Growth and yield studies of potato development in a semi-arid region. 3. Effect of water stress and amounts of nitrogen top dressing on physiological indices and on tuber yield and quality of several cultivars

Summary The response of five potato cultivars (Alpha, Cardinal, Désirée, Spunta and Up-to-Date) to a range of amounts of irrigation nitrogen top dressing (N.t.) in a rainless region was studied by means of the line-source sprinkler method. The irrigation-to-evaporation ratio,K _p, ranged from 0.14 to 1.27 and N.t. from 12 kg/ha to 201 kg/ha, respectively. In all cultivars, the yield increased linearly up toK _p=1.0; at higher ratios there was a yield decline in all cultivars except for Cardinal, in which the yield function flattened off. Spunta was the highest yielding cultivar (16t/ha) in the dry range (K _p=0.14; N.t.=12 kg/ha). Désirée was the highest yielding cultivar (64 t/ha) in the wet range (K _p=1.0; N.t.=201 kg/ha), and Alpha was the lowest yielding cultivar in both the dry and wet range (9 and 46 t/ha, respectively). Leaf permeability, leaf water potential and photosynthesis rate decreased, and tuber dry matter percentage increased with decreasingK _p: these indices also varied with plant age, and among cultivars. Yields were adversely affected when soil water potential at the 30-cm depth dropped below −0.4 bar. Contributon from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No E-811, 1983 Series.     

追肥结束期对烤烟生长发育及产质量的影响

以K326为材料，在南昌进行了3个追肥结束期对烤烟生长发育和产质量影响的研究。试验结果表明，追肥结束期早(栽后25d)有利于提高烟株的株高、总叶数、有效叶数、单株叶面积及上部10叶的叶面积和产量；追肥结束期中(栽后35d)有利于提高上等烟比例、均价和产值；追肥结束期晚(栽后45d)有利于提高平均单叶重及上中等烟比例。认为烤烟追肥结束期以栽后25～35d为宜。     

Tuber yield and tuber quality of several potato cultivars as affected by seasonal high temperatures and by water deficit in a semi-arid environment

Summary The effects of high temperatures and water deficit on potatoes were investigated under field conditions. Nine cultivars and one un-named seedling were grown in the spring and in the summer under high temperatures. In both seasons the cultivars were grown under 3 water regimes: adequate water supply, moderate water deficit, and severe water deficit that were achieved by a modification of the single line source sprinkler irrigation system. Severe drought reduced tuber yields in both seasons. Moderate tolerance to a moderate water deficit in the spring season was exhibited by Draga, Désirée, and Monalisa. Late and intermediate cultivars produced high tuber yields in the spring season, and early cultivars had relatively smaller yield losses in the summer. The extent of tuber disorders, sprouting, rotting and malformation, varied considerably. High temperatures enhanced sprouting, rotting and malformation and drought may enhance sprouting and malformation. This investigation was supported by a grant from the Ministry of Foreign Affairs, Technical Assistance Department, Netherlands.     

Effect of seedpiece spacing and nitrogen fertilization on tuber yield, yield components, and nitrogen use efficiency parameters of two potato cultivars

The effect of seedpiece spacing on the efficiency of nitrogen (N) use by the potato crop is generally unknown. The objective of this experiment was to determine the effect of seedpiece spacing on tuber yield, yield components and N use efficiency parameters of two potato cultivars. Potato cultivars Atlantic and Shepody were grown at two rates of N fertilization (0 or 100 kg N ha^?1) and three seedpiece spacings (20, 30, or 40 cm) in 2000 to 2002. Wider seedpiece spacing increased mean tuber weight and the number of tubers per stem, but decreased total tuber yield. The higher tuber yield at the narrow seedpiece spacing was attributed to higher biomass production in combination with lower tuber specific gravity. Seedpiece spacing had no consistent effect on plant N accumulation, and therefore no consistent effect on N uptake efficiency (plant N accumulation /N supply from the soil plus fertilizer). However, a small increase in soil NO₃-N concentration in the hill at topkill at wider seedpiece spacing suggested plant N accumulation was slightly reduced at wider seedpiece spacing, but at a level that could not be detected from a plant-based measure of N accumulation. The reduced dry matter accumulation, but similar plant N accumulation, resulted in lower N use efficiency (plant dry matter accumulation / N supply) at wider seedpiece spacing. Wider seedpiece spacing also resulted in generally lower values of N utilization efficiency (plant dry matter accumulation / plant N accumulation) for the 40-cm compared with the 20- and 30-cm seedpiece spacings. Effects of seedpiece spacing on N use efficiency parameters were generally consistent across cultivars and fertilizer N rates. Wider seedpiece spacing did reduce the efficiency of N use by the potato crop; however, the magnitude of the effect was small under the conditions of this study.     

