Brown Rice Weight Research Articles

Mapping of QTLs for Brown Rice Traits Based on Chromosome Segment Substitution Line in Rice (Oryza sativa L.)

Brown rice traits are critical to both grain yield and quality. In the present study, the chromosome segment substitution lines (CSSLs) population derived from a cross between japonica Koshihikari and indica Nona Bokra was used to analyze the brown rice length (BRL), brown rice width (BRW), length–width ratio of brown rice (BLWR), brown rice thickness (BRT), brown rice perimeter (BRP), brown rice area (BRA), thousand-grain weight of brown rice (BRGW), brown rice ratio (BRR), taste value of brown rice (BTV), and water content of brown rice (BWC). Correlations analysis showed that most of the brown rice traits had significant correlations with each other, except for BRR, BTV, and BWC. A total of sixty-one QTLs for these traits were identified under three environments, which mapped to chromosomes 1, 2, 3, 5, 6, 7, 8, 10, 11, and 12, with the LOD ranging from 2.52 to 16.68 and accounting for 2.60 to 25.38% of the total phenotypic variations. Moreover, thirty pairs of epistatic interactions for BRL, BRW, BLWR, BRP, and BRA were estimated and distributed on all chromosomes except 10. These findings will provide a further understanding of the genetic basis of brown rice traits and facilitate the genetic improvement of rice yield and quality through breeding.

Resveratrol-enriched rice identical to original Dongjin rice variety with respect to major agronomic traits in different cultivation years and regions

ABSTRACT Resveratrol is synthesized by the catalysis of resveratrol synthases (RS) in a limited number of higher plants. Resveratrol shows potential health-promoting properties, including as an antioxidant and in preventing cardiovascular diseases. Recently, resveratrol-enriched rice has been produced as a novel source of resveratrol. This study aimed to investigate the major agronomic characteristics of resveratrol-enriched rice, Iksan526 (I526) and compared them with those of a nontransgenic and commercial rice variety, Dongjin (DJ). Transgene (RS) integration was confirmed using Southern blot analysis, and homologous recombination was achieved after digestion with the SacI restriction enzyme. The phenotypic traits of I526 grown in Iksan were similar to those grown in Milyang but not similar to those grown in Suwon. In Suwon, I526 had slightly earlier heading dates [i.e., number of days from sowing to heading) and shorter culm lengths. When I526 was treated with 0.4% Basta in the seedling stage, no significant difference was observed among all the agronomic traits compared with nontreated I526; particularly, the culm length, panicle length, number of panicles per hill, 1,000 grain weight of brown rice, and brown rice yield of the Basta-treated rice were similar to those of the nontreated I526, regardless of their cultivation region. The resveratrol content of I526 grown in Suwon and Milyang was increased by 18% and 37%, respectively, than that of I526 grown in the Iksan area. Therefore, DJ and I526 are not significantly different in terms of major agronomic traits depending on variety/year and variety/cultivation region. The results indicated that I526 has the potential to become a commercialized variety in the near future.

Efficacy of N-methyl-N-nitrosourea (MNU) Mutation on Enhancing the Yield and Quality of Rice

Mutation technology has been applied more in recent decades to achieve novel products that are not commonly found in nature. An experiment was conducted to examine the effects of an N-methyl-N-nitrosourea (MNU) mutation on the growth, yield, and physicochemical properties of rice. Seeds of two rice cultivars (K1: DT84, and K3: Q5), along with their mutant lines (K2: mutated DT84, and K4: mutated Q5), were sown, and the established seedlings were transplanted to an open field. Ten hills per plot were randomly selected to evaluate growth parameters, yield, and components. Physicochemical attributes, including protein, amylose, and lipid contents, as well as taste score were measured by a quality tester device. The results showed that plant length, tiller number, and panicle length were higher in mutant lines than those of their cultivars. Furthermore, mutant lines took longer to reach heading and maturity stage. The highest panicle number, spikelet number, repined ratio, 1000 grain weight, 1000 brown rice weight, and grain yield were obtained in mutant lines, as compared to cultivars. The greatest grain yield was obtained in the K4 mutant line (11.6 t/ha), while the lowest was recorded in the K1 cultivar (7.7 t/ha). Lower amylose, protein, and lipid contents were observed in mutant lines compared to those in cultivars. The taste score, which increased from 67.7 to 73.7, was found to be correlated with lower amylose, protein, and lipid contents. The mutation approach increased the grain length but decreased the grain width of tested varieties. This study highlights and suggests the importance of MNU mutation in terms of rice yield improvement with preferable quality.

