Effects of Different Sowing Dates and Sites on Starch RVA Profile Characteristics of Different Ecotypes of Rice (Oryza sativa, L. japonica)

[Objective] This study aimed to investigate the effects of different sowing dates and sites on starch RVA profile characteristics of different ecotypes of japonica rice. [Method] Five different ecotypes of japonica rice were sown at seven different dates in four rice planting regions in Jiangsu Province to analyze the differences in starch RVA profile parameters among different rice varieties. [Result] Among eight parameters of rice starch RVA profile, peak time exhibited no significant differences among different sites, while other seven parameters varied significantly or extremely significantly among different sites, sowing dates and varieties. Specifically, rice variety exerted the most significant effects on rice starch RVA profile parameters. Starch RVA profile characteristics varied significantly among different ecological conditions but exhibited no significant differences among different latitudes. To be specific, in different sites, peak viscosity （PKV）, hot paste viscosity （HPV） and breakdown viscosity （BDV） demonstrated a descending order of Huai＇an 〉 Suzhou 〉 Lianyungang 〉 Yangzhou. Cool paste viscosity （CPV） and consistence viscosity （CSV） were higher in the north than in the south; specifically, CPV and CSV were significantly higher in Lianyungang and Huai＇an than in Yangzhou and Suzhou. Setback viscosity （SBV） showed an increasing trend with increasing latitude; specifically, SBV was significantly lower in Suzhou than in other three sites. Pasting temperature （PAT） and peak time （PET） changed slightly among different latitudes. With the postponing of sowing date, peak viscosity （PKV）, hot paste viscosity （HPV）, cool paste viscosity （CPV） and peak time （PET） showed a decreasing trend, setback viscosity （SBV） and consistence viscosity （CSV） increased, breakdown viscosity （BDV） increased first and then decreased, whereas pasting temperature （PAT） decreased first and then increased. Furthermore, rice starch RVA profile parameters showed the same variation trend with sowing date in different sites; early sowing within suitable sowing dates could effectively improve the parameters of rice starch RVA profile. However, different parameters exerted different variations among different sites and most parameters were higher in the north than in the south, which indicated that starch RVA profile parameters were significantly affected by sowing date in the north of Jiangsu Province. Among eight starch RVA profile parameters, setback viscosity exhibited the maximum variation coefficient, while peak time exhibited the minimum variation coefficient. Among five rice varieties, Nanjing 46 exhibited the highest peak viscosity and breakdown viscosity and the lowest setback viscosity and consistence viscosity, suggesting that Nanjing 46 had the most appropriate starch RVA profile characteristics and the best cooking and eating quality. Lianjing 4 exhibited relatively high peak viscosity and breakdown viscosity, and relatively low setback viscosity and consistence viscosity, suggesting that Lianjing 4 had good starch RVA profile characteristics. Different sowing dates and sites exerted significant effects on starch RVA profiles of different eco- types of japonica rice. Rice starch RVA profile characteristics varied significantly among different sites but exhibited no significant variations among different latitudes. In addition, starch RVA profile characteristics varied significantly among different sowing dates. Therefore, early sowing of the same variety was conducive to improving starch RVA profile characteristics in appropriate planting regions. [Conclusion] This study provided a theoretical basis for producing high-quality rice and improving the eating quality of rice in Jiangsu Province.

Study on Sowing Date for Mechanicaltransplanting Rice under Wheat-Rice Cropping System in Chengdu Basin

Nurturing sturdy mechanical-transplanting seedlings is the key to achieve high yield using mechanical-transplanting technology under wheat-rice cropping conditions in Chengdu Basin. In this study, super hybrid rice II You 602 was adopted as experimental material, to investigate the effects of sowing date on seedling growth,transplanting quality, growth process and yield of mechanical-transplanting seedlings in wheat-rice cropping region of Chengdu Basin, thus exploring supporting high-yield cultivation techniques for mechanical-transplanting technology in Chengdu Basin, Results showed that the appropriate sowing date for mechanical transplanting in wheatrice cropping region of Chengdu Basin was April 10-15, and the appropriate seedling age was 45-50 d, which led to the highest yield of mechanical-transplanting seedlings. Although postponing sowing was conducive to improving transplanting quality and increasing the percentage of earbearing tillers, it would result in lagged group growth, poor spike quality and reduced effective number of panicles, grain number, seed-setting rate, 1 000-seed weight and other yield components, thus declining the yield. Yield reduction rate would be above 10% with sowing date postponed by 15 d.

Effects of Different Sowing Dates and Sites on Grain Quality and RVA Profile of Nanjing 46,a Popular Cultivar of Japonica Rice(Oryza sativa L.)

[Objective] This study was performed to determine the effects of sowing dates and sites on grain quality and Rapid Viscosity Analyzer （RVA） profile of Nan-jing 46. [Method] The field experiments were carried out at five sites in Jiangsu Province, and in every site, the seeds were sowing on seven different dates. RVA related indices were measured after harvest. [Result] Along with the delay of sowing date, the mil ing quality of Nanjing 46 increased at first and then reduced, while its appearance quality went up and the cooling and edible quality decreased. With the sowing sites moving southward, the rice mil ing quality, appearance quality, and cooling and edible quality of Nanjing 46 decreased at first and then increased. Grain traits responded variably to the sowing dates and sites. The brown rice rate, grain width, grain length, length/width, mil ed rice rate and head mil ed rice rate were less affected, while the chalky rice rate and chalkiness degree were more af-fected. The gelatinization temperature, protein content, amylose content, gel consis-tency and eating value were in-between. The RVA profile analysis revealed that the breakdown value, setback value and pasting temperature were affected by the sow-ing date and geographical environment. The peak viscosity, hot viscosity, cool vis-cosity and peak time were influenced more by geographical environment. With the delay of the sowing date, peak viscosity, hot viscosity, cool viscosity, setback value and pasting temperature decreased at first and then increased, while the breakdown value changed inversely, and the peak time did not exhibit a regular trend. With the decrease of latitude, the peak viscosity, hot viscosity, breakdown and cool viscosity declined at first and then increased, the setback value and peak time decreased, while the pasting temperature increased. [Conclusion] This study wil provide refer-ences for the effective production of Nanjing 46.

Research of an Appropriate Sowing Quantity of Double-cropping Machine-transplanted Rice in Low and Medium Yielding District of Southern Jiangxi Province

[Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five different seeding quantities treatments, and compared with conventional seedling treatment, and the appropriate seeding quantities of double season machine-transplanted rice in middle and lowyielding district of southern Jiangxi Province was discussed. [Result] The yields were highest when the seeding quantity was 70 g per tray of early rice by mechanical transplanting and 60 g per tray of late rice. The yield of early rice by mechanical transplanting showed significantly positive correlation with the number of productive ear and the number of seed per ear, and late rice yield showed significant correlation with the number of productive ear by mechanical transplanting. It is key for improving high yields by guaranteeing the number of productive ear. [Conclusion] The issue of proper sowing quantity should be taken into consideration for double-cropping rice in the region, which is crucial for high yields.

The Development and Application of 2BDQ-8 Rice Direct Sowing Machine

[Objective] The aim was to introduce the development and application of 2BDQ-8 rice direct sowing machine and provide a theoretical basis for rice mechanization production. [Method] 2BDQ-8 rice