Inferior Grains Research Articles

Physiological basis for the differences of productive capacity among tillers in winter wheat

The quality or structure of a wheat population is significantly affected by the compositions of tillers. Little has been known about the physiological basis for the differences of productive capacity among tillers. Two winter wheat cultivars, Shannong 15 (SN15) and Shannong 8355 (SN8355), were used to investigate the differences of productive capacity among tillers and analyze the physiological mechanisms that determine the superior tiller group. Low-position tillers (early initiated tillers) had a higher yield per spike than high-position tillers (late initiated tillers) in both cultivars, which was due to their more grain number per spike, more fertile spikelet per spike, less sterile spikelet per spike and higher grain weight. According to cluster analysis, tillers of SN15 were classified into 2 groups: superior tiller group including main stem (0), the first primary tiller (I) and the second primary tiller (II); and inferior tiller group including the third primary tiller (III) and the first secondary tiller (I-p). Tillers of SN8355 were classified into 3 groups: superior tiller group (0 and I), intermediate tiller group (II and III) and inferior tiller group (I-p). In comparison with other tiller groups, the superior tiller group had higher photosynthetic rate of flag leaves, higher antioxidant enzyme (SOD, POD and CAT) activities and lower levels of lipid peroxidation in leaves, higher grain filling rate in both superior and inferior grains during grain filling, higher single-stem biological yield and larger single-stem economic coefficient. Correlation analysis showed that yield per spike was positively and significantly correlated with the flag leaf photosynthetic rate, grain filling rate, the antioxidant enzyme activities and soluble protein content (except for SN15 at 5 days post-anthesis (DPA)) of flag leaf, the single-stem biological yield, and the single-stem economic coefficient. Remarkable negative correlation was also found between yield per spike and MDA content of flag leaf. These results suggested that superior tiller group had stronger leaf photosynthetic capacity, more predominance in terms of grain filling, slower senescence rate, higher biological yield and larger economic coefficient, and therefore, showed greater productive capacity than other tiller groups.

Dynamic Analysis of Gene Expression in Rice Superior and Inferior Grains by RNA-Seq.

Poor grain filling of inferior grains located on lower secondary panicle branch causes great drop in rice yield and quality. Dynamic gene expression patterns between superior and inferior grains were examined from the view of the whole transcriptome by using RNA-Seq method. In total, 19,442 genes were detected during rice grain development. Genes involved in starch synthesis, grain storage and grain development were interrogated in particular in superior and inferior grains. Of the genes involved in sucrose to starch transformation process, most were expressed at lower level in inferior grains at early filling stage compared to that of superior grains. But at late filling stage, the expression of those genes was higher in inferior grains and lower in superior grains. The same trends were observed in the expression of grain storage protein genes. While, evidence that genes involved in cell cycle showed higher expression in inferior grains during whole period of grain filling indicated that cell proliferation was active till the late filling stage. In conclusion, delayed expression of most starch synthesis genes in inferior grains and low capacity of sink organ might be two important factors causing low filling rate of inferior grain at early filling stage, and shortage of carbohydrate supply was a limiting factor at late filling stage.

Superior grains determined by grain weight are not fully correlated with the flowering order in rice

Rice panicles are composed of many branches with two types of extreme grains, the superior and the inferior. Traditionally, it has been well accepted that earlier flowers result in superior grains and late flowers generate inferior grains. However, these correlations have never been strictly examined in practice. In order to determine the accurate relationship between superior and inferior grains and the flowering order, we localized all the seeds in a panicle in four distinct rice species and systematically documented the rice flowering order, flower locations and the final grain weight for their relationships. Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the flowering order. Despite earlier flowering has a positive correlation with the grain weight in general, grains from flowers blooming on the second day after anthesis generally gained the highest weight. This suggests earlier flowers may not result in superior grains. Therefore, we concluded that superior and inferior grains, commonly determined by grain weight, are not fully correlated with the flowering order in rice. Following the order of the grain weight, the superior grains are generally localized at the middle parts of the primary branches, whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle. In addition, the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators, indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.