播种方式对费乌瑞它马铃薯生长与产量品质的影响

试验通过改变马铃薯种薯播种方式(芽眼朝向),研究其对南方冬作区费乌瑞它马铃薯生长、产量与品质的影响。结果表明,播种深度10 cm,以芽眼朝下方式播种马铃薯,收获的马铃薯产量与商品薯率(667 m22150.66 kg,90.59%)均比芽眼朝上(667 m2 2 001.95 kg,80.44%)播种方式高,并且植株长势健壮,青薯率低。南方地区适合运用种薯芽眼朝下播种方式进行马铃薯种植。     

土壤酸碱度对甜菜生长发育及产量的影响

１９９８－１９９９年进行了甜菜酸性土壤改良试验,结果表明,施用熟石灰可有效地中和土壤酸度,补充甜菜所需要的钙,在１５ｃｍ耕层内增施熟石灰３１．３ｇ／ｍ＾２,Ｐ珂提高０．１。土壤ＰＨ值越接近中性越有利于甜菜生长,土壤越酸,土壤越酸,施熟石灰增产效果越显著。     

Effects of water stress on photosynthesis and chlorophyll fluorescence of five potato cultivars

Summary Reduction of leaf photosynthesis due to water stress has been analyzed into various components and genetic variation in these components has been evaluated. Five potato cultivars were grown on nutrient solution in a conditioned glasshouse. Water stress was imposed by adding polyethylene glycol to the nutrient solution. Photosynthesis, transpiration and chlorophyll fluorescence were measured on intact leaves during the stress period and after recovery from the stress. Water stress reduced photosynthesis, initially as a consequence of stomatal closure, but after 3 days increasingly by inhibiting directly the photosynthetic capacity (mesophyll limitation). Stomatal closure correlated with the reduction in photosynthesis, but it was not the sole cause of this reduction because the internal CO₂ concentration in the leaves was not affected by water stress, indicative of inhibitory factors other than stomatal ones. Chlorophyll fluorescence emission suggested that the Calvin cycle was inhibited, while quantum efficiency was not affected at 17°C. Increasing the temperature to 27°C reduced quantum efficiency but only in the stress environment. The recovery of young leaves after relief of the stress was associated with a lower stomatal conductance but a higher mesophyll conductance compared with the control, which caused a low internal CO₂ concentration and probably invoked photo-inhibition and leaf damage. Cultivar differences in photosynthetic rate were highly significant under both optimal and stress conditions, and corresponded with differences in mesophyll conductance.     

Observations on the effects of relief of late water stress in potato

Summary Experiments on crops of three cultivars of potato showed the effects of the relief of water stress towards the end of the growing season. Treatments imposed showed the starting condition and the responses of crops which were actively growing, newly had their tops removed, or were without active roots. Water was taken up only by tubers of plants with active roots, and there was no translocation of reserves from stem bases. Stress sprouting increased only in the treatments with intact roots, and only the sprouts of intact plants developed chained tubers. Growth cracking occured in the tubers of rooted plants of two of the crops. In the intact plants of the other crops average tuber fresh weight increased by 50% and dry weight by 35% showing that increased water uptake and rapid growth may be necessary but are not sufficient conditions for the formation of growth cracks.

