Utilization of potatoes for life support systems in space. I. Cultivar-photoperiod interactions

The productive potential of potatoes (Solanum tuberosum L. cvs. Norland, Superior, Norchip, and Kennebec) was assessed for life support systems being proposed for space stations and/or lunar colonies. Plants were grown in walk-in growth rooms for 15 weeks at 20 C under 12-, 16- and 20-h photoperiods of 400 μmol m^t-2s^t-1 photosynthetic photon flux (PPF). Norland yielded the greatest tuber fresh weight, producing 2.3, 2.4, and 2.9 kg/plant under 12-, 16-, and 20-h photoperiods, respectively. The respective yields for the other cultivars under 12-, 16-, and 20-h were: Superior, 1.9, 1.5, and 1.8 kg/plant; Norchip, 1.8, 1.4, and 2.0 kg/plant; and Kennebec, 2.3, 0.2, and 0.8 kg/plant. Shoot and total plant biomass increased with lengthening photoperiods except for Kennebec, which showed increased shoot growth but no change in total growth with the longer photoperiods. Kennebec shoot growth under the 20-h photoperiod, and to some extent under 16-h, was noticeably stunted with shortened internodes. In addition, leaves of these plants showed mild chlorosis with rusty “flecking” of the surfaces. The harvest index (ratio of tuber yield/total biomass) was highest for all cultivars under the 12-h photoperiod, with a maximum of 0.69 for Norland. Similarly, the tuber yield per input of irradiant energy also was highest under 12-h for all cultivars. The tuber yield expressed on an area basis for the highest yielding treatment (Norland under 20-h) equaled 2.2 kg dry matter m^t-2. Over 15 weeks this equates to a productivity of 20.7 g tuber dry matter m^t-2 day^t-1. Assuming 3.73 kcal per g tuber dry matter and a daily human dietary requirement of 2800 kcal, then 36 m² of potatoes could supply the daily energy requirement for one human. Potential for increasing productivity is discussed.     

Photoperiodin vitro affects subsequent yield of Greenhouse-grown potato tubers

In vitro potato plantlets of cultivar (cv.) Shepody (Solatium tuberosum L.) were exposed to 12-or 16-hr photoperiods for 8 weeks. Plantlets were acclimatized to the greenhouse and grown under 14-hr photoperiods until they senesced, and minitubers were harvested. Greenhouse-grown potato plants developed from tissue-culture plantlets exposed to a 16-hr photoperiod were taller and had more nodes than plants developed from plantlets exposed to 12-hr photoperiods. However, yield data of minitubers from greenhousegrown plants indicated that the 12-hr photoperiodic treatment increased the numbers, dry weight and specific gravity of minitubers. A further advantage of the 12-hr photoperiodic treatment was the greater numbers of minitubers in the 15–40 g size class compared with tubers in the <15 g and >40 g size classes. Thus, for the cv. Shepody, plant height and node number of greenhouse-grown plants were not good indicators of minituber yield from that crop. Seed potato nuclear stock facilities producing minitubers should investigate the possibility of optimizing minituber production by exposing multiplication cultures to shorter daylengths.     

Utilization of potatoes for life support systems II. The effects of temperature under 24-H and 12-H photoperiods

The growth and tuberization of Norland potatoes were studied under five different temperatures and two photoperiods. Treatment levels included 12, 16, 20, 24, and 28 C with either a 24-h (continuous light) or a 12-h photoperiod at 400 μmol m^-2 s^-1 PPF. Plants were grown in 6-liter containers and harvested at 56-days-age. Stem length increased with increasing temperature under both photoperiods. The highest tuber yield occurred at 16 C under the 24-h photoperiod (755 g/plant) and at 20 C under the 12-h photoperiod (460 g/plant). Little or no tuber formation occurred at 28 C under either photoperiod or at 24 C under continuous light. As with tuber yield, the highest total plant dry weights also occurred at 16 C under the 24-h photoperiod and at 20 C under the 12-h photoperiod. Harvest index (tuber dry weight to total dry weight ratio) decreased with increasing temperatures and with continuous light. Results indicate that good growth and tuberization can occur under continuous light, and that increasing the photoperiod from 12 to 24 h effectively decreased the optimal temperature for tuber formation from near 20 C to 16 C. Alternatively, the results imply that at cooler temperatures, the potato becomes less obligate for dark period stimulation of tuberization.     

