利用近红外透射光谱技术同步测定糙米的多项品质指标初报

利用FOSS TECATOR 公司生产的1241型近红外透射光谱仪,对266份整粒糙米样品进行了光谱扫描并测定了其多项品质指标。借助于近红外定标软件WINISI,建立了利用近红外透射光谱同时测定糙米多项品质指标的模型。结果表明,蛋白质模型的分析效果最好,其外部检验 (经校正的) 工作标准误\[SEP (C) \] 为0.312,检验决定系数(RSQ )为0956,而其他4项指标直链淀粉含量、糊化温度(碱消值)、透明度（透光率）和垩白度模型的SEP (C)分别为1.672、 0.389、 0034和4.024,RSQ分别为0.745、0.838、0.797和0.714。分析了近红外测定的重复性并讨论了该模型在水稻遗传育种等方面的应用前景。     

The difference in amylose content within a panicle as affected by the panicle morphology of rice cultivars

The variation of amylose content (AC) among grains within a panicle and its relation to panicle morphology were investigated using 44 japonica rice cultivars differing in grain density (GD), panicle bending degree (BD) and palatability. Morphological traits of the rice panicle were poorly associated with mean grain AC on the average of the whole panicle, but closely related to AC variation and spatial distribution within a panicle, with the compact-panicle cultivars (GD>6.5 grain/cm and BD< 30°) having greater variation than loose-panicle cultivars (GD<6.0 grain/cm and BD>70°). The extent of AC differences among the rachides within a panicle was also cultivar-dependent, and greater differences were found between middle and top rachides for the compact-panicle cultivars, and between middle and bottom rachides for the loose-panicle cultivars. The difference in spatial distribution of AC variation between Bing110 (a compact-panicle cultivar) and XS11 (a loose-panicle cultivar) indicated that grains with low AC were principally distributed on interior rachis of middle branches for Bing110, but on bottom-rachis for XS11. Such a distribution is basically associated with the difference in the timing procedure of floret initiation and development, and final grain weight.     

Variation in rice quality of different cultivars and grain positions as affected by water management

A field experiment was conducted to study the effect of cultivar and grain position on rice quality under different water management treatments. Water treatments significantly affected all quality traits in the study, except alkali digestibility (AD). There were significant interactions of water treatment by grain position and genotype for brown rice rate (BRR), chalky grain rate (CGR) and amylose content (AC), and interactions of grain position by water treatment and cultivar for head milled rice rate (HMRR). The interaction of water treatment by genotype for protein content (PC) was also significant. Of all variance components, water treatment ranked the highest for PC. Similarly grain position was ranked the highest for AC, BRR, CGR and HMRR. In comparison with wet cultivation, plastic-film mulched cultivation had significantly lower BRR, HMRR, CGR and higher PC. There were marked differences in milled quality, appearance and AD among differently positioned grains within a spike. For appearance and PC, the difference between plastic-film mulched cultivation and wet cultivation was greater for upland rice than paddy rice. For milled and cooking–eating quality, the difference between plastic-film mulched cultivation and wet cultivation was greater for the good quality paddy rice than the upland rice and the poor quality paddy rice. In plastic-film mulched cultivation, top grains showed lower milled quality and PC. While in wet cultivation, the opposite result was seen. With the decrease in soil water content, BRR and appearance showed increased and decreased differences among grains within a spike, respectively. The results indicate the possibility of improving rice quality by use of better water management and suitable cultivars.     

麦秸还田与氮肥运筹对超级稻强弱势粒粒重与品质的影响

 以两个超级稻品种（籼稻扬两优6号和粳稻南粳45）为材料,设置麦秸还田和氮肥运筹两种处理方式,研究其对籽粒粒重与主要米质的影响。结果表明,两处理的影响程度在品种类型与不同粒位间（强、弱势粒）存在差异。与麦秸不还田相比,麦秸还田提高籽粒千粒重、粗蛋白含量和崩解值,降低了整精米率、垩白度、直链淀粉含量和消减值;与m基蘖肥∶m穗粒肥=5∶5处理相比,m基蘖肥∶m穗粒肥=7∶3处理增加了千粒重、垩白度、直链淀粉含量、崩解值,降低了整精米率、粗蛋白含量和消减值。两处理对弱势籽粒千粒重、整精米率、垩白度等的调控作用显著大于强势粒;对千粒重、整精米率、粗蛋白含量等的影响,麦秸还田与氮肥运筹之间存在互作效应;麦秸还田方式下,氮肥比例控制在5.5∶4.5或6∶4左右,可以较好地协调粒重与米质。     

Variation in Yield and Physicochemical Quality Traits among Mutants of Japonica Rice Cultivar Wuyujing 3