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Zusammenfassung Gegen Ende der Wachstumsperiode wurden den trocken-heissen Bedingungen des Somvier Kartoffelschl?ge mit drei Sorten, unter mers 1983 aufgewachsen, experimentellen Behandlungen unterzogen. 1. Die Pflanzen wurden geerntet, die Knollen gewogen, die Trockenmasse festgestellt und alle Abweichungen registriert. 2. Die Pflanzen wuchsen im Ganzen drei Wochen l?nger. 3. Zur Simulierung der Krautentfernung durch Schlagen wurden die Triebe entfernt. Wurzeln und Stolonen blieben intakt. 4. Die Pflanzen wurden gehoben, die Knollen von ihren Stolonen abgetrennt und wieder eingegraben. Die Pflanzungen erhielten 25 mm Beregnung und 10 mm Regen in 24 Stunden, drei Wochen sp?ter nochmals 60 mm Regen. Die Knollen in den Behandlungen 2 und 3 nahmen im Frischgewicht zu (Tab. 1). Nur in Behandlung 2 ergab sich ein Anstieg beim Trockengewicht—der prozentuale Anteil der Knollen-Trockenmasse fiel jedoch (Tab. 1). Es ergaben sich keine deutlichen Verlagerungen von Reserven von der Stengelbasis oder der Wasseraufnahme über die Peridermis der Knollen (Behandlung 4). Nur bei aktiven Wurzeln zeigten sich in zwei Best?nden Wachstumsrisse, ‘Mangelsprosse’ und Sekund?rknollen (Tab. 1). In der Sorte Record stieg der Anteil rissiger Knollen von 4% auf 16% der ursprünglichen Knollen, bei einem Bestand von Maris Piper von 1% auf 18%. Die Messung der durchschnittlichen Knollengr?sse (Tab. 2) zeigt, dass in Behandlung 2 der Best?nde ohne Wachstumsrisse das Frischgewicht um fast 50% und das Trockengewicht um 35% anstieg. Die Ergebnisse zeigen, dass fluktuierende Bodenfeuchtigkeit und rapider Wechsel in der Knollen-Wachstumsrate an sich noch keine ausreichenden Bedingungen für Wachstumsrisse darstellen. Die Erkl?rung, warum an einigen Knollen Wachstumsrisse entstehen, an anderen jedoch nicht, bedarf weiterer Untersuchungen.

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Résumé En fin de période de végétation et durant la période de sécheresse de l'été 1983, quatre expérimentations ont été réalisées sur 3 variétés: 1. Les plantes ont été arrachées et les tubercules pesés; leur teneur en matière sèche a été mesurée et aucune anomalie n'a été constatée. 2. Les plantes ont été maintenues encore 3 semaines en végétation. 3. Les tiges ont été supprimées afin de simuler un défanage chimique. Les racines et les stolons sont gardés intacts. 4. Les plantes ont été arrachées et les tubercules séparés de leurs stolons avant d'être remis en terre. Les cultures ont re?u 25 mm d'eau par irrigation et 10 mm de pluie en 24 h, suivi d'une pluviométrie de 60 mm en 3 semaines. Le poids frais des tubercules des traitements 2 et 3 a augmenté (tabl. 1). Le poids sec a augmenté uniquement dans le traitement 2 mais la teneur en matière sèche a diminué (tabl. 1). Le transfert des réserves à partir de la base des tiges ainsi que l'absorption en eau à travers le périderme des tubercules (traitement 4) ne sont pas significatives. Des crevasses, des germinations anormales et des tubercules de seconde génération ont été observés dans les deux traitements ou l'activité des racines a été maintenue (tabl. 1). Pour la variété Record, le taux de crevasses augmente de 4 à 16% par rapport aux tubercules initiaux et de 1 à 18% dans une culture du cv. Maris Piper. On constate que, sur la taille moyenne des tubercules (tabl. 2), le poids frais dans le traitement 2 a augmenté de presque 50% et le poids sec de 35% pour les 2 cultures n'ayant pas présenté les phénomènes de crevasses. Les résultats montrent que la variation d'humidité de sol et le changement rapide de la croissance des tubercules n'expliquent pas à eux seuls les formations de crevasses. Des études complémentaires sont souhaitables afin d'expliquer les raisons pour lesquelles certains tubercules crevassent et d'autres non.

     

Study of water stress effects in different growth stages on yield and yield components of different rice (Oryza sativa L.) cultivars

A field experiment was conducted during 2001-2003 to evaluate the effect of water stress on the yield and yield components of four rice cultivars commonly grown in Mazandaran province, Iran. In northern Iran irrigated lowland rice usually experiences water deficit during the growing season include of land preparation time, planting, tillering stage, flowering and grain filing period. Recently drought affected 20 of 28 provinces in Iran; with the southeastern, central and eastern parts of the country being most severely affected. The local and improved cultivars used were Tarom, Khazar, Fajr and Nemat. The different water stress conditions were water stress during vegetative, flowering and grain filling stages and well watered was the control. Water stress at vegetative stage significantly reduced plant height of all cultivars. Water stress at flowering stage had a greater grain yield reduction than water stress at other times. The reduction of grain yield largely resulted from the reduction in fertile panicle and filled grain percentage. Water deficit during vegetative, flowering and grain filling stages reduced mean grain yield by 21, 50 and 21% on average in comparison to control respectively. The yield advantage of two semidwarf varieties, Fajr and Nemat, were not maintained under drought stress. Total biomass, harvest index, plant height, filled grain, unfilled grain and 1000 grain weight were reduced under water stress in all cultivars. Water stress at vegetative stage effectively reduced total biomass due to decrease of photosynthesis rate and dry matter accumulation.     

