Non-Uniformity of Grain Characteristics and Milling Quality of California Rice (Oryza sativa L.) of Different Maturities

Head rice recovery is one of the most important factors in determining a grower's income. While previous investigators have shown that certain physical characteristics of rice kernels influence per cent head rice, the impact of the non-uniformity of these characteristics on rice milling quality is largely unknown. The objectives of this study were to investigate the effect of non-uniformity of kernel characteristics on the milling quality of rice cultivars with different maturities, and to determine the plant traits that are associated with the non-uniformity of kernel characteristics. Six rice cultivars representing different maturities and grain shapes were used in the experiments. Kernel characteristic data were obtained for grains at the upper, middle and lower parts of a panicle. The range values amongst these panicle parts were used to measure the non-uniformity of the characteristics. There was a trend for a decrease in kernel dimensions, volume and density from the upper to the lower parts of the panicle. This indicated that growth and development of grains were associated with the position of the grains on the panicle. There was also a trend for a decrease in the non-uniformity of kernel characteristics from very early and early maturing cultivars to intermediate and late maturing cultivars. The results also demonstrated that selection of phenotypes that have a low ratio of panicle length to phytomass can improve the uniformity of kernel characteristics, which in turn leads to higher recoverable head rice yield.     

高海拔地区水稻遮光、剪叶和疏花对米质影响的研究

通过遮光、剪叶和疏花等措施研究了高海拔地区水稻源库关系对籽粒灌浆及稻米品质的影响以及灌浆物质和灌浆动态与稻米品质的关系。结果表明,遮光提高整精米率,特别是对强势粒;遮光对垩白度的影响因品种和粒位而异;剪叶提高垩白度,疏花降低垩白度;遮光降低稻米直链淀粉含量和稻米淀粉RVA谱的最高黏度和崩解值,延长米胶长度;稻米主要品质指标既与灌浆物质量有关,也与灌浆动态有关;灌浆结实前期的灌浆速率、灌浆量及其比例对垩白面积、垩白度、最高黏度、崩解值等影响最大,后期其次,中期的影响较小;垩白面积和垩白度随结实前期灌浆速率、灌浆量及其比例的增加而降低,随结实后期灌浆速率、灌浆量及其比例的增加而增加,最高黏度、崩解值则相反。     

Genomic regions associated with milling quality and grain shape identified in a set of random introgression lines of rice (Oryza sativa L.)

Rice milling quality is the final part of grain yield making it fit for eating and a complex trait that remains poorly understood genetically. Three components of rice milling quality, i.e. brown rice rate, milled rice rate and head rice rate and related rice grain shape traits were genetically dissected by the QTL mapping approach using a set of 231 random rice introgression lines and 160 SSR markers. A total of 10 genomic regions were found to be associated with rice grain shape and milling quality traits. Of these, one major QTL on chromosome 7 had large effects on rice grain shape and milling quality and was detected consistently in several related populations of rice, which offers an opportunity for marker‐aided improvement of rice milling quality and QTL cloning.     

水稻籽粒灌浆的影响因子及其机制研究进展

水稻籽粒灌浆是籽粒形成的最重要生理过程,也是决定粒重、产量和稻米品质的决定性阶段。为充分了解水稻籽粒灌浆内在特性,促进水稻高产栽培和优良品质育种,对水稻籽粒灌浆的生物学特性、生理机制以及内源激素、酶活、基因、蛋白以及环境等影响因子进行综述,并对籽粒灌浆研究进行展望,提出从蛋白质组学、基因组学、基因表达等分子生物学方面深入研究籽粒灌浆机制的可能性。     

川西北大穗大粒型小麦灌浆规律研究

摘要：本文研究大穗大粒小麦籽粒灌浆干物质积累模型及灌浆特性与粒重的相关分析。结果表明：小麦籽粒干重变化呈“S”曲线,灌浆速率和籽粒水分含量均呈正态曲线。最大灌浆速率Rmax,渐增期(R1)快增期(R2)和缓增期速率(R3),渐增期持续天数(T1)是影响粒重的重要参数,各阶段灌浆速率与持续时间呈显著负相关。因此在大穗大粒高产小麦栽培和育种中可通过选育高灌浆速率,尤其是高快增期灌浆速率的品种;通过适当的栽培措施协调灌浆速率与持续时间的矛盾,增加缓增期灌浆速率而提高粒重     

Effect of Nitrogen and Water Management on Panicle Development and Milling Quality of California Rice (Oryza sativa L.)

