Wx与ALK主要等位基因不同组合对稻米品质的影响

【目的】稻米蒸煮和食味品质主要受Wx和ALK两个主效基因的调控。这两个基因在栽培稻中存在多个复等位变异,本研究旨在明确Wx和ALK基因的主要等位变异及其组合对稻米品质的影响。【方法】将Wx的3个主要等位基因(Wx^a、Wx^b和wx)与ALK的2个主要等位基因(ALK^a和ALK^c)进行不同的组合,在粳稻品种日本晴(Nip)背景下创建6个含有Wx和ALK基因不同等位变异组合的近等基因系。通过测定近等基因系的稻米理化品质明确不同等位基因及其组合对稻米品质的效应。【结果】在相同的ALK基因型背景下,含Wx^a等位基因稻米的糊化温度极显著低于wx型和Wxb型的近等基因系。稻米黏滞性受Wx和ALK等位基因组合影响较大,Wx等位变异主要影响稻米的峰值黏度、峰值时间和冷胶黏度;在相同Wx背景下,ALK等位基因主要影响稻米RVA谱的起浆温度,对稻米崩解值和消减值的影响不显著。总体来看,Nip-Wx^a/ALK^a和Nip-Wx^a/ALK^c型稻米具有较高直链淀粉含量和崩解值,较低的胶稠度,因而食味值较差;Nip-wx/ALK^a和Nip-Wx^b/ALK^a型水稻具有适中的直链淀粉含量、较软的胶稠度以及较低的糊化温度,因此这两个近等基因系热饭和冷饭的食味值较好;虽然Nip-Wx^b/ALK^c的糊化温度较高,但因其适中的直链淀粉含量和较高的胶稠度,其冷饭食味值降幅较小;Nip-wx/ALK^c稻米的热饭食味值与Nip-wx/ALK^a、Nip-Wx^b/ALK^a和Nip-Wx^b/ALK^c无差异,但因其较高的糊化温度,其冷饭食味值显著下降。【结论】Wx基因变异主要影响稻米直链淀粉含量和胶稠度,对糊化温度有一定的影响;ALK基因变异主要影响糊化温度,对直链淀粉含量无显著影响,对胶稠度存在微效影响。     

不同收获时期对稻米品质的影响

水稻在最适时期收获可获得高的精米率和好的蒸煮品质,1989和1990年我们利用6个生产上广泛应用的品种为材料,每个品种种植600m2的小区,不设重复,研究了不同成熟期收获对稻米品质的影响。试验在淹水栽培下进行,记载抽穗期(50%抽穗的日期)。在抽穗期后27～42天,每3天收获1次,每亚区6m2,重复3次。收后在太阳光下晒干,2个月后用Satake水稻去壳机(型号THU-35A)和BurrowsMcGill3号精米机碾成精米,然后用过量水法煮成米饭。稻谷成熟期对稻米品质有很大的影响(见表)。我们观察到当稻谷含水量在20%～23%时收获,可获得较高的总精米率和整精米率,较…     

不同海拔高度对稻米品质性状的影响

对10个杂交稻组合在同一生态区5个不同海拔高度12个品质性状的变异特点进行了研究.结果表明,不同品质性状在不同海拔高度的变异存在很大差异,糙米率、精米率、粒长相对稳定,各组合平均变异系数仅为0.75%,0.60%和3.16%;而垩白度、垩白粒率波动较大,各组合平均变异系数高达92.28%和66.54%.通过聚类分析,可根据稻米品质性状在不同海拔高度的变异系数大小划分为3种类型,第1种是对气候条件变化最敏感的生态敏感型,如垩白度、垩白粒率,第2种是对气候条件变化反应迟钝的生态迟钝型,如糙米率、精米率、粒长,第3种是介于二者之间的中间型.随海拔升高,灌浆结实时间延长,整精米率增大,垩白度、垩白粒率变小,说明高海拔有利于改善稻米品质.     