Identification and characteristics of quantitative trait locus for grain protein content, TGP12, in rice (Oryza sativa L.)

Grain protein content is an important analysis target to determine grain quality in rice. This study analyzed quantitative trait loci (QTLs) for the content of grain protein and amylose using the chromosomal segment substitution lines developed from ‘Koshihikari’ and ‘Nona Bokra’. It also evaluated the effects of target QTL on eating and cooking quality through the physical properties of cooked rice and its gel consistency. QTL analysis over 3 years detected the QTL on chromosome 12, TGP12, which consistently decreased total grain protein content via the ‘Nona Bokra’ allele. Selected CSSL with TGP12, CSSL-TGP12, showed a lower content of total grain protein in brown and milled rice, and had similar amylose content, grain size, and weight of brown rice, compared with ‘Koshihikari’. Based on the results of sodium dodecyl sulfate polyacrylamide gel electrophoresis, brown rice with CSSL-TGP12 had no remarkable decrease or loss in any specific protein. Regarding eating and cooking quality, CSSL-TGP12 did not show stable effects on physical properties, hardness, stickiness, or adherability of cooked rice or its gel consistency. These results suggest that TGP12 could be one of the key genetic factors for the alteration of grain protein content without an effect on eating or cooking quality.

Moisture distribution in rice grains used for sake brewing analyzed by magnetic resonance imaging

Water absorption in individual white-core and non-white-core grains of rice varieties used in sake brewing was observed during soaking by magnetic resonance imaging (MRI). Water was absorbed faster in white-core grains than in non-white-core grains and was pooled in the core. Moisture distributions were compared using the line profiles of nuclear magnetic resonance signal intensities (SI profiles) generated from magnetic resonance images of grains soaked for 2 h. SI profiles of white-core and non-white-core grains overlapped despite slight differences in the central and intermediate regions of the grains. A white-core-like structure with loosely packed starch granules was found to exist in the endosperm of non-white-core grains. SI profiles of grains polished to 70% of the yield weight of brown rice were similar in shape to those of grains polished to 90% of the yield, but their overall moisture content was higher after the removal of the hydrophobic grain periphery. A varietal difference in the thickness of the intermediate region, which may affect fissuring resistance in the polishing process, was detected in SI profiles. Differences in water absorbability between parents and their offspring were also apparent from their SI profiles. MRI enabled the detection of variety-specific water-absorption properties in grains.

Changes in Enzyme Activities Involved in Starch Synthesis and Hormone Concentrations in Superior and Inferior Spikelets and Their Association with Grain Filling of Super Rice

The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain filling was analyzed. Four super rice cultivars, Liangyoupeijiu, IIyou 084, Huaidao 9 and Wujing 15, and two high-yielding and elite check cultivars, Shanyou 63 and Yangfujing 8, were used. The activities of sucrose synthase (SuSase), adenosine diphosphoglucose pyrophosphorylase (AGPase), starch synthase (StSase) and starch branching enzyme (SBE), and the concentrations of zeatin + zeatin riboside (Z + ZR), indole-3-acetic acid (IAA) and abscisic acid (ABA) in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed. Maximum grain filling rate, the time reaching the maximum grain-filling rate, mean grain filling rate and brown rice weight for superior spikelets showed a slight difference between the super and check rice cultivars, but were significantly lower in the super rice than in the check rice for inferior spikelets. Changes of enzyme activities and hormone concentrations in grains exhibited single peak curves during the grain filling period. The peak values and the mean activities of SuSase, AGPase, StSase and SBE were lower in inferior spikelets than in superior ones, as well as the peak values and the mean concentrations of Z + ZR and IAA. However, the peak value and the mean concentration of ABA were significantly higher in inferior spikelets than in superior ones and greater in the super rice than in the check rice. The grain filling rate was positively and significantly correlated with the activities of SuSase, AGPase and StSase and the concentrations of Z + ZR and IAA. The results suggested that the low activities of SuSase, AGPase and StSase and the low concentrations of Z + ZR and IAA might be important physiological reasons for the slow grain filling rate and light grain weight of inferior spikelets in super rice.