To select elite germplasms, 112 mutants derived from japonica rice cultivar Wuyujing 3 were evaluated. The yield components such as panicle number per square meter, grain number per panicle, and grain weight were measured. The quality traits such as percentage of chalky grains(PCG), brown rice yield(BRY), milled rice yield(MRY), degree of milling(DM), amylose content(AC), protein content(PC), and relationships among traits were inverstigated. Results showed that grain yield ranged from 2.15 to 12.49 t/hm~2 with a mean of 6.4 t/hm~2 and number of grains per square meter contributed for 94.64% in grain yield variation. For quality traits, all rice mutants had short size(grain length ≤ 5.5 mm) and bold shape(grain length to width ratio = 1.10–2.00). Most of rice mutants(87.5%) had PCG values below 20%. All mutants had MRY values above 50%, AC values below 20%, and PC values below 10%. Percentage of chalky grains was significantly negatively correlated with MRY and positively correlated with DM. BRY and MRY were significantly negatively correlated with DM. PC was significantly and positively correlated with MRY and negatively correlated with DM, while AC had no significant correlation with these quality traits. It was concluded that there were 25 rice mutants which fulfilled the major requirements of Jiangsu standard japonica rice such as low percentage of chalky grains, low amylose content, optimal protein content, and which could be used as elite germplasms. Thus the mutants identified may lead to significant progress in improvement of rice quality.     

Characterizing stress effects on rice grain development and filling using grain weight and size distribution

Abiotic stresses such as salinity affect rice yield components and grain quality. Among these components, 1000-grain weight (TGW) is thought to be quite constant due to a rigid hull whose size is genetically determined, but chilling and salinity stresses have been reported to strongly reduce TGW. A new, automated methodology is presented to analyze grain weight, length and width distributions for grain samples. Frequency distribution analyses on the basis of histograms generally gave bimodal patterns for grain weight (filled and unfilled grains) and monomodal patterns for grain dimensions. These histograms permit the distinction of unfilled, partially filled and fully filled grains. Peak shape and location on the histogram provide further information potentially useful for the diagnosis of physiological stresses affecting grain hull development, spikelet fertility and filling, and may be of value in breeding and grain quality research. The methodology was applied to rice grain samples taken from farmer's fields having different levels of soil salinity in the Camargue delta region in France. High salinity levels were associated with an increased fraction of unfilled spikelets and reduced grain dimensions and weight, which point at salinity affects taking place before flowering during hull development. The methodology is being further developed with a biometric tool for histogram analysis, and will be extended to other stresses and germplasm.     

Modeling the effects of N application on growth,yield and plant properties associated with the occurrence of chalky grains of rice

The objective of this study was to propose a model for explaining rice responses to a wide range of N application rates in various growth attributes associated with the occurrence of chalky grains. We improved the sub-model for N uptake process of a previous rice model which was originally developed for explaining genotypic and environmental variations in the whole growth processes, considering the difference in the rate of N loss from the plant-soil system between indigenously supplied soil mineral N and fertilizer N. A total of 80 growth datasets of cultivar ‘Koshihikari’ grown at Shiga prefecture, Japan, in 2010 was utilized for the calibration and validation of the model. The rice growth model well explained the above-ground biomass growth (RMSD = 78.7 g m^?2) and rough dry grain yield (RMSD = 83.2 g m^?2) for the validation data-set, simultaneously. The simulated carbohydrate content available per single spikelet was negatively correlated with the observed percentage of the milky-white grain which includes white-cored grain (r = ?.77, p < .001) for all the data-sets of calibration and validation. On the other hand, the observed percentage of the sum of white-back and white-base grains was closely correlated with the simulated plant N content available per single spikelet (r = ?.59, p < .001). It was suggested that the present rice growth model would rationally explain the effects of N application on the occurrence of the chalky grains through the dynamic change of the carbohydrate content and plant N content available per single spikelet.     

Quality characteristics and field performance of selectable marker-free transgenic rice with antisense Wx gene and improved quality derived from the elite parents of hybrid indica rice

In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types.     

Estimating the amino acid composition in milled rice by near-infrared reflectance spectroscopy

This study was conducted to develop near-infrared reflectance spectroscopy (NIRS) equations to predict the amino acid and nitrogen content of milled rice powder. The samples were scanned by NIRS and analyzed for amino acid composition and total nitrogen by HCl hydrolysis–HPLC methodology and Kjeldahl method, respectively. The NIRS equations of 15 different amino acids, except for cystine, methionine and histidine, showed high coefficients of determination (RSQ=84.8–97.5%) and low standard errors in calibration (SEC) with 3 g samples for NIRS scanning, while the calibration models of cystine and histidine could explain less variation (RSQ with 77.7 and 65.0%). Calibration for methionine was not suitable to estimate methionine because of its very low RSQ (10.2%). The equations for total amino acids and nitrogen also showed high RSQ and lower SEC, respectively. Furthermore, calibration equations developed with only about 500 mg samples showed similar accuracy and reliability to those with the full cup by using the same calibration set. The equations developed for relative contents of total amino acids did not show good, effective calibration and cross-validation. Only eight different amino acids can be predicted using the equations because their RSQs of calibration were higher than 50.6% (50.6–73.9%). The others cannot be estimated with confidence by their relative contents due to lower RSQ in calibration. Moreover, their relative contents can be calculated from their absolute contents estimated by NIRS calibration.     

