Genetic Variability and Phenotypic Correlations Study among Grain Quality Traits and Mineral Elements Concentrations in Colored and Non-Colored Rice (Oryza sativa L.)

Twenty-four rice genotypes were examined to assess genetic variability,heritability,and correlations for seven-grain quality traits,eight nutritional elements,and protein.ANOVA revealed significant differences for the quality traits studied.For every trait under study,the phenotypic coefficient of variation was higher than the correspon-dence genotypic coefficient of variation.Heritability in a broad sense varied from 29.75%for grain length to 98.31%for the elongation trait.Hulling percentage recovery had a highly significant positive correlation with milling and head rice percentage.Consequently,milling percentage had a highly positive correlation with head rice percentage.In amylose percentage,all the genotypes belonged to low amylose except the Hassawi-1 variety,which had intermediate amylose content.Mineral nutrition contents of magnesium(Mg),sodium(Na),potas-sium(K),calcium(Ca),copper(Cu),manganese(Mn),zinc(Zn),iron(Fe),or protein percentage gave different variations for 24 rice genotypes under all the nutritional elements.Among the 24 genotypes,ten rice genotypes–HighNutrient-1,HighNutrient-2,HighNutrient-9,HighNutrient-8,HighNutrient-3,Hassawi-2,HighNutrient-7,HighNutrient-6,Hassawi-1,and HighNutrient-4–had the highest heist value for all nutritional and protein con-tents,and could be used as a donor to improving new varieties.There was a positive and significant correlation between magnesium Mg,K,Zn and Fe.Consequently,K had a positive correlation with zinc Zn,Fe,and protein percentage.Clustering analysis was divided into two groups:thefirst group included all genotypes rich in nutri-ents,while the remaining genotypes with low nutritional content were included in the second group.

Translocation and Distribution of Carbon-Nitrogen in Relation to Rice Yield and Grain Quality as Affected by High Temperature at Early Panicle Initiation Stage

Due to climate change, extreme heat stress events have become more frequent, adversely affecting rice yield and grain quality. The accumulation and translocation of dry matter and nitrogen substances are essential for rice yield and grain quality. To assess the impact of high temperature stress(HTS) at the early panicle initiation(EPI) stage on the accumulation, transportation, and distribution of dry matter and nitrogen substances in various organs of rice, as well as the resulting effects on rice yield and grain quality, pot experiments were conducted using an indica rice cultivar Yangdao 6(YD6) and a japonica rice cultivar Jinxiangyu 1(JXY1) under both normal temperature(32 ℃/26 ℃) and high temperature(38 ℃/29 ℃) conditions. The results indicated that exposure to HTS at the EPI stage significantly decreased rice yield by reducing spikelet number per panicle, grain-filling rate, and grain weight. However, it improved the nutritional quality of rice grains by increasing protein and amylose contents. The reduction in nitrogen and dry matter accumulation accounted for the changes in spikelet number per panicle, grain-filling rate, and grain size. Under HTS, the decrease in nitrogen accumulation accompanied by the reduction in dry matter may be due to the down-regulation of leaf net photosynthesis and senescence, as evidenced by the decrease in nitrogen content. Furthermore, the decrease in sink size limited the translocation of dry matter and nitrogen substances to grains, which was closely related to the reduction in grain weight and the deterioration of grain quality. These findings significantly contribute to our understanding of the mechanisms of HTS on grain yield and quality formation from the perspective of dry matter and nitrogen accumulation and translocation. Further efforts are needed to improve the adaptability of rice varieties to climate change in the near future.

Decreased panicle N application alleviates the negative effects of shading on rice grain yield and grain quality