Detecting relationships between amylose content and amino acid contents of indica rice with conditional approach

The relationship between the genetic effects of endosperm, cytoplasm and maternal plant on amylose content (AC) and amino acid contents of indica rice was studied using unconditional and conditional analysis methods. The results indicated that the protein content (PC) and brown rice weight (WBR) could significantly affect the relationships between AC and amino acid contents of rice. The phenotypic and genotypic covariances between AC and amino acid contents were most significantly negative under the interference of PC or WBR, but most of the relationships for the paired traits were not significant after excluding the influence of PC or WBR on AC. For the conditional genetic relationship analysis of different genetic systems including endosperm, cytoplasm and maternal plant, visible changes were found in many genetic correlation components between AC and amino acid content after eliminating the influences of PC, especially, for the endosperm or maternal additive effects, endosperm additive or dominance interaction effects and maternal additive interaction effects. The relationships of the paired traits conditioned on WBR were mainly controlled by the endosperm dominance or additive interaction effects.

Post-Anthesis Changes in Concentrations of Polyamines in Superior and Inferior Spikelets and Their Relation with Grain Filling of Super Rice

Success in super rice breeding has been considered a great progress in rice production in China. However, many un-filled inferior spikelets limit the realization of great yield. As polyamines have been frequently described as endogenous plant growth regulators or intracellular messengers mediating physiological processes, this study investigated whether and how poly-amines are involved in the regulating post-anthesis development of rice spikelets. Four super rice cultivars, Liangyoupeijiu and II you 084 (indica hybrids), Huaidao 9 and Wujing 15 (japonica), and two high-yielding check cultivars, Shanyou 63 (indica hybrid) and Yangfujing 8 (japonica), were field grown. Concentrations of putrescine (Put), spermidine (Spd) and spermine (Spm) in both inferior and superior spikelets during the grain filling period and grain filling rate were determined. The relationship between polyamine concentrations and grain filling rate were analyzed, and chemical regulators were applied to verify the roles of poly-amines in grain filling. The results showed that the maximum grain filling rate, mean grain filling rate, and brown rice weight for superior spikelets showed small difference between the super rice and check rice, but those of inferior spikelets were significantly lower for super rice than for check rice cultivars. Changes in concentrations of polyamines in grains exhibited single peak during the grain filling period. The peak and mean concentrations of Put were greater in inferior than in superior spikelets. The peak and mean concentrations of Spd and Spm were greater in the superior than in the inferior, and greater in the check rice than in the su-per rice. The mean grain filling rate and brown rice weight were negatively and very significantly correlated with the Put concen-trations, and positively and very significantly correlated with Spd and Spm concentrations, Spd/Put, and Spm/Put. Application of Spd or Spm to panicle at the early grain filling stage significantly enhanced activities of sucrose synthetase, adenine di-phosphoglucose pyrophosphorylase, and soluble starch synthetase in inferior spikelets, and significantly increased grain filling rate, seed setting rate and grain weight of inferior spikelets. Application of Put or methylglyoxal-bis (guanylhydrazone) (MGBG, an inhibitor of S-adenosyl-L-methionine decarboxylase) exhibited an opposite effect. The results suggest that polyamines play a role in regulating grain filling. Low concentrations of Spd and Spm and low Spd/Put and Spm/Put may be an important physiological reason for the small grain filling rate and low grain weight of inferior spikelets in super rice.

Post-Anthesis Changes in Concentration of Polyamine in Superior and Inferior Spikelets and Their Relationship with Grain Filling of Super Rice

To reveal the physiological role of polyamines and the mechanism involved in grain-filling of rice ( Oryza sativa L.) superior and inferior spikelets, the relationship between grain-filling rate and polyamine concentrations was analyzed and verified using 4 super rice cultivars and 2 high-yielding cultivars (controls). Compared with the controls, super rice had similar maximum grain-filling rate, mean grain-filling rate, and brown rice weight in superior spikelets and significantly lower values in inferior spikelets. The concentrations of putrescine (Put), spermidine (Spd), and spermine (Spm) varied in single-peak curves in both inferior and superior spikelets during grain-filling period. The peak and mean concentrations of Put were greater in inferior spikelets than in superior spikelets. However, the peak and mean concentrations of Spd and Spm were greater in superior spikelets than in inferior spikelets. The control cultivars had higher concentrations of polyamines than super rice. The mean grain-filling rate and brown rice weight were negatively correlated with Put concentration, and positively correlated with Spd and Spm concentrations and the ratios of Spd/Put and Spm/Put. Spraying of Spd or Spm to panicle at early grain-filling stage significantly enhanced activities of sucrose synthetase, adenine diphosphoglucose pyrophosphorylase, and soluble starch synthetase in inferior spikelets, resulting in improvement of grain-filling rate, seed-setting rate, and grain weight. Application of Put or methylglyoxal-bis (guanylhydrazone) (MGBG, an inhibitor of S-adenosyl- L-methioninedecarboxylase) exhibited an opposite effect. These results indicated a regulative function of polyamines during grain filling. The low grain-filling rate and grain weight in inferior spikelets of super rice are probably in relation to the low concentrations of Spd and Spm and the small ratios of Spd/Put and Spm/Put in inferior spikelets.