Качественные показатели работы зерноочистительного агрегата

The urgency of the issue of grain production as the most important branch of agricultural production is described. Equally important for refined grains has such an indicator of quality of grain as it is damage that at harvest and post-harvest handling especially when grain reaches significant values. Therefore, we evaluated the quality of grain handling of various cultures on the production line of winnowing machine 3AB-40 LLC "Fakel" of Petropavlovsky district of Voronezh region. The results of studies of the 3AB-40 are presented, quality performance of machines are defined that are part of the production line. Nature of changes in the purity of the grain at the output of each machine of production line is considers. Detailed table of the fractional composition of the grain heap of cultures during processing on machines 3AB-40 is presented, in particular the composition of the grain heap entering the post-harvest treatment on the content the whole grain, crushed grain and weeds. A plot of the purity of the grain heap is presented when it is processed. Also the level of injury of seeds separately for each culture, and as it passes through each machine 3AB-40 is detailed. Analyzing numerous studies it was found that post-harvest technology of grain heap and technical resources for its implementation should ensure the allocation of the weeds at a very early stage of processing, biologically inferior grain and most of the injured grain. From above it follows the need to improve this production line in order to increase the purity of grain at the output and reduce its damage. Recommendations for installing in the process line of pre-cleaning machine МПО-50, better air-sieved cleaning machine, for example, ОЗФ-50 and ОЗФ-80. That will provide almost complete separation of light impurities, large impurities and partially puny grain, thereby improving the operation of subsequent machines that will surely affect the purity of the grain at the output of the line.

Grain-filling pattern of super hybrid rice Liangyoupeijiu under direct seeding and transplanting condition

To evaluate the grain-filling pattern, Chinese first super hybrid rice, Liangyoupeijiu was grown under tillage and establishment methods at a spacing of 20 cm × 20 cm with one seedling hill-1 and at a seeding rate of 22.5 kg ha-1 in Changsha, Hunan Province, China in 2012. Our results showed that, superior grain weight in TP had always higher than DS up to 24 DAH but at 36 DAH, grain weight had similar in both TP and DS. Middle grain weight was higher in TP than DS up to 18DAH but it was higher in DS than TP at 24 – 36 DAH and at 36 DAH, grain weight of DS had significantly higher than TP. Inferior grain weight was higher in TP than DS up to 12 DAH but it was higher in DS than TP at 24 -36 DAH and at 36 DAH, grain weight of DS had significantly higher than TP. Grain-filling rate of superior grain had higher in TP than DS up to 18 DAH but it was higher in DS than TP at 30 DAH. In middle grain, it was higher in TP at 6DAH but in DS, it was higher at 30 DAH. In inferior grain, it was higher in TP at 36 DAH but in DS, it was higher at 30 DAH. The heavier grain was found in TP only in superior grain but DS had heavier grain both in middle and inferior grain. Grain-filling rate of superior grain was higher in TP than DS and it was similar in both TP and DS in middle grain. But in inferior grain, it was significantly higher in DS than TP. Transplanting method produced slightly higher grain yield due to higher sink size (more number of spikelet’s caused by longer panicle and more number of spikelet per cm of panicle) but it was statistically similar with DS. DOI: http://dx.doi.org/10.3329/ijarit.v4i1.20972 Int. J. Agril. Res. Innov. & Tech. 4 (1): 11-15, June, 2014

Interval mapping and meta-QTL analysis of grain traits in common wheat (Triticum aestivum L.)

Common wheat is unique in providing a large number of diverse end-products, including chapati, biscuits, bread and noodles. Grain weight and other grain traits contribute to grain yield and milling quality. Many earlier QTL studies reported at least 332 QTLs for grain traits including grain weight. We conducted a QTL analysis (composite interval mapping) of grain traits using a set of 92 recombinant inbred lines (RILs) derived from a cross between Rye Selection 111 (superior grain traits) and Chinese Spring (inferior grain traits). Forty-five QTLs for six grain traits, on 19 of the 21 chromosomes (except 2D and 3D) were identified. Nineteen of these QTLs, each for 2–3 traits were located on six chromosomes (2A, 3B, 6B, 6D, 7A and 7D). The pleiotropic nature or tight linkage of QTLs controlling different correlated traits (except the one on 6DS) was confirmed by joint MCIM. Meta-QTL (M-QTL) analysis of grain traits (including grain weight) was conducted using earlier reported QTL results (including QTLs reported in the present study). From this analysis, 23 M-QTLs were identified on eight chromosomes. These results were compared with those of our current QTL analysis and previous studies; three M-QTLs were identified as relatively more important for molecular breeding and will facilitate further work on genetic architecture and cloning of QTLs for grain traits including grain weight.