Light deficiency is a growing abiotic stress in rice production.However,few studies focus on shading effects on grain yield and quality of rice in East China.It is also essential to investigate proper nitrogen(N)application strategies that can effectively alleviate the negative impacts of light deficiency on grain yield and quality in rice.A two-year field experiment was conducted to explore the effects of shading(non-shading and shading from heading to maturity)and panicle N application(NDP,decreased panicle N rate;NMP,medium panicle N rate;NIP,increased panicle N rate)treatments on rice yield-and quality-related characteristics.Compared with non-shading,shading resulted in a 9.5-14.8%yield loss(P<0.05),mainly due to lower filled-grain percentage and grain weight.NMP and NIP had higher(P<0.05)grain yield than NDP under non-shading,and no significant difference was observed in rice grain yield among NDP,NMP,and NIP under shading.Compared with NMP and NIP,NDP achieved less yield loss under shading because of the increased filled-grain percentage and grain weight.Shading reduced leaf photosynthetic rate after heading,as well as shoot biomass weight at maturity,shoot biomass accumulation from heading to maturity,and nonstructural carbohydrate(NSC)content in the stem at maturity(P<0.05).The harvest index and NSC remobilization reserve of NDP were increased under shading.Shading decreased(P<0.05)percentages of brown rice,milled rice,head rice,and amylose content while increasing(P<0.05)chalky rice percentage,chalky area,chalky degree,and grain protein.NMP demonstrated a better milling quality under non-shading,while NDP demonstrated under shading.NDP exhibited both lower chalky rice percentage,chalky area,and chalky degree under non-shading and shading,compared with NMP and NIP.NDP under shading decreased amylose content and breakdown but increased grain protein content and setback,contributing to similar overall palatability to non-shading.Our results suggested severe grain yield and quality penalty of rice when subjected to shading after heading.NDP improved NSC remobilization,harvest index,and sink-filling efficiency and alleviated yield loss under shading.Besides,NDP would maintain rice’s milling,appearance,and cooking and eating qualities under shading.Proper N management with a decreased panicle N rate could be adopted to mitigate the negative effects of shading on rice grain yield and quality.

Breeding and Application of Japonica CMS Line Yangfujing 7A with Fine Grain Quality, Disease Resistance and High Combining Ability in Rice

Yangfujing 7A, derived from the cross between Xu 9201A and Yangfujing 7 and its successive backcrosses, is a BT-type japonica CMS line developed by the Agricultural Institute of Riparian Region of Jiangsu Province. It shows good integrat- ed characteristics, stable male sterility, good flowering habits, high out crossing rate, strong disease resistance, fine grain quality （reaching the 1st class of national standards for fine quality rice） and high combining ability. In 2012, it was technically identified in Jiangsu Province. Its F1 hybrid combination Tongyoujingl （Yangfujing 7 A/R98）, showing high yield and good grain quality, was registered and released to commercial production by Jiangsu Crop Variety Appraisal Committee in 2013.

Effects of Lodging at Different Filling Stages on Rice Yield and Grain Quality

The effects of lodging of rice plants from 20 d after full heading to maturity on yield and grain quality were investigated with a hybrid rice combination Liangyoupeijiu and a japonica rice cultivar CY-6. The results showed that, except for brown rice rate, almost all parameters for yield and grain quality including ratio of grain length to grain width, gelatinization temperature and gel consistency, were significantly influenced by lodging and thus deteriorated. Regression analysis suggested that, lodging one day earlier at the grain-filling stage could cause 2.66% to 2.71% of yield loss, 1.8 to 2.6 percentage points decrease of seed-setting rate, 0.26 to 0.32 g reduction of lO00-grain weight, 0.097 to 0. 155 percentage point decline of milled rice rate, as well as 0.13 to 0.27 percentage point increase of chalky grain rate, and 0.021 to 0.024 percentage point rise of protein content, and subsequently lower the eating quality.

Application of moderate nitrogen levels alleviates yield loss and grain quality deterioration caused by post-silking heat stress in fresh waxy maize

High temperature(HT)during grain filling is one of the most important environmental factors limiting maize yield and grain quality.Nitrogen(N)fertilizer is essential for maintaining normal plant growth and defense against environmental stresses.The effects of three N rates and two temperature regimes on the grain yield and quality of fresh waxy maize were studied using the hybrids Suyunuo 5(SYN5)and Yunuo 7(YN7)as materials.N application rates were 1.5,4.5,and 7.5 g plant-1,representing low,moderate,and high N levels(LN,MN,and HN,respectively).Mean day/night temperatures during the grain filling of spring-and summer-sown plants were 27.6/21.0°C and 28.6/20.0°C for ambient temperature(AT)and 35/21.0°C and 35/20.0°C for HT,respectively.On average,HT reduced kernel number,weight,yield,and moisture content by 29.8%,17.9%,38.7%,and 3.3%,respectively.Kernel number,weight,yield,moisture,and starch contents were highest under MN among the three N rates under both temperature regimes.HT reduced grain starch content at all N levels.HT increased grain protein content,which gradually increased with N rate.Mean starch granule size under MN was larger(10.9μm)than that under LN and HN(both 10.4μm)at AT.However,the mean size of starch granules was higher under LN(11.7μm)and lower under MN(11.2μm)at HT.Iodine binding capacity(IBC)was lowest under MN and highest under HN among the three N levels under both temperature regimes.In general,IBC at all N rates was increased by HT.Peak viscosity(PV)was gradually reduced with increasing N rate at AT.In comparison with LN,PV was increased by MN and decreased by HN at HT.Retrogradation percentage gradually increased with N rate at AT,but was lowest under MN among the three N rates at HT.LN+AT and MN+HT produced grain with high pasting viscosity and low retrogradation tendency.MN application could alleviate the negative effects of HT on the grain yield and quality of fresh waxy maize.

