Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. III. Influence of viral infection on field plants and new technology of clone selection of virus-free planting potato

At the end of potato plants vegetation virus in-fection induced both decrease in maximum amplitude of delayed fluorescence maximal amplitude and increase half time of its decrease, as well as reduction in the amount of stems, plants’ height and assimilation area surface, yield, acceleration of plants development and their early die-off. The differences of DF pa-rameters and yields between strongly and weakly infected plants increase in case of a combined virus infection. In industrial test of the selection of virus-free planting potato by the use of DF parameter, a rise in the yield and de-crease degree of viral infection of crops was obtained.

Effects of Planting Density on Yield and Sourcesink Characteristics of Sweet Potato[Ipomoea batatas(L.) Lam]

[Objective] The aim was to resolve the issue of sparsely planting （37 500-40 500 plants/hm2） of sweet potato in hilly areas. [Method] The starch-oriented Jishu No.21 and raw-eating oriented Jishu No.22 were studied to explore effects of planting density on yield and sink and source characteristics of sweet potato. [IRe- suit] Leaf area index of Jishu No.21 and Jishu No.22 were increasing upon planting density. Leaf area index of the same planting density showed a single-peak curve. Specifically, leaf area index grew fast during the 40th-80th d after planting, and reached the peak on the 80th d after planting, followed by decreasing. What＇s more, ventilation and sunshine transmission both declined upon planting density, as well as the number of leaf, the number of branch, the length of vine, dry and fresh weights of stem and leaf. When planting density exceeded 75 000 plants/hm2, the yield of sweet potato dropped dramatically. Besides, the optimal planting density tended to be volatile upon cultivars. For example, the range of 45 000-60 000 plants/hm2 is the optimal planting density of Jishu No.21 and the range of 60 000-75 000 plants/hm2 is the optimal planting density of Jishu No.22. [Conclusion] It can be concluded that rational planting densities would well coordinate sweet potato growth of ground parts and underground parts to get a high yield by providing a rational group structure. Considering the optimal planting density differs upon cultivars, it is necessary to take genotype, environment, soil fertility and planting density into consideration in determining planting density.

Construction of Efficient Multiple Planting Patterns of Potato for Tridimensional Climate in Subtropical Region of China

[Objective] The aim was to make full use of light-heat resources to expand the potato planting area on the base of ensuring the production of main grain crops and the limited arable land. [Methods] Through catch crops, multiple cropping and intercropping, new multiple planting patterns of potato with efficiency are constructed, for the purpose of increasing yield and benefit of potato. [Result] In irrigated plain and hill area, three new planting patterns such as autumn potato/rope-rice,winter potato-rice-autumn potato, and autumn（winter） potato-rice were constructed.In dry land of plain and hill area, three new planting patterns such as spring（winter）potato/maize/sweet potato, spring（winter） potato/maize-autumn potato, and wheat ＋ winter potato/maize/sweet potato were constructed. In plateau mountainous area, spring potato/maize was constructed. [Conclusion] With use of new planting patterns, the cropping index of new patterns was 200%-300%, while the accumulated temperature utilization was 68.9%-93.4%, light energy utilization was 0.98%-1.59% and straw utilization was 50%-100%. To compared with traditional planting patterns, the yield increased by 2.6%-93%, and benefit increased by 15.8%-284.3%. Furthermore,multiple planting patterns of potato have become main planting patterns in increasing yield and income in Sichuan.

Standardized Production Technology of Virus-free Seed Potato

The research reviewed standardized production technology of virus-free seed potato, including stem tip isolation, tissue culture seedling production, breeder＇s seed and protospecies production, and standard potato tubers＇ production, and concluded a set of standardized production technology for virus-free seed potato, in order to provide theoretical references for improving potato yield.

Planting Adaptability of Four Kinds of Common Vegetabless in Shanghai

[Objectives]To explore the planting adaptability of vegetables in Shanghai.[Methods]In this paper,cowpea(Vigna unguiculate(L.)Walp.),cucumber(Cucumis sativus L.),eggplant(Solanum melongena L.)and potato(Solanum tuberosum L.)were selected as experimental materials and planted in the open air.The growth status,the occurrence of diseases and insect pests,and the taste evaluation of these four kinds of common vegetables were mainly studied.[Results]The results showed that the four kinds of common vegetables in Shanghai had strong growth,strong adaptability,less pests and diseases,and good taste.[Conclusions]The cowpea,cucumber,eggplant,and potato are suitable for planting in Shanghai.