The concentration and distribution of essential elements in brown rice associated with the polishing rate: Use of ICP-AES and Micro-PIXE

The concentration and distribution of essential elements in brown rice grains ( Oryza sativa L. var. japonica) associated with the polishing rate was determined. Rice samples were collected in Japan and polished to 5%, 10%, 15% and 20% loss of the total weight of brown rice. Concentrations of eight essential elements (P, K, Ca, Mg, Cu, Fe, Mn and Zn) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), and distributions of the elements in a single grain were visualized as elemental distribution maps of a cross section by micro particle induced X-ray emission (Micro-PIXE) analysis. Results of ICP-AES analysis indicated that in rice which polished from 0% to 10% loss of weight, there were three patterns in the P/ B ratio, which is the mean concentration of an element in polished rice divided by that of the element in the brown rice: no change (Cu and Zn), a gradual decrease (P, Mg, Mn and Fe), and a decrease after a constant phase (Ca and K). There was no remarkable change of the P/ B ratio in rice grains which polished from 10% to 20% loss of weight. Micro-PIXE analysis images showed that P, K, Ca, Mg, Fe and Mn were present in large amounts in the surface layer (approx. <200 μm thickness) of brown rice. Two sub-layers were mainly recognized in the grain surface layer in the elemental distribution maps of a cross section. The first sub-layer was approximately 130–170 μm thick. The second sub-layer was approximately 20–50 μm thick, and the primary part of the grain (endosperm cells and starch granules) was under it. The images showed Cu and Zn were uniformity distributed in brown rice, and their concentrations of polished rice were not affected by the polishing rate. Although ICP-AES measurements could not provide the detail structure of the surface layer of the rice grains, the trend of concentration of the elements generally agreed with the elemental distribution maps obtained Micro-PIXE analysis.

Analysis of the genetic relationships from different genetic systems between the amylose content and the appearance quality of indica rice across environments

The genetic relationships between amylose content (AC) and appearance quality traits of indica rice (Oryza sativa L.) were investigated using conditional analysis and unconditional analysis in present experiment. The results from the unconditional analysis indicated that AC of rice positively correlated with brown rice (BR, i.e., dehulled but unmilled rice) length (BRL), width (BRW) and thickness (BRT), but was negatively correlated with the ratio of length to width (RLW). The conditional analysis showed that weight of brown rice (WBR) negatively affected the genetic relationships between AC and the appearance quality traits of rice except between AC and BRW, while the genetic relationships between AC and most appearance quality traits were negatively affected by protein content (PC). However, these influences were not apparent due to the impact of WBR or PC on the most covariance components of the different genetic systems between AC and the appearance quality traits. The conditional analysis showed that it was possible to improve AC while significantly reduce BRL and BRT under maintaining WBR. Furthermore, AC could be improved when BRL was reduced under maintaining PC, but BRW and BRT could be significantly increased.

