Biochemical Changes Associated with Germinating Rice Grains and Germination Improvement

To determine biochemical changes during the germination of rice grains （Oryza sativa L. subsp, indica var. Mottaikaruppan） and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate （SDS） （1.0 g/L） and Triton-X-100 （1.0 mL/L）], whole rice grains soaked in distilled water for 12 h at 30℃were germinated in the dark at 30℃ for five days. The highest germination rate （77.1%） was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM （dry matter） was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5^th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic （1.1 to 190.0 U/g DM） and proteolytic （0 to 0.12 U/g DM） activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid （0.1 g/L） and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment （grains germinated in distilled water）, whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.

Polyamines in developing rice grains and their relations with grain filling

Many studies have reported that polyamines have an effect on a number of growth and developmental process in plants, such as cell division, embryogenesis, senescense, and flowering. However, there are few reports on the physiological significance in of polyamines grain filling of rice. We studied the level of polyamines in the developing grains and their relations with grain filling and grain weight, using 8 rice varieties including hybrid combinations. It was showed that the content of Put (puterscine), Spd (spermidine), and Spm (spermine), especially Spd and Spm, was

Description of Aphelenchoides besseyi from Abnormal Rice with ‘Small Grains and Erect Panicles’ Symptom in China

The abnormal rice with small grains and erect panicles were found on a large scale in China, which showed shortend rice panicle and decreased number of grains in comparison with normal rice, and the grain was small and black-brown, and some of them were distorted, while the flag leaf was normal. A kind of nematode of Aphelenchoides was isolated from the grains of rice variety Wuyujing 3 which performed ＇small grains and erect panicles＇ symptom. There were 2014 nematodes in one hundred grains infected, and up to 74 in single grain, 92 percent of the grains tested had nematodes in the infested panicles. The diagnosis characters of nematode include lateral fields about one-fourth as wide as body, with 4 incisures. The terminus bears a mucro of diverse shape with 3-4 pointed processes. The female post-vulval uterine sac extends less than 50% of distance from vulva to anus, no sperm in it. Oocytes usually arrange in 2-4 rows. The male spicules have a moderately developed rostrum. Morphological measurements showed it to be conspecific with Aphelenchoides besseyi Christie, 1942.

Genetic Analysis of Notched Grain in Rice水稻腹缺米的遗传分析

调查了1366份水稻品种和品系,腹缺米的发生频率为5.63%,腹缺米频率与粒重的相关r=+0.6195。1978、1979和1981年,用腹缺米和饱满米配制了17个组合,F_1、F_2和 BF的分析发现,腹缺米受两对显性互补基因控制,环境条件只影响腹缺米的程度。这种障碍在早期世代进行连续选择即可消除。

Variation of grain Cd and Zn concentrations of 110 hybrid rice cultivars grown in a low-Cd paddy soil

Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil （Entic Haplaquept） with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer （GFAAS） and flame atomic adsorption spectrophotometer （AAS） respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods （MOHC and SSC, 2005）, calculated potential risk of food Cd exposure with ＂Zn hungry＂ through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.

Rapid Identification of Rice Samples Using an Electronic Nose

Four rice samples of long grain type were tested using an electronic nose (Cyranose-320).Samples of 5 g of each variety of rice were placed individually in vials and were analyzed with the electronic nose unit consisting of 32 polymer sensors.The Cyranose-320 was able to differentiate between varieties of rice.The chemical composition of the rice odors for differentiating rice samples needs to be investigated.The optimum parameter settings should be considered during the Cyranose-320 training process especially for multiple samples,which are helpful for obtaining an accurate training model to improve identification capability.Further,it is necessary to investigate the E-nose sensor selection for obtaining better classification accuracy.A re- duced number of sensors could potentially shorten the data processing time,and could be used to establish an application pro- cedure and reduce the cost for a specific electronic nose.Further research is needed for developing analytical procedures that adapt the Cyranose-320 as a tool for testing rice quality.

Effect of High Temperature on Sucrose Content and Sucrose Cleaving Enzyme Activity in Rice Grain During the Filling Stage

Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.

