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 1000-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.     

Lodging Resistance Related to Root Traits for Mechanized Wet-Seeding of Two Super Rice Cultivars

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings.However,there is limited knowledge regarding the effects of the establishment of furrows on growth,lodging and yield,and their relationships with root traits.In this study,field experiments were conducted during 2012 and 2013 using two super rice varieties(hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan)under three furrow establishment treatments(T1,both water and seed furrows were established by the machine;T2,only seed furrows were established by the machine;and T3,neither water nor seed furrows were established by the machine).Lodging index,lodging-related traits,grain yield,above-ground dry weight and root traits were measured.The results showed that the lodging index was significantly affected by the treatments with furrows(T1 and T2).The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment(T1)in both 2012 and 2013.Lodging resistance was strongly related to the breaking resistance.No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice.Therefore,the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance,which was related to root traits.     

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.     

Effects of Aerated Irrigation on Leaf Senescence at Late Growth Stage and Grain Yield of Rice

With the japonica inbred cultivar Xiushui 09,indica hybrid combinations Guodao 6 and Liangyoupeijiu as materials,field experiments were conducted in 2007 and 2008 to study the effects of aerated irrigation on leaf senescence at late growth stage and grain yield of rice.The dissolved oxygen concentration of aerated water evidently increased and decreased at a slow rate.The soil oxidation-reduction potential under aerated irrigation treatment was significantly higher than that of the CK,contributing to significant increases in effective panicles,seed setting rate and grain yield.In addition,the aerated irrigation improved root function,increased superoxide dismutase activity and decreased malondialdehyde content in flag leaves at post-flowering,which delayed leaf senescence process,prolonged leaf functional activity and led to enhanced grain filling.     

Comparison of Grain Quality Characteristics Between F1 Hybrids and Their Parents in Indica Hybrid Rice

Sixteen widespread elite indica parents including seven CMS lines and nine restorer lines, and their 63 F1 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 F1 hybrids were generally lower than the means of their parents in quality characteristics. There existed apparent disparity in grain quality performance among F1 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 F1 hybrids in these traits in breeding. The mean values of F1 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.     

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(HP,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.     

Parental Selection in Rice Cultivar Improvement

The evaluation of rice (Oryza sativa L.) cultivars assists breeders in identifying useful trait relationships and in selecting parents as donors of specific traits. This study was conducted to compare long-grain rice cultivars using genotype × trait (GT) biplot analysis and determine potential donors of traits related to grain yield and quality. Seventeen cultivars in the 2005 and 2006 Uniform Regional Rice Nursery in Beaumont, Texas, USA were analyzed for 20 traits using GT biplot analysis. The GT biplots showed the diversity among cultivars with regards to yield-related traits. Cultivars recommended as donor parents were: Trenasse, Spring, Presidio, and Cocodrie for high grain yield and head rice rate; Trenasse and Presidio for semi-dwarfness; Banks for tall plant height; Wells for high flag leaf area, panicle weight, and number and mass of filled grains per panicle; Hidalgo for high tiller density; Francis for high number of spikelets per panicle; Spring and Trenasse for short flowering duration; Cheniere for more days to heading and maturity and Spring for less days; and Spring and Hidalgo for high grain weight. Breeders can use these cultivars with specific traits to increase grain yield and quality.     

Difference in Grain Yield and Quality among Tillers in Rice Genotypes Differing in Tillering Capacity

A japonica variety and its iso-allelic mutant with high tillering ability were used to investigate the differences in grain yield and quality among different tillers. There was a distinct difference in panicle weight among tillers during grain filling for both genotypes, with Xiushui 11 having a greater increase rate in panicle weight, and being earlier in reaching the maximum panicle weight than the mutant. There was a great significant difference between the two genotypes in grain yield and its components, with Xiushui 11 having higher grain yield, more grains per panicle, higher filled grain percentage and grain weight than the mutant for each type of tiller. Moreover, a significant difference was found in grain yield and yield components among different tillers for both genotypes, with grain number per panicle showing the greatest variation over tillers among all yield components. Compared with Xiushui 11, the mutant had higher brown rice rate and greater ratio of length to width of brown rice, and lower chalky rice rate, amylose content, and protein content of rice. Furthermore, there was a significant difference in grain quality among tillers within a plant for both genotypes, with later initiated tillers being lower in chalky rice rate, amylose and protein contents than early initiated ones. The variation of most quality parameters among tillers within a plant was markedly larger for the mutant than for Xiushui 11.     

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.     

