Effects of desprouting on growth and yield of physiologically old seed of the potato variety Ulster Sceptre

Summary Desprouting of physiologically old seed at planting delayed emergence but had no effects on final number of above-ground stems, final number of tubers or leaf dry weight at the end of June. Tuber yields were reduced by desprouting throughout the harvesting period. At the beginning of harvesting desprouted seed had no saleable yield. The results suggest that desprouting delays but does not alter the morphology of plants, nor the growth pattern of physiologically old seed.     

Effects of hydrogen cyanamide on seed potato

Summary The effect of hydrogen cyanamide on sprouting of seed potato was examined using cvs Brador and Kennebec. Tuber respiration and content of polyamines were also studied. Tuber dormancy was released after 1 min treatment with 0.5–1 M concentration of the preparation. Apical dominance was also reduced; the treated tubers produced more sprouts and shoots after planting; higher concentrations and longer exposures though more effective, caused tuber injury. Tuber respiration sharply increased after treatment and the level of polyamines decreased during the first 7 days after treatment and increased again when tubers began to sprout. Since there was a marked difference in the rate of response between the cultivars, more research is required before the preparation can be advised for practical application.     

Osmotic priming of true potato seed: Effects of seed age

Summary The effects on germination and early seedling growth of presowing true potato seed in water or gibberellic acid (GA) at 1500 ppm and of priming in −1.0, −1.25 and −1.5 MPa solutions of KNO₃+K₃PO₄ were studied using 30, 18, 6 and 3/4 month-old seed. The influence of light during presowing on the effectiveness of treatments was also investigated. Overall, priming in the light at −1.0 MPa was the most, and GA the least successful treatment for enhancing emergence and subsequent seedling growth. Though GA increased final emergence from about 20 to 70% in the most recently harvested lot (3/4 mo), the rate and extent of final germination or emergence in this dormant seed was still much lower than that of the nondormant lots (6–30 mo), especially when the latter were primed. For all lots, dry weight per seedling was 40% lower in dormant than in nondormant seed, and 20% higher when seeds were primed at −1.0 MPa than when GA treated. In conclusion, the use of nondormant seed may be a requirement for both effective priming and sowing of potato crops via true seed.     

The effect of potato virus X on the yield of the potato variety Hudson

The effect of a mild strain of PVX on the yield of the recently released potato variety Hudson was determined in split-plot experiments at three locations in New York. Two other varieties, Katahdin and Bake-King, were included for comparison. The yield data compared were total tuber yield, tuber yield > 2 1/4 in. and > 1 7/8 in. diameter and tuber number> 2 1/4 in. and > l 7/8 in. diameter. The effect of the mild strain was not great. Hudson appeared to be more tolerant to the mild strain of PVX than the other two varieties although the variety X virus interaction was very low.     

Variation in symptoms caused by potato virus M on the potato variety Uran

Summary Symptoms caused by potato virus M (PVM) on the potato variety Uran vary from mild mosaic to plant dwarfing. The first severe disease symptoms appear not earlier than in the third year after infection. From tubers collected from plants with severe symptoms, plants with mild symptoms may arise and vice versa.

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Zusammenfassung Die Symptome, die durch das Kartoffelvirus M/PVM an der Kartoffelsorte Uran verursacht werden, schwanken von mildem Mosaik bis zur Pflanzenverzwergung. Unter Feldbedingungen wurden w?hrend vierj?hrigem Anbau ein Ansteigen der PVM-Infektion und eine zunehmende Intensit?t der Krankheitssymptome festgestellt (Abb. 1). In den ersten zwei Jahren wurden nur schwache oder milde Symptome beobachtet, aber nachher fand man Zwergpflanzen. Unter den infizierten Pflanzen der Sorte Uran liessen sich 4 Klassen von Symptomen entsprechend ihrer Intensit?t unterscheiden. Bedeutende Schwankungen in den Symptomen wurden beim Anbau in aufeinanderfolgenden Jahren beobachtet. Im 4. Jahr des Anbaus von Pflanzen, die von vier Gruppen stammten, bestand kein grosser Unterschied, ob die Pflanzen von solchen mit schwachen Symptomen oder von verzwergten Pflanzen stammten (Abb. 2). Diese Schwankung in der Reaktion, die bei der Sorte Uran festgestellt wurde, und die wahrscheinlich auch in andern Kartoffelsorten mit schwachen und schweren Symptomen auf PVM reagiert, dürfte bei der S?uberung von Pflanzkartoffeln betr?chtliche Schwierigkeiten bereiten.

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Résumé Les sympt?mes provoqués par le virus M de la pomme de terre sur la variété Uran varient de la mosa?que légère au nanisme de la plante. Une augmentation de l'infection et de l'intensité des sympt?mes a été constatée durant 4 années de reproduction, en plein champ (fig. 1). Les 2 premières années, seuls des sympt?mes légers et modérés ont été observés; par la suite, des plantes naines apparurent. Entre les plantes infectées de la variété Uran, 4 classes de sympt?mes ont été différenciées selon leur intensité. Des variations considérables de sympt?mes ont été observées au cours de plusieurs années consécutives de reproduction des plantes provenant des 4 groupes. La quatrième année, il n'y avait pas beaucoup de différence entre la descendance de plantes présentant des sympt?mes légers et celle de plantes naines. Cette variation de réaction, en fonction des sympt?mes légers et graves du virus M, présentée par la variété Uran et probablement par d'autres variétés de pomme de terre, peut être la cause de difficultés considérables dans la sélection des semences de pomme de terre.

     

Effect of pre-planting temperature and light treatments of seed tubers on potato yield and tuber size distribution

Summary From 1985 to 1987 field experiments were caried out to test the influence of different pre-planting storage treatments on yield and size distribution of potato crops. The storage treatments included 4, 8 and 12°C in the light and in the dark, for different periods before planting. Subjecting the seed tubers to light at low temperatures induced crops to produce a larger proportion of smaller sized tubers while storing seed tubers at higher temperatures in the dark led to an increase of tubers >55 mm. These observations were confirmed in five field experiments with two cultivars at two sites and in three growing seasons.     

The effects of (S)-(+)-carvone treatments on seed potato tuber dormancy and sprouting

Summary Potato seed tubers may suffer from premature sprouting during storage, thus limiting their suitability for cultivation. Commonly used sprout suppressant treatments negatively affect but viability and therefore a reliable method to inhibit bud development must still be found for seed tubers. The monoterpene carvone ((S)-(+)-carvone) was tested in small scale experiments. The vapour of this compound fully inhibited bud growth of tubers cv. Monalisa stored at 23°C without affecting bud viability throughout 6 months of treatment. The most effective range of carvone vapour concentrations was between 0.34 and 1.06 μmol mol⁻¹. With these qualities we can expect carvone to become a suitable sprout suppressant for seed tubers.     

Notice to potato seed growers of the release ofBelchip,a new potato variety combining high quality,pest resistance,and wide adaptation

American Journal of Potato Research -     

Effects of seed treatments and storage on the changes in lipids of pearl millet meal

Lipids in pearl millet meal showed a rapid hydrolytic decomposition during storage. The magnitude of such degradation was influenced significantly by the nature of the storage container used, the temperature and heat treatments given to the seeds. The hydrolytic breakdown of lipids was significantly low in the meals stored in polyethylene bags, plastic boxes and under refrigerated (5±2 °C) conditions. Hot water blanching at 98 °C for 10 sec and dry heating of seeds at 100 °C for 120 min were found to be most effective in minimising the undesirable changes in lipids of the meal during storage.