Effect of Cold-Water Irrigation on Grain Quality Traits in japonica Rice Varieties from Yunnan Province,China

The response of grain quality traits to cold-water irrigation and its correlation with cold tolerance were studied in 11 japonica rice varieties from Yunnan Province, China. The results indicated that the response of grain quality traits to the cold-water stress varied with rice varieties and grain quality traits. Under the cold-water stress, grain width, chalky rice rate, whiteness, 1000-grain weight, brown rice rate, taste meter value, peak viscosity, trough viscosity, breakdown viscosity and final viscosity significantly decreased, whereas grain length-width ratio, head rice rate, alkali digestion value, protein content and setback viscosity markedly increased. However, the other traits such as grain length, amylose content, milled rice rate, peak viscosity time and pasting temperature were not significantly affected by the cold-water stress. Significant correlations were discovered between phenotypic acceptability and cold response indices of taste meter value, protein content, peak viscosity and breakdown viscosity. Therefore, it would be very important to improve the cold tolerance of Yunnan rice varieties in order to stabilize and improve their eating quality.

Bentonite-humic acid improves soil organic carbon,microbial biomass,enzyme activities and grain quality in a sandy soil cropped to maize(Zea mays L.) in a semi-arid region

A bentonite-humic acid(B-HA) mixture added to degraded soils may improve soil physical and hydraulic properties, due to effects such as improved soil structure and increased water and nutrient retention, but its effect on soil physicochemical and biological properties, and grain quality is largely unknown. The effect of B-HA, added at 30 Mg ha^(-1), was studied at 1,3, 5 and 7 years after its addition to a degraded sandy soil in a semi-arid region of China. The addition of B-HA significantly increased water-filled pore space and soil organic carbon, especially at 3 to 5 years after its soil addition to the soil. Amending the sandy soil with B-HA also increased the content of microbial biomass(MB)-carbon,-nitrogen and-phosphorus, and the activities of urease, invertase, catalase and alkaline phosphatase. The significant effect of maize(Zea mays L.) growth stage on soil MB and enzyme activities accounted for 58 and 84% of their total variation, respectively. In comparison, B-HA accounted for 8% of the total variability for each of the same two variables. B-HA significantly enhanced soil properties and the uptake of N and P by maize in semi-arid areas. The use of B-HA product would be an effective management strategy to reclaim degraded sandy soils and foster sustainable agriculture production in northeast China and regions of the world with similar soils and climate.

Breeding and Application of Medium-maturing Late Season Indica Hybrid Rice Taoyou Xiangzhan with Good Grain Quality

Taoyou Xiangzhan, derived from the indica CMS line Taonong 1A and Huanghuazhan （a fine quality conventional rice variety）, is a new medium-maturing late season indica hybrid rice combination. It was evaluated as the 2nd class of fine quality rice variety in Hunan Province in 2012. It is characteristic of high-yielding ability, fine grain quality, good plant type, good lodging resistance and fertilizer tolerance, strong tillering ability and good discoloring at the late growth stage. Taoyou Xiangzhan was registered for release to commercial production by Hunan Provincial Crop Variety Appraisal Committee in June, 2015.