Analysis of the Conditional Correlations from Different Genetic Systems Between the Protein Content and the Appearance Quality Traits of Indica Rice

A factorial mating design in two environments was conducted using 7 cytoplasmic male sterile lines (A) and 5 restorer lines (R) along with their F 1 (A × R) and F 2 populations. The unconditional and conditional analyses of genetic models and the corresponding statistic methods, including endospermic, cytoplasmic, and maternal plant genetic systems, were used to analyze the genetic relationships between protein content (PC) and the appearance quality traits of indica rice ( Oryza sativa L.). The results from unconditional analysis indicated that PC was significantly correlated with the appearance quality traits of rice, except for the brown rice thickness (BRT). Only the genetic covariance between PC and the brown rice width (BRW) was positively correlative, whereas all the other pairwise traits were negatively correlative. The results from conditional analysis revealed that the weight of brown rice (WBR) or the amylose content (AC) could significantly affect the relationships between PC and the appearance quality traits of indica rice. The conditional analysis showed that WBR might negatively affect the relationships between PC and the brown rice length (BRL), BRW, or BRT through the genotype × environmental (GE) interaction effects, but positively affected the relationships between PC and the ratio of brown rice length to width (RLW) or the ratio of brown rice length to thickness (RLT). The amylase content could positively affect the relationships between PC and BRL, RLW, RLT through the cytoplasmic effects and maternal additive effects, but negatively affected the relationships between PC and BRW.

Correlation of the Weight of Brown Rice per Panicle with the Vertical Distribution of Leaf Area and the Nitrogen Content of Leaves on the Tillers at Each Nodal Position and Nodal Order in Rice Canopy

本報告では, 主茎や分げつの発生次位・節位の違いにより着生籾の玄米重が異なる要因を明らかにするため, 出穂期以降の水稲群落における主茎や次位・節位別分げつの葉面積と葉面積あたりの葉身窒素量の垂直分布を検討した. その結果, 玄米重の重い主茎や分げつは 1)1穂籾数は多いが精玄米歩合や精玄米千粒重は低下せず, 2)葉面積は大きいが, 籾あたり葉面積に差がなく, 3)相対照度の高い群落上層に葉面積あたりの葉身窒素量の多い葉身が多く分布した. これらの結果から, 主茎や次位・節位別分げつにおける着生籾の玄米重の違いは, 出穂期以降の群落空間における各茎の葉面積および葉面積あたりの葉身窒素量の垂直分布が異なることが要因と考えられた.

Prediction of grain weight, brown rice weight and amylose content in single rice grains using near-infrared reflectance spectroscopy

The potential of near-infrared reflectance spectroscopy (NIRS) for simultaneous analysis of grain weight (mg), brown rice weight (mg) and milled rice amylose content (AC, %) in single rice grains was studied. Calibration equations were developed using 474 single grain samples, scanned as both rice grain and brown rice. An independent set containing 90 F 2 generation grains was used to validate the equations. In general, equations developed using the first derivative resulted in superior calibration and validation statistics compared with the second derivative and those developed using brown rice were superior to those developed from the rice grain. Fitting equations were developed and monitored with an external validation set. The standard error of prediction (corrected for bias) SEP(C) for AC, brown rice weight and rice grain weight for equations developed using brown rice were 2.82, 1.09 and 1.30, with corresponding coefficient of determinations ( r 2) of 0.85, 0.71 and 0.67, and SEP(C)/S.D. of 0.39, 0.57 and 0.59, respectively. It was demonstrated that NIRS provides a convenient way to screen single intact grains. This will be advantageous in early generation selection in rice breeding programs.

Effects of High Air Temperature and Insufficient Solar Radiation during Ripening Period on the Palatability and Physicochemical Properties of Rice in 1999 in Kyushu Regions.

This study was carried out to demonstrate the effect of high air temperature and the insufficient solar radiation during the ripening period on the palatability and physicochemical properties of rice produced in 1999. Using eight cultivars in Fukuoka Prefecture, we compared the grain ripening and physicochemical properties of rice produced in 1999 with those in 1996 and 1998, years that were characterized by normal air temperature and normal solar radiation, high air temperature and normal solar radiation, respectively. Since the 1000-grain weight and grain thickness of rice in 1999 were lower than in 1996 and 1998, the rice in 1999 ripened insufficently. Milled rice in 1999 showed lower amylose content and breakdown values, and a higher protein content and Hardness/Adhesiveness ratio (H/A3) than in 1996 and 1998. The 1000-grain weight of brown rice produced from 1994 to 2000 showed a negative correlation with the amylose content of milled rice in each year, and the 1000-grain weight of brown rice produced from 1995 to 2000 showed a positive correlation with the protein content of milled rice in each year. As a result, insufficient grain filling caused the increase of amylose content and the decrease of protein content. It was concluded that the shortage of solar radiation in 1999 was due to insufficient grain filling, which led to the abnormal physicochmical properties. Furthermore, it was estimated that not only were the physicochemical properties of rice in 1999 inferior to those of rice produced in 1996 and 1998, but also was the palatability of rice.