Characterization of dielectric behavior in ZnO electroceramic: Superior grain boundary, inferior grain boundary and grain

Delicately fabricated ZnO bicrystals of varying nonlinearity, along with as-grown ZnO single crystal, are investigated by broadband dielectric spectroscopy to reveal the rate process involved in individual grain boundary and grain of ZnO electroceramics. Two types of low frequency dispersion phenomena, originating from the transport across the interface of double-Schottky barrier, present in individual grain boundaries. Investigation on the temperature dependence of loss peak frequency of bicrystal samples which obeys the Arrhenius law reveals that intrinsic donor species Zni• and Zni•• may contribute to the occurrence of loss peaks.

Factors influencing hybrid rice adoption: a Bangladesh case

As rice constitutes the major share in cereal consumption in South and East Asian countries that ranges from as low as 40 per cent in India to 97 per cent in Myanmar, to ensure food security, governments in these countries are encouraging farmers to adopt hybrid rice. This is mainly because hybrid rice provides a yield gain of 15–20 per cent over conventionally bred varieties in general. Yet, despite strenuous government efforts, farmers’ adoption rates have remained low in India, Bangladesh and Vietnam compared with China. Although studies often claim that higher seed costs and inferior grain quality are the major factors limiting hybrid rice adoption, very few studies examine the importance of socio‐economic factors and infrastructure in the adoption of hybrid rice. Using Bangladesh as a case, a comparative analysis has been made on the adoption of hybrid and modern varieties relative to traditional rice varieties and land allocation to these varieties. Econometric results indicate that general land characteristics, loan facilities and general infrastructure, such as roads, irrigation facilities and the availability of government‐approved seed dealers, significantly influence the adoption of hybrid and modern rice varieties and land allocation to these varieties compared with traditional varieties.

Effects of Exogenous ABA and 6-BA on Protein Content and Grain Filling Process in Different Types of Stay-Green Wheat

This study aimed to understand the grain filling process and protein biosynthesis in grain of stay-green wheat in response to exogenous hormones. At blooming stage, plants of Wennong 6(stay-green cultivar) and Jimai 20(control) were sprayed with 10 mg L-1 abscisic acid(ABA) and 6-benzyladenine(6-BA) for four days. Compared with Jimai 20, Wennong 6 had longer grain-filling duration(t3) and the active growth phase(D), higher mean grain-filling rate(Gmean) and maximum grain-filling rate(Gmax), larger thousand-grain weight(TGW), and greater grain yield(GY). All parameters for grain filling were higher in superior grain than in inferior grain. Gmean, Gmax, TGW, and GY were promoted by ABA or 6-BA treatment in both cultivars. However, the effects of exogenous hormones on t3 and D were interacted with grain position in a panicle and genotype. Exogenous ABA and 6-BA treatment obviously increased protein content at 35 days after anthesis(DAA). The glutenin contents in ABA-treated and 6-BA-treated Wennong 6 significantly increased at 35 DAA; however, those in Jimai 20 decreased at 35 DAA. Exogenous ABA increased endogenous zeatin(ZR) content from 7 DAA to 21 DAA. In Wennong 6, GA3 content in superior grain was significantly decreased from 7 DAA to 21 DAA by 6-BA treatment, however, its content in inferior grain was enhanced. In both cultivars, ap-plication of ABA and 6-BA resulted in significant increases of endogenous auxin(IAA) and ABA contents from 7 DAA to 21 DAA, along with significant enhancement of glutamine synthetase(GS) activity.

Инновационное направление совершенствования послеуборочной обработки зерна

The results of the study of treatment quality of wheat grain heap in grain cleaning machines ОЗС–50, Petkus U–80–12G, Petkus 12, 3–3,5 and Cimbria Delta 146 in cleaning mode and ОЗФ–80 in fractionation mode are given. For fractionation of grain heap on the machine ОЗФ–80 grading sieve have been established with the holes of 2.6 mm width. In the traditional treatment of grain heap, content of biologically inferior grain decreased in 1.26, crushed grain in 2.3 and contaminants in 1.9 times.