Photoperiod effects on2n pollen production,response to anther culture,and net photosynthesis of a diplandrous clone ofsolanum phureja

Flow-cytometric analysis of pollen samples obtained fromSolanum phureja, clone PP5, grown under 10, 14, and 18 hour photoperiods at the Southeastern Plant Environment Laboratories of North Carolina State University yielded two populations of pollen based on size parameters. These populations corresponded to pollen separation based on propidium iodide staining of DNA. Anther culture response from plants grown under 14 and 18 hour photoperiods for 8, 10, 12, and 14 weeks was greatest from 8 week old plants grown under a 14 hour photoperiod. Net photosynthesis was significantly higher for plants grown under a 10 hour photoperiod than for plants grown under either a 14, or 18 hour photoperiod. A significant positive correlation was found between net photosynthesis and tuber yield. Results suggest that vegetative growth is increased under short photoperiods, floral development is favored under long photoperiods, and androgenesis is greatest from young plants grown under an intermediate photoperiod.     

Effects of temperature and photoperiod on early growth and final number of tubers in potato (Solanum tuberosum L.)

Summary A phytotron experiment with all combinations of two photoperiod (12 or 18 h) and four temperature (18/12, 22/16, 26/20 or 30/24 °C; 12h/12h) treatments was carried out to analyse quantitative effects on early tuber growth, dry-matter partitioning and number of tubers of two cultivars. Higher temperatures and longer photoperiod delayed the onset of expolinear tuber growth and the onset of linear tuber bulking. Higher temperatures also gave lower absolute tuber growth rates. Photoperiod did not affect absolute tuber growth rate at lower temperatures. Higher temperature and longer photoperiod gave lower relative rates of partitioning of dry matter to the tubers. Differences between treatments in numbers of tubers initiated were inconsistent. This quantitative analysis of the effects of temperature and photoperiod on characteristics of tuber growth should prove useful in potato modelling.     

Utilization of potatoes for life support systems in space: III. Productivity at successive harvest dates under 12-H and 24-H photoperiods

Potatoes are among several crops under consideration for use in controlled ecological life support systems (CELSS) being proposed for space colonies. Efficient crop production for such life support systems will require nearoptimal growing conditions with harvests taken when production per unit area per unit time is maximum. To determine this maximum for potato, cv. Norland plants were grown in walk-in growth rooms under 12-h and 24-h photoperiods at 16 C and harvested at 42,63, 84,105,126 and 148 days from planting. At 42 days, plants were encaged in wire fence cylinders with a cross-sectional area of 0.2 m². The dry weights (dwt) of tubers and of the entire plants increased under both photoperiods until the final harvest date (148 days), reaching 572 g tuber dwt and 704 g total dwt under 12-h, and 791 g tuber dwt and 972 g total dwt under 24-h. At a spacing of 0.2 m² per plant, the 148-day tuber production from plants under continuous light would equate to nearly 40t ha^-1 dry matter (200t fresh weight), approximately twice that of exceptionally high field yields. Tuber productivity (g m^-2 day^-1) under the 24-h photoperiod reached a maximum of 29.4 g dwt m^-2 day^-1 at 126 days, but continued to rise throughout the experiment under the 12-h photoperiod, reaching 19.5 g dwt m^-2 day^-1 at 148 days. With a productivity of 29.4 g tuber dwt m^-2 day^-1, approximately 25 m² would continuously provide the daily dietary energy requirements for one human.     