Large-ridge Mechanized Planting Technology of Potato in Hailar District of Hulunbeier City

The mechanized large-ridge production technology of potato was summarized,including preparation before sowing,deep tillage and land preparation,deep application of chemical fertilizer,sowing,intertillage,disease and pest control,harvesting and other related contents.The comparative experimental study of large ridge and small ridge modes focused on the effects of ridge spacing on soil bulk density,temperature,water retention,crop growth and yield.The technology has the advantages of time saving,labor saving,seed saving,and fertilizer saving.It can significantly improve production efficiency,and is a high-yield and high-efficiency planting mode that increases potato yield.This model can increase yield by 370 kg/hm 2 and improve income by 160 yuan/hm 2.The results of this study have greatly promoted the promotion and application of mechanized largo-ridge potato planting technology.

Effects of different planting systems on yield of potato crop in Kaghan Valley: A mountainous region of Pakistan

Conversion of potato from conventional methods to wide bed planting systems may increase water and nitrogen use efficiency in commercial potato production system by reducing the amount of irrigation water and water applied nitrogen fertilizer bypassing the potato root zone. Potato (Solanum tuberosum L) cv. Desiree was tested against different planting system for yield and yield components at Kaghan, a high mountainous Himalayan region ofPakistan. The experiment was carried out at Himalayan Agricultural Research Station (HARS), Kaghan during the summer season of 2005. The results showed that maximum tuber growth (88.7%), number of stems per plant (3.5), plant expansion (45.5 cm), average number of tubers per plant (10.1) and yield per hectare (12.4 t/ha) were significantly different and higher when potatoes were planted on wide bed and covered with soil from one side. Tallest plants (53.4 cm) were observed when potatoes were sown on the ridges. Maximum number of green potatoes (12.5) and injured potatoes (5.3%) were observed when the tubers were planted following local farmers’ method. Keeping in view the soil type, land slopping, we recommend sowing potatoes on relatively plain wide beds and covering it with soil from one side, for potato cultivation in the area.

Ecological Suitability Evaluation and Planting Division of Potato in County Based on GIS——A Case Study of Shangnan County of Shaanxi Province

Potato is one of the important food crops in Shangnan County,Shaanxi Province.Potato planting strategy in this region has great significance for potato planting,according to local conditions and for optimizing regional layout.The ecological suitability of potato cultivation in Shangnan County was evaluated by using geographic information system(GIS)technology,county cultivated land resource management information system and analytic hierarchy process(AHP).The evaluation index system of ecological suitability of potatoes in Shangnan County was established by screening the evaluation index of each ecological factor with expert experience method.The AHP and fuzzy evaluation method were applied to the quantitative calculation of the weight of each index.The ecological suitability assessment map of potato planting in Shangnan County was obtained by using the overlay analysis function of ArcGIS 10.2.The results showed that highly suitable area for potato cultivation was 6974.04 hm^2,accounting for 28.07%of the cultivated land.The suitable area was 11205.75 hm^2,accounting for 45.10%of the cultivated land area.These two types of arable land mainly distributed in the shallow hilly area,the middle mountain landform and the river valley area.The remaining arable land in this region mainly distributed in the shallow hills and the mid-mountain landscapes,including the arable land which was reluctantly suitable for potato cultivation and unsuitable for potato cultivation,with 5646.15 and 1022.33 hm^2,respectively,accounting for only 22.72%and 4.11%of the total arable land areas.Therefore,based on the statistics and analyses of potato planting environment in Shangnan County,the pattern of local ecological adaptability distribution was summarized and the spatial distribution map was drawn,thus providing scientific basis for rational distribution and planning of potato in Shangnan County.

Modeling the Effect of Planting Dates and Nitrogen Application Rates on Potatoes Water Productivity in Jordan Valley

Agricultural sector in Jordan is facing serious challenges in meeting the growing needs of food security because of its low water availability. Maintaining and enhancing agricultural water productivity under such prevailing environmental constraints are hard to achieve. Potatoes water productively in Jordan Valley was modeled using Decision Support System for Agrotechnology Transfer (DSSAT) under six nitrogen applications (0, 60, 80, 100, 120 and 140 kg/ha) and twelve planting dates every two weeks from October 1 to March 15 scenarios. The potatoes yield increased from 0% to 100% nitrogen treatment and then no considerable increase occurred. The potatoes’ crop yield increased from October 1st to January 15 and then decreased after which until the last day of planting date. The seasonal cumulative crop evapotranspiration for potatoes about doubled from 0% to 60% nitrogen treatment and then kept increasing gradually until the last treatment. The growing season cumulative crop evapotranspiration for potatoes increased gradually from October 1 to March 1. The water productivity increased from 0% nitrogen treatment to 100% and then decreased. The potatoes’ water productivity increased from October 1 until November 15 and then decreased to the end. From these results, we recommend that 100% of nitrogen requirements should be applied. The best window for potatoes’ planting date is the last two weeks in November.