Nighttime Warming Will Increase Winter Wheat Yield Through Improving Plant Development and Grain Growth in North China

A better understanding of the actual impacts of nighttime warming on winter wheat growth will assist in breeding new varieties and agronomic innovation for food security under future climates. A 3-year experiment was conducted over an entire growth period of winter wheat using a passive warming facility in North China. An increase of 1.1 °C in mean nighttime temperature promoted wheat development, causing a 6-day reduction of the preanthesis period but a 5-day extension of the postanthesis period. This warming significantly stimulated the rate of leaf respiration at nighttime, resulting in higher carbohydrate depletion compared to that of the unwarmed control. However, stimulation of nighttime respiration and carbohydrate depletion could be compensated for by warming-led promotion of daytime photosynthesis and carbohydrate assimilation. Meanwhile, the flag leaf area per plant and the total green leaves area were significantly higher in the warmed plots than in the unwarmed plots. Besides extending the duration of grain filling, nighttime warming significantly promoted the filling rates of the superior and inferior grains, resulting in a significant increase in the 1,000-grain weight by 6.3 %. Consequently, this moderate increase in nighttime air temperature significantly increased wheat aboveground biomass and grain yield by 12.3 and 12.0 % (p < 0.05), respectively. A moderate warming at nighttime can improve the sink-source balance of winter wheat for higher yield. Our results suggest that climatic warming may benefit winter wheat production through improvement of plant development and grain growth in North China.

Depth-Resolved Residual Stress Analysis with Conical Slits for High-Energy X-Rays

A conical slit cell for depth-resolved diffraction of high-energy X-rays was tested at the high-energy materials science beamline HEMS at PETRA III and used for the analysis of residual stresses in a laser beam welded steel overlap joint. With a conical slit width of 20 µm and beam cross-sections below 100 µm, depth resolutions well below 1 mm were achieved. The residual stress distributions obtained from the steel joint were in very good agreement with previous results from neutron diffraction measurements, although they were still noisier because of inferior grain statistics.

Interactions between polyamines and ethylene during grain filling in wheat grown under water deficit conditions

This study was to test the hypothesis that polyamines (PAs) and ethylene may be involved in mediating the effect of water deficit on grain filling. Two wheat cultivars, drought-tolerant Shannong16 (SN16) and drought-sensitive Jimai22 (JM22), were used and subjected to well-watered and severe water deficit (SD) during grain filling. SD reduced the weight of superior and inferior grains, by 7.38 and 23.54 % in JM22, 13.8 and 2.2 % in SN16, respectively. Higher free-spermidine (Spd) and free-spermine (Spm) concentration and lower free-putrescine (Put) concentration, ethylene evolution rate (EER) and 1-aminocylopropane-1-carboxylic acid (ACC) concentration were found in superior grains than those in inferior ones. Opposite to the variations of Spd and Spm concentration, ACC, Put concentration and EER were significantly increased under SD. The percentage variation of PAs and ACC differed with cultivars and grain types. ACC concentration of superior and inferior grains under SD increased significantly at 21 days post-anthesis, by 90 and 164 % in JM22, 65 and 13.2 % in SN16, respectively. The equivalent value of Put concentration was 1.04 and 7.9 % in JM22, 34.4 and 10.3 % in SN16. Spd concentration of superior grains showed a higher decrease than that of inferior ones in both cultivars, while Spm exhibited an opposite trend between both grain types. These percentage variations were highly consistent with the differed responses of weight of both grain types to SD in JM22 and SN16. Grain filling rate was negatively correlated with EER and ACC concentration, while positively correlated with Spd and Spm concentration as well as the ratio of Spd or Spm to ACC. Exogenous Spd or aminoethoxyvinylglycine (an inhibitor of ethylene synthesis by inhibiting ACC synthesis) obviously reduced ACC concentration and EER and increased Spd and Spm concentration, while exogenous ethephon (an ethylene-releasing agent) or methylglyoxal-bis (an inhibitor of Spd and Spm synthesis) showed the opposite effects. The results suggested that it would be good for wheat to have the physiological traits of higher Spd and Spm, as well as a higher Spd/ACC or Spm/ACC, under SD.