Review grain yield and nitrogen use efficiency in rice production regions in China

As one of the staple food crops, rice（Oryza sativa L.） is widely cultivated across China, which plays a critical role in guaranteeing national food security. Most previous studies on grain yield or/and nitrogen use efficiency（NUE） of rice in China often involved site-specific field experiments, or small regions with insufficient data, which limited the representation for the current rice production regions. In this study, a database covering a wide range of climate conditions, soil types and field managements across China, was developed to estimate rice grain yield and NUE in various rice production regions in China and to evaluate the relationships between N rates and grain yield, NUE. According to the database for rice, the values of grain yield, plant N accumulation, N harvest index（HIN）, indigenous N supply（INS）, internal N efficiency（IE_N）, reciprocal internal N efficiency（RIE_N）, agronomic N use efficiency（AE_N）, partial N factor productivity（PEPN）, physiological N efficiency（PE_N）, and recover efficiency of applied N（RE_N） averaged 7.69 t ha^（–1）, 152 kg ha^（–1）, 0.64 kg kg^（–1）, 94.1 kg kg^（–1）, 53.9 kg kg^（–1）, 1.98 kg kg^（–1）, 12.6 kg kg^（–1）, 48.6 kg kg^（–1）, 33.8 kg kg^（–1）, and 39.3%, respectively. However, the corresponding values all varied tremendously with large variation. Rice planting regions and N rates had significant influence on grain yield, N uptake and NUE values. Considering all observations, N rates of 200 to 250 kg ha^（–1） commonly achieved higher rice grain yield compared to less than 200 kg N ha^（–1） and more than 250 kg N ha^（–1） at most rice planting regions. At N rates of 200 to 250 kg ha^（–1）, significant positive linear relationships were observed between rice grain yield and AE_N, PE_N, RE_N, IE_N, and PFPN, and 46.49, 24.64, 7.94, 17.84, and 88.24% of the variation in AE_N, PE_N, RE_N, IE_N, and PFPN could be explained by grain yield, respectively. In conclusion, in a reasonable range of N application, an increase in grain yield can be achieved accompanying by an acceptable NUE.

Cold Plasma:A Potential Alternative for Rice Grain Postharvest Treatment Management in Malaysia

Use of pesticides,herbicides and fertilizers is among the techniques to control insect pests and fungal pathogens.However,the technique is the major contributor to severe environmental implications in terms of air,water and soil pollution.Besides,variable inconsistency becomes an important issue in the implementation of inclined bed dryers,leading to significant rice grain loss.Cold plasma technology has been widely proposed as a potential alternative for rice grain postharvest treatment management due to the presence of generated ionised gas that eventually produces reactive oxygen species or reactive nitrogen species.These species are used to decontaminate foodborne pathogens,mycotoxins and bacterial diseases.This review explores the current literature regarding cold plasma treatment technology,focusing on its efficiency as the microbial decontamination medium and insect pest mortality medium,and on the enhancement functional,nutritional and cooking properties,especially in rice grains.Previous studies have successfully demonstrated the ability of cold plasma treatment to significantly reduce the microbial count of foodborne pathogens,detoxify mycotoxins,and control seedborne rice seedling bacterial diseases.Previous studies have also proved that the implementation of cold plasma technology in postharvest management should be seriously considered for improving rice grain quantity and quality in Malaysia.

Relationship Between Plant Type and Grain Quality of Japonica Hybrid Rice in Northern China

Plant type and grain quality are two major aspects in rice breeding. Using canonical correlation analysis and canonical redundancy analysis, the relationship between plant type traits and rice grain quality traits was studied with 100 crosses derived from 10 sterile lines × 10 restorer lines. There was a complex relationship between parts of the traits of the two aspects. The angle of the 2nd leaf from the top and single panicle weight played important roles in plant type system and amylose content and grain length in grain quality system. The angle of the 2nd leaf from the top, plant height and single panicle weight had a great effect on grain quality traits, and amylose content, brown rice rate and translucency were easily influenced by plant type traits. Selection index model indicated that japonica hybrid rice in Northern China with good quality was characterized by broad flag leaf and 2nd leaf from the top, narrow and short 3rd leaf from the top, low plant height, short culm, long and more panicles and low single panicle weight.