Effect of short- and long-term exposure of seed tubers to low temperatures on the growth and yield of five potato cultivars

Trials were conducted in Alberta with Norchip, Norland, and Russet Burbank and in Ontario with Kennebec, Russet Burbank, Norchip, and Superior tubers to determine their response to short-term exposure to air temperatures of 0, ?1, and ?5 C and to long-term exposure to ?1, 0, 1,2, and 3 C. Exposure of seed tubers to ?1 C from 6 hours to 5 days did not affect growth characteristics or tuber yield of any of the five cultivars studied. Long-term (October–May) exposure to ?1 C in one study severely reduced emergence and tuber yield of Norchip (P<0.05). While the marketable yield of Russet Burbank was also reduced (P<0.05) by this treatment, Norland was not affected. Tubers of all cultivars exposed to air temperatures of ?3 or ?5 C for longer than 24 hours were severely injured and were not planted in the field trials at either location. In Alberta exposure of seed tubers of Norchip, Norland, and Russet Burbank to ?5 C for 6 and 12 hours caused a reduction (not significant) in yield. In Ontario, long-term storage at 1, 2, and 3 C and in combination with short-term (2 weeks) exposure to 0 or 10 C had no effect on growth or marketable yield of Norchip, Russet Burbank, Superior, and Kennebec seed tubers.     

Effect of inorganic nitrogen nutrition on cytokinin-induced potato microtuber production in vitro

Summary The effect of inorganic nitrogen nutrition on the induction and development of microtubers by cytokinin-induced tuberization was studied in four potato genotypes belonging to different maturity groups. The objective of this study was to investigate whether a reduction in total nitrogen level in the Murashige & Skoog medium would improve cytokinin-induced tuberization rate. The effect of three levels of total nitrogen (15, 30 and 45 meq) on tuberization was studied at constant (20 meq K) and varying potassium levels approximating to 5, 10 and 15 meq. Reducing the total nitrogen supply increased the number but decreased the size of nitrogen level on the rate of assimilate partitioning (harvest index) during cytokinin-induced microtuberization.     

Jasmonate effect on in vitro tuberization of potato (Solanum tuberosum L.) cultivars under light and dark conditions

Summary Effects of jasmonic acid (JA) on in vitro tuberization of six potato cultivars were examined. Tuberization was carried out in the dark, or with 8 h photoperiod on MS media with vitamins, 8% sucrose, 0.6% agar and either 2.5 μM JA (JAMed) or no JA using explants either preconditioned with 2.5 μM JA (JAPret) or not. Cultivars Amisk, Russet Burbank, Sangre and Umatilla Russet produced the most (1.0–1.7) and the largest microtubers per explant. Tuberization was inconsistent in Shepody and poor in Atlantic. All cultivars tuberized significantly better in 8 h than in the dark. JA effects were cultivar specific and larger in the dark than in light. In the dark, Amisk, Atlantic and Umatila Russet tuberized better in JAMed than in JAPret. These cultivars did not benefit from JA treatments in light. Russet Burbank and Sangre tuberized in the dark better from JAPret cuttings than on JAMed medium. JA had no effect on tuberization in Shepody. JA double treatment in light vs. control and individual JA treatments significantly reduced tuberization in Shepody and Russet Burbank.     

The influence of leaf area,light interception and season on potato growth and yield

Summary Light interception in the photosynthetically active radiation (PAR) range (400 700 nm) was measured over two years in potato crop canopies. Light interception increased linearly with increasing leaf area index (L) up to values of 2.25, light interception increased at a decreasing rate until L=4.0 was attained when around 95% of the incoming radiation was intercepted. The equation I_l=I_oe^kl accounted for 92% of the variance in the relationship between light interception and L, where I_l is the irradiance on a horizontal plane below a leaf area index of L., and k (light extinction co-efficient)=0.335+0.151 (L) 0.0129 (L)². Crop growth rate was found to be linearly related to the PAR intercepted by the canopy in 1980, in the absence of any apparent water-stress. The photosynthetic conversion efficiency of the canopy (g dry weight MJⁱ PAR intercepted) was 3.42 and 2.49 for 1980 and 1979, respectively. Tuber yields were also found to be linearly related to PAR intercepted by the canopy over the whole season.

