施氮水平对优质稻产量、品质及稻米Hg、As、Cd含量的影响

以优质稻桂小占为材料,通过田间小区试验的方法,研究了空白,低肥（75 kg/hm2）、中肥（150 kg/hm2）、高肥（225 kg/hm2）4种施氮量对水稻产量、稻米品质和食用安全性（稻米Hg、As、Cd含量）的影响。结果表明,当施氮量低于150 kg/hm2时,随着施氮量的增加,水稻有效穗数显著增加,从而显著提高水稻产量,而当施氮量超过150 kg/hm2时,增产效果不显著。随着施氮水平的提高,出糙率、精米率、整精米率和蛋白质含量也逐渐增加,而垩白粒率、垩白度、直链淀粉含量和胶稠度则有所降低。其中出糙率、精米率、整精米率在高肥、中肥、低肥3种施肥处理下差异不显著,但均显著高于不施肥处理。中肥、高肥水平下的垩白粒率、垩白度无显著差异,并均显著低于低肥处理。蛋白质含量、直链淀粉含量和胶稠度在不同施氮水平间的变化最大,各肥料处理间的差异均达到显著水平。施氮量的提高对稻米中Hg含量的影响不明显,但可导致As、Cd含量的升高,其中稻米Cd含量在高肥与中肥水平下的差异显著,As含量在各施氮水平处理间均存在显著性差异。在此试验条件下,适量的增施氮肥,有利于优质稻获得高产并将稻米品质提升到较高水平;通过降低施肥量可减少稻米对As、Cd的吸收和积累,提高食用安全性。在优质稻栽培过程中应适量增加氮肥,施氮水平以不超过150 kg/hm2为宜。     

对我市优质稻发展思路的建议

稻米品质包括碾米品质、外观品质、蒸煮食味品质、营养品质、市场品质和卫生品质六个方面.碾米品质包括出糙率、精米率及整精米率;外观品质由米粒透明度、垩白率、垩白度及米粒形状等因素组成;蒸煮食味品质主要是指糊化温度、直链淀粉含量、胶稠度、香味及膨胀性等指标;营养品质是指蛋白质、氨基酸、脂肪等成分的含量;卫生品质主要是指稻米中农药的残留量和其它有毒物质含量;市场品质是指产品的水分、不完善粒、黄米粒和杂质含量等.在稻米品质各项指标中,垩白、整精米及食味相关的理化性状显得尤为重要.     

植物生长调节物质对食用稻米品质的影响研究

灌浆结实期对两优培九、汕优63和扬稻六号三个不同品质的品种进行PDJ、BR和ALA三种植物生长调节物质处理试验,研究表明：植物生长调节物质对灌浆期稻米品质的存在影响。BR及ALA导致稻米的整精米率下降和垩白粒率的上升,而PDJ处理结果与之相反;不同浓度的ALA处理后,导致稻米的整精米率的下降、垩白度以及垩白粒率的上升,但对稻米品质的加工品质如糙米率及精米率和外观品质等其他指标影响不大。三种植物生长调节物质均可使供试验的三个品种的结实率明显提高,并使千粒重增加,且使杂交稻稻米的胶稠度一般呈上升趋势,而常规稻的胶稠度有所下降。生长调节物质对稻米氨基酸含量有影响但规律性不强。     

氮、磷、钾有机肥对水稻产量和品质的影响

试验结果表明，增施N肥增产显著。增施K肥，有机肥也有一定增产效果。以施NPK 有机肥的产量最高，施用K肥能降低垩白率，增施有机肥能降低垩白度。以N，P，K处理的稻米外观综合品质较好，整精米率较高，垩白率和垩白度较低。因此NPK配合施用。产量较高，又能改善稻米外观综合品质，同时尽可能增施有机肥，既可增产又可降低垩白度。     

覆膜旱作稻米品质的初步研究

以常规水管稻为对照,研究了水稻在覆膜旱作生态条件下的稻米品质。结果表明：与常规水管相比较,糙米率、粒长、长宽比、透明度、直链淀粉含量几乎没有变化;精米率、垩白度、杂交籼稻的湖化温度略有增加,蛋白质含量、杂交籼稻的整精米率明显增加;胶稠度、粳稻品种的整精米率略有下降,垩白粒率明显减小。依据部颁《优质稻米标准》ＮＹ１２２－８６综合评价,覆膜旱作稻米品质有一定程序的提高。     