温度对稻米品质影响的研究进展

水稻灌浆期的温度条件是影响稻米品质的主要环境因子。从稻米碾米品质、外观品质、蒸煮食味品质和营养品质四个方面,综述了温度对稻米品质影响的研究进展。     

不同收获时期对超级稻沈农014主要稻米品质影响

以沈农014为试材,根据不同抽穗天数进行收获,研究水稻不同收获时期对产量和主要稻米品质的影响。结果表明,过早收获,稻谷的含水量较高,千粒重相对较低,严重影响了产量。从加工品质来看,过早收获对糙米率和精米率影响较小,对整精米率影响较大,过晚收获也会使整精米率下降。从稻米外观品质来看,过早收获使垩白粒率和垩白度增加。从营养和食味品质来看,收获期对蛋白质含量的影响不大,但对直链淀粉和脂肪酸影响较大,对食味值的影响则无明显规律。确定沈农014在9月30日至10月10日达到最佳收获期。     

稻田不同生态种养模式对稻米品质的影响

通过田间试验探讨了稻田不同生态共作方式,包括稻蛙种养、稻鳅种养、稻鳖种养、稻蟹种养、稻鸭种养等对水稻稻米品质的影响。结果表明,各生态种养模式均能显著降低稻米垩白粒率、垩白度,降低直链淀粉含量和蛋白质含量,同时提高碱消值,但处理间未达到显著水平。因此,生态种养模式能改善了稻米品质,为水稻的优质生产提供了一条较好的技术途径。     

不同施钾量级对寒地水稻产量及稻米品质的影响

试验研究不同施钾量级对水稻干物质积累量、产量及稻米品质的影响,结果表明:当施钾量(K2O)为5.25 kg/667m2时,水稻产量最高为635.6 kg/667 m2;当施钾量为3.5 kg/667 m2时,品质各项指标均较好,可以确定施钾量在3.5~5.25kg/667 m2时产量及品质各项指标较好。     

不同土壤背景下秸秆全量还田对水稻产量及稻米品质的影响

为了探明北方地区不同土壤背景下水稻秸秆全量还田对水稻产量及稻米品质的影响,以辽粳2501为材料,通过盆栽试验,比较分析了在总施纯氮200 kg/hm²条件下不同处理（砂壤土、砂壤土+秸秆、盐碱土、盐碱土+秸秆、棕壤黏土、棕壤黏土+秸秆）辽粳2501的产量结构和品质表现。结果表明,与秸秆不还田处理相比,棕壤黏土背景下秸秆全量还田处理产量提高4.45%,而在砂壤土和盐碱土背景下秸秆全量还田处理表现为显著减产,减产幅度分别为2.20%和3.84%;秸秆全量还田均能显著提高不同土壤背景下的每穗颖花数,尤其是二次枝梗颖花数,但降低了盐碱土和砂壤土背景下的有效穗数;秸秆全量还田显著增加了稻米胶稠度和米饭食味值,但降低了盐碱土和砂壤土背景下稻米的垩白粒率和垩白度。     

栽培模式对稻米品质特性的影响

以超级稻组合88S/1128和常规优质稻品种湘晚籼17号为材料,探讨了不同栽培模式(旱作覆膜、水作覆膜、旱作不覆膜、常规栽培等)对稻米品质的影响。结果表明,2个品种一致表现为旱作覆膜栽培的糙米率、精米率最高,水作覆膜栽培的整精米率最高;同一品种不同栽培模式的粒长和长宽比无显著差异,但覆膜栽培的垩白粒率、垩白大小更高。88S/1128旱作覆膜与常规栽培相比,直链淀粉含量降低、胶稠度变小、糊化温度升高;而湘晚籼17号旱作覆膜与常规栽培相比,直链淀粉含量降低、胶稠度变大、糊化温度降低。2个品种蛋白质含量表现一致,均为旱作不覆膜常规栽培旱作覆膜水作覆膜。稻米品质性状变异度最大的为外观品质,其次为蒸煮食味品质,碾米品质变异度相对较小。     

Grain Quality as Affected by Down-regulation of Expression of Different ALK Alleles in indica Rice (Oryza sativa L.)