Epoxiconazole Improved Photosynthesis,Yield Formation,Grain Quality and 2-Acetyl-1-Pyrroline Biosynthesis of Fragrant Rice

Epoxiconazole is a triazole compound.However,the effects of epoxiconazole on crop productivity and quality were rarely reported.In this study,we investigated the effects of epoxiconazole application on yield formation,grain quality attributes,and 2-acetyl-1-pyrroline(2-AP)content in fragrant rice.A three-year field experiment was carried out with a fragrant rice variety,Meixiangzhan 2.At the heading stage,0,0.02,0.04,0.08,0.16 and 0.32 g/L epoxiconazole solutions were foliar applied to fragrant rice plants,respectively.The results showed that epoxiconazole application significantly increased grain yield,seed-setting rate and 1000-grain weight.Chlorophyll content and net photosynthetic rate of fragrant rice during the grain-filling stage significantly increased due to epoxiconazole application.Foliar application of epoxiconazole at 0.08 g/L increased grain protein content and decreased both chalky rice rate and chalkiness area ratio of fragrant rice.Epoxiconazole also substantially increased grain 2-AP content by inducing the regulation in contents of related synthetic precursors,including proline,pyrroline-5-carboxylic acid,Δ1-pyrroline and methylglyoxal.Overall,foliar application of epoxiconazole could be used for the improvement in grain yield,grain quality and 2-AP content in fragrant rice production when applied concentration at 0.08-0.32 g/L.Our findings provided the new roles of epoxiconazole in crop production.

Comparison of Grain Quality Characteristics Between F_1 Hybrids and Their Parents in Indica Hybrid Rice

Sixteen widespread elite indica parents including seven CMS lines and nine restorer lines, and their 63 F_1 hybrids were chosen to compare the eleven traits of grain quality. Overall results showed that the frequency of negative over-dominance, dominance and partial dominance was much higher than that of positive ones and heterosis, indicating that the values of F_1 hybrids were generally lower than the means of their parents in quality characteristics. There existed apparent disparity in grain quality performance among F_1 hybrids varied with the traits. The characteristics of chalky area percentage, chalky grain percentage, gel consistency and head rice recovery had a great variation in all kinds of tested heterosis indices including the mid-parent heterosis index, over high-value parent heterosis index and over low-value parent heterosis index, which suggested that special attention should be paid to the selection of F_1 hybrids in these traits in breeding. The mean values of F_1 hybrids were significantly lower than those of their higher parents in all the traits but close to or significantly lower than those of their mid-parent values except for kernel length and amylose content; and significantly higher than those of their lower parents except for brown rice recovery, milled rice recovery and gel consistency.

Grain Quality and Genetic Analysis of Hybrids Derived from Different Ecological Types in Japonica Rice (Oryza sativa)

The performance and inheritance of 7 quality traits were studied using F2 rice grain derived from 8×8 diallel crossing made by employing 8 parents of different ecological japonica rice types. Differences in each trait among 8 parents were not obvious, but in F2 generation, transgressive phenomena were found in all the traits studied, indicating that the genes controlling these traits among parents were segregated. The inheritance of grain width, grain weight, chalkiness score (CS), gelatinization temperature (GT) and gel consistency (GC) were suitable to additive-dominant model, and dominant effect contributed mainly for the 5 traits. The inheritance of grain length (GL) and amylose content (AC) did not fit into additive-dominant model, existing epistatic interactions. Dominant genes for grain width and grain weight had the efficiency of decreasing effect, and dominant genes for CS, GT and GC had the efficiency of enhancing effect. Koshihikari contained more recessive genes for gelatinization temperature than other varieties. Zhendao 88 had more dominant genes in grain width and grain weight than other varieties. Xiushui 04 possessed more dominant genes for GL and GC, and more recessive genes for CS than other varieties.

Effects of Phosphorus on Grain Quality of Upland and Paddy Rice under Different Cultivation

We investigated how upland and paddy japonica rice responded to phosphorous （P） fertilizer under two cultivation methods. The upland rice Zhonghan 3 and the paddy rice Yangfujing 8 were both grown under moist cultivation （MC, control） and bare dry cultivation （DC） with three P levels, low （LP, 45 kg/hm2）, normal （NP, 90 kg/hm2） and high （HI：）, 135 kg/hm2）. As P level increased, grain yields of both upland and paddy rice increased under DC. There were no significant differences in grain yields between HP and NP for either rice, although upland rice slightly increased and paddy rice slightly decreased in grain yield. Under DC at LP, Zhonghan 3 showed a higher head milled rice rate and better appearance, cooking and eating qualities than at HP or NP. Yangfujing 8 was similar to Zhonghan 3 except that Yangfujing 8 had better appearance quality at NP. Under MC, Zhonghan 3 had a higher head milled rice rate at LP and better cooking and eating qualities at NP. Yangfujing 8 was similar to Zhonghan 3 except in appearance quality. DC improved head milled rice rate and appearance quality of both upland and paddy rice, and cooking and nutrient qualities of paddy rice. Compared with paddy rice, upland rice had better processing, nutrient and eating qualities. The results suggest that upland and paddy rice respond differently to cultivation method and phosphorus level.