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Zusammenfassung In den Jahren 1979 und 1980 wurde die Lichtaufnahme der photosynthetisch aktiven Strahlung (PAR) im Bereich von 400–700 nm in Kartoffelbest?nden im Vereinigten K?nigreich gemessen. Die meteorologischen Daten zeigten, dass der Niederschlag in den Jahren sehr unterschiedlich war (Abb. 2); 1979 war überwiegend trocken, vor allem in der sp?teren Vegetationszeit, w?hrend 1980 allgemein ein nasses Jahr war. Die Lichtaufnahme stieg linear mit dem zunehmenden Blattfl?chenindex (L) bis zu L=2,25 an (wobei rund 73% der einfallenden Strahlung aufgenommen wurde) und über L=2,25 nahm die Lichtaufnahme mit einer abnehmenden Rate bis zu L=4,0 zu, wobei rund 95% der einfallenden Strahlung aufgenommen wurden (Abb. 3). Die Gleichung I_L=I_oe^kL gilt für 92% der Varianz in der Beziehung zwischen Lichtaufnahme und Blattfl?chenindex (L), wobei I_L=Strahlung auf einer horizontalen Fl?che unter einem Blattfl?chenindex von L und k (Lichtextinktionskoeffizient)=0,335+0,151(L)−0,0129(L)². Wenn die Konstante k (=0,72) verwendet wurde (Abb. 3) entsprach die Varianz für das ausgew?hlte Modell 88%. Zwischen dem Gesamttrockengewicht (TDW) und der PAR, die aufgenommen wurde, bestand in beiden Jahren ein signifikantes lineares Verh?ltnis. Abb. 4 zeigt die Daten für 1980. Durch den Nullpunkt geführt ergibt sich ein TDW=3,42 (PAR) und 2,49 (PAR) für 1980 bzw. 1979, das bedeutet, dass die Umwandlung von Lichtenergie in Trockensubstanz ohne ersichtlichen Wassermangel 1980 wirkungsvoller war. Abb. 5 zeigt die photosynthetische Wirksamkeit (g Trockengewicht MJ^l PAR) w?hrend der Vegetationszeiten zusammen mit den ?nderungen im Blattfl?chenindex L. Die Wachstumsrate des Bestandes stand 1980 in einem linearen Verh?ltnis zu der von den Bl?ttern aufgenommenen PAR, w?hrend sich für 1979, wo der Bestand stark unter Trockenheit litt, eine Abweichung ergab (Abb. 6). Obwohl w?hrend der beiden Jahre die photosynthetische Wirksamkeit (g Knollentrockengewicht MJ^l PAR, aufgenommen w?hrend der gesamten Vegetationszeit) für das Knollengewicht unterschiedlich war: Knollentrockengewicht=1,97 (PAR) und 2,37 (PAR) für 1979 bzw. 1980, zeigen die Daten, dass ein gesteigertes Wachstum entsprechend einer h?heren Lichtaufnahme zu h?heren Knollenertr?gen führt, unabh?ngig von einer Reihe ackerbaulicher Massnahmen.

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Résumé L'interception des radiations actives pour la photosynthèse (PAR), dans des longueurs d'onde de 400 à 700 nm, est mesurée durant très différente les deux années; 1979 fut particulièrement sec, surtout en fin de saison, alors que 1980 fut une année humide. La quantité de lumière interceptée, augmente linéairement avec l'index de surface foliaire (leaf area index) jusqu'à une valeur de L=4,25 (correspondant à 73% de radiations interceptées) et pour des valeurs supérieures, l'interception augmente à une vitesse décroissante jusqu'à L=4,0 correspondant à 95% de radiations captées (fig. 3). La relation I_L=I_oe^kL interpréte 92% de la variation dans la liaison entre la lumière interceptée et l'index de surface foliaire (L), où I_L est le rayonnement atteignant un plan horizontal situé sous un index foliaire L et K (coefficient d'extinction lumineuse)=0,335+0,151(L) −0,0129(L)². Si on fixe k à 0,72 (fig. 3), la part de variation expliquée par le modèle est de 88%. Une relation linéaire significative entre la matière sèche totale (TDW) cumulée et le PAR intercepté cumulé, a été établie pour les deux années et les données de 1980 sont portées dans la figure 4. Si on fait passer la régression par l'origine, on écrira pour 1979: TDW=2,49× deux années, 1979 et 1980, dans des cultures de pomme de terre du Royaume-Uni. Selon les données météorologiques, la pluviométrie fut et pour 1980: TDW=3,42×PAR. Ces relations indiquent que la conversion de lumière en matière sèche a été plus efficace en 1980 en l'absence de déficit hydrique. L'efficacité de la conversion photosynthétique (g de matière sèche/PAR intercepté) au cours de la saison, est indiquée avec les variations de L dans la figure 5. La vitesse de croissance de la culture est liée linéairement au PAR capté par la végétation en 1980, alors que cette liaison s'écarte de la linéarité en 1979, lorsque la culture est affectée par la sécheresse (fig. 6). Bien que l'efficacité de la conversion photosynthétique (g de poids sec de tubercule/PAR captée durant toute la saison) pour le poids de tubercules soit légèrement différente pour les deux années (en 1979 elle est égale à 2,37 (PAR), en 1980 elle est égale à 1,97 (PAR)). Les données indiquent que l'augmentation de la croissance de la récolte totale, expliquée par l'augmentation de la lumière captée, résultent également du rendement de plus en plus grand des tubercules (fig. 7), sur une série de traitements agronomiques.