Nitrogen fertilization and water management are the most important agronomic factors in determining the yield and milling quality of rice. Yet little information is available on the effect of nitrogen and time of drainage on the uniformity of rice grain development on a panicle. The objectives of this study are 1) to evaluate the effect of nitrogen application on the uniformity of grain development on a panicle, and 2) to determine the combined effect of time of drainage and nitrogen application on rice yield and milling quality. Results show that nitrogen has a significant effect on grain filling characteristics. Nitrogen reduces grain filling rate, increases duration of grain filling, increases tiller numbers and decreases grain weight. The time of drainage is critical to the recovery of head rice. Generally speaking, late drainage tends to increase the head rice recovery, and its impact on rice milling quality is increased with an increased rate of nitrogen application.     

Influence of Male Sterile Cytoplasms on the Physico-Chemical Grain Quality Traits in Hybrid Rice (Oryza Sativa L.)

Summary Possible unfavourable influence of sterility inducing cytoplasm on physico-chemical grain quality traits in rice hybrids is one of the important concerns hindering the large-scale adoption of hybrid rice technology. Produce from 23 pairs of CMS line × restorer (AF₁) and maintainer line × restorer (BF₁) cross combinations carrying different cyto-sterile sources (WA, ARC, Mutagenized IR 62829B and Kalinga I) was compared for various grain and cooking quality traits. The milling recovery in rice hybrids was not influenced by the sterile cytoplasm. For kernel dimensions before and after cooking there were both favourable and unfavourable cytoplasmic effects, which varied in magnitude depending upon the sterile cytoplasm and parental combinations. Similar results were obtained for kernel elongation and gelatinization temperature. The most widely used WA cytoplasm had minimum instances of unfavourable influence. In general, the cytoplasmic influence was found to be highly cross-specific and depended on the nuclear background of CMS line and fertility restorer. Availability of alloplasmic CMS lines carrying different cyto-sterile sources in the same nuclear background would help in ascertaining the cytoplasmic influence in a more comprehensive manner.     

结实期水分胁迫对水稻强弱势粒主要米质性状及淀粉粘滞谱特征的影响

以汕优63和武香粳9号为供试品种,研究了结实期土壤水分胁迫对水稻强、弱势粒稻米主要米质性状和淀粉粘滞谱特征的影响,结果表明：(1)两品种强势粒和弱势粒达到最大粒重和最小垩白时的结实期处理土水势是相同的,均为－20 kPa,在此土水势下,强势粒和弱势粒加工品质和蒸煮品质无显著变化,改善了营养品质,米质相对较优;(2     

水稻穗上不同部位籽粒垩白性状的差异

以中熟籼稻扬稻6号和中熟粳稻武育粳3号为材，研究了在不同施肥水平下，稻米垩白度与垩白粒率在穗上不同部位和不同粒位籽粒间的差异及其分布特点。结果表明，在稻穗同一部位，籽粒的垩白度和垩白粒率二次枝梗高于一次枝梗；一次枝梗上第6粒位籽粒的垩白度较高，第1粒位籽粒的垩白度较低；在二次枝梗上，第1粒位籽粒的垩白度较低，第3、4粒位籽粒的垩白度较高；垩白粒率，一般穗下部>中部>上部；一次枝梗上第2粒位籽粒最高，第1或第6粒位籽粒最低；在二次枝梗上，一般以第1粒位籽粒最低。在0～240 kg/hm2范围内增施氮肥可以降低垩白度和垩白粒率。     

密穗型水稻品种的籽粒灌浆特性研究

应用Richards方程对密穗型和散穗型水稻品种的籽粒灌浆过程进行拟合,研究了两类水稻品种的灌浆特性.密穗型品种灌浆时不同粒位的养分竞争作用较强, 弱势粒的灌浆过程受强、中势粒的抑制作用较强,特别是灌浆前期,从而导致穗内不同粒位间灌浆速率和持续时间有较大的差异,使强、弱势粒灌浆过程呈明显的异步性,在灌浆特性上表现为     