Study on Virus-free Breeding Technology of Potato Microtuber

It is the simplest,fastest and effective way to improve the yield level of potato by selecting high quality virus-free seed potato for field production and maintaining the original characters of virus-free minituber. Microtuber is featured by small volume,no pathogen,convenient storage and transportation,which can be induced in summer with high temperature and humidity,and overcome a series of problems such as poor survival rate of transplanted test-tube plantlets,and easy pollution of cutting tips. Therefore,it can replace conventional test-tube plantlets directly for reproduction. Meantime,if minitubers are sown ahead of time using cold frame,the growth stage of potato minituber will avoid the occurrence period of aphids. The use of gauze cover for insect prevention has good effect on maintaining the excellent characters of microtuber. The yield and quality of virus-free potato are greatly improved by means of virus-free culture of shoot tip seedlings,subculture propagation of virus-free seedlings,induction of microtubers by dark culture,cultivation of breeder’s seeds in greenhouse and screenhouse to preserve the characters of potato.

Difference between Responses of Potato Plant Height to Corrected FAO-56-recommended Crop Coefficient and Measured Crop Coefficient

This study was conducted to establish a simple convenient method for calculating crop coefficient, and provide a certain basis for the research of the empirical formula for calculating crop coefficient with plant height which could be measured conveniently with regional differences, especially for the establishment of accurate irrigation schedule of potato in Yunnan. By the field experiment on potato under the condition of drip irrigation, it was found that the models of plant height with corrected FAO-56-recommended K and measured K were a quartic polynomial and a cubic polynomial, respectively, and the polynomial of potato plant height with measured crop coefficient was simpler with higher degree of fitting; and the differences between the period with the highest change rate of potato plant height and the periods with the greatest FAO-56-recommended K and measured K exhibited a differences of 3 d. In conclusion： In the future study of simple or empirical formula calculation of crop coefficient, plant height should be considered as a main dependent variable in that the calculation result would be closer to the measured crop coefficient with the problem of regional difference existing in the FAO method solved and the formula might be simpler; and the irrigation time of potato should be 3 d earlier than the irrigation time determined according to the corrected FAO-56-recommended crop coefficient, especially in the key water requirement stages of potato.

Effects of Plant Growth Regulators on the Contents of Reducing Sugar and Starch in Potato(Solanum tuberosum L.)

[Objective] The aim was to investigate the effects of plant growth regulators on contents of reducing sugar and starch in potato（Solanum tuberosum L.）.[Method]A potato cultivar named ＇Holand-212＇ with three treatments by spraying Diethyl aminoethyl hexanoate（DTA-6）,Uniconazole（S3307）and SOD mimics（SODM）were employed to compare differences of the contents of reducing sugar and starch in potato leaves,stolons and tubers in a field experiment.[Result]DTA-6 treatment could significantly reduce the contents of starch and reducing sugar in potato stolons in the period of 100-110 d after seeding,and it could also reduce the content of reducing sugar in tubers,but there is an opposite result in leaves in the same period,significantly.S3307 could extremely significantly increase the content of starch,and can promote the transfer of starch in stolons,in addition,it also could reduce the content of reducing sugar in tubers,and extremely significantly increase the content of starch in leaves at the 110 d after sowing.Moreover,there is a similar effect between SODM and S3307.[Conclusion]The research results are significant for understanding mechanisms of plant growth regulators and promoting application of plant growth regulator in potato.

Plant Regeneration of Sweet Potato via Somatic Embryogenesis from Different Explants

[Objective] This study aimed to regenerate plants of sweet potato (Ipomoea batatas) cultivar Xushu22 via somatic embryogenesis, using leaf and shoot apex as explants. [Method] The leaf and shoot apex of Xushu 22 were separately cultured on MSB medium and MSD medium. The induced embryogenic calluses were then cultured on MS medium. The regeneration frequency of leaf and shoot apex explants were respectively calculated. [Result] The average frequency of leaf explants developing somatic callus was 95.69% compared to 30.56% in case of shoot apex explants. There were different types of morphogenic structures in the process of somatic embryo development. Leaf explants gave a high regeneration frequency to 60.61%, while the regeneration frequency of shoot apices was 22%. In addition, no morphological variations were observed in the regeneration plants. [Conclusion] Leaf explant was better than shoot apices in plant regeneration of Xushu22 via somatic embryogenesis.