     

The rate of respiration of potato tubers during storage. 2. Results of experiments in 1972 and 19731,2

Summary The rates of respiration of potato tubers in storage were determined with a number of commercial cultivars and breeding lines in 1972 and, in a more systematical way, with six commercial cultivars in 1973. The ranges of respiration rates in mg CO₂ kg⁻¹ h⁻¹ during the main storage period were 1.5–4.0 at 2.5°C, 1.5–2.5 at 5.0°C, 1.0–2.0 at 7.5°C, 1.0–3.0 at 10.0°C, 1.5–5.5 at 12.5°C and 2.5–12.5 at 15.0°C. At the start of the storage season, the rates, particularly at 2.5 and 5.0°C, were higher than during the main storage period. During late winter and early spring the rate of respiration of the tubers stored at the highest temperatures increased considerably. The minimum rates of respiration were found in December, except at 2.5°C when the minimum was in February. The rate of respiration was a clear characteristic of the cultivar, independent form both earliness in the field and length of dormant period. The rate of respiration increased noticeably when sprouts were at least 1 cm long.

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Zusammenfassung Die Atmungsrate von Kartoffeln, die bei verschiedenen Temperaturen gelagert waren, wurde gemessen, indem Kartoffelproben von ungef?hr 2 kg mehrere Stunden in verschlossenen Weithalsflaschen lagen und der CO₂-Gehalt (in %) in einer Luftprobe mit einem Lloyd Gasanalysator bestimmt wurde. Wenn die Versuchszeit so gew?hlt wurde, dass die CO₂-Konzentration 3% nicht überschritt, hatte es keinen hemmenden Einfluss auf die Atmungsrate (Abbildung 1). Im bereich des Knollengewichtes. (70–250 g), der in einem Vorversuch gew?hlt wurde, zeigte die Knollengr?sse keine Beziehung zur Atmungsrate. In den Hauptversuchen war der Bereich viel kleiner. 1972 wurden die Atmungsraten von vielen Handelssorten und Zuchst?mmen im Oktober, Janu?r, M?rz und Mai w?hrend der Lagerung bei 2,5, 5,0, 7,5, 10,0, 12,5 und 15°C gemessen, mit Ausnahme der Proben, die bei 12,5 und 15°C gelagert waren und die nach der Messung im Januar wegen Keimung verworfen wurden. Tabelle 1 zeigt signifikante Unterschiede in der Atmung zwischen den bei 7.5°C gelagerten Sorten. Eine hoch signifikante Interaktion bestand zwischen der Lagertemperatur (5,0, 7,5, 10°C) und der Lagerungsdauer, verursacht durch eine sehr hohe Atmungsrate bei 5,0°C im Oktober (Tabelle 2). Abb. 2 zeigt den betr?chtlichen Einfluss der Keimung auf die Atmung w?hrend der Lagerung bei 12,5 und 15°C. Die Beziehung zwischen der Temperatur und der Atmungsrate im Januar 1973 war sehr verscheiden von der im Oktober 1972 (Abb. 3). 1973 wurden bei gleichen Lagertemperaturen nur 6 Handelssorten verwendet. Die Atmungsraten wurden von November bis M?rz monatlich gemessen. Im April und Juni wurden nur die bei 10°C und tiefer gelagerten Proben gemessen. Tabelle 3 zeigt die Varianzanalyse der Ergebnisse von November bis M?rz. Die Ver?nderungen, die aus Tabelle 3 ersichtlich sind, wurden haupts?chlich durch sortenspezifische Reaktionen auf die vielen unterschiedlichen Kombinationen zwischen Lagertemperatur und-dauer verursacht. Die Abb. 4 und 5 zeigen die Ergebnisse für die Sorten Katahdin und Russet Burbank. Um eine durch die Keimung verursachte Steigerung der Atmung messen zu k?nnen, mussen die Keime 1 cm oder l?nger sein (Abb. 6). Die Beziehung zwischen der Lagertemperatur und der Atmungsrate ?nderte sich in der Lagerperiode kontinuierlich, vor allem bei Temperaturen von 10°C oder h?her (Abb. 7). Wie 1972 lag das Minimum der Atmungsrate bei 7,5°C. Im Dezember war bei fast allen Temperaturen die geringste Atmungsrate erreicht, bei 2,5°C jedoch erst einen oder 2 Monate sp?ter. Keine Beziehung ergab sich zwischen der Atmung und der Frühreife einer Sorte oder der L?nge ihrer Keimruhe.