灌浆结实期低温弱光复合胁迫对稻米品质的影响

近年来,南方水稻抽穗灌浆期低温寡照天气发生频率明显增加,为探明其对稻米品质的影响,在水稻灌浆结实期不同时间段(1~7d、8~14d、15~21d、22~28d、29~35d)设置低温弱光复合胁迫(LW)、单一弱光(WN)、单一低温处理(LN)和常温常光(NN)4个处理,研究低温弱光复合胁迫对稻米加工品质、外观品质、蒸煮食味品质、RVA谱特征值等的影响。结果表明,不同处理方式间的垩白米率、垩白大小和垩白度均表现为LW>LN>WN>NN,且灌浆结实期各阶段的复合胁迫均较对照NN差异极显著或显著,除了2016年灌浆结实1~7d的垩白度外,灌浆结实21d内的复合胁迫与单一弱光、低温差异也显著或极显著,单一胁迫低温、弱光在灌浆结实21d内较对照NN差异极显著或显著,其中单一低温与弱光在部分处理下差异达显著水平,灌浆结实21d后,复合胁迫与单一弱光、低温部分差异显著,弱光与低温无显著差异。不同处理间的糙米率、精米率和整精米率均表现为NN>WN>LN>LW,其中,灌浆结实21d内,复合胁迫及单一低温、弱光较对照NN差异极显著或显著,灌浆结实21d后,部分时间段差异显著或极显著。低温弱光复合胁迫及单一胁迫对加工品质影响程度按大小依次为整精米率、精米率、糙米率,且灌浆结实21d内处理的影响大。对蒸煮食味品质,低温弱光复合胁迫极显著或显著降低了稻米的直链淀粉含量、胶稠度、外观、黏度和食味值,显著或极显著提高了蛋白质含量和硬度,单一胁迫低温、弱光表现与复合胁迫相同的影响,且灌浆结实21d内,除2016年的胶稠度,单一低温、弱光较对照NN差异显著或极显著,单一低温、弱光较复合胁迫差异也多显著或极显著。从水稻RVA谱特征值来看,低温弱光复合胁迫及单一胁迫造成稻米的峰值黏度、热浆黏度与崩解值下降,最高黏度、消减值与峰值时间上升,除灌浆结实29~35d的崩解值外,复合胁迫较对照NN差异达极显著或显著水平,部分指标的低温、弱光较对照NN差异也达显著水平。总之,灌浆结实期各时间段的低温弱光复合胁迫及单一胁迫造成稻米品质不同程度下降,且以灌浆结实21d内复合胁迫的影响较大。     

Effects of allelic variations in starch synthesis-related genes on grain quality traits of Korean nonglutinous rice varieties under different temperature conditions

Influences of allelic variations in starch synthesis-related genes (SSRGs) on rice grain quality were examined. A total of 187 nonglutinous Korean rice varieties, consisting of 170 Japonica and 17 Tongil-type varieties, were grown in the field and in two greenhouse conditions. The percentages of head rice and chalky grains, amylose content, alkali digestion value, and rapid visco-analysis characteristics were evaluated in the three different environments. Among the 10 previously reported SSRG markers used in this study, seven were polymorphic, and four of those showed subspecies-specific allele distributions. Six out of the seven polymorphic SSRG markers were significantly associated with at least one grain quality trait (R² > 0.1) across the three different environments. However, the association level and significance were markedly lower when the analysis was repeated using only the 170 Japonica varieties. Similarly, the significant associations between SSRG allelic variations and changes in grain quality traits under increased temperature were largely attributable to the biased allele frequency between the two subpopulations. Our results suggest that within Korean Japonica varieties, these 10 major SSRG loci have been highly fixed during breeding history and variations in grain quality traits might be influenced by other genetic factors.     