【Objective】Gelatinization temperature (GT) is one of the key physicochemical properties in rice quality, which is mainly regulated by ALK (SSII-3) gene. In general, there are two ALK alleles among indica cultivars. To detect their functional differentiation in indica rice,【Method】Zhenshan 97B (a high GT variety carrying ALKc allele) and Longtefu B (a low GT variety carrying ALKb allele), were used as receptors for the generation of transgenic rice with down-regulation of ALK expression by RNA interference (RNAi).【Result】Down-regulation of ALK gene significantly decreased the GT of the transgenic lines. Due to the difference of original GT between the two receptors, the GT of transgenic rice lines derived from Zhenshan 97B (a high GT variety) decreased significantly, but it is slightly decreased in transgenic plants derived from Longtefu B (a low GT variety). The differential scanning calorimetry (DSC) results showed that the initial temperature of RNAi transgenic rice was significantly lower than the corresponding control and the transgenic lines were gelatinized in advance. The peak value of GT(Tp) in RNAi rice grains was significantly lower than that of the control under Zhenshan 97B background. However, Tp of RNAi rice grains under Longtefu B background was significantly lower than the control to a lesser extent. Also, down-regulation of ALK expression had a significant effect on rice physical-chemical characteristics. An increase of apparent amylose content in RNAi transgenic plants was detected due to the decreased expression of ALK gene. Besides, the pasting properties showed that down-regulation of ALK gene had obvious effects on peak viscosity and breakdown value, improving the taste of the transgenic rice. The gel consistency was significantly different among Zhenshan 97B RNAi lines and their parents, but no difference was found in Longtefu-derived transgenic lines.【Conclusion】RNA interference to ALK allele expression had a significant effect on rice quality, especially the gelatinization characters. Down-regulated expression level of ALKc allele would cause larger variation of physical-chemical characteristics between transgenic rice and their parent than that of ALKb allele.     

水稻粒重及其相关性状的遗传解析

 应用292个 Lemont/ 特青F13重组自交系(RILs)和272个标记的遗传连锁图谱分析粒重及籽粒长、宽、厚、长/宽、体积和容重6个相关性状的遗传。所有性状在RILs中出现超亲分离。粒重与其他籽粒性状均呈显著正相关，而涉及籽粒品质的容重与粒宽、粒厚呈显著负相关。检测到影响粒重及其相关性状的主效QTL 48个和互作位点38对，这些QTL解释了各性状55%以上的表型变异。80%以上的主效QTL呈现一因多效或生理相关。QGl3和 QGl2等通过籽粒体积间接影响粒重， Lemont增效等位基因有利于籽粒品质的改良，而QGw5、QGt1和QGv7的特青增效等位基因增加粒重同时降低籽粒容重及品质。通过标记辅助选择进行不同QTL的重组，有望在增加粒重的同时改善籽粒品质。     

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.     

不同生态类型间杂交粳稻品质性状及其遗传分析

研究了8个不同生态类型的粳稻品种所配成的8×8双列杂交的F2稻米的7个品质性状的表现及遗传。结果表明：（1）8个亲本各品质性状表观差异不大,但F2代出现超亲现象,表明亲本间基因呈分散分布。（2）米粒宽、米粒重、垩白率、糊化温度、胶稠度5个性状的遗传符合加性 显性模型,且均以显性效应为主。粒长和直链淀粉含量2个性状的遗传不符合加性 显性模型,存在上位性。（3）粒宽、粒重2个性状的显性基因具减效作用,垩白度、糊化温度和胶稠度3个性状的显性基因具增效作用。（4）越光在糊化温度性状上比其他品种带有较多的隐性基因;镇稻88在粒宽、粒重2个性状上带有较多的显性基因;秀水04在粒长和胶稠度2个性状上带有较多的显性基因,在垩白度性状上带有较多的隐性基因。     

水稻小粒基因SG101的鉴定和精细定位

【目的】籽粒大小是决定水稻产量的重要农艺性状之一,开展水稻籽粒大小相关基因的克隆和功能研究对于阐述水稻产量形成的遗传调控机制具有重要意义。【方法】利用甲基磺酸乙酯诱变粳稻品种中花11,筛选获得一小粒突变体,命名为sg101(small grain 101)。通过形态学、细胞学手段调查了SG101的突变对籽粒大小、穗部主要性状及颖壳细胞数目和大小的影响,通过测定叶夹角和胚芽鞘长度分析其对外施油菜素内酯的差异响应,结合定量PCR技术分析了油菜素内酯合成途径和信号途径相关基因表达情况,并利用图位克隆的手段精细定位了水稻小粒基因SG101。【结果】与野生型相比,突变体sg101粒长和粒宽均极显著减小,从而导致千粒重极显著降低。此外,sg101还表现出结实率降低、穗长变短、二次枝梗数减少、植株变矮等。细胞学观察发现sg101的颖壳细胞大小没有改变,但细胞数目明显减少。定量PCR检测表明sg101中的细胞周期相关基因表达显著下降。另外,突变体sg101对外施油菜素内酯响应迟钝,其油菜素内酯合成途径和信号途径相关基因表达亦显著降低。【结论】遗传分析表明sg101突变体由隐性单基因控制,通过图位克隆的方法将SG101精细定位于第1染色体上,物理距离为265 kb的区间内。这为该基因的克隆及深入的功能研究奠定了基础。     