The Effect of Plastic-Covered Ridge and Furrow Planting on the Grain Filling and Hormonal Changes of Winter Wheat

Although plastic-covered ridge and furrow planting (RF) has been reported to produce substantial increases in the grain weight of winter wheat, the underlying mechanism is not yet understood. The present study used two cultivars, Xinong 538 and Zhoumai 18, and RF and traditional flatten planting (TF, control) with the objective of investigating the effect of RF on wheat grain filling and the possible relationship of hormonal changes in the wheat grains under RF to grain filling. The results indicated that RF significantly increased the grain weight, although the effects on grain filling were different: RF significantly increased the grain-filling rate and grain weight of inferior grains, whereas RF had no significant effect on grain-filling rate and grain weight of superior grains. The final grain weight of inferior grains under RF was 39.1 and 50.7 mg for Xinong 538 and Zhoumai 18, respectively, 3.6 and 3.4 mg higher than the values under TF. However, the final grain weight of superior grains under RF was only 0.6 and 0.8 mg higher than under TF for Xinong 538 and Zhoumai 18, respectively. RF significantly decreased the ethylene and gibberellic acid content in the inferior grains and increased the indole-3-acetic acid, abscisic acid and zeatin + zeatin riboside content in the inferior grains; however, no significant difference between RF and TF was observed for the hormonal content in the superior grains. Based on these results, we concluded that RF significantly modulated hormonal changes in the inferior grains and, thus, affected the grain filling and grain weight of the inferior grains; in contrast, RF had no significant effect on grain filling, grain weight and hormonal changes in the superior wheat grains.

Differences of Starch Granules in Grains from Different Spikelet Positions and Their Correlation with Grain Weight in Winter Wheat

The purpose of this study was to reveal the differences in development and size-distribution of starch granules in endosperm of wheat grains in different grain positions and spikelet positions. The endosperm cell size, and the number, volume and surface area distribution of starch granules in mature caryopsis, as well as the changes of starch granule number during endosperm development, were studied using wheat cultivar Jimai 20 grown in the field. The results showed that the development of starch granule was closely related with grain position and spikelet position. In the same spikelet position, starch grains formed 4–5 d earlier in superior grains (the first and the second grains) than in inferior grains (the third and the fourth grains).At the same grain position, starch granules developed first in the grains of the middle spikelets, and then in grains of upper and lower spikelets. The amount of starch granules was the highest in the middle spikelet grains all the time. The lower spikelet grains had the least starch granules at the beginning of grain filling, however, the number of starch granules increased gradually and surpassed that of the upper spikelet grains as caryopsis matured. Correlation coefficients between grain weight and starch granule amount became more significant with grain filling, which reached 0.88 ** (large starch granule) and 0.78 ** (small starch granule) at mature stage. Correlation coefficients between grain weight and large starch granule amount were higher than 0.96 ** , and had no difference among different spikelet positions. Correlation coefficients between grain weight and small starch granule amount were higher than 0.93 ** , and had a trend of upperlowermiddle in different spikelet positions. The trend of size distribution was BL-typeBS-typeA-type. There were more BS-type granules in superior grains than in inferior grains. The number of BS-type granules increased with the spikelet position rising, whereas the number of BL-type granules showed a reverse trend. The size distribution of starch granules had similar changes to volume and surface area. The formation and size distribution of starch granules were affectedsignificantly by grain position and spikelet position, and inferior grains had the potential of increasing grain weight through increasing the quantity of starch granules.