结实期水分胁迫对水稻反义Wx基因转化系主要米质性状及米饭质地的影响

以反义Wx基因的转化系及其受体亲本武运粳7号(9522)为材料,研究了结实期水分胁迫对主要品质性状及米饭质地的影响。结果表明,与水层灌溉处理相比,结实期水分胁迫使整精米率和垩白粒率提高;崩解值明显降低,而最终黏度和消减值却明显提高;米饭的硬性增加,黏附性减小,稻米的蒸煮食味品质有着变劣的趋势。     

穗发芽深度对早稻米品质和 RVA谱特征值的影响研究

以3个早稻品种（组合）为材料,采用发芽箱人工诱导模拟穗发芽的方法,研究了不同穗发芽深度对水稻稻米品质和RVA谱特征值的影响。结果表明：穗发芽严重影响稻米品质,发芽引起糙米率、精米率和整精米率下降,垩白粒率增多和垩白大小增大,碱消值降低,糊化温度升高,胶稠度减小,粗蛋白含量降低,其中整精米率下降幅度最大,最大降幅达50%以上,其次是垩白大小。因此发芽严重影响了稻米的加工品质、外观品质和蒸煮品质,营养品质;发芽还使RVA谱的特征值最高黏度和崩解值度减小,降低稻米的食味品质。     

种植方式对陆稻中旱3号和水稻武香粳99-8米质的影响

在大田试验条件下,以陆稻中旱3号和水稻武香粳99-8为材,设覆膜旱种和裸地旱种2种方式,以水层湿润灌溉为对照,研究了种植方式对米质的影响。结果表明,与水种(对照)相比,中旱3号覆膜旱种的产量显著降低,而武香粳99-8覆膜旱种的产量则无显著差异,裸地旱种的产量均较对照显著降低。旱种可降低垩白度、粒长/粒宽、直链淀粉含量、胶稠度、峰值黏度,提高蛋白质含量和糊化温度;中旱3号覆膜旱种和裸地旱种以及武香粳99-8裸地旱种的垩白粒率显著低于对照,而武香粳99-8覆膜旱种则无显著差异。三种种植方式中,两品种均以覆膜旱种的垩白度、直链淀粉含量、胶稠度、崩解值和灌浆期稻株含N率下降值最小,蛋白质含量和消减值最大,籽粒Q酶活性维持在较高的水平。与武香粳99-8相比,中旱3号的垩白粒率和胶稠度显著降低,垩白度没有显著差异,粒长/粒宽、直链淀粉含量、蛋白质含量、崩解值和糊化温度显著提高。Q酶活性、籽粒灌浆参数与米质指标关系密切。旱种有利于改善稻米的外观和营养品质,但蒸煮食味品质有所变劣。     

不同温度条件下优质食用稻籽粒灌浆特性与整精米率的关系

通过对优质食用稻品种爱华5号进行不同播种期处理，研究在不同气候条件下，其籽粒灌浆特性与整精米率的变化规律。结果表明：优质食用稻籽粒灌浆后20d日平均温度在27.9~29.8℃时，籽粒灌浆前、中期速度快，后期速度慢，整精米率相对较低；籽粒灌浆后20d日平均温度在25.2~25.9℃左右时，籽粒灌浆前、中期速度慢，后期速度快，整精米率相对较高。     

不同穗型超级稻品种籽粒灌浆特性

为探明不同穗粒型超级稻产量构成特点、籽粒灌浆特性及其与后期生理指标的关系。以不同生育期品种准两优527、两优培九、Y两优1号、玉香油占、黄花占为试验材料,在大田栽培条件下分期播种以确保不同生育期品种在相似的温光条件下灌浆结实。结果表明,不同播期平均产量及其构成因子的品种间差异显著,以两优培九产量最高(9.47 t hm^-2),玉香油占产量最低(8.39 t hm^-2)。依据每穗粒数和千粒重系统聚类分析,可将品种分为大粒型(准两优527)、中粒型(两优培九、Y两优1号)和小粒型(玉香油占、黄花占)。籽粒灌浆强度及持续时间的品种间差异明显。其中,大粒型品种籽粒灌浆起步快、强度大、峰值持续时间短,上、中、下部枝梗籽粒均为一段式灌浆;中粒型品种籽粒灌浆起步快、强度较小、峰值持续时间长,其上部枝梗籽粒为一段式灌浆,中、下部枝梗籽粒为两段式灌浆,高峰值分别在抽穗后12~18 d和24~30 d;小粒型品种籽粒灌浆起步慢、强度小、峰值持续时间长,其上、中部枝梗籽粒为一段式灌浆,下部枝梗籽粒为两段式灌浆。平均籽粒灌浆速率与品种的穗粒类型密切相关,其中,大粒型品种为0.68 mg d^-1,中粒型品种为0.48~0.51 mg d^-1,小粒型品种为0.41~0.47 mg d^-1。籽粒灌浆强度及持续时间与后期剑叶、根系生理指标有关,籽粒灌浆启动后,叶绿素含量、叶绿素a/b值、类胡萝卜素含量逐渐降低,剑叶可溶性糖含量、MDA含量逐渐上升,POD活性、CAT活性及根系活力先后出现2次升降过程。可见,不同穗粒型超级稻品种产量构成及籽粒灌浆特点的差异明显,籽粒灌浆强度及持续时间与品种的穗粒型及枝梗着生的部位有关,也与后期剑叶及根系衰老生理指标的变化趋势一致。     

