Progeny from the crosses of two antisense potato plants exhibit ectopic xylem differentiation

Progeny from the crosses of two transgenic potato lines csr2-1 and csr4-8, containing two different antisense constructs, csr2 and csr4 had been previously characterized to exhibit altered tuber production. Histochemical staining and microscopic examinations of the tubers were made to investigate cellular phenotype in the tubers. We observed ectopic proliferation of xylem, which is most pronounced in the csr2 tubers. Light microscopy of csr2 tubers revealed that the proliferation of xylem was associated with lignification of their cell walls. This paper provides evidence of cellular phenotype as a consequence of the presence of the antisense construct

Comparison of production systems for potato (Solanum tuberosum L.) minituber production with different cultivars : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science in Nursery Production

The purpose of these studies is to determine the effect of different production systems (Aeroponic (AP), Deep flow (DF), Nutrition film technique (NFT) and Bark) on production of first generation (prebasic) potato (Solanum tuberosum L.) minitubers with different cultivars (Russet Burbank, Rua, Kenebec, Atlantic and Diésrée). Prebasic tubers usually multiplied in a greenhouse in a bark medium. Replacing the bark based system by a highly intensive aeroponic system is viable. The aeroponic system significantly produced higher tuber numbers per plant and produced a higher percentage (82%) of 1 -2g size tuber than other systems evaluated. In aeroponic and deep flow systems, the time to tuberization is higher. When tuberization is delayed, stolons grow continuously in the deep flow and aeroponic systems. In hydroponic systems a developing stolons did not encounter sufficient mechanical resistance to limit growth, they grew extremely vigorously and very wide of diameter (1.92- 2.42 mm). When roots and stolons filled the aeroponic and deep flow containers some root rustication occurred then tubers were initiated. Acid treatment efficiently synchronised tuberization in the aeroponic systems, tubers were visible four days after acid treatment. Optimum acid treatment depends on the specific cultivar or stage of stolon development. Rua produced the highest yield per plant and highest tuber number per plant. The pH and treatment time significantly affected the tuber number per plant. Acid treatment at pH 3.5 produced the highest tuber number (19.8) per plant. Minitubers show a dormant period immediately after they are harvested. Application of GA is a useful method to break minituber dormancy. Fifty percentage of the GA treated tubers sprouted within 20 days after treatment, while untreated control took 37 days. Overall, sprouting was highest for 100 ppm treatment, but was not significantly different from 30 ppm. The highest and lowest sprouting cultivars were Russet Burbank and Atlantic respectively. Potato cuttings can be propagated in an aeroponic system. Application of IBA treatment at 0.1 to 0.3% significantly induced root formation and root growth. About 80% of the IBA treated cuttings rooted and produced longer roots than untreated cuttings. From these studies we found the aeroponic system to be suitable for minituber production as well as the propagation of potato cuttings. Production of high tuber number per plant in aeroponic systems will reduced the production cost and reduce the number of field multiplications required before final cropping

RESPONSE OF POTATO TO HEAT STRESS AND STRATEGIC METHODS TO COPE WITH IT

Because of its importance in the human diet, potato growth and development have received considerable scientific attention, especially the regulation of tuber development. The trend of potato production has been toward greater acreage in warm climates using cultivars that were developed for production in cool climates. However, low land tropical regions are characterized by high temperatures that limit successful potato cultivation. High temperatures in potato promote haulm growth and suppress tuber production, whereas disbudding and paclobutrazol have the opposite effect, promoting tuber production and reducing the growth of the haulms by inhibiting GA biosynthesis which was increased by high temperature. In addition, the germplasm base for potato is large and assessments of germplasm performance under challenging conditions have revealed new possibilities

Will the Three Gorges Dam affect the underwater light climate of Vallisneria spiralis L. and food habitat of Siberian crane in Poyang Lake?

Almost 95% of the entire population of the Siberian crane (Grus leucogeranus) winter in Poyang Lake, China, where they forage on the tubers of the submerged aquatic macrophyte Vallisneria spiralis. The Three Gorges Dam on the Yangtze River may possibly affect this food source of the Siberian crane by affecting the light intensity reaching the top of the V. spiralis canopy. In this study, the photosynthetically active radiation at the top of the V. spiralis canopy (PARtc) in Lake Dahuchi was modeled from 1998 to 2006, and the potential impacts of changes in water level and turbidity on the underwater light climate of V. spiralis were analyzed. PARtc was calculated from incident irradiance while the losses due to reflection at the water surface, absorption, and scattering within the water column were taken into consideration. The results indicated significant differences in PARtc between years. Six years of water level and Secchi disk depth records revealed a seasonal switching of the lake from a turbid state at low water levels in autumn, winter, and spring to a clear state at high water levels during the monsoon in summer. The highest PARtc occurred at intermediate water levels, which were reached when the Yangtze River forces Lake Dahuchi out of its turbid state in early summer and the water becomes clear. The intended operation of the Three Gorges Dam, which will increase water levels in May and June, may advance the moment when Lake Dahuchi switches from turbid to clear. We suggest that this might increase production of V. spiralis and possibly improve the food habitat conditions for wintering Siberian crane in Poyang Lake