Genome-Wide Analysis of 24-nt siRNAs Dynamic Variations during Rice Superior and Inferior Grain Filling

24 nt-siRNAs are the most abundant small interfering RNAs in rice grains aside from microRNAs. To investigate the roles that 24 nt-siRNAs played in the poor grain filling of rice inferior grains, dynamic variations of 24 nt-siRNAs in inferior grains were compared with those of superior grains by using small RNA deep sequencing technology. The results showed that 24 nt-siRNAs derived from multiple regions of rice genome, and the maintenance of the two strands of 24 nt-siRNA duplex was a non-random process. The amounts of 24 nt-siRNAs declined with the process of grain filling in both superior and inferior grains, but 24 nt-siRNAs in inferior grains was much higher than that of superior grains in each period we sampled. Bioinformatics prediction indicated that 24 nt-siRNAs targeted on more genes involved in most of the known KEGG rice pathways, such as the starch and sucrose biosynthesis pathway. Combined with digital gene expression profiling of target genes, 24 nt-siRNAs mapped on the antisense strands of exons were specifically investigated, but the abundance of 24 nt-siRNAs did not show negative correlations with their corresponding target genes. The results indicated that 24 nt-siRNAs were not involved in down-regulation of target genes. The potential biological meanings for this inconsistency were probably the results of methylation directed gene expression activation, or competition for small RNA stability methylation.

Effects of conservation tillage on grain filling and hormonal changes in wheat under simulated rainfall conditions

The objective of this study was to investigate the effect of conservation tillage (CT) on wheat grain filling under different precipitation levels and the relationship with endogenous hormonal changes. In the present study, CT was compared to traditional bare soil tillage (BT) under different precipitation conditions simulated during the wheat growth stage, and the resulting hormonal changes in the grains were measured. The results indicated that the effect of CT on wheat grain filling is significantly related to precipitation. At the 220-mm rainfall level, CT significantly promoted grain filling of the superior and inferior grains. CT also significantly promoted the grain filling of inferior grains at 260-mm rainfall yet had no significant effect on filling of the superior grains. In contrast, CT had no significant effect on the grain-filling rates and grain weight of superior and inferior grains at the 300-mm rainfall level. At 220- and 260-mm rainfall, CT significantly increased the indole-3-acetic acid (IAA) and zeatin (Z)+zeatin riboside (ZR) contents and decreased the abscisic acid (ABA), ethylene (ETH), and gibberellic acid (GA) contents in the inferior grains, whereas CT only had these effects in the superior grains at the 220-mm rainfall level. The IAA, ABA, and Z+ZR contents in the grains were positively and significantly correlated with the maximum grain weight and the maximum and mean grain-filling rates; the ETH concentration was negatively and significantly correlated with the maximum grain weight and the maximum and mean grain-filling rates. In addition, both precipitation and CT significantly increased the soil moisture during the grain-filling stage. Based on these results, we conclude that the CT treatment significantly increased the soil moisture, thus regulating the grain filling of wheat, and that this process was significantly related to the balance of hormones in the grains.

Difference of Bleeding Intensity in Different Parts of Rice Plant and Its Relationship with Grain Plumpness

This study aimed to illustrate the mechanism of inferior grain plumpness in rice. A field experiment with 0, 90 and 180 kg ha1 N spike fertilizer application in the stage of rice young ear differentiation was carried out in 2005 and 2006 on the farm of Henan Agricultural University, Henan Province, China. Two varieties (indica and japonica rice) were used to study the periodical changes of basal and neck internode bleeding intensity, soluble sucrose in bleeding, daily change of bleeding intensity and the relationship between the bleeding intensity and soluble sucrose of neck internode with grain plumpness in the grain filling stage. The results showed that the changes of bleeding intensity between the basal and neck internodes were obviously different. The bleeding intensity in the basal internode reached the maximum value in the fifth day after anthesis and presented the drop tendency afterwards. The bleeding intensity of the neck internode appeared two peak values in the fifth and seventeenth days after anthesis. There was a valley value in the eleventh day after anthesis on average. The average bleeding intensity in the neck internode was higher under zero N lever than high N level. The daily change of bleeding intensity in the neck internode was low in the daytime and high at night, which reduced with rising N fertilizer application. Correlation analysis showed that there existed significantly positive correlation or highly signification between inferior grain plumpness and the bleeding intensity of neck internode in the 10, 15, 25, and 35 days after anthesis for the japonica, but not for the indica rice. The relationship between solublesucrose in the bleeding of neck internode and inferior grain plumpness showed highly significantly positive correlation, while that of the basal internode was not notable. It indicated that the relationship between bleeding in the neck internode and the inferior grain plumpness is close. The bleeding intensity of neck internode can be used as a index for measuring inferior grain plumpness. Therefore, increasing the bleeding intensity of neck internode by regulating N application can improve the inferior grain plumpness.