Expression of natural antimicrobial human lysozyme in rice grains

In the present study, we explored the expression of human lysozyme in maturing rice grains. Particle bombardment-mediated transformation was utilized to deliver the codon-optimized structural gene for human lysozyme to the callus of rice cultivar Taipei 309. Lysozyme expression is controlled by the promoter and signal peptide sequence for rice storage protein Glutelin 1. A total of 33 fertile plants were regenerated from independent transformation events and 12 of them with significant expression levels of lysozyme were advanced to further generations. The transgenes were characterized by PCR and Southern blot analysis. Segregation analysis indicated a typical Mendelian 3: 1 inheritance, suggesting a single locus or closely linked loci of gene insertion. The expression levels of lysozyme reached 0.6% of the brown rice weight or 45% of soluble proteins. Seven transgenic breeding lines have been selected and followed over six generations. Lysozyme expression levels were maintained in all generations. Biochemical, biophysical and functional comparisons of native and recombinant human lysozyme revealed identical N-terminal sequence, molecular weight, pI and specific activity. Similar thermal and pH stability was observed for lysozyme from two sources. Furthermore, similar bactericidal activity was displayed towards a laboratory strain of E. coli. The possibility of improving medical and nutritional quality of infant formulas and baby foods with rice flour or rice extract containing recombinant human lysozyme is discussed.

Effects of Salty Wind on the Yield and Quality in Rice Using a Wind Tunnel.

The effects of salty wind on the brown rice weight and quality of rice were investigated using a wind tunnel. Two varieties, cv. Hinohikari, cv. Yumehikari, were grown in 1/2000a Wagner's pots containing paddy field soil. The brown rice weight of a plot (non-salty water and non-water sprinkling) was 36.2 g/plant, D and H plots (weak wing treatment; 7.1±1.6 m/s, strong wind treatment; 14.4±4.3 m/s) with salty water treatment were 11.0 g/plant, 15.0 g/plant, respectively and under the condition of 60l/40 min water sprinkling treatment after salty water treatment were 21.7∼22.1 g/plant. The effects of salty water, water sprinkling, wind speed and treatment time on brown rice weight and 1000 grain weight were analyzed by the type I quantification method. According to the result of analysis of salty water treatment of brown rice weight, category scores were 6.47 and -9.71, and the partial correlation was 0.949. On the other hand, with water sprinkling treatment on brown rice weight, category scores were -1.87 and 2.81, and the partial correlation was 0.655. However, the partial correlation of wind speed or treatment time with brown rice weight was low.

Influence of Leaf Nitrogen Content on Grain Weight at Early Ripening Period and Relationship between Root Respiration and Leaf Area per Spikelet of Rice Plant.

The same seedlings of three rice cultivars were transplanted into both paddy fields, experimental fields of Tottori University (Koyama) and skillful farmer's field (Hojo), and given their respective manuring practice. Hojo plants kept a high level nitrogen content in leaves (LN%) until harvest time because the amount of nitrogen fertilizer in Hojo was two to three times greater. The weight of whole brown rice of Hojo plants at 15 days after the full heading date (FHD) was lighter than that of Koyama rice plants. The causes of this different in brown rice weight were studied on concerning factors, leaf area per spikelet (F/spikelet), LN% and ammonium concentration in brown rice. The relationship between F/spikelet and increasing rate of weight of whole brown rice had a positive correlation throughout the grain filling period. At 15 days after FHD, the correlation between LN% and the weight of whole brown rice was negative comparing among plants of F/spikelet levels. The weight of whole brown rice at 15 and 30 days after FHD showed a highly negative correlation with the ammonium concentration in the brown rice which was closely related to LN%. Therefore, it seemed that the grain filling of Hojo plants was delayed by the ammonium concentration in brown rice increased due to excessive high LN% at the early ripening period. The F/spikelet supporting the increase of grain filling had high correlation with LN%, and the relation between F/spikelet and root respiratory rate was highly positive. Therefore, the amount of F/spikelet was sustained with a high root respiratory rate, supported by root nitrogen and sugar content, throughout the ripening period.

Case Studies on High Yields of Paddy Rice in Jiangsu Province, China. II. Analysis of characters related to lodging.