水稻强弱势籽粒核酸和蛋白质代谢差异

以两系杂交稻两优培九和培两优500为试验材料,对强弱势粒核酸和蛋白质含量进行了测定。水稻抽穗当天,强势粒单位质量子房中总RNA、mRNA含量都高于弱势粒,蛋白质含量却低于弱势粒。抽穗后第5天,强势粒单位质量子房中总RNA含量仍然高于弱势粒,mRNA含量两者差异不大,蛋白质含量依然低于弱势粒。不论是强势粒还是弱势粒,从抽穗到开花后第5天,其总RNA、mRNA和蛋白质单粒含量都有显著的增加,且各时期强势粒都高于弱势粒。抽穗当天强势粒有两条特异蛋白质带出现,而弱势粒没有,抽穗后第5天弱势粒才出现其中的一条。这说明强势粒与籽粒灌浆有关的基因表达比弱势粒早,强度高。     

Quality characteristics and field performance of selectable marker-free transgenic rice with antisense Wx gene and improved quality derived from the elite parents of hybrid indica rice

In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types.     

水稻和陆稻籽粒灌浆特性的比较

应用Richards方程对水作和旱作水稻与陆稻的籽粒灌浆过程进行拟合,研究两种稻灌浆特性在不同水分管理条件下的差异。结果表明,与水作相比,水稻旱作穗数和粒重明显降低,产量下降;强势粒和弱势粒的灌浆速率降低,活跃灌浆期缩短,强势粒和中势粒的起始生长势减弱,到达最大灌浆速率的时间延迟,强、弱势粒进入灌浆盛期的间距缩短,从而影响弱势粒的灌浆,强、弱势粒灌浆速率的差异增大,最终导致粒重和结实率降低。陆稻旱作与水作相比,除活跃灌浆期略有缩短以及强、弱势粒进入灌浆盛期的间隔略有延长外,整体上灌浆过程变化不大。与水稻相比,陆稻在两种水分条件下灌浆过程和产量及其构成因子的差异较小,表现为籽粒灌浆的起始生长势特别是强、中粒位势的起始生长势低,灌浆前、中期灌浆较强,强、中势籽粒对同化物的激烈竞争使弱势粒灌浆变差,籽粒灌浆期短,特别是灌浆后期持续时间短,导致结实率和粒重低,最终影响产量。旱作条件下,水稻与陆稻相比,籽粒灌浆速率较小,活跃灌浆期较长,强、弱势粒灌浆呈现明显的异步性。     

直立与弯曲穗型水稻穗上不同部位籽粒碾磨品质的比较

以直立穗型和弯曲穗型水稻材料为对象,研究了穗上不同部位和不同粒位籽粒在碾米品质上的差异。弯曲穗型材料整穗籽粒的糙米率、精米率及整精米率以及粒重均高于直立穗型材料,其中整精米率差异达到显著水平。总体而言,在稻穗的同一部位,两穗型材料一次枝梗籽粒的糙米率、精米率、整精米率和粒重均高于二次枝梗的籽粒;一次枝梗上以第2 或第3粒位籽粒的糙米率、精米率和整精米率较高,第1 粒位籽粒的较低;穗上同一部位二次枝梗籽粒的碾米品质在两穗型材料间的差异大于一次枝梗,而穗型与其排序并无直接关系;两穗型材料籽粒粒重在穗上的分布与排序基本一致。因此,可以通过育种选择来改良直立穗型材料的碾磨品质。     

两系杂交水稻光合速率与粒重的关系

以粒重差异明显的个大穗型两系杂交水稻组合为材料,对粒重与光合特性的关系进行了初步研究.结果表明:供试组合整穗实粒平均千粒重与结实期顶部3片功能叶的"净光合速率/实粒"及"叶总面积/实粒"成正相关,实粒平均千粒重差异程度随结实期顶部3片功能叶的净光合速率和叶面积的变化而异.     

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.     

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.     