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Résumé L'intensité respiratoire des tubercules conservés à différentes températures a été mesurée sur des échantillons de 2 kg environ, enfermés pendant plusieurs heures dans des bouteilles à large goulot, en déterminant le pourcentage de gaz carbonique de l'air à l'aide d'un analyseur de gaz Lloyd. Si la durée de l'expérience est telle que la concentration en gaz carbonique ne dépasse pas 3%, il n'y a pas d'effet inhibiteur sur l'intensité respiratoire (fig. 1). Au cours d'une expérience préliminaire effectuée sur une gamme de poids de tubercules (70 à 250 g), aucune relation entre le calibre et l'intensité respiratoire n'a pu être mise en évidence. Dans l'expérimentation principale, la gamme de poids était beaucoup plus petite. En 1972, l'intensité respiratoire de nombreuses variétés a été mesurée en octobre, janvier, mars et mai après une conservation à 2,5°C, 5.0°C, 7,5°C, 10,0°C, 12,5°C, et 15,0°C, à l'exception des échantillons stockés à 12,5°C et 15,0°C qui avaient été éliminés après la mesure de janvier à cause de leur germination. Des différences significatives ont été enregistrées entre les variétés stockées à 7,5°C (tableau 1). Une interaction hautement significative a été constatée entre la température (5,0, 7,5 et 10,0°C) et la durée de conservation, provoqué principalement par une intensité respiratoire très élevée à 5,0°C en octobre (tableau 2). A 12,5 et 15,0°C la germination a un effet considérable sur l'intensité respiratoire. La relation entre température et intensité respiratoire en janvier 1973 était très différente de celle d'octobre 1972 (figure 3). En 1973, les mêmes températures furent étudiées mais avec seulement 6 variétés. L'intensité respiratoire a été déterminée chaque mois, de novembre à mars. Les mesures ont aussi été effectuées en avril et juillet, mais uniquement sur des échantillons conservées à 10°C et moins de 10°C. L'analyse de variance des résultats obtenus de novembre à mars est présentée dans le tableau 3. Les variations enregistrées sont d?es principalement à la réaction spécifique des variétés aux différentes combinaisons température-durée de conservation. Les figures 4 et 5 donnent les résultats obtenus avec les variétés Katahdin et Russet Burbank. Les germes doivent avoir 1 cm de long pour qu'une élévation de l'intensité respiratoire provoquée par la germination soit mesurable (figure 6). La relation entre température et durée de conservation évolue continuellement au cours du stockage particulièrement à 10°C et au-dessus de 10°C (figure 7). Comme en 1972, une intensité respiratoire minimale a été constatée à 7,5°C. Les intensités respiratoires les plus basses ont été observées en décembre, sauf pour la température de 2,5°C (un ou deux mois plus tard). Aucune relation n'a été trouvée entre l'intensité respiratoire et la précocité ou la durée du repos végétatif des variétés.

     

Effect of high water temperature during vegetative growth on rice growth and yield under a cool climate

Global warming is likely to increase spring temperatures in regions with a cool climate. To examine the effects of this change on rice productivity, we exposed rice plants to a higher (by +2.7 to +2.8 °C) water temperature (T_w) during the vegetative growth period (for 35-50 days) under three levels of N fertilization. High T_w during vegetative growth made the heading stage occur 4-7 days earlier for all levels of N fertilization in both years. The crop growth rate during the treatment period was greatly enhanced by high T_w: by 51-82% in 2008 and by 49-62% in 2009. There was no T_w × N fertilizer interaction. This increased growth was associated with increased leaf expansion and increased canopy radiation capture rather than with increased radiation-use efficiency. However, the positive effect decreased during subsequent growth stages under all levels of N fertilization, leading to no significant differences in total biomass at maturity. High T_w during vegetative growth greatly reduced SPAD values during the grain-filling stage compared with SPAD values in the control T_w treatment, for all levels of N fertilization, and decreased leaf photosynthesis during the mid-grain filling stage. Grain yield was not significantly affected by high T_w at any N fertilizer level or in either year.     