Heterosis Expression of Hybrid Rice in Natural-and Short-Day Length Conditions

Development of hybrid rice is an important strategy to increase yields of irrigated rice in China. Day length is a highly important environmental factor for hybrid rice adaptability,productivity and quality. Heterosis of hybrid rice has been utilized under natural-(long) day length conditions in the middle and lower reaches plain of Yangtze River Valley in China for a long time. However,whether the hybrid rice can show heterosis under short-day length conditions is unknown. In this study,we analyzed plant height,grain number per panicle,and other yield related traits of hybrid rice Liangyoupeijiu(LYP9) and its parents(Pei’ai 64 S and 93-11) under natural- and short-day length conditions and compared the respective heterosis. Results showed that earlier heading,reduced plant height,and reduced grain number per panicle were found in these three varieties under short-day length conditions relative to those under natural-day length conditions. In either natural- or short-day length conditions,heterosis of LYP9 was mainly displayed in grain number per panicle and plant height. This study may help in breeding and selecting suitable hybrid rice for different regions with natural- or short-day length.     

不同施氮量和栽插密度下三角形强化栽培杂交稻抗倒伏性与群体质量的关系

 以杂交水稻组合Ⅱ优498为材料,在三角形强化栽培(TSRI)条件下,研究了施氮量和栽插密度对水稻群体质量及抗倒伏能力的影响,并探讨了主要群体质量指标与茎秆抗倒伏性及产量间的关系。结果表明,TSRI下,施氮量及栽插密度对水稻产量、群体质量以及茎秆基部各节间抗倒伏能力均存在显著的调控作用。施氮量为150 kg/hm2与栽插规格40 cm×40 cm配合可提高结实期叶面积指数(LAI)、群体透光率,协调茎秆基部各节间弯曲力矩与抗折弯矩,缓和高产栽培的穗粒矛盾,显著提高籽粒产量;而施氮量增加至225 kg/hm2,应适当降低栽插密度,来缓解群体质量指标的恶化,降低倒伏指数,栽插规格50 cm×50 cm为宜。相关性分析表明,不同施氮量和栽插密度下水稻群体质量指标与茎秆基部各节间抗倒伏能力显著或极显著相关;结合产量表现,尤以齐穗期、齐穗后30 d中部的群体透光率以及齐穗后30 d的根系伤流量对水稻产量及抗倒伏性影响显著。     

抗倒酯对北方优质稻抗倒伏能力、产量和米质的影响

[目的]研究抗倒酯对优质稻抗倒伏能力及产量与米质的影响.[方法]以优质稻品种丰锦和沈农09001为试材,在分蘖期、拔节初期、孕穗期叶面喷施不同浓度(0、90、180和360 mg/L,1200 L/hm2)的抗倒酯,以倒伏指数、抗折力以及抗推力作为评价植株抗倒伏能力的指标,研究抗倒酯对优质稻抗倒伏能力及产量和米质的影响...     

云南机插籼稻品种产量潜力分析

以36个籼稻品种为材料,在云南省永胜县三川镇开展了机插稻种植试验研究,对品种产量、群体质量、倒伏情况等指标进行了分析。结果表明,高产机插籼稻平均产量10.03 t/hm^2,颖花量5.62万/m^2,结实率72.23%,收获指数0.56,最大叶面积指数9.91,抽穗期干物质量1619.28 g/m^2,倒伏指数79.16,总叶龄18.22,其中产量最高的品种为C两优华占,产量为11.46 t/hm^2;低产机插籼稻平均产量7.03 t/hm^2,颖花量5.27万/m^2,结实率53.87%,收获指数0.46,最大叶面积指数7.89,抽穗期干物质1494.12 g/m^2,倒伏指数85.05,总叶龄17.56。总之,结实率是机插籼稻产量形成的主导因素,高产品种在适当降低有效穗数的基础上增加结实率可以获得超高产,低产品种只有在增加移栽基本苗数的基础上提高有效穗数才能获得较高产量。     

不同机直播方式对南方优质晚籼稻产量及抗倒伏特性的影响

【目的】研究不同机直播方式对南方优质晚籼稻茎秆抗倒伏能力及产量的影响,为南方优质晚籼稻高产抗倒栽培提供参考。【方法】以籼型常规稻品种黄华占和籼型杂交稻品种泰优398为材料,设置旱直播、湿直播和淹水直播3个处理,分别测定优质晚籼稻的产量及产量构成、出苗率、干物质生产、叶面积指数和茎秆形态与力学特性。【结果】与湿直播方式或淹水直播方式相比,旱直播方式可显著提高供试晚稻品种的出苗率,增幅为6.10% ~ 22.96%,且干物质生产和叶面积指数均增加。同时,旱直播方式有利于提高供试晚稻品种产量,两品种增产幅度为6.99%~27.77%,其中泰优398产量增幅高于黄华占,从产量构成因素来看,机械旱直播方式下供试晚稻品种产量的提高主要得益于有效穗数增加。此外,旱直播方式下供试水稻株高相对较矮,基部各节间较短,但茎秆粗壮,茎壁较厚,有利于提高植株茎秆抗折力和秆型指数,降低弯曲力矩与倒伏指数。相关分析表明,茎粗、壁厚和秆型指数与抗折力显著正相关,而与倒伏指数显著负相关;株高、穗长、弯曲力矩与抗折力显著负相关,与倒伏指数显著正相关。【结论】采用机械旱直播方式不仅有利于增加南方优质晚籼稻产量,还能显著增加茎秆强度,提高植株抗倒伏能力,降低直播生产的风险。     