Influence of high temperature during filling period on grain phytic acid and its relation to spikelet sterility and grain weight in non-lethal low phytic acid mutations in rice

Low phytic acid (lpa) crop is considered as an effective strategy to improve crop nutrition. However, the inferior agronomic performance of lpa crops and their environmental growth adaptation have not yet been fully understood. Three rice lpa lines and their corresponding wild-types were used to compare their differences in grain phytic acid (PA) in response to high temperature (HT) and its relation to spikelet sterility and grain weight at a controlled temperature at the filling stage. Results showed that HT caused an increase in grain PA and inorganic phosphate contents, with more substantial increase of PA content for lpa lines compared with corresponding wild-types. This increase in PA content in high temperature-ripened grains was not simply attributed to the reduction in grain weight and relatively enhanced proportion of aleurone-layer fraction to whole grains. Significant increase in PA contents was also detected in milled rice. Moreover, spikelet sterility and grain plumpness of lpa lines were more susceptible to HT stress than those of wild-types. Exogenous PA spraying with an appropriate concentration could increase grain PA content, but it had only a slight contribution to the enhancement of heat-tolerance and injury alleviation for rice exposed to stressful HT.     

超级稻花后强、弱势粒淀粉合成相关酶活性和激素含量变化及其与籽粒灌浆的关系

 种植4个超级稻品种\[两优培九和Ⅱ优084（杂交籼稻）、淮稻9号和武粳15（粳稻）\]和2个高产对照品种\[汕优63（杂交籼稻）和扬辐粳8号（粳稻）\],观察其结实期强、弱势粒中蔗糖合酶（SuSase）、腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）、淀粉合酶（StSase）和淀粉分支酶（SBE）活性及玉米素+玉米素核苷（Z+ZR）、3 吲哚乙酸（IAA）和脱落酸（ABA）含量的变化,并测定了强、弱势粒灌浆速率。结果表明,超级稻品种强势粒的最大灌浆速率、到达最大灌浆速率的时间、平均灌浆速率和糙米重与对照品种差异较小,超级稻品种弱势粒的灌浆速率和糙米重显著低于对照。灌浆期强、弱势粒的SuSase、AGPase 、StSase 和SBE活性变化及Z+ZR、IAA 和ABA 含量变化均呈单峰曲线。弱势粒的SuSase、AGPase、StSase 和SBE的峰值活性和平均活性及其Z+ZR 和IAA的峰值含量和平均含量均低于强势粒。弱势粒的ABA 峰值含量和平均含量显著高于强势粒,超级稻品种高于对照品种。籽粒灌浆速率与SuSase、AGPase和StSase 活性及Z+ZR 和IAA含量均呈显著或极显著正相关,与SBE活性及ABA含量的相关不显著。说明超级稻品种弱势粒中较低的SuSase、AGPase和StSase活性及较低的Z+ZR和IAA含量是其灌浆速率小、粒重轻的一个重要原因。     

Non-destructive prediction of chemical composition in sunflower seeds by near infrared spectroscopy

Near infrared reflectance spectroscopy (NIRS) was explored as a technique to predict moisture (M), oil and crude protein (CP) content on intact sunflower seeds (Helianthus annuus L.). Three hundred samples were scanned intact in a monochromator instrument NIRS 6500 (NIRSystems, Silver Spring, MD, USA). Calibration equations were developed using modified partial least square regression (MPLS) with internal cross validation. Samples were split in two sets, one set used as calibration (n=250) where the remaining samples (n=50) were used as validation set. Two mathematical treatments (first and second derivative), none (log 1/R) and standard normal variate and detrend (SNVD) as scatter corrections were explored. The coefficient of determination in calibration (R_cal²) and the standard error in cross validation (SECV) were 0.95 (SECV: 3.3) for M; 0.96 (SECV: 13.1) for CP and 0.90 (SECV: 22.3) for oil in g kg⁻¹ on a dry weight basis (second derivative, 400–2500 nm). Prediction models accounted for less than 65, 70 and 72% of the total variation for oil, M and CP, respectively. However, it was concluded that NIRS is a suitable technique to be used as a tool for rapid pre-screening of quality characteristics on breeding programs.     

烯效唑对杂交水稻籽粒灌浆及产量的影响研究

以杂交稻组合汕优63为材料,探讨了不同施药时期(浸种、孕穗期喷施)和不同质量浓度(0,10,20,40,80 mg/L)烯效唑处理对籽粒生长过程及产量的影响.结果表明,烯效唑对强势粒生长有一定抑制作用,但同时却促进了弱势粒的生长,在一定程度上具有协调强、弱势粒灌浆的作用,降低成熟期强势粒单粒重而提高弱势粒单粒重;使强势粒的终极生长量降低,达最大生长速率的时间延后,从而延长弱势粒的灌浆时间,提高弱势粒的灌浆速率及最大干重;由于烯效唑对弱势粒生长的促进作用,显著提高了其穗实粒数,进而提高了单穗籽粒干重及水稻产量.处理时期不同,其最佳浓度不同;浸种处理以质量浓度为40mg/L时产量最高,喷施处理以20mg/L时的产量最高.