马铃薯叶面喷施植物生长调节剂对植株和产量的影响

通过对马铃薯叶面喷施不同浓度植物生长调节剂(多效唑)和微量元素,研究不同浓度多效唑和微量元素配合喷施对马铃薯叶绿素含量、光合速率、淀粉含量、产量等的影响。结果表明,不同浓度多效唑和微量元素配合使用,可使马铃薯顶端生长受到明显抑制,茎粗增加,叶绿素含量增加,光合速率增加到一定程度有所下降。淀粉含量随着浓度增加而增加,到一定程度也有下降的趋势。     

The effects of nitrogen and iron fertilization on growth,yield and fertilizer use efficiency of soybean in a Mediterranean-type soil

Poor seed yield of soybean in Mediterranean-type environments may result from insufficient iron (Fe) uptake and poor biological nitrogen (N) fixation due to high bicarbonate and pH in soils. This study was conducted to evaluate the effects of N and Fe fertilization on growth and yield of double cropped soybean (cv. SA 88, MG III) in a Mediterranean-type environment in Turkey during 2003 and 2004. The soil of the experimental plots was a Vertisol with 176 g CaCO₃ kg⁻¹ and pH 7.7 and 17 g organic matter kg⁻¹ soil. Soybean seeds were inoculated prior to planting with commercial peat inoculants. N fertilizer rates were 0, 40, 80, and 120 kg N ha⁻¹ of which half was applied before planting and the other half at full blooming stage (R2). Fe fertilizer rates were 0, 200 and 400 g Fe EDTA (5.5% Fe and 2% EDTA) ha⁻¹. It was sprayed as two equal portions at two trifoliate (V2) and at five trifoliate stages (V5). Plants were sampled at flower initiation (R1), at full pod (R4) and at full seed (R6) stages. Application of starter N increased biomass and leaf area index at R1 stage whereas Fe fertilization did not affect early growth parameters. N application continued to have a positive effect on growth parameters at later stages and on seed yield. Fe fertilization increased growth parameters at R4 and R6 stages, and final seed yield in both years. This study demonstrated an interactive effect of N and Fe fertilization on growth and yield of soybean in the soil having high bicarbonate and pH. There was a positive interaction between N and Fe at the N rates up to 80 kg N ha⁻¹. However, further increase in N rate produced a negative interaction. Fertilization of soybean with 80 kg N ha⁻¹ and 400 g Fe ha⁻¹ resulted in the highest seed yield in both years. We concluded that application of starter and top dressed N in combination with two split FeEDTA fertilization can be beneficial to improve early growth and final yield of inoculated soybean in Mediterranean-type soils.     

磷对大豆不同品种产量和品质的影响

土壤盆栽试验表明,低磷处理下大豆品种的籽粒产量很低,籽粒中蛋白质含量高,脂肪含量低。施磷后大豆的产量极显著增加,但增产效果品种间差异也极显著。施磷大大降低籽粒中蛋白质和氨基酸含量,而增加脂肪含量;对脂肪酸组成中的油酸和亚油酸含量也有影响。     

铝胁迫对花生不同基因型生长发育的影响

盆栽花生铝胁迫试验表明,铝对花生形态发育和产量性状均有较大的影响,花生不同基因型耐铝毒害具显著差异。根系性状是评价花生受害程度和耐铝毒潜能的重要指标。高产和低产材料中都存在耐铝毒基因型。     

Incidence, appearance and development of potato mop-top furovirus-induced spraing in potato cultivars and the influence on yield, distribution in Denmark and detection of the virus in tubers by ELISA

Summary 23 potato cultivars were grown in fields infested with potato mop-top virus and spraing was assessed on tubers at harvest and after storage. Large differences in spraing susceptibility were found between cultivars. Compared with other countries, spraing in Denmark is characterised by a high incidence at harvest, a low increase during storage and a very low proportion of superficial spraing. Decrease in spraing during storage was recorded in two cultivars. DASELISA tests for PMTV in tubers revealted a high reliability. Mapping of PMTV in important Danish potato growing areas showed that the virus is widespread. Occurrence of spraing did not influence total yield or dry matter content. Soil acidity did not influence incidence of spraing but it was more common on coarse-grained soil than on finer sandy soils. PMTV in viruliferous resting spores ofSpongospora subterranea was inactivated by heating to 90°C for 15 minutes.