Carbon dioxide effects on potato growth under different photoperiods and irradiance

Carbon dioxide concentration can exert a strong influence on plant growth, but this influence can vary depending on irradiance. To study this, potato plants (Solanum tuberosum L.) cultivars Norland', Russet Burbank', and Denali' were grown in controlled-environment rooms at different levels of CO2 and irradiance. Carbon dioxide levels were maintained either at 350 or 1000 micromoles mol-1 and applied in combination with 12- or 24-h photoperiods at 400 or 800 micromoles m-2 s-1 photosynthetic photon flux. Air temperatures and relative humidity were held constant at 16 degrees C and 70%, respectively, and plants were harvested 90 d after planting. When averaged across all cultivars, CO2 enrichment increased tuber yield and total plant dry weight by 39 and 34%, respectively, under a 12-h photoperiod at 400 micromoles m-2 s-1; 27 and 19% under 12 h at 800 micromoles m-2 s-1; 9 and 9% under 24h at 400 micromoles m-2 s-1. It decreased dry weights by 9 and 9% under 24 h at 800 micromoles m-2 s-1. Tuber yield of Denali showed the greatest increase (21%) in response to increased CO2 across all irradiance treatments, while tuber yields of Russet Burbank and Norland were increased 18 and 9%, respectively. The results show a pattern of greater plant growth from CO2 enrichment under lower PPF and a short photoperiod.     

Contrasting Ppd alleles in wheat: effects on sensitivity to photoperiod in different phases

Photoperiod sensitivity is an important feature of flowering time regulation, which enables wheat plants to adapt to a wide range of environments. Although some work has been done on how time to heading or flowering respond to photoperiod in relation to particular Ppd alleles, there is little evidence on whether these alleles contribute to responses at different phases and to associated yield component generation. The aims of this paper were: (i) to analyse the effects of photoperiod on substitution lines with contrasting Ppd alleles, in terms of duration of particular phases, (ii) to determine if there is any relationship between these alleles and the parameters of photoperiod response (photoperiod sensitivity, optimum photoperiod and basic length of the phase), and (iii) to analyse the effects of different photoperiods applied before and after the onset of terminal spikelet on yield component generation. The effects of length and timing of photoperiod extensions on these traits were analysed under field conditions in Chinese Spring and two substitution lines differing in photoperiod sensitivity.Although time to anthesis was similar in the three genotypes in photoperiods longer than 14.5 h, they did differ in their response to photoperiod in particular phases. Sensitivity to photoperiod for daylengths shorter than 14.5 h was also markedly different. The number of leaves generated was affected by photoperiod, determining the duration of the phase from emergence to floral initiation (EM-FI). The length of the phase from floral initiation to terminal spikelet (FI-TS) was determined by the number of spikelets generated and their rate of initiation, which was also affected by photoperiod. The terminal spikelet to anthesis phase (TS-ANT) was only affected by photoperiod in the most sensitive genotype, in which direct photoperiod effects, other than the effects on leaf number and phyllochron, were evident. There was no apparent relation between photoperiod response parameters such as basic length of the phase (Lb) and optimum photoperiod (Po) and particular Ppd alleles.     

Effect of incandescent and fluorescent lighting used in photoperiod extension on the vegetative growth and floral development of four lines of pigeonpea