我国南方稻区的稻米品质

稻米品质可分为贮藏品质、碾米品质、市场品质、蒸煮食用品质、营养品质和加工品质等。贮藏品质即稻米的耐贮藏性。碾米品质包括糙米率、精米率和整粒精米率等。市场品质即稻米的外观,包括稻米的长度、形状、胚乳透明度和垩白等。蒸煮食用品质是由其理化性质决定的,主要包括直链淀粉含量、胶稠度、糊化温度、米粒延长性和香味等。营养品质即稻米的蛋白质含量和赖氨酸含量等。稻米的加工品质即稻米酿酒、加工成各种副食品的品……     

水、旱栽培条件下稻米主要品质性状的比较研究

以旱稻品种IRAT109的116个株系与水稻品种越富杂交构建的DH群体及其亲本，在水、旱2种栽培条件下种植，研究了稻米加工、外观、蒸煮和营养等品质性状的变化规律及其各品质性状间的相关性。结果表明，在11个稻米品质性状中，蛋白质含量、整精米率、胶稠度和碱消值等4个性状水、旱2种不同栽培条件下差异较大，说明这些性状受水分条件影响较大；粒长、粒宽、直链淀粉含量和垩白率也有一定的差异，一定程度受土壤水分环境影响。旱栽条件下稻米蛋白质含量、整精米率、胶稠度、碱消值等均有不同程度的升高，其中蛋白质含量平均提高37.9%，平均增加3.02个含量百分点，而垩白率下降，稻米米粒变小，总体上旱栽稻米品质有变优趋势。糙米率、精米率和长宽比在2种栽培条件下没有差异，基本上不受土壤水分环境影响。此外，对同一品质性状在水、旱2种不同栽培条件下相关性分析，表明加工品质性状的基因与环境互作较大，外观、蒸煮和营养等品质性状比较稳定。因此，通过水稻和旱稻相互杂交，可将旱稻的抗旱基因导入外观品质、蒸煮、食用品质以及营养品质优良的目标水稻亲本中，选育出抗旱、优质的水稻或旱稻品种。     

新型植物生长调节物质对水稻产量及品质的影响研究

灌浆结实期对两优培九、汕优63和扬稻6号3个不同品质的品种进行PDJ、BR和ALA3种植物生长调节物质处理试验,研究结果表明:植物生长调节物质对水稻产量及品质均产生影响。BR及ALA导致稻米的整精米率下降和垩白粒率的上升,而PDJ处理结果与之相反;不同浓度的ALA处理后,导致稻米的整精米率下降、垩白度以及垩白粒率上升,但对糙米率、精米率和外观品质等其他稻米品质的指标影响不大。3种植物生长调节物质均可使供试验的3个品种的结实率明显提高,并使千粒重、单位面积产量增加。     

不同栽培环境对稻米品质的影响

以6个不同类型水稻品种为供试材料，进行大田栽培和水培，并在结实期进行两种水培营养液浓度(标准Espino浓度和1／2Espino浓度)处理，研究栽培方法及营养液浓度对稻米品质的影响。结果表明：(1)大多数品种在大田栽培条件下的精米率、整精米率、垩白粒率、直链淀粉含量、胶稠度要显著或极显著高于水培条件，蛋白质含量和偏基准温度(PT)则低于水培条件；栽培条件对糙米率和粒型等影响不大。(2)与低营养液浓度(1／2Espino浓度)相比，结实期高营养液浓度(标准Espino浓度)显著或极显著地增加了稻米的整精米率、垩白粒率、垩白度、蛋白质含量和偏基准温度(PT)。对不同栽培方式和营养条件对稻米品质影响的原因进行了讨论。     

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。     

Optimizing selection for rough rice yield, head rice, and total milled rice

High rough rice yields are important for the profitable production of rice (Oryza sativa L.). The value of rough rice is determined primarily by head rice (whole milled grains) and broken rice, together referred to as total milled rice. The objective of this study was to optimize selection for rough rice yield, head rice, and total milled rice using path-coefficient analysis and selection indices. Thirty-seven long grain pure lines were grown in an experiment at three Arkansas locations during 1993 and 1994. In another test, twenty-eight F₁ hybrids obtained from an eight-parent half diallel of long-grain rices were grown at two locations in Arkansas during 1991. For the pure lines, path analysis revealed that rough rice yield was approximately twice as important in determining total milled rice/ha than head rice. Path analysis for the hybrids revealed that rough rice yield was an even greater component in determining total milled rice/ha. Based on yield components for hybrid rice, panicle density had the largest direct effect determining total milled rice/ha. Filled grain/panicle, grain weight, and head rice, in that order, were secondary, but positive, factors determining total milled rice/ha. A selection index for pure lines based only on selection for head rice was 19.2 percent as effective as selection for total milled rice/ha directly. When selection for total milled rice/ha was based solely on rough rice yield, selection was 82.7 percent as effective as selecting for total milled rice/ha directly. Selection to improve total milled rice/ha should concentrate on increasing both rough rice yield and head rice. Rough rice yield should receive greater priority than head rice in selection strategies. This revised version was published online in July 2006 with corrections to the Cover Date.     