To clarify lodging resistance of high yield examples, characters related to lodging of Shan You 63 (F1 hybrid rice) with 965 gm-2 of a brown rice weight were analyzed. There were various factors for early lodging regarding external morphological characters. The lodging index (a distance between fulcra in 5 cm) at the 4th internode from the top (N4) at maturity was more than 200. High yield of Shan You 63 was obtained under quite dangerous conditions as regards lodging. The reason for increase in the lodging index at N4 was low breaking resistance. This phenomenon could be explained by a high rate of translocation of non-structural carbohydrate (NSC) and total nitorogen (N) from the culm and leaf to ear, and an extreme decrease in dry weight per unit length of the portion lower than N4 at maturity. To consistently obtain a yield exceeding 965 gm-2 in Shan You 63, it is necessary to develop cultivation techniques to store more NSC, N and dry matter in the culm and leaf sheath and ear.

On the Grain Texture of Rice : 3. On the factors concerned in milling-loss of hulled rice

With the purpose of making clear the factors concerned in milling-loss of hulled brown rice, laboratry milling-test was conducted on 80 samples of 36 varieties. Checked grains, opapue grains and the other abnormal grains were exluded from each sample prior to milling to obtain the reasonable and fundamental data on normal grains, for these abnormal grains have complicated effects upon milling-loss according to the degree of imperfection. Milling-loss was discussed in conformity to the following designation; Usual milling loss(%)=(1-Weight of white rice after milling/Weight of brown rice before milling)×100 Pure milling-loss (%)=(1 Mean weight of white rice of perfect shape/Mean weight of brown rice)×100 Therefore, usual milling-loss=Pure milling-loss+Crushing-loss Pure milling-loss(%)=Milling-loss of endosperm+Milling-loss of embryo Mean weight of embryo Milling-loss of embryo (%)≒weight of embryo/Maen weight of brown rice×100 Because, almost all embryos fall off by usual milling. 1. Relation between percentage of embryo to grain in weight and pure milling-loss. The ratio of embryo to grain in weight is varied by environment as well as by variety, and increases under high temperature during ripening and the other unfavourable environment for grain growth. The percentage of embryo to grain in weight forms itself a part of milling-loss as above mentioned, therefore, fairly high correlation (r=+0.888) was recognized between the percentage of embryo to grain and pure milling-loss. (fag. 1) 2. The milling-loss of endosperm is supporsed to be affected by thickness of bran and depth of groove (crease) on kernel. Thickness of bran on dorsal side and on lateral side and depth of the deepest groove on grain were measured, then the measurements were indicated as the ratios to √^3(grain weight.) drain weigh. Correlation coefficient between thickness of dorsal bran and milling-loss of endosperm and that between thickness of lateral bran and milling-loss of endosperm were 0.475 and 0.481 respectively, consequently, it is supporsed that more important and basic factror will concern to milling-loss of endosperm. (fig. 2, 3) Any significant correlation could not be recognized between depth of groove and milling-loss of endosperm. (fig. 4) 3. Relation between percentage of basal-white grains to normal grains and milling-loss of endosperm. Percentage of basal-white grains to normal grains (basal-white grains are included in normal grains.) in number (x) indicates the grade of insufficiency of starch accumulation into grain and high number of this percentage shows low density of starch in cells especially in peripheral region of basal portion of grain, and low density of starch in cell shows softness of cell. Correlation between log and milling-loss of endosperm was very high (+0.922) as shown in fig. 5, therfore, it is pointed out that soft starch cells in peripheral region are easily pared off by milling and milling-loss of endosperm depends mainly on the amount of soft starch cells pared off by milling. (fig. 6) 4. Relation between percentage of basal-white grains to normal grains in number (x) and pure milling-loss is composed of milling-loss of endosperm and milling-loss of embryo. Milling-loss of embryo is nearly equal to the percentage of embryo to grain in weight, and the percentage of embryo to grain has fairly high correlation (+0.702) between log x (fig. 7), and milling-loss of endosperm is also closely correlated with log x, consequently, high correlation (+0.851) is recognized between log x and pure milling-loss. (fig. 8) 5. Relation between pure milling-loss and usual milling-loss. The grains which have more numerous soft starch cells in peripheral region have higher pure milling-loss and at the same time, some of them are crushed more easily by milling on basal portion of them, then they have higher usual milling-loss. Accordingly, high correlation (+0. [the rest omitted]