两优培九稻米淀粉黏滞性(RVA谱)的纬度地域和播期变化

在江苏4个稻作区的5个不同纬度点（纬度范围为31.3°N~34.7°N）,设置了5个播期处理,研究了优质高产的两系杂交中籼稻两优培九的稻米RVA谱变化特征。 两优培九稻米RVA谱易受环境影响,该品种最佳的稻米RVA谱主要出现在纬度点32.4°N及以南地区,北移种植则导致RVA谱品质下降,即峰值黏度下降,消减值、糊化温度增加。RVA谱随播期的推迟呈变劣的趋势。结实期较高的平均温度可显著增加峰值黏度、降低消减值,因此两优培九以早播栽培为佳。     

不同机直播方式对南方优质晚籼稻产量及抗倒伏特性的影响

【目的】研究不同机直播方式对南方优质晚籼稻茎秆抗倒伏能力及产量的影响，为南方优质晚籼稻高产抗倒栽培提供参考。【方法】以籼型常规稻品种黄华占和籼型杂交稻品种泰优398为材料，设置旱直播、湿直播和淹水直播3个处理，分别测定优质晚籼稻的产量及产量构成、出苗率、干物质生产、叶面积指数和茎秆形态与力学特性。【结果】与湿直播方式或淹水直播方式相比，旱直播方式可显著提高供试晚稻品种的出苗率，增幅为6.10% ~ 22.96%，且干物质生产和叶面积指数均增加。同时，旱直播方式有利于提高供试晚稻品种产量，两品种增产幅度为6.99%~27.77%，其中泰优398产量增幅高于黄华占，从产量构成因素来看，机械旱直播方式下供试晚稻品种产量的提高主要得益于有效穗数增加。此外，旱直播方式下供试水稻株高相对较矮，基部各节间较短粗、壁厚和秆型指数与抗折力显著正相关，而与倒伏指数显著负相关；株高、穗长、弯曲力矩与抗折力显著负相关，与倒伏指数显著正相关。【结论】采用机械旱直播方式不仅有利于增加南方优质晚籼稻产量，还能显著增加茎秆强度，提高植株抗倒伏能力，降低直播生产的风险。，但茎秆粗壮，茎壁较厚，有利于提高植株茎秆抗折力和秆型指数，降低弯曲力矩与倒伏指数。相关分析表明，茎     

黑龙江省水稻主栽品种（系）节水抗旱栽培下的抗倒性研究

倒伏是严重影响水稻产量与品质的一个因素。通过常规灌溉和节水抗旱栽培模式下与水稻抗倒性密切相关的性状指标的变化,探讨了黑龙江省各积温带水稻主栽品种（系）的抗倒性。结果表明,节水抗旱处理使部分品种（系）的倒伏指数减小,倒2节带鞘抗折力增加,节间干物质量增加,节间横切面积减少,茎壁增厚;抗倒性、抗旱力指数和实测产量等指标表现均较高的品种（系）第一积温带有龙稻16和龙稻24,第二积温带有绥粳4号、绥粳17、绥粳18、北稻7号、绥锦089290,第三积温带有绥粳15、龙粳56、龙粳51、龙粳58、龙粳20、龙交08119、龙丰12500、龙粳3100和龙粳1424,第四积温带有龙粳24、龙粳1525、龙交13S6,第五积温带有龙粳4344。通过对倒伏性状的调查研究,了解各积温带主栽品种（系）的抗倒性情况,可为黑龙江省水稻节水抗旱栽培和抗倒伏种质的研究与利用奠定基础。     

金华市单季杂交晚稻引种试验初报

金华市于2013年引入21个杂交籼稻新品种进行品比试验,结果表明,产量超过对照两优培九的品种有8个,表现较好的品种为A五优143、中新优30、五优930、浙辐优11-19。简述了表现较好品种的生育特性及产量表现。     

不同类型水稻品种钵苗机插高产群体特征及其产量研究

以常规粳稻武运粳24号和杂交稻甬优2640为材料,设置钵苗机插高产示范田,探明不同类型品种群体结构特征及其产量形成特点。研究结果表明,甬优2640秧苗素质较高,拷苗后发根力明显优于武运粳24号;群体后期干物质积累及光合势均明显高于武运粳24号;抗倒力矩为64.1 g/茎,较武运粳24号的51.4 g/茎高24.7%,抗倒能力优势明显;最终实测产量为774.6 kg/667 m2,较武运粳24号高6.4%。