冻融法纯化水稻胚乳RNA及稻米品质重要相关基因表达谱研究

 提出了一种从水稻胚乳组织中快速分离总RNA的方法，可以简便地去除RNA中存在的淀粉等多糖类杂质，所获的胚乳总RNA其质量可满足Northern印迹、微阵列制备等分子生物学实验要求。将从966个水稻品种的胚乳中分离所得的RNA制备RNA阵列，用于稻米品质重要基因Wx基因的表达谱分析，结果证实：水稻Wx基因表达丰度总体上与水稻胚乳的直链淀粉含量呈正相关；应用于Northern印迹实验，表明在水稻胚乳组织中，淀粉分支酶Rbe1具有两个长度不同的同源基因，其中一个分子量大的为胚乳特异表达，分子量小的则在水稻各组织中共表达。     

Effects of Different Combinations of Wx and ALK Main Alleles on Rice Grain Quality

【Objective】Rice eating and cooking qualities are mainly controlled by two key genes, Wx and ALK. There are multiple alleles of both genes among rice cultivars. In this study, our aim is to clarify the effects of the main allelic variation combinations of Wx and ALK genes on rice grain quality.【Method】Three main alleles of Wx (Wxa, Wxb and wx) and two of ALK (ALKa and ALKc) were combined within a series of near-isogenic lines (NILs) in the japonica Nipponbare (Nip) background. The effects of different allelic combinations on grain quality were determined by measuring the physical and chemical characteristics of NILs.【Result】Gelatinization temperature (GT) was regulated by the major gene ALK and the minor gene Wx. Under the same ALK allele background, there was no significant difference in GT between rice lines carrying wx and Wxb alleles, but the GT of Nip-Wxa rice lines was significantly lower than that of Nip-Wxb and Nip-wx. The starch viscosity was greatly affected by the combination of Wx and ALK alleles. The breakdown value of Nip-Wxa rice line was lower and the setback value was higher (lower tasting value) than those of Nip-Wxb and Nip-wx. Under the same Wx allele background, ALK allelic variation mainly affected the pasting temperature of RVA curve, but had little effect on breakdown value and setback value. Nip-Wxa/ALKa and Nip-Wxa/ALKc rice grains had poor tasting value due to the high AC and breakdown value and low GC. But the protein content in above two NILs was higher than other rice lines. Nip-wx/ALKa and Nip-Wxb/ALka rice grains had better tasting value of hot cooked and cooled cooked rice due to the moderate AC, GC and protein content, as well as lower GT. Although the GT of Nip-Wxb/ALKc grains was higher, the moderate AC and high GC of this line resulted in a slight decrease in the tasting value of cooled cooked rice compared with hot cooked rice. The tasting value of hot cooked rice of Nip-wx/ALKc rice remained the same as those of Nip-wx/ALKa, Nip-Wxb/ALKa and Nip-Wxb/ALKc, but the tasting value of cooled rice decreased dramatically because of its high GT. 【Conclusion】Amylose content (AC) and gel consistency (GC) were mainly controlled by Wx gene; while ALK gene had no significant effect on AC, but a slight effect on GC.     

栽培密度和施肥方法对稻米品质影响的研究

选用早籼品种二九丰和浙辐802,晚粳品种秀水48和矮粳23,分别在1986年早季和晚季进行试验。结果表明稀植（比密植）和分次施氮（比一次施氮）有提高出糙率、精米率、整米率、米粒透明度的趋势,而施用钾肥有降低出糙率、精米率、整米率的趋势,而施用钾肥对米粒垩白度无明显影响。稀植降低米粒长度,分次施氮有增加米粒长度的趋势,施钾则对米粒长度无影响。密度对蛋白质含量影响因品种而异,分次施氮能明显提高蛋白质含量,施钾有降低蛋白质含量的趋势。各处理对支链淀粉含量、糊化温度和胶稠度无明显影响。