Relationship between the eating quality and the physico-chemical properties of high grain quality rice in China

Relationship between eating quality(EQ)andphysico-chemical properties of 78 high grainquality rice varieties,45 indica and 33 japoni-ca,were studied in 1995.The samples werecollected from different rice growing regions in20 provinces.The physico-chemical proper-ties,including grain length(GL),length towidth ratio(L/W),chalky grain rate(CG),chalkiness(CH),translucency(TR),gela-tinization temperature(GT,measured by alka-li spreading value),gel consistency(CA2),amylase content(AC),and protein content(PC)were measured according to the standard

Nitrogen Fertilizer Optimization and Cultivar Selection for Rice Grown near Mountainous Slopes in Orissa,India—A Field Experiment and Simulation Model Study

Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia, is suffering from lack of suitable cultivar and N fertilizer management, when grown near mountainous slopes under rain-fed agro-ecosystem. An investigation through a field experiment and simulation study was conducted at United Nations University, Tokyo to select suitable rice cultivars and N fertilizer level for the rice grown near mountainous slopes in Orissa, India. The field experiment was conducted during wet season （June to November） of 2001 at Kasiadihi village of Dhenkanal district, Orissa, India with eight popular rice cultivars of medium （120～130 d） and long duration （135～150 d） group and four N levels （0, 40, 80 and 120 kg·ha^-1）. Highest grain yield of 5,680 kg·ha^-1 was obtained from cultivar Ranjit of long duration group followed by 4,730 kg·ha^-1 from cultivar Mahamaya of medium duration group, across N levels. CERES-Rice model was used to simulated grain yield of these two selected cultivars using historical weather data of the past 18 years （1983～2000）. Long duration cultivar Ranjit registered higher yield with lower stability as compared medium duration cultivar Mahamaya over the past 18 years. An optimum N fertilizer level of 80 kg·ha^-1 was recommended for rice grown under rain-fed ecosystem near mountainous slopes in Orissa, India to attain optimum yield potential of cultivar.

Breeding Novel Short Grain Rice for Tropical Region to Combine Important Agronomical Traits, Biotic Stress Resistance and Cooking Quality in Koshihikari Background

Breeding program strategies to develop novel short grain white rice varieties such as japonica(short grain)that introgress biotic stress resistance and high grain quality have been developed usingindica rice(Pin Kaset+4 and Riceberry)for applications in japonica rice(Kashihikari)improvement.Fourbreeding lines showing promising agronomic performance with short grain and low amylose content(<20%)were obtained.In addition,sensory testing of these breeding lines showed high scores thatsimilar to Kashihikari.Two promising lines,KP48-1-5and KP48-1-9,which possessed a combination offour genes resistance to different biotic stresses(Bph3+TPS+Xa21+Pi-ta)and four genes for grainquality(G83+SSlla+w+badh2),were deveiaped using marker-assisted selection(MAS)with thepedigree method.The current study clearly illustrated the successful use of MAS in combining resistanceto multiple biotic stresses while maintaining a high yield potential and preferred grain quality.Moreover,the results indicated that this breeding program,which includes crossing temperate japonica with indica,can create novel short grain rice varieties adapted to a trapical environment like the japonica type.

Research Progresses on QTLs for Main Grain Shape Genes in Rice

The performance of rice quality affects the market competitiveness of rice to a certain extent,and grain shape is an important factor for yield traits and appearance quality.The mapping and cloning of major rice grain type genes were briefly reviewed,and the utilization of related genes in breeding was prospected.

Conditional genes for grain yield in rice

Grain yield in cereal crops was an eternal theme.The number of panicles perplant(PN),filled spikelets per panicle(FSP),and 1000-grain weight(TGW)were the three important yield components.Some QTLs for rice yield had beenmapped,but conditional QTLs for grain yield had not been analyzed.Phenotypicvalues of yield traits,which had no influence on the given components,wereused for QTLs conditional analysis.This study was to uncover conditional QTLsfor rice yield in a RIL population,and to search for evidences on the geneticbasis of yield QTLs.