Effects of Nitrogen Fertilizer on Grain Quality of Different Cultivars of Japonica Rice

Three cultivars of Japonica rice:hybrid Japonica rice,inbred Japonica rice and soft Japonica rice,were used to study the effects of recommended nitrogen fertilizer on grain quality including milling,appearance,nutrition,cooking and eating quality,pasting property and their relationships in direct seeding rice.Recommended nitrogen fertilizer improved the brown rice rate,the milled rice rate,and the protein content;increased the chalky grain rate and the chalkiness,and reduced the amylose content,palatability and pasting viscosity.The nitrogen fertilizer caused the appearance,the cooking and the eating quality to deteriorate.Lower amylose content and protein content were found in soft Japonica rice compared to those in hybrid Japonica or inbred Japonica rice under the condition of the recommended rate of nitrogen fertilizer,contributing to high cooking and eating quality.Correlation analysis indicated that palatability was negatively correlated with amylose content,protein content,hardness and gelatinization temperature,and was positively correlated with stickiness,peak viscosity and breakdown.Therefore,the decreased amylose and protein content of the soft Japonica rice cultivar planted under the condition of the recommended rate of nitrogen fertilizer is beneficial to achieving high taste quality.

Variability in Grain Quality Characters of Upland Rice of Assam,India

The grain quality of 100 uplandlahu rice genotypes from Assam, India was assessed. The characteristics measured were grain length, grain width, cooked grain length, cooked grain width, grain elongation ratio after cooking, grain widening ratio after cooking, alkali spreading value, gel consistency, as well as starch, amylose, amylopectin and total soluble sugar contents. Considerable genetic variability among the 100 rice genotypes was observed for the characteristics under study. Analysis of vadance revealed highly significant differences among the genotypes for all the characteristics. The difference between genotypic coefficient of variation （GCV） and phenotypic coefficient of variation （PCV） was very small for all the characteristics analyzed. High GCV and PCV were found in the characteristic of total soluble sugar content followed by alkali spreading value. The high values for these traits signify the scope for selection to develop superior genotypes. High heritability was recorded in all the characteristics analyzed along with diverse genetic advance which varied from 9.71% to 52.83%. The characteristic of total soluble sugar content showed high heritability with high genetic advance, whereas alkali spreading value and grain widening ratio presented high hedtability with moderate genetic advance. This implies that these characteristics are mainly under additive gene effects and could be relied upon further selection based on phenotypic performance. The genotypic correlation coefficient was higher than the phenotypic correlation coefficient, indicating strong inherent associations among the characteristics studied.

Differential Response of Grain Quality to Cold Water Irrigation in Cold Tolerant and Sensitive Lines of Rice

Three rice varieties and several F3 lines with high and low cold tolerance, selected from F3 segregation lines of two crossesMilyang 23/Tong 88-7 and Milyang 23/TR22183 were used to analyze the effects of cold tolerance on the response of grainquality to cold water irrigation. The result showed that cold water irrigation led to the decrease of rice grain size. Thelength, length-width ratio and weight of brown rice grain were more sensitively affected by cold water irrigation than thewidth and thickness. The shape of brown rice grain was not significantly affected by the selection for cold tolerance at theseedling stage (CTS). The gel consistency, amylose content, peak viscosity, cool viscosity, breakdown viscosity andconsistency viscosity were decreased, while alkali digestibility value and protein content were increased by cold waterirrigation. Under normal irrigation condition the physicochemical properties of milled rice and viscogram components ofmilled rice flour were not significantly different between lines with high and low cold tolerance. Under cold water irrigationthe amylose content, peak viscosity, hot viscosity, final viscosity of rice lines with high CTS or high cold tolerance at thebooting stage (CTB) were higher, while the protein content, setback viscosity, breakdown ratio and setback ratio werelower, than those of rice lines with low cold tolerance. This implied that the cold water response of rice grain quality wasless sensitive in the lines with high cold tolerance than in the lines with low cold tolerance, and the varietal improvementfor cold tolerance would be important for grain quality improvement at the same time.