Seed yam tuber production from vine cuttings

Seed yam tuber production accounts for 30 per cent to 50 per cent of total cost of production. Efforts to obtain seed yam tubers from vine cuttings are still rudimentary, and research information available is scanty and sparse. Studies to compare the effectiveness of vine cuttings for seed yam tuber production were conducted in 2010 at International Institute of Tropical Agriculture, Ibadan, Nigeria, with a clone of Dioscorea rotundata (white yam) TDr 95/18544. Vine cuttings (VCs), with one node, one leaf, and 10 – 15 cm long were cut from the middle portion of the stems of 90-days old mother plants. Healthy VCs were planted singly in a rooting medium, and the rooted VCs were transplanted to the field at 40 days after planting, and harvested 110 days after transplanting when the leaves had senesced. Screenhouse-derived plants (SDP) originated from tissue culture have a higher survival percentage than cuttings from field-derived plants (FDP). Higher shoot formation was also observed in SDP whilst no shoot from FDP. Mean yield of tubercles from SDP was 8.5 times higher (P = 0.05) than yield from FDP. The mean percentage change in the yield of tubercles obtained from the cut mother plants and the uncut mother plants was 16 times more in SDP than FDP. Production of healthy seed yam tuber is possible using healthy mother plants for vine cuttings

Environmental and cultural considerations for growth of potatoes in CELSS

The white potato (Solanum tuberosum) was evaluated for use in the Closed Ecology Life Support System (CELSS) because of its high ratio of edible to inedible biomass and highly nutritious tuber that consists of readily digestible carbohydrates and proteins. Results are given for conditions that will produce the highest yields. The results, given in tabluar form, indicate the optimum temperatures, irradiance, carbon dioxide concentration, root environment, plant spacing, root and stolen containment, and harvesting times

Effect of pot size, planting date and genotype on minituber production of Marfona potato cultivar

This study was carried out to evaluate the effects of pot size, planting date and type of genotype on mini-tuber production of Marfona potato cultivar (Solanum tuberosum L.) in greenhouse conditions.Four genotypes (M-129, M-128P, M-127P and M-124P) originated from virus free sprouts and a genotype of the same cultivar (Marfona) originated from apical meristem, in 3 sizes of pot and 3 planting datewere investigated. The results showed that using larger pots of 3-liter has no advantage and pots smaller than 2-liter is not suitable for mini-tuber production. Also, time of Nov 18 was the best of datefor planting of potato in studied conditions and delay in date of planting reduced the mini-tuber production. The reduction in number of mini-tubers and growing period was greater for the genotype M-129 compared with the other potato genotypes. Furthermore, higher numbers of mini-tubers were produced by the M-127P and M-124P genotypes and M-127P had the highest total weight of mini-tubers.However the number of mini-tubers per plant was higher for genotypes originated from meristem culture than genotypes obtained from sprouts. It seems that genotypes originated from potato sprouts are not as efficient as the apical meristem ones. On the other hand, later genotype showed more homogenous in growth rate and phenotype

Controlled environment life support system: Growth studies with potatoes

Results of experiments conducted to maximize the productivity of potatoes grown under controlled environmental conditions are discussed. A variety of parameters is examined which affect potato growth, specifically, photoperiod, light intensity, temperature, nitrogen nutrition, carbon dioxide concentration and culture techniques. These experiments were conducted using five different cultivars, Russet Burbank, Norchip, Superior, Kennebec and Norland. To achieve high productivity, three specific objectives were explored: (1) to develop effective cultural procedures, (2) to determine the most effective photoperiod and (3) to develop a mist culture system. It is felt that the productivity obtained in this study is below the maximum that can be obtained. High irradiance levels coupled with tuber-promoting conditions such as cooler temperatures, increased CO2 levels and lowered nitrogen concentrations should allow increases in tuber production. Tuberization appears to be accelerated by short daylengths although final yields are not increased. Mist culture techniques have not yet produced fully developed tubers. The use of supporting media and alteration of the nitrogen content of the mist solution are being explored as a way to allow tubers to develop to maturity

Comparative Analysis of the Impact of World Bank Root and Tuber Expansion Programme on Poverty Alleviation of Peri-Urban and Rural Communities in Benue State, Nigeria

This study examined in 2005 t he impact of World Bank Expanded Programme for Root and Tuber Production (RTEP) on the poverty alleviation of peri-urban and rural communities in Benue State, Nigeria. It aimed at delineating causal effect disparity in poverty alleviation of two major producer communities. Data were collected from two hundred and eight (208) respondent s randomly drawn from ten (10) typically rural and ten (10) peri-urban communities. Simple descriptive statistics (percentages) and discriminant function analysis were used to analyze the collected data. The discriminant function was fitted on the poverty alleviation score to analyze causal and effect relationship. The study found disparities in valued output, quality of life, income and a homogeneous non-significant age disparity in both rural and peri-urban root and tuber crops producer communities. Major contributors to t he poverty alleviation were: Income realized from market able surplus (X3), distance in kilometers to the nearest urban market of best sales (X1), the kilometer distance traveled to evacuate produce (X2), with 5 5%, 15% and 10% contributions respectively in that sequence to the tot al discriminant score(Z) of 87%. Other contributory indicators were average revenue receipt per unit of root and tuber in the best market (X4), quality of life score (X5) and mobility score (X6). The study recommends that developing nations should re-focus their policy framework to provide better markets and marketing opportunities as well as improved transportation and communication infrastructures for the typically rural to accelerate poverty alleviation.World Bank, Poverty Reduction programme valued output, Discriminant Function, Crop Production/Industries, Food Security and Poverty,