Effect of phytate on the amylosynthetase activity and rice grain quality

Phytate of three concentrations was sprayed on the leaves of an indica rice Yuanfengzao in heading stage, full heading stage, filling stage and wax ripeness stage respectively. The effects of phytate on the enzyme activity in endosperm and rice grain quality were determinated. Plants sprayed with distilled water were used as control. It was showed that spraying solutions in full heading stage had the most manifest effect. The activity of amylosynthetase between the 100mg/kg and 150mg/kg phytate treatment was identical, which was 7.4% higher than that of 50mg/kg treatment. On the other hand, amylase activity on the 50mg/kg treatment was 12.5% and 8.7% lower than those

The heterotic effects on dry matter production and grain yield formation in hybrid rice

We studied the characteristics of dry matterproduction and matter partitioning in hybridrice and the relationships of them with heterot-ic effect in 1993. Two popular indica hybrids, Shanyou 63(Zhenshan 97A/Minhui 63 ) and Teyou 63(Longtepu A/Minhui 63), as well as theircommon restorer line, Minhui 63 (elite cultivar

Analysis of genetic relationships between grain milling quality traits and plant agronomic traits of rice

Since seed and maternal plant are in different generations,the grain milling traits and plant agronomic traits of rice are based on differentgenetic models.Using the genetic modelswhich could estimate covariance componentsbetween two traits with unequal design matri-ces,we analyzed the gentic relationships be-

The kinase OsSK41/OsGSK5 negatively regulates amylose content in rice endosperm by affecting the interaction between OsEBP89 and OsBP5

Amylose content(AC) is the main factor determining the palatability, viscosity, transparency, and digestibility of rice(Oryza sativa)grains. AC in rice grains is mainly controlled by different alleles of the Waxy(Wx) gene. The AP2/EREBP transcription factor OsEBP89 interacts with the MYC-like protein OsBP5 to synergistically regulate the expression of Wx.Here, we determined that the GLYCOGEN SYNTHASE KINASE 5(OsGSK5, also named SHAGGY-like kinase 41 [OsSK41]) inhibits the transcriptional activation activity of OsEBP89 in rice grains during amylose biosynthesis. The loss of OsSK41 function enhanced Wx expression and increased AC in rice grains. By contrast, the loss of function of OsEBP89 reduced Wx expression and decreased AC in rice grains. OsSK41 interacts with OsEBP89 and phosphorylates four of its sites(Thr-28,Thr-30, Ser-238, and Thr-257), which makes OsEBP89 unstable and attenuates its interaction with OsBP5. Wx promoter activity was relatively weak when regulated by the phosphomimicvariantOsEBP89E–OsBP5but relatively strong when regulated by the nonphosphorylatable variant OsEBP89A–OsBP5.Therefore, OsSK41-mediated phosphorylation of OsEBP89 represents an additional layer of complexity in the regulation of amylose biosynthesis during rice grain development. In addition, our findings provide four possible sites for regulating rice grain AC via precise gene editing.

Profiling the ionome of rice and its use in discriminating geographical origins at the regional scale, China

Element profile was investigated for their use to trace the geographical origin of rice （Oryza sativa L.） samples. The concentrations of 13 elements （calcium （Ca）, potassium （K）, magnesium （Mg）, phosphorus （P）, boron （B）, manganese （Mn）, iron （Fe）, nickel （Ni）, copper （Cu）, arsenic （As）, selenium （Se）, molybdenum （Mo）, and cadmium （Cd）） were determined in the rice samples by inductively coupled plasma optical emission and mass spectrometry. Most of the essential elements for human health in rice were within normal ranges except for Mo and Se. Mo concentrations were twice as high as those in rice from Vietnam and Spain. Meanwhile, Se concentrations were three times lower in the whole province compared to the Chinese average level of 0.088 mg/kg. About 12% of the rice samples failed the Chinese national food safety standard of 0.2 mg/kg for Cd. Combined with the multi-elemental profile in rice, the principal component analysis （PCA）, discriminant function analysis （DFA） and Fibonacci index analysis （FIA） were applied to discriminate geographical origins of the samples. Results indicated that the FIA method could achieve a more effective geographical origin classification compared with PCA and DFA, due to its efficiency in making the grouping even when the elemental variability was so high that PCA and DFA showed little discriminatory power. Furthermore, some elements were identified as the most powerful indicators of geographical origin： Ca, Ni, Fe and Cd. This suggests that the newly established methodology of FIA based on the ionome profile can be applied to determine the geographical origin of rice.