花后低温对水稻籽粒灌浆与内源激素含量的影响

以籼粳杂交稻甬优538、甬优17和籼稻中浙优1号、粳稻浙粳88为材料,设置灌浆期不同时段低温处理,分析籽粒灌浆过程中内源激素含量的动态变化及其差异。结果表明,花后不同时段低温对籽粒灌浆的影响表现为前期>中期>后期,而中、后期与对照差异不大,且低温对甬优17、中浙优1号籽粒灌浆的影响大于对甬优538和浙粳88。花后前期低温显著降低甬优17号籽粒灌浆,延长灌浆时间,而甬优538与对照差异不明显。花后不同温度处理下供试品种内源激素含量变化存在一定差异,其变化与品种灌浆动态保持一致。花后前、中期低温明显降低甬优17号籽粒中IAA、ZR含量,显著增加GA3、ABA含量;而对甬优538显著下降GA3含量和略增加IAA、ZR含量,这可能是籽粒正常灌浆的主要原因。生产中可通过适宜的激素调控措施来提高水稻籽粒低温灌浆。     

直播种植模式下水稻剑叶光合、强弱势籽粒灌浆特性及产量的氮素调控

为探讨不同施氮水平对水稻剑叶光合、籽粒灌浆特性和产量的影响。以生育期较短的‘新稻567’、‘新稻568’和‘新科稻31’为试验材料,在直播种植模式下,设置3个施氮水平0、255、300 kg/hm²,分别测定抽穗后剑叶光合速率、强弱势籽粒灌浆速率和产量等指标,研究氮肥调控水稻产量的生理机制。结果表明,随着施氮量的增加,3个品种产量均呈先增加后降低的趋势;高效叶面积率和粒叶比表现为中氮水平较高,高氮水平较低。灌浆期剑叶光合速率呈先增加后降低趋势,不同氮肥处理间基本表现为中氮处理高于高氮处理;强弱势籽粒灌浆速率在整个灌浆期内呈开口向下的抛物线趋势,不同氮肥处理间的差异在灌浆盛期至灌浆中后期较大,表现为无氮和中氮处理高于高氮处理,灌浆末期处理间差异较小。产量与灌浆期剑叶光合速率呈正相关关系,与强弱势籽粒灌浆速率在灌浆初期呈负相关在灌浆中后期呈正相关关系。适度的氮肥施用量有利于提高直播水稻高效叶面积率、粒叶比,增加剑叶光合速率、强弱势籽粒灌浆速率,从而促进水稻高产。     

不同熟期夏玉米品种籽粒灌浆脱水特性和激素含量变化

本文旨在研究不同熟期夏玉米品种籽粒灌浆与脱水特性和内源激素含量与平衡的变化,以期为黄淮海夏玉米机械化收获籽粒和高产高效品种筛选提供理论依据。以早熟玉米品种登海518(DH518)、衡早8号(HZ8)和晚熟玉米品种郑单958(ZD958)、登海605(DH605)为试验材料,研究玉米籽粒形成过程中干物质积累、水分含量及内源激素含量变化。结果表明,早熟品种较晚熟品种灌浆期短,籽粒开始脱水早,脱水速率高,生理成熟期粒重低,产量低,但早熟品种中DH518的产量显著高于HZ8。不同熟期玉米品种籽粒内源激素含量及其变化模式不同,但同一激素含量随籽粒发育的变化趋势一致。两早熟品种籽粒的ABA含量高于两晚熟品种,尤其表现在灌浆中后期。各品种籽粒灌浆、脱水速率均与内源激素含量有关,两早熟品种的籽粒脱水速率与玉米素核苷(ZR)含量呈显著正相关。