Effects of Seed Rate on Root Twining Power and Seedling Quality of Machine-transplanted Super Rice

In order to investigate the effects of seed rate on root twining power and seedling quality of machine-transplanted super rice cultivars, Yongyou 12 and Zhongzheyou No.l, total 6 seed rates were arranged, and the growth characteris- tics, quality and root twining power of machine-transplanted rice seedlings were studied. The results showed that seed rate had great effects on root twining power and qualityof rice seedlings; with the increase of seed rate, the root twining power of rice seedlings was increased, but the quality of rice seedlings was significantly reduced; under the condition of high seed rate, rice seedlings were weak with less accumulate dry matter and nonuniform growth, and the proportion of weak seedlings was higher. When the seed rate of both rice cultivars was reduced by 10 g/tray, the average seedling height was increased by 0.5 cm, leaf age was increased by 0.1, stem base diameter was increased by 0.1 cm, and root number per plant was increased by 0.3. When the seed rate was increased by 10 g/tray, the accumulated dry matter per plant was reduced by 5.1 mg. With the increase of seed rate, the seedling quality of Zhongzheyou No.1 was decreased rapidly, and the proportion of weak seedlings was increased rapidly. However, Yongyou 12 has a larger elasticity in seed rate. When the seed rate reached to 50 g/tray, blanket seedlings of Yongy- ou 12 were nursed with uniform growth and higher quality, but the shoots were sparse with lower leaf area index. However, when the seed rate was up to 50 g/tray, blanket seedlings of Zhongzheyou No.1 were nursed with uniform growth and higher quality, as well as higher-density shoots. From a comprehensive point of view, the optimum seed rates of Yongyou 12 and Zhongzheyou No.1 were 65 and 50 g/tray, respectively.

Effects of Seed Soaking with Uniconazole and Substrate Formula on Seedling Quality of Rapeseed

[Objective] To cultivate blanket rapeseed seedlings suitable for automatic mechanical transplanting, the effects of seed soaking with uniconazole and substrate formula on seed germination and seedling quality of rapeseed were investigated using HY4 as the material. [Method] The rapeseed seeds were soaked in different concentrations（0, 5, 10, 20, 30, 40 and 50 mg/L） of uniconazole for 0, 1, 2, 4 and8 h, respectively. Subsequently, they were dried naturally. After the preliminary screening carried out in petri dishes and in a laboratory, the optimum soaking concentration and time of uniconazole were obtained. On the other hand, the rapeseed seeds were soaked in different concentrations（0, 5, 10, 15 and 20 mg/L） of uniconazole for 0, 1 and 2 h, respectively for outdoor pot experiment. At the same time, the screening of optimum substrate formula for cultivating blanket rapeseed seedlings was carried out. The field test was carried out to verify the screened optimum substrate formula. [Result] The results of petri dish experiment showed that seed soaking with uniconazole could delay seed germination, reduce seed germination rate, inhibit hypocotyl elongation and promote root growth. When the soaking concentration exceeded 30 mg/L and soaking time exceeded 2 h, the effect of seed soaking with uniconazole on seed germination was greater, and the seed soaking inhibited root growth. The results of outdoor pot experiment showed that the soaking concentrations and times all significantly reduced seedling height, slowed shoot growth and promoted root growth, which all contributed to the cultivation of blanket rapeseed seedlings suitable for automatic mechanical transplanting. In the substrate formula, the lower the proportion of soil was, the better the seedling growth was. In the substrate with lower proportion of soil, the seed germination rate, plant height,root vigor and dry matter accumulation were all increased（P〈0.05）, which was verified by the field test. When the soaking concentration was less than 10 mg/L and soaking time was less than 1 h, the uniconazole showed weaker regulation effect on seedling growth, and the rapeseed seedlings were higher. In the substrate with soil proportion less than 50%, the adequate fertility relatively weakened the regulation effect of uniconazole on seedling growth, and the rapeseed seedlings were larger. [Conclusion] When the soaking concentration ranged within 15-20 mg/L and soaking time ranged within 1-2 h and the proportion of soil in substrate was 50%,the height of cultivated rapeseed seedlings was less than 18 cm, there were 5-6leaves remained on each plant and the nursing period was shortened to 30-40 d,which were all beneficial to industrial production.