国外稻种资源在广西水稻育种中的应用

水稻种质资源是育种的物质基础。水稻育种要在米质、产量、抗性上有新的突破,除了有新的育种技术外,还要有丰富的遗传资源。国际水稻遗传评价试验网(INGER)的参试材料集中了世界上主要产稻国家和国际研究机构提供的优良种质,来源广泛,遗传基础丰富。广西农科院从1980年起,参加由国际水稻研究所协调的国际水稻遗传评价试验网的国际合作研究工作,到2002年累计从各试验圃获得试验材料15890份,大大丰富了广西水稻新品种选育的物质基础,经试验评价,筛选出一批高产、优质和恢复源种质材料提供育种利用,并育成一批高产、优质、抗病的优良水稻品种…     

“云大— 120 ”浸种对水稻秧苗素质及产量影响的研究

试验结果表明：用“云大— 120 ”浸稻种对种子的发芽势、发芽率、秧苗素质、有效穗和稻谷产量具有一定的促进作用，发芽势比对照提高 12.68% — 23.94% ；发芽率提高 3.75% — 18.75% ；有效穗提高 0.5% — 7.43% ；产量增加 1.03% — 8.49% 。其使用方法简单易行，在生产上具有重要的推广价值。     

Analysis of Vietnamese rice germplasm provides an insight into Japonica rice differentiation

Genetic differentiation among landraces of rice in northern Vietnam that lie in the centre of genetic diversity of Asian cultivated rice was analysed using DNA markers, and morphological and physiological traits to obtain an insight into the genetic differentiation of Asian rice. Principle coordinate analysis, based on nuclear RFLP data, divided Vietnamese rice varieties into three groups, designated A, B and C. Chloroplast DNA variation discriminated group A, which corresponded to the Indica rice varieties, from both groups B and C, which corresponded to the Japonica rice varieties. Physiological characteristics for Indica‐Japonica and tropical‐temperate Japonica discrimination suggested groups A and B consisted of typical Indica and Japonica varieties, respectively, while the characteristics of group C were distinct from those of the other two groups. This suggests that the genetic differences between groups B and C represent a new aspect of genetic variation that has not been previously reported in Japonica rice. Groups C and B corresponded with upland and lowland rice, respectively. Eight marker loci were associated with upland‐lowland differentiation in Japonica rice. Highlighted chromosomal regions might have been selected during the history of cultivation under different cultural conditions, and thus contain genes related to adaptation.     

Quality of head and chalky rice and deterioration of eating quality by chalky rice

Chalk, an opaque area in the rice grain, is an important quality characteristic in rice and occurs most commonly when grains are exposed to high temperatures during development. Chalky rice decreases the value of rice because of its undesirable appearance and eating quality for consumers. We investigated the chemical composition, morphological structure, cooking, texture properties of cooked rice, and pasting and gelatinization properties to evaluate the reason for the deterioration in eating quality of chalky rice.     

Objective evaluation of whiteness of cooked rice and rice cakes using a portable spectrophotometer

The whiteness of cooked rice and rice cakes was evaluated using a portable spectrophotometer with a whiteness index (WI). Also, by using boiled rice for measurement of Mido values by Mido Meter, it was possible to infer the whiteness of cooked rice without rice cooking. In the analysis of varietal differences of cooked rice, ‘Tsuyahime’, ‘Koshihikari’ and ‘Koshinokaori’ showed high whiteness, while ‘Satonoyuki’ had inferior whiteness. The whiteness of rice cakes made from ‘Koyukimochi’ and ‘Dewanomochi’ was higher than the whiteness of those made from ‘Himenomochi’ and ‘Koganemochi’. While there was a significant correlation (r = 0.84) between WI values and whiteness scores of cooked rice by the sensory test, no correlation was detected between the whiteness scores and Mido values, indicating that the values obtained by a spectrophotometer differ from those obtained by a Mido Meter. Thus, a spectrophotometer may be a novel device for measurement of rice eating quality.     