Mapping QTL underlying tuber starch content and plant maturity in tetraploid potato

Tuber starch content and plant maturity are two important agronomic traits of potato. To investigate the complex genetic basis of these traits in the cultivated potato, as well as the relationship between them, we developed a linkage map in a tetraploid population of 192 clones derived from the cross Longshu 8 × Zaodabai and mapped quantitative trait loci(QTL) for tuber starch content and plant maturity using data collected in three diverse environments over two years. We detected eleven QTL for tuber starch content distributed on seven chromosomes, of which four, on chromosomes I, II, and VIII, were expressed in at least three environments. For plant maturity, we identified six QTL on chromosomes II, IV,V, VII, and XI, one of which, on chromosome V, showed LOD peaks ranging from 45.2 to 62.5 cM and explained 21.6%–26.6% of phenotypic variation was expressed in five of the six environments. Because the reproducible QTL for plant maturity and tuber starch content mapped to different chromosomes and neither overlapping QTL, nor any genetic interaction between QTL were detected, we infer that tuber starch content and plant maturity are controlled by independent genetic loci. This inference supports the prospect of breeding potato for both early maturity and high starch content.

Botanicals and plant strengtheners for potato and tomato cultivation in Africa

This review provides a summary of botanicals and plant strengtheners that have potential uses for disease and pest management in potato and tomato cultivation in African.We discuss their possible use to prevent major diseases and pests which infest potato and tomato,such as early and late blight,bacterial wilt,potato tuber moth,and tomato leafminer.There are several examples of the successful uses of botanicals for pathogen and pest control relevant for different African climatic conditions;however,most of these studies have been conducted in vitro and often lack field verification.Plant strengtheners(substances that induce and improve crop resistance,yield,and quality)are little studied and used in Africa in comparison to North America and Europe.The possible benefits of using botanicals and plant strengtheners instead of conventional pesticides are discussed here in relation to human health and the environment as well as their modes of action and accessibility to farmers.Lack of knowledge of the composition and active ingredients of extracts,environmental concerns,uncertainties regarding stability and formulation,lack of legislation and limited support from governments,hamper the development of botanicals and plant strengtheners for use in sustainable African agriculture.

Impact of Plant Density on the Formation of Potato Mimitubers Derived from Microtubers and Tip-Cuttings in Plastic Houses

The potato minitubers have been widely used for the elite seed propagation to improve the seed potato system in China. However, little information is available for an efficient production of the minitubers with high plant density in the protected growing conditions like plastic houses. In present research, the minitubers of a wide-grown potato variety, Favorita, were produced with the microtubers from tissue culture and the tip-cuttings of the microtuber plants. Three plant densities, 200, 400 and 600 microtubers or plants m-2 were set up with the randomized block design of 3 replications and the experiment was repeated in 4 seasons in 2009-2010. The canopy development, light interception, dry weight production and partitioning, tuberization and tuber weight were investigated to elucidate the mechanism by which the plant density affects the formation and growth of the minitubers. The results showed that the number of the tubers formed per unite area was in line with the increase in plant density. The difference in leaf area index （LAI） between the plant densities, especially in early stage of the plant growth, resulted in more radiation interception and dry weight producing in higher plant density than in lower one. However, our analysis demonstrated that the conversion coefficient of the cumulative intercepted radiation to plant weight and the dry weight partition rate to the tubers were constant between plant densities, suggesting that less amount of the photoassimilates partitioned to individual tubers is causal for more small tubers in high plant density. A negative exponential curve model, determined by total number of tubers produced per unit area and the mean tuber weight, fitted well to the tuber size distribution pattern. The optimum plant density could be estimated from this model for a maximum production of the minitubers with desired size.