The effects of light quality, as used in photoperiod extension, on vegetative growth and floral development of pigeonpea [Cajanus cajan (L.) Millsp.] were studied using three photoperiod-insensitive lines, QPL2, Prabhat, and Hunt, and one photoperiod-sensitive line, Royes. Plants were grown in controlled-environment cabinets under day/night temperature regimes of 24/16°C (low) and 28/24°C (high) for 72 days after emergence (DAE). The five light treatments consisted of 12 and 16-h photoperiods and a 12-h photoperiod extended to 16 h with low-intensity lighting from either incandescent (I), fluorescent (F), or incandescent plus fluorescent (I+F) lamps.Little genetic variation occurred in vegetative response (main stem length and node number, leaf area and shoot dry weight) to extension light source. Response varied with temperature, plant age and growth stage. Main stem node appearance and stem extension tended to decline following floral initiation (FI), whereas leaf area and shoot dry weight accumulation increased rapidly after 35 or 42 DAE, irrespective of whether plants were vegetative or floral. Plants were larger under the high-temperature regime. Temperature altered plant response to extension light source. I-extension promoted growth under both temperature regimes, whilst I+F promoted growth under high temperatures but was unexpectedly inhibitory under low. Under high temperatures F extension was inhibitory prior to FI, but promoted later growth during floral bud development (FBD). Under low temperatures, F-extension was not inhibitory during the pre-initiation phase.The four genotypes differed in their floral response to extension light source, the effect on initiation and development of floral primordia varying dependent upon temperature. Low temperatures resulted in sensitivity to extension light source, delaying FI and FBD. In Royes, failure to initiate under low temperatures was associated with small plant size (≤3.5 g shoot dry weight). High temperatures tended to negate the delaying effects of extension light source, but resulted in photoperiod sensitivity, delaying FI in the early-flowering lines QPL-2 and Prabhat. Under high temperatures, Royes was insensitive (FI and FBD) to extensions containing incandescent light (I, I+F). Under high temperatures, time of flowering was least affected by incandescent extensions (I, I+F), and most by F-extension, which delayed FBD in all lines. Under low temperatures, I+F extensions resulted in the greatest variation in flowering time.It was concluded that where heterogeneity exists in floral response to the intensity and/or quality of light, use of artificial lighting to select for photoperiod sensitivity may lead to misclassification.     

The Effect of Photoperiod on Tuberisation in Cultivated × Wild Potato Species Hybrids

Wild Solanum species offer a valuable source of genetic diversity for potato improvement. Most of these species are found in equatorial South and Central America and they do not tuberise under long-day photoperiods typical of those in the major potato production areas of North America, Europe and Asia. Crosses between two haploids of Solanum tuberosum Chilotanum Group as females and two wild Solanum species clones generated four hybrid families. The parents and progeny were subjected to two greenhouse trials to evaluate tuberisation at 20-, 14-, and 8-h photoperiods. Parents and offspring tuberised most readily at the 8-h photoperiod, and poorly or not at all at the 20-h photoperiod. Segregation for tuberisation in hybrids was apparent at the 14-h photoperiod and depended on the cultivated parent, but not the wild species parent. The data support previous studies and best fit a model in which tuber production under long photoperiods is controlled by two dominant genes in cultivated × wild species hybrids.     

Effects of photoperiod on kinetin-induced tuberization of isolated potato stolons culturedin vitro

Are short-day (SD) conditions inductive or permissive for potato tuberization? This question was addressed using anin vitro culture system. Kinetin induction ofin vitro tuberization in potato stolons cultured in the dark can be partially inhibited by light treatments. Photoperiod required for a major inhibition varied with cultivars: 8 hours for cv. Red Pontiac and 16 hours for cv. Kennebec. Short photoperiods decreased kinetininduced tuberization for all cultivars. Stolons cultured on kinetin-free medium generally did not tuberize, regardless of light treatment. Effects of kinetin and photoperiod on stolon and tuber development are observed. Relationships among kinetin, photoperiod and tuber-inducing stimulus produced under short days are discussed.     

光周期对光敏核不育水稻小孢子发生和花粉发育的超微结构的影响

 以光敏核不育水稻农垦58S为材料，在杭州中国水稻研究所人工气候箱(Koitotron S-153W )群中进行光周期处理。自秧苗6叶期开始，先经10 h／d的短日照处理10 d 到幼穗开始分化，然后分别在13.14 h／d的光周期条件下发育。通过透射电镜观察探索光周期在决定花粉育性中的作用。结果发现，在13 h／d光周期条件，花粉发育正常，而在14h／d的光周期条件下，花粉在单核晚期败育，表现在核糖体呈聚合状态，内质网、质体、线粒体等细胞器逐渐解体，缺乏淀粉积累，吞噬泡增多，细胞质稀薄，最终变成不育。另一方面，绒毡层细胞保持完整状态，无解体迹象。     

