploid genotypes exhibited normal growth and internode length in response to GA₃, while diploid genotypes tended to show a rosette-type growth at the apical end. These results suggest thatga ₁ mutants can be affected by a series of modifier genes and/or iso-alleles. The importance of variable response to GA among dwarf individuals is two fold: (1) experiments measuring GA response should choose and clonally multiply one genotype to ensure uniform optimal response to GA application; and (2) variation betweenga ₁ mutant phenotypes could be used to characterize GA-response modifier genes.     

Tuberization in potato at high temperatures: Responses to exogenous gibberellin,cytokinin and ethylene

Summary In potato (Solanum tuberosum L., cv. Sebago), benzyladenine (BA) promoted tuberization at high day/night temperatures (32°/18°C), while gibberrellic acid (GA) and chlorethylphosphonic acid (CEPA) reduced tuberization at low day/night temperatures (22°/18°C). These results are consistent with the hypothesis that temperature exerts its influence on tuber formation by altering the balance between endogenous gibberellins, cytokinins and inhibitors, but not ethylene.     

Importance and control of potato virus YN (PVYN) in seed potato production

Summary The tobacco veinal necrosis strain of potato virus Y (PVY^N) first became epidemic in several European countries in the 1950s. To prevent PVY^N-infections, account must be taken of virus sources both within and without potato fields; for forecasting, the aphid vector species, their vector efficiency, and their flight activity must all be known. Well-timed haulm destruction needs knowledges of PVY^N-translocation in potato plants and of the development of mature plant resistance. For successful virus control, also reliable methods for virus detection are needed, and for this ELISA has been well established for many years in seed potato certification schemes. A combined treatment of mineral oil and pyrethroids reduces aphid populations and the spread of stylet-borne viruses in the fields. In breeding for resistance, the major gene Ry induces complete protection against infections of all known PVY-strains.     

Gibberellic acid (GA3) induced changes in proanthocyanidins and malt quality of two and six-row husked barleys

Analysis of husked barleys for proanthocyanidins and malt qualityattributes has shown that not a single variety is free ofproanthocyanidins. The proanthocyanidins in barley grains variedfrom 3.85 to 4.94 mg/g as catechin equivalent. The concentrationof proanthocyanidins decreased, while total soluble sugars, reducingsugars, diastatic power and -amylase activity increasedduring maltings as well as with exogenous gibberellic acid (GA₃)application. Alfa 93 (two-row) and RD2560 (six-row) varietiesappeared to be superior for malting and brewing purposes on thebasis of proanthocyanidins, total phenols, diastatic power and-amylase activity. It is suggested that exogenous applicationof GA₃ at 15 ppm may be useful for producing good quality maltfrom barley grains.     

Elimination of viruses and hypersensitivity to potato virus Y (PVYo) in an important sudanese potato stock (Zalinge)

Viruses that infect naturally an important Sudanese potato stock Zalinge were detected using enzyme-linked immunosorbent assay, immunosorbent electron microscopy and sap-inoculation to test plants. All of the 19 plants of Zalinge tested were infected with potato leaf roll virus (PLRV) and potato virus S (P VS), and five plants also with potato virus X (PVX). No potato virus Y (PVY), A (PVA) nor M (PVM) were found. The viruses were eradicated with thermo and chemotherapy using standard procedures. The combination of both therapies did not result in any virus-free plants, but resulted in poor plant survival. Thermotherapy reduced the incidence of PLRV and PVS by 45% and 50%, respectively, and one virus-free plant was obtained. It grew vigorously in the greenhouse, was symptomless and had a significantly increased tuber yield compared to the virus-infected plants. Following sap-inoculation with PVY^O, Zalinge showed mosaic symptoms, developed necrosis in the leaves and stem and died 14 days post-inoculation. However, the plants of Zalinge infected with PVY^N remained symptomless, which suggested that hypersensitivity was specific to PVY^O. The fast development of lethal necrosis following infection with PVY^O may contribute to the low incidence of PVY in Zalinge in the field in Sudan.     

Germination response of endophytic Festuca rubra seeds in the presence of arsenic

Epichloë fungal endophytes colonize the intercellular space of aerial organs of their plant hosts without causing symptoms. These symbionts are known to improve the performance of their host grasses in some situations of biotic and abiotic stress, leading to the suggestion that they can be used to improve grass tolerance to contaminants. The grass Festuca rubra is a host of the endophyte Epichloë festucae. We used two half‐sib lines of F. rubra, each line composed of infected (E+) or endophyte‐free (E?) seeds, to study the effect of varying levels of arsenic (6, 12, 25, and 50 mg L^?1), and of the endophyte in seed germination and radicle growth. The results showed that seed germination was not significantly affected by arsenic (As) levels lower than 25 mg L^?1, indicating that this grass has a relatively high tolerance of As at the germination stage. The decrease in germination observed at 25 and 50 mg L^?1 was due to increased seed mortality and to the reversible inhibition of the germination of viable seeds caused by As. The presence of the endophyte did not change the germination response to arsenic of one line, but affected negatively the germination of the other line. In contrast to the process of germination, radicles of E+ seeds of both lines were longer than those of endophyte‐free seeds. The results of this work indicate that Epichloë endophytes can affect the performance of some F. rubra genotypes when As is present in the soil.