Transcriptome analysis reveals effects of red and blue lightemitting diodes(LEDs)on the growth,chlorophyll fluorescence and endogenous plant hormones of potato(Solanum tuberosum L.)plantlets cultured in vitro

Red and blue light illumination has been reported to significantly affect plantlet growth.Potato is an important food and feed crop in the world and potato plantlet cultured in vitro plays an important role in potato production.However,few studies have documented the effects of red and blue light on the growth of potato plantlets revealed at the transcriptome level.The objective of this study was to determine the growth and physiological responses of potato plantlets cultured in vitro under monochromatic red(RR),monochromatic blue(BB)as well as combined red and blue(RB)LEDs using the RNA-Seq technique.In total,3150 and 814 differentially expressed genes(DEGs)were detected in potato plantlets under RR and BB,respectively,compared to RB(used as control).Compared to the control,the DEGs enriched in"photosynthesis"and"photosynthesis-antenna proteins"metabolic pathways were up-regulated and down-regulated by BB and RR,respectively,which might be responsible for the increases and decreases of maximum quantum yield(F_(v)/F_(m)),photochemical quantum yield(φ_(PSII)),photochemical quenching(q_(P))and electron transfer rate(ETR)in BB and RR,respectively.Potato plantlets exhibited dwarfed stems and extended leaves under BB,whereas elongated stems and small leaves were induced under RR.These dramatically altered plantlet phenotypes were associated with variable levels of endogenous plant hormones gibberellin(GAs),indoleacetic acid(IAA)and cytokinins(CKs),as assessed in stems and leaves of potato plantlets.In addition,monochromatic red and blue LEDs trigged the opposite expression profiles of DEGs identified in the"plant hormone signal transduction"metabolic pathway,which were closely related to the endogenous plant hormone levels in potato plantlets.Our results provide insights into the responses of potato plantlets cultured in vitro to red and blue LEDs at the transcriptomic level and may contribute to improvements in the micro-propagation of potato plantlets cultured in vitro from the light spectrum aspect.

Influences of Different Distances between Ridges or Plants on Yield of Sweet Potatoes

Based on the combination test of various distances between ridges or plants, the influences of corresponding cultivation techniques on the per unit area yield of a variety of sweet potatoes Xushu 22 in Xianning City were analyzed. The results show that different distances between ridges or plants had significant effects on the per unit area yield of Xushu 22; when the distances between ridges and plants for Xushu 22 planted in the city were 80 and 21 cm respectively, the per u- nit area yield of Xushu 22 was the highest, up to 48 340.7 kg/hm2.

The Effect of Plant Growth Regulator and Active Charcoal on the Development of Microtubers of Potatoes

With the detoxicated seedling of a potato cultivation breed named “Mire” as the material, the effect of auxins CCC, 6-BA, and active carbon to microtubers of potato (Solanum tubersum L.) was investigated under the in-vitro circumstances. The result indicated the exogenous auxins improved the production and quality of microtubers of potatoes. The effect of induction can be described as CCC > CCC + 6-BA > 6-BA > CK, the number of microtubers in per flask is 8.17 > 7.67 > 7.29 > 5.46, and the number of large potatoes in per flask is 6.33 > 5.17 > 3.17 > 1. In addition, by adding 0.5‰ of active charcoal, the growth period was shortened from 25.0 days to 9.33 days on average, and the amount of larger potatoes increased 8.54%. These results benefited the growth of microtubers of potato.

Insecticidal Effect of Three Different Plant Extracts on Potato Tuber Moth[Phthorimaea operculella Zeller(Lep.:Gelechiidae)]

Potato tuber moth[Phthorimae operculella Zeller(Lep.:Gelechiidae)]is the most important insect causing damage of potatoes.It also causes significant damage to tomato and eggplant.The application of plant extracts to control insects is an effective alternative.In this study,the efficacy of extracts from Leptospermum petersonii Bailey(Myrtaceae),Achillea wilhelmsii C.Koch(Asteraceae)and Tanacetum parthenium L.(Asteraceae)on potato tuber moth using two different methods was investigated.Bioassays were used to determine the effect of varying concentrations(for L.petersonii 0.05%,0.1%,0.3%and 0.4%,for A.wilhelmsii and T.parthenium 1%,3%,6%and 12%)of extracts.Experiments were carried out using potato tuber of Solanum tuberosum L.Fourth instar larva of about were used in tuber dipping and larvae dipping methods.In tuber dipping method,the highest mortality(100%)occurred at concentration of 0.4%while the smallest mortality was at 0.05%the extracts of L.petersonii.It was determined that the extract of A.wilhelmsii and T.parthenium had the highest mortality at the highest concentration 85%and 90%respectively.In larva dipping method,the extracts of L.petersonii.A.wilhelmsii and T.parthenium showed the highest mortality at the highest concentrations 100%,82%and 87%respectively.The research was undertaken under laboratory conditions at the Plant Protection Central Research Institute.