Microscopic Structures of Endosperms Before and After Gelatinization in Rice Varieties with Varied Grain Quality

The microscopic structures of the endosperm of indica rice varieties with different quality before and after gelatinization were observed using scanning electron microscope. The results showed that the degree of gelatinization varied in different parts of the grain and in different varieties under the same experimental conditions. The gelatinization of dorsal side was the most complete. Its cells were decomposed totally into puff-like or flocculent materials. The ventral side gelatinized less thoroughly, appearing agglomerate and some cell frames were still visible. The middle part gelatinized most incompletely and the cells were still integrated. Evident differences in gelatinization were observed among different varieties, the dorsal, ventral and middle parts of high quality varieties gelatinized more thoroughly than those of the corresponding parts of low quality varieties respectively. An obvious concavity often appeared in the middle of the cross-section of the low quality grains while the cross-section of high quality grains was normally flat. The same phenomenon was noted when comparing the early maturing indica rice and the late maturing indica rice. Varietal difference of gelatinization in dorsal sides was not as distinct as in middle parts and ventral sides. The difference among dorsal side, middle part and ventral side in gelatinization was greater in low quality grains than that of high quality grains. In addition, a lot of ruptured cells were observed in the cross-section of high quality rice, while few of them could be found in the low quality rice. Apparently, the number of ruptured cells is positively correlated with rice quality. Quality of rice grain also has positive correlation with the rate of water absorption and extension. High rates of water absorption and extension lead to better gelatinization of rice grain, and hence indicate good quality.

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.

Effects of hexanal fumigation on fungal spoilage and grain quality of stored wheat

The prevention of fungal spoilage is an essential consideration in wheat storage.Recent studies have revealed that volatile organic compounds(VOCs),possibly with natural fungicidal properties,could be produced from stored wheat grains.In this study,the antifungal effect of hexanal,a main component of VOCs from stored wheat,against spoilage fungi on agar plate and in high-moisture wheat grains were investigated via the gas fumigation method.And the impact of hexanal fumigation on grain quality was evaluated through analysis of the malondialdehyde content,fatty acid values,germination percentages and vigor of 16%and 18%moisture wheat grains fumigated with 1.66,2.49,and 3.31 mmol/L hexanal vapor.The results of in vitro antifungal experiments on agar plates revealed that the minimum inhibitory concentration and minimum fungicidal(fatal)concentration of hexanal against the five fungi were 4–14 folds and 4–7 folds lower than those of propionic acid,respectively.The fungal spoilage of high-moisture wheat grains inoculated with pure fungal spores and with naturally occurring fungi could be completely inhibited by 1.66 mmol/L hexanal vapor.During 5-week storage of high-moisture wheat grains fumigated with 1.66,2.49,and 3.31 mmol/L hexanal vapor,the malondialdehyde content in high-moisture wheat grains did not change significantly in all samples,and fatty acid values were slightly higher in 18%moisture wheat than in 16%moisture wheat.The germination percentages and vigor of wheat samples decreased with increased hexanal vapor concentrations and moisture content.These results indicated that hexanal fumigation could be used as an alternative chemical control method to prevent the fungal spoilage of postharvest wheat.

Utilization of Aromatic Rice in Improving Grain Quality of Hybrid Rice(Ⅰ)

To improve grain quality of the high-yielding hybrid rice in China, we introduced the aromatic rice MR365, an improved Indian cultivar, from IRRI in 1984 and began to transfer its aroma and good quality characters into the existing maintainer lines. In the meantime, the research on the inheritance of aroma for increasing the breeding efficiency was also conducted.It was found that the inheritance of aroma in MR 365 and its derivatives was controlled by one pair of recessive major genes based on the KOH-soaking method. There existed disparity in aroma degree among different grains of F2 generation, and different aromatic CMS lines derived from the same aromatic donor had also a little difference in the degree of aroma, which implies that, besides the major genes, aroma may also be affected by the genetic backgrounds or minor genes.Xiangxiang 2A, developed from the cross of V20A//V20B/MR365, is the first aromatic CMS line bred in China. It is not only aromatic but also has good grain quality and combining ability. Using it as female parent, Xiangyou 63 (Xiangxiang 2A / Minghui 63), the first quasi-aromatic hybrid rice combination in China, was developed, and released to farmers in 1995. Xiangyou 63 is characteristic of quasi-aromatic or partially aromatic (because only a portion of or not all grains are aromatic), good grain quality, high-yielding ability, good blast resistance and wide adaptability.