The host range ofSpongospora subterranea f. sp.subterranea in the United States

This study was performed to determine the host range ofSpongospora subterranea f. sp.subterranea on common crops and weeds in the northeastern United States. Seedlings of the plants were grown in nutrient solutions and inoculated with spore balls ofS. subterranea. The roots were microscopically examined for the presence of plasmodia or zoosporangia 14 days after inoculation. The plants were then transferred to a greenhouse and grown in a soilless mix. The roots were examined for the presence of symptoms and spore balls after 4 months. Of 26 species within 10 families from monocotyledons and dicotyledons tested, 16 species were found to be susceptible toS. subterranea. Twelve species were newly recorded hosts forS. subterranea. Gall symptoms were observed on the roots of six species and spore balls were found on three species. Evidence is presented for the first time that galls and spore balls ofS. subterranea might form on non-Solanaceous species. This investigation is important for the cultural management of potato powdery scab disease because there currently are no effective controls.     

Effects of photoperiod,night temperature,and irradiance on flower production in the potato

Summary The influence of three environmental factors on the incidence of arrested floral development (bud abortion) in different potato clones was studied. The first experiment measured flower production in growth chambers when a 12-h photoperiod was extended by 4 h dim light. The second experiment, also in growth chambers, contrasted flower production under night temperatures of 10°C and 20°C (day temperature 30°C, photoperiod 12 h). A third experiment examined bud abortion in plants grown in the greenhouse under shade cloths which reduced incoming irradiance to ca. 50% of normal. Both the longer photoperiod and warmer night temperature promoted flower production, in some of the clones tested, by reducing bud abortion. Reduced irradiance completely suppressed flower development (but not bud formation) in all clones. In all experiments, the number of flowers developing to anthesis was significantly correlated with shoot dry weight, indicating that treatments which promote shoot growth reduce the incidence of bud abortion. Paper No. 854, Department of Vegetable Crops, Cornell University.     

Growth analyses of eleven potato cultivars grown in the greenhouse under long photoperiods with and without heat stress

Six potato cultivars from North America were grown in two greenhouses under 18-h photoperiods. All plants were started in a greenhouse that was well ventilated and maintained as close as possible to summer ambient temperatures. One month after planting, half the plants of each cultivar were moved to a greenhouse that was kept at 30 C during the night and was allowed to reach 40 C or higher during the day. Plants from each treatment were harvested at monthly intervals for growth analyses. Concurrently, five clones considered to be heat tolerant were subjected to a similar test in a second experiment. In response to high temperatures, plants in both experiments were taller with smaller leaves, lower tuber yields, higher ratios of stem to leaf dry matter, and lower ratios of tuber to leaf and to stem dry matter. Tubers were lower in percent dry matter, maturity was delayed, and cuttings developed fewer tubers. Cultivars differed greatly in the degree to which they were affected by the heat. In the first experiment, Norchip had outstanding heat tolerance. LT-2 was the most tolerant of the clones in the second experiment. For the cooler treatment the best performance in either experiment was from two clones originally selected in the lowland tropics.     

光周期对青饲玉米养分吸收及利用的影响

通过3个对光周期不同敏感型的玉米品种进行光周期试验,研究了光周期对玉米的营养生长及其N、P、K养分吸收及利用率的变化。结果表明,光周期对敏感型青饲玉米品种华农1号的地上部营养生长、根系生长和养分吸收有显著的调控作用,而对相对不敏感型的青饲玉米品种粤农9号的调控作用则不显著。华农1号在长日照条件下根干物重较短日照条件下增幅为390.38 %,光周期相对敏感型品种大暑麦的增幅为119.34 %,粤农9号的增幅为45.47 %;华农1号与粤农9号吸收的N总量分别增加了42.42 %和12.38 %,吸收P总量分别增加了171.76 %和12.23 %,吸收的K总量分别增加了319.27 %和62.42 %。试验结果还表明,随着光照时数的延长,光周期敏感型品种在长日照条件下的N养分利用率提高了,而P、K养分利用率却与光周期敏感特性无显著直接关系。     

Effect of photoperiod on tuberization in the Livingstone potato (Plectranthus esculentus N.E.Br. Lamiaceae)