Inheritance of resistance to rice stripe virus in rice line `BL 1'

Rice stripe is the most serious virus disease in temperate rice-growing countries. The most economical and environmentally safe practice for controlling this disease is virus-resistant cultivars. ‘BL 1’ is an elite germplasm line with the blast resistance gene Pib, and has been used as a differential line for testing the pathogenicity of the blast fungus. We found that certain progenies from BL 1 showed resistance to both blast and rice stripe virus (RSV). The objectives of this study were to evaluate the RSV resistance in the field and under artificial conditions, to assess the reaction to the insect vector(small brown plant hopper, SBPH), and to examine its inheritance and its relationship to blast resistance in BL 1.BL 1 was susceptible to SBPH, but resistant to RSV in field and artificial inoculation tests. The inheritance of RSV resistance in F₃ lines from the cross Nipponbare (NPB)/BL 1 was studied using artificial inoculation with a population of viruliferous SBPH. A serological assay for RSV infection using an enzyme-linked immunosorbent assay (ELISA) was used. RSV resistance in BL 1 was controlled by a single major gene with incomplete dominance. The locus responsible for RSV resistance was genetically independent of the blast resistance gene Pib. The resistance gene for RSV infection in BL 1 was also independent of Stvb-i, a gene widely distributed in resistant Japanese cultivars. Resistance to RSV must be diversified in rice cultivars considering the potential for future emergence of new RSV strains. The new resistance gene identified in BL 1, which has improved plant type and blast resistance, is considered useful for breeding RSV-resistant cultivars in japonica rice. This revised version was published online in August 2006 with corrections to the Cover Date.     

New sources of rice blast resistance obtained from Thai indigenous upland rice germplasm

Upland rice production plays an important role in both household consumption and crop rotation. Until now, a blast resistant upland variety has not been released in Thailand. The bimodal pattern of rain distribution in Thailand’s upland rice production areas create a favorable environment for the outbreak of leaf blast when seedling-tillering, and neck blast within the heading stage. The use of genetically resistant cultivars has proven to be an effective way to cope with this problem. In this study, 256 indigenous upland rice plants were screened for blast resistance under greenhouse and field conditions. Ten indigenous upland rice varieties, ULR292, ULR242, ULR219, ULR162, ULR161, ULR134, ULR109, ULR098, ULR081, and ULR066, were identified as resistant to leaf blast disease in both natural infection and artificial inoculation, under greenhouse conditions. Additionally, six of the ten varieties, ULR162, ULR161, ULR134, ULR109, ULR098, and ULR081, were found to be resistant to neck blast under field conditions. These new sources of blast resistance identified from indigenous upland rice varieties proved more resistant than the check varieties, depicting their potential for further use in Thailand’s rice blast resistance improvement program.     

Inheritance of scent in rice

Summary Inheritance of scent in rice and its association with pigmented characters were studied in T-141 × K-44-1. Four complementary genes appeared to control scent, one of them showing linkage with a complementary gene for glume colour and a supplementary gene for red pigment in apiculus. This group formed part of V (Prp)linkage group of Misro et al. (1966) in which case Pg and P were additions.Pl.480 Project on linkage maps in rice.     

寒地早粳品种对稻米品质的影响

以近几年主栽的水稻品种为试材,采取相关统计分析和对比试验等方法,研究了水稻品种对早粳稻米品质的影响,旨在为寒地稻作区优质米品种的选育和高产栽培提供理论依据和技术支持。研究取得如下主要结果：（1）不同熟期碾米品质的3项指标中,糙米率的平均值分别为83.1%、82.9%、83.1%、83.0%;精米率的平均值分别为71.9%、71.9%、72.0%、73.0%。不同品种的糙米率,不同熟期间差异很小,晚熟品种的精米率略高于早熟和中熟品种,品种间表现有差异。不同熟期的整精米率的平均值分别为61.7%、61.7%、66.5%、67.2%,晚熟品种比早熟和中熟品种高,品种间差异较大。早熟和中熟品种的整精米率变异系数较晚熟品种增加1.2个百分点,说明品种间差异较大。稻米垩白米率与胶稠度（0.0566）呈正相关,这一点与（李雅娟,1995）的研究结果一致。垩白米率与精米率（-0.4827）呈显著负相关,因此,在育种上筛选垩白米率低的种质资源是关键。（2）直链淀粉含量是影响稻米食味品质的最重要指标之一,很多研究认为,直链淀粉含量偏高影响稻米食味品质（佐佐木忠雄,等．1982）。关于直链淀粉含量姬田正美（1996）研究认为,直链淀粉含量越高,稻米食味越差。本研究结果直链淀粉含量一般在16.67%~22.40%,平均含量为18.8%,品种间差异较大。直链淀粉含量与蛋白质含量（-0.8207）呈极显著负相关。