Study on Seedling Quality of Double-cropping Late Rice Sowed at Different Dates in Guangdong

[Objective] The aim was to study seedling quality of rice sowed at different dates so as to provide theoretical basis for determining the best seeding time.[Method] By investigating the characters of shoot and root of different varieties sowed at different dates,the best seeding time of double-cropping late rice was determined.[Result] The first leaf sheath height and the second leaf length shared significantly positive correlation,which fit the quadratic equation well.The effects of different sowing dates on shoot and root of three rice varieties appeared significant difference.[Conclusion] The best seeding time of Tianyou428 was in June 25-July 2 and that of Tianyou998 and Yuxiangyouzhan was in July 2-9.

Effects of Different Upland Seedling Nurturing Modes on Shed Temperature and Rice Seedling Quality

In order to compare the advantages and disadvantages of large-shed,middle-shed and small-shed upland seedling nurturing modes in japonica rice planting regions of North China, in this study, Tongyin 58, Tonghe 836 and Tonghe 835 were used as experimental materials and cultivated with large-shed, middle-shed and small-shed upland seedling nurturing modes to investigate active and effective accumulated temperature and rice seedling quality. According to the results, active and effective accumulated temperature in three different upland seedling nurturing treatments during seedling nurturing period were generally in a descending order of large shed 〉 middle shed 〉 small shed. The occurrence frequency of temperature exceeding the biological upper limit for rice growth in different upland seedling nurturing treatments demonstrated a descending order of large shed 〉 small shed 〉middle shed; the occurrence frequency of temperature below the biological lower limit demonstrated a descending order of small shed 〉 middle shed 〉 large shed.Plant height, root number, aboveground dry weight, underground dry weight and emergence rate varied significantly among different upland seedling nurturing modes,which showed a descending order of large shed 〉 middle shed 〉 small shed; leaf age and stem number in large shed was significantly higher than that in middle and small sheds, but there was no significant difference in leaf age and stem number between middle and small sheds; underground dry weight varied slightly between large and middle shed, but underground dry weight in large and middle shed was remarkably higher than that in small shed. In production, large-shed upland seedling nurturing is most appropriate technique, followed by middle-shed upland seedling nurturing. In large-shed upland seedling nurturing, ventilation and seedling hardening should be strengthened. Small-shed upland seedling nurturing technique is not recommended to be used in regions with low accumulated temperature at night. In small-shed upland seedling nurturing, the minimum temperature at night should be concerned, and heat preservation measures should be taken immediately when there is a sudden drop in temperature.

Growth of tandem long-mat rice seedlings using controlled release fertilizers:Mechanical transplantation can be more economical and high yielding

The traditional soil-based rice seedling production methods for mechanical transplanting are resource-intensive,time consuming and laborious.The improvement and optimization of nutrient management in soil-less nursery raising methods like tandem long-mat seedlings(TLMS)are necessary for the resource-efficient cultivation of rice.In the present study,a controlled-release fertilizer(CRF)-polymer-coated compound fertilizer with 3 months release period(PCCF-3M)was applied as seedling fertilizer(SF),and five different dosages of SF(SF-0,SF-10,SF-20,SF-30,and SF-40)were compared with an organic substrate as the control(CK).Among all SF treatments,the best results were obtained with the application of 20 g/tray of SF(SF-20),as the seedling quality and machine transplanting quality were comparable to those of CK.In contrast,the lower dosages(SF-0 and SF-10)resulted in low nitrogen content and reduced shoot growth,while the higher dosages(SF-30 and SF-40)resulted in toxicity(increased malondialdehyde accumulation)and inhibited the root growth.Similarly,SF-20 increased panicle number(5.6-7.0%)and yield(4.3-5.3%)compared with CK,which might be related to the remaining SF entangled in the roots supporting the tiller growth of rice seedlings in the field.Moreover,SF-20 reduced the seedling block weight(53.1%)and cost of seedling production(23.5%)but increased the gross margin,indicating that it was easy to handle and economical.Taken together,our results indicate that SF-20 is a cost-effective way to promote the growth and transplanting efficiency of rice seedlings.To our knowledge,this study is the first to determine the optimum dosage of CRF for the soil-less production of rice seedlings.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings （HLMS） on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar （Wuyunjing 23） was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, whJch was selected as the control. Root number, root twJstJng power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates andcontrol. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seed- lings. In the HLMS, the content of gibberellin acid （GA3） decreased while abscisic acid （ABA） content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

Coinoculation of bioinoculants improve Acacia auriculiformis seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.

Studies on Tomato Seedling Quality Indices Under Simulated Shipping and Storage Conditions

Indices of the tomato seedling quality maintenance level after production before field planting were studied through simulated experiments, small—scale operation, indoor analyses and measurements, and field observation. The results showed that under simulated shipping and storage conditions, seedling quality change following different durations (days) of shipping and storage was correlated significantly or even very significantly with certain physiological and morphological indices. With various measured indices following different periods of shipping and storage treatment subjected to multinomial successive regressive correlation analysis, the principal factors influencing seedling quality maintenance level are identified to be chlorophyll content →dry short weight → leaf freshness index in order of their importance. Significance analysis with multinomial fitted equation indicated that correlations between any one of above three factors and the growth index after field planting reached very significant difference level.

Effects of SSA Dosages on Seedling Quality and Yield by Mechanical Transplanting

[Objective] The aim was to research the influence of gradient dosages of seedling-strengthening agent （SSA） on rice seedling quality and yield. [Method] The influence of four dosages of SSA on late rice seedling quality and yield was investi- gated, using Oryza sativa cv. Yongyou 9 and Huanghuazhan as test materials. [Re- sult] The results showed that applying SSA significantly increased several indexes of seedling quality including the leaf age, basal stem width and dry matter weight. In addition, SSA greatly increased the rice yield, mainly through influencing two yield component factors, effective panicle number and grain number per panicle. [Conclu- sion] SSA was beneficial to nurse strong seedling which satisfied mechanical trans- plant and improve yield. Considered both seedling quality and yield trait, the optimal SSA dosage is 50 g/m2 under this cultivating condition.

Controls of seed quantity and quality on seedling recruitment of smith fir along altitudinal gradient in southeastern Tibetan Plateau

Alpine treeline ecotones are harsh environment for tree establishment due to low temperature. Tree establishment at treelines requires favorable climate, suitable microsites, and viable seeds. But most researches have been addressed treeline microclimate and its effects on tree regeneration, the knowledge of seed quantity and quality and its controls on seedling recruitment were limited. We measured seed rain, soil seed bank, seed germination rate and seedling recruitment in natural forests in combination with seed transplanting manipulation to evaluate the controls of seed quantity and quality on seedling recruitment of Abies georgei var. smithii （smith fir） along altitudinal gradient, with focus on treeline ecotone in the Sygera Mountains, southeastern Tibetan Plateau. Both seed quantity and seed quality of smith fir decreased with increasing altitude and was thereby associated with decline in seed germination rate. Seed quantity and seedling recruitment were better in north-facing slope than in south slope. The treeline ecotone above 42oo m appeared as the threshold altitude to sharply decrease seed quality and seedling recruitment. The emergence and overwintering rates of transplanting seeds from 3600-38oo m also went down remarkably above 4200 m at north-facing slope. It also underpins the fact that treeline ecotone is the bottleneck of seedling recruitment. Our results suggest that seed quantity and quality are the principal limitation of treeline upward advance. This study also provides evidence to support stable treeline position in southeastern Tibetan Plateau.

Effects of Warming Seedling Cultivation Technology on Growth, Yield and Quality of Fluecured Tobaccos

An experiment of seedling nursing which used film mulching technology in greenhouse to increase temperature was carried out in the south of Hunan province in 2014. The results showed that the average surface temperature of seedling tray and the average water temperature of nursing pool at 10：00 and 16：00 in treatment1 which used film mulching technology in a greenhouse were higher than that of CK（no film mulching）, suggesting the warming effect of mulching film in a greenhouse is obvious. The growth potential of tobacco seedling is stronger in treatment1 than CK, and tobacco seedling quality index including the fresh and dry weight of stem, leaves and roots increased. Plant height, stem girth and leaves area of the treatment 1 were higher and more than that of CK after transplanting. Squaring,topping and maturity period were slightly earlier in the treatment 1, compared with that of CK. Average yield of treatment 1 was 2 308.8 kg/hm^2, which increased by6.03% and was significantly higher than that of CK,and the output value of the treatment 1 was 50 184.75 yuan/hm^2, which increased by 5.61%.

STUDY ON IMPROVING THE GROWTH QUALITY OF PLANTED SEEDLING OF PINUS KORAIENSIS IN INITIAL STAGE

Each link in initial process of artificial regeneration of Pinus koraiensis in clear cutting site was researched. The seedling recovery processes after transplantation. the affecting seedlings survival factors in different time, and the characters of seedling growth were analyzed. Results of this study suggest that the root recovery of Korean pine secdlings after transplanting is the key link in the artificial regeneration management. The synthetically management was proposed on basis of seedling root recovery process.

EFFECTS OF SOIL MOISTURE CONTENT ON DRY NURSERY SEEDLING QUALITY OF LATE DOUBLE CROPPING RICE IN SOUTH CHINA

In the present paper, an experiment was conducted to study the effects of soil moisture content on dry nursery seedling quality in Guangzhou in 1995. Through comparing the difference of dry nursery seedlings and wet nursery seedlings, we found a close relationship between soil moisture content and seedling growth. The seedling emergence of dry nursery seedling was more even, tidy and faster, and the survival rate was higher than that of wet nursery seedling. Dry nursery seedlings had small plant stature, slow leaf stretching speed and low individual seedling dry weight, but had high dry/fresh weight ratio. This was abeneficial factor for seedlings to recover from transplanting shock more quickly. As com-pared with the wet nursery seedlings, dry nursery seedlings had poor rooting ability,but had more vigorous white roots and fewer rust roots. It was the possibly important reasonfor dry nursery seedlings to form strong“explosive force”.

Effects of Different Seedling Raising Substrates on Quality of Rice Seedlings

Five different seedling raising substrates were used to take the place of the nutrient soil to cultivate rice seedling mechanical transplanting in Anqing,Anhui Province.The emergence rate,survival rate,quality of aboveground parts of seedlings,root system and dry weight and fresh weight were surveyed and analyzed.The results showed that the rice seedling raising substrates could significantly improve the seedling quality and survival rate of mechanically transplanted seedlings,especially the seedling raising substrates produced by Anhui Province Lufu Agriculture Science and Technology Stock Co.,Ltd.and Anhui Anqing Yike Seedling Material Co.,Ltd.Finally,it is recommended to promote the seedling raising substrate in large area,to lay a solid foundation for realizing high yield,high quality,and high efficiency of rice.

Explaining First-Year Seedling Survival from Quality Distributions of Bare-Root Seedlings and Microsites in Industrial Plantations

First-year seedling survival impacts all subsequent management planning in plantation forestry. Descriptive statistics of first-year seedling survival data from the Louisiana Department of Agriculture and Forestry (LDAF) indicated that survival success reaches a plateau at between 79% - 85% under normal weather conditions. We provide an explanation for this plateau based on an analysis of seedling and microsite qualities involved in operational pine plantations by: 1) using a conceptual model demonstrating how variation in seedling quality and microsite quality interact to determine plantation survival, 2) presenting an example to characterize quality distributions of seedling and microsite qualities, and 3) comparing model outcomes based on measured distributions to realistic values of first-year survival. Simulation results indicated that consistent survival could result from random pairings of initial seedling and site quality distributions. LDAF data analysis indicated that 72% of seedlings were associated with the most frequent quality class that comprised seedlings with stem caliper between 3.2 to 4.7 mm and average stem height and volume of 25.75 cm and 3.43 cm3, respectively. Similarly, assessment of microsites at planting sites in Southeast Louisiana indicated that 48% of planted seedlings were associated with the most frequent microsite quality class which supported first-year height increment between 9 to 29 cm. Modelling of current operational practice indicated that using seedlings with larger caliper size would increase first year survival, but would result in higher establishment costs. The conceptual model could be modified to for use in other regions regardless of species types involved.

Effects of Different Seedling Grades on Yield and Commercial Quality of Codonopsis pilosula

[Objectives] This study was conducted to further explore the yield increasing potential of Codonopsis pilosula, and to seek seedlings suitable for efficient production of C. pilosula. [Methods] The effects of C. pilosula seedlings of different sizes on root yield and commercial quality under different cultivation densities were studied. [Results] The fourth-grade seedlings had the least input, the highest yield of 6 948 kg/hm^2, the largest output-to-input ratio at 18.3, the highest root weight proportion of the second-grade product at 58.1%, and the lowest root weight proportion of the first-grade product at 17.6%. Considering the yield, quality and economic benefits comprehensively, the treatment of the fourth-grade seedlings(seedling diameter≤4 mm) is the best choice, and the suitable plant spacing is 8 cm×22 cm. [Conclusions] The study provided a reference basis for the cost saving and efficiency improvement of C. pilosula production.

Effect of Seedling Quality on Growth,Yield and Quality of Angelica sinensis

[Objectives]Aiming at the problems of high bolting rate,low yield and poor quality traits in the production of Angelica sinensis in Qinghai Province,this study investigated the effect of seeding quality on the growth,yield and quality of A.sinensis.[Methods]Field experiments were carried out in five aspects,including different seedling shapes,different seedling sizes,different seedling ages,different seedling raising methods,and different seedling sources.The effect of seedling quality on the survival rate,bolting rate,main quality traits(root length,root fresh weight,root head thickness,root head length)and yield of A.sinensis was investigated.[Results]The seedlings,0.2-0.5 cm in diameter,100-110-d old,raised from three-year-old provenance in cultivated land by conventional method,were more preferable,and their survival rate was high,bolting rate was low,yield is high,and quality traits performed well.[Conclusions]The seedlings,0.2-0.5 cm in diameter,100-110-d old,raised from three-year-old provenance in cultivated land by conventional method,were more preferable,and their survival rate was high,bolting rate was low,yield is high,and quality traits performed well.

Effects of Organic Fertilizer Application Amount on Seedling Quality under No-tillage Semi-Solid State Direct Seeding

With early rice variety Zhongzao 39 as test material,this paper investigated the effects of organic fertilizer application rate on seedling quality under no-tillage semi-solid state direct seeding.The results showed that the seedling quality of no-tillage semi-solid direct seeding was better than that of traditional direct seeding,and different application rates of organic fertilizer under no-tillage semi-solid direct seeding also had signi ficant effects on seedling emergence rate,dry matter weight in ground and underground,stem base width,root activity,chlorophyll content and seedling growth index of rice seedlings.When the organic fertilizer dosage was A4(0.10∶1),it was most beneficial to the growth and development of rice seedlings under no-tillage semi-solid state direct seeding,it could effectively improve the quality of rice seedlings and enhance their resistances,the cultivated seedlings could lay a good foundation for high yield of rice in late stage.

Research on Potted-Tray Grown Rice Seedling Transplanting by Machine

[Objective] In order to cultivate seedlings that are adaptable to farming system and transplanter, the technology for transplanting potted-tray grown rice seedlings with machine was introduced and studied. [Method] The transplanter-spe-cific seedlings were cultivated with potted-tray, bowl-shaped blanket tray and soft plastic flat plate respectively. The seeding rate and 20-50-day-old seedling height were investigated for the 3 sowing patterns. After the transplanting, the missing transplanting rate, upright seedling rate, seedling injury rate and green-returning pe-riod were investigated. [Result] Nursing seedlings with potted-tray had the advan-tages of saving seeds, high sowing precision, high seedling rate and high seedling rate. The 20-40-day-old seedlings had relatively high leaf age, seedling height and root number. However, 40 d after the transplanting, the growth of seedlings was slowed. The quality difference was smal est among the 20-day-old seedlings that were nursed with 3 different patterns, but since then the quality advantage of pot-ted-tray grown seedlings had been more and more prominent. There was smal dif-ference in quality among the 30-day-old seedlings. However, for the seedlings that were older than 40 d, the transplanting quality of potted-tray grown seedlings was higher than that of bowl-shaped blanket tray grown seedlings and soft plastic flat plate grown seedlings. In addition, the green-returning period of the potted-tray grown seedlings was significantly shortened. [Conclusion] Compared to the bowl-shaped blanket tray grown seedlings and soft plastic flat plate grown seedlings, the potted-tray grown seedlings were more suitable to transplant by machine in the wheat-rice double cropping areas of Chengdu Plain.

Effects of Seedling Cultivation Methods on Seedling Cultivation of Major Vegetables

Objective] The alm was to expIore the effects of cuItivation methods on vegetabIe growth in seedIing stage. [Method] The test incIuded 4 treatments, as foI-Iows： treatment 1 （T1） where seedIings were cuItivated as per water fiIm-based cuI-tivation and irrigation proceeded reguIarIy; treatment 2 （T2） where irrigation proceed-ed continuousIy as per water fiIm-based cuItivation; treatment 3 （T3） where seedIings were cuItivated as per fIoating nursing; controI treatment （CK） where seedIings were cuItivated as per seedIing-tray cuItivation in order to survey the number of germinated seedIings per tray. [Result] Both of water fiIm-based cuItiva-tion and fIoating nursing took advantages in germination speed and aduIt seedIing rate, compared with tray cuItivation method. [Conclusion] Water fiIm-based cuItivation and fIoating nursing make innovations in water management during seedIing cuItiva-tion, which improve germination speed, aduIt seedIing rate and seedIing quality, making contribution to Iarge-scale production of greenhouse vegetabIes through ap-pIications and practices.