Warming impacts on winter wheat phenophase and grain yield under field conditions in Yangtze Delta Plain, China

A five-year experiment with Free Air Temperature Increase facility was conducted to investigate the actual responses of winter wheat phenophase and yield to warming in Yangtze Delta Plain, China. Air temperature increase of around 1.5°C in wheat canopy advanced crop phenophases significantly, leading to a reduction in length of the entire growth period by 10 days (P<0.05). This reduction was mainly found in the length of pre-anthesis phase, while the length of post-anthesis phase was prolonged slightly. Warming increased grain yield by 16.3% (P<0.05) whereas no significant effects were found on the aboveground biomass. Warming tended to increase the numbers of productive spike and filled grain and the harvest index. The areas of flag leaf and total green leaf at anthesis and the 1000-grain weight were 36.0, 19.2 and 5.9% higher in the warmed plots than the un-warmed control (P<0.05), respectively. Warming stimulated the filling rate of inferior grain (P<0.05), while the rate of superior grain stayed almost unchanged. The above evidences suggest that anticipated warming may facilitate winter wheat production in East China.

Influence of Planting Methods on Grain-filling Properties of Super Rice

To explore grain-filling properties of high-yielding rice under different planting methods,we studied the grain-filling processes of superior and inferior grains of two super rice cultivars(Huaidao 9 and III you 98) with Richards equation W=A/(1+Be-Kt)1/N and three planting methods,i.e.precision artificial transplanting with dry nursery middle and strong seedlings(ATR),mechanical transplanting with small seedlings(MTR) and direct seeding(DSR).The results were as follows:(1) The super rice yields under different planting methods were significantly different,ATR was the highest,followed by the MTR,and the lowest was the DSR.Compared with ATR and MTR,the 1000-grain weight and seed-setting rate of DSR were significantly lower,but the changes between ATR and MTR were different due to different types of cultivar.(2) The grain-filling processes of superior and inferior grains of super rice under different planting methods were obviously asynchronous type.The time reaching the maximum grain-filling rate(Tmax) of superior grains was early,maximum grain-filling rate(GRmax),mean grain-filling rate(GRmean),the final weight of a kernel(A) and initial grain-filling potential(R0) were significantly greater than those of inferior grains.However,the active grain-filling period(D) and effective grain-filling time(T99) of the superior grains were significantly less than those of inferior grains.(3) Compared with ATR and MTR,the GRmax and GRmean of superior grains of DSR were significantly lower,Tmax was obviously delayed,D and T99 significantly increased.The GRmax and GRmean of inferior grains of MTR were the highest,and ATR was slightly lower than DSR.For Tmax,DSR was the earliest,MTR was the second,and the latest was ATR.D and T99 reduced in order for ATR,MTR,and DSR.(4) For grain-filling characteristics of different stages,the maximum of mean grain-filling rate and contribution rate was present at the middle stage,and the contribution rates of superior and inferior grains were up to 60.53% and 50.78%,respectively.The grain-filling days,mean grain-filling rate and contribution rate of the early,middle and late stages among different planting methods were different due to grain positions.(5) 1000-grain weight was positively correlated with maximum grain-filling rate,mean grain-filling rate and active grain-filling period of superior and inferior grains,and the correlations with maximum grain-filling rate and mean grain-filling rate of inferior grains were significant.Seed-setting rate had in a degree of positive or negative correlations with the grain-filling parameters of the superior and inferior grains,however,except the active grain-filling period of superior grains,all of the correlations were not significant.The results suggested that planting methods have significant influence on grain-filling properties of super rice.Although the grain-filling processes are all asynchronous types,the grain-filling parameters such as maximum grain-filling rate and the time reaching the maximum grain-filling rate of superior and inferior grains have great difference among different planting methods.It would play an important role in improving 1000-grain weight and grain-filling rate,especially the grain-filling rate of inferior grains under the conditions maintaining the final weight of a kernel and seed-setting rate stable.