The Livingstone potato (Plectranthus esculentus N.E.Br.) produces a cluster of edible tubers at the base of the stem that are used as a potato substitute in many areas of Africa. No information is available on factors affecting tuberization in this species. Photoperiod is known to influence storage organ formation in a wide range of crops, and pilot trials indicated that it also played a role in tuberization in P. esculentus. The critical photoperiod for tuber induction, as well as the number of short-day cycles required to induce tubers, were investigated in glasshouse trials using in vitro plants. Nine photoperiod treatments (30-min intervals from 10 to 14 h of light) were applied in the critical photoperiod experiment. To determine the number of short-day cycles required to induce tuberization, plants were exposed to short days (10 h light) for periods ranging from 0 to 20 days at 2-day intervals. Data were collected from both intact plants and sub-apical two-node cuttings made after the experimental treatments were completed. The critical photoperiod for the specific genotype used in this study was between 12.5 and 13 h, with cuttings giving a slightly exaggerated result over that of intact plants. It was established that exposure to four short-day cycles was sufficient to induce tuberization in this species.     

Geographic Variation of Diapause and Sensitive Stages of Photoperiodic Response in Laodelphax striatellus Fallén (Hemiptera: Delphacidae)

Large numbers of the small brown planthopper Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) occur in temperate regions, causing severe losses in rice, wheat, and other economically important crops. The planthoppers enter diapause in the third- or fourth-instar nymph stage, induced by short photoperiods and low temperatures. To investigate the geographic variation in L. striatellus diapause, we compared the incidence of nymphal diapause under various constant temperature (20 and 27°C) and a photoperiod of 4:20, 8:16, 10:14, 12:12, 14:10, and 16:8 (L:D) h regimes among three populations collected from Hanoi (21.02° N, 105.85° E, northern Vietnam), Jiangyan (32.51° N, 120.15° E, eastern China), and Changchun (43.89° N, 125.32° E, north-eastern China). Our results indicated that there were significant geographic variations in the diapause of L. striatellus. When the original latitude of the populations increased, higher diapause incidence and longer critical photoperiod (CP) were exhibited. The CPs of the Jiangyan and Changchun populations were ∼12 hr 30 min and 13 hr at 20°C, and 11 hr and 11 hr 20 min at 27°C, respectively. The second- and third-instar nymphs were at the stage most sensitive to the photoperiod. However, when the fourth- and fifth-instar nymphs were transferred to a long photoperiod, the diapause-inducing effect of the short photoperiod on young instars was almost reversed. The considerable geographic variations in the nymphal diapause of L. striatellus reflect their adaptation in response to a variable environment and provide insights to develop effective pest management strategies.     

光照对木薯单爪螨发育与繁殖的影响

为探讨木薯单爪螨的生态适应性机理,揭示其种群扩散蔓延机制,进行了不同光照对木薯单爪螨生长发育及繁殖的影响研究.结果表明,木薯单爪螨需要光照时间长于10h才可正常完成发育与繁殖,其中12～14h为木薯单爪螨发育与繁殖的适宜光照时长.光照主要通过影响卵和前若螨的发育历期影响木薯单爪螨总发育历期,对幼螨和后若螨的发育历期无显著影响.随着光照时间的延长,木薯单爪螨总发育历期呈逐渐缩短趋势.光照时间为12h和14h时,后代卵孵化率可达100％,光照小于1Oh木薯单爪螨后代卵的孵化率显著降低,成螨寿命显著缩短;随光照时间从6h延长至14h,木薯单爪螨平均每雌产卵量逐渐增加,随后开始缓慢降低.光照对木薯单爪螨后代性比无显著影响.     

泉花系列花生品种高产性状及生理特性研究

试验对泉花系列花生新品种的高产性状及生理特性等进行了研究。结果表明,供试的花生新品种均表现分枝多、结荚多、出仁率较高、单株生产力高等优良特性。泉花系列品种还表现花多且集中在花前期,叶面积系数和光合势大,叶绿素含量较高,干物质累积较快较多,叶片过氧化物酶活性和根系活力强等优良生理特性。高产育种上应把分枝多、果多、果饱、出仁率高等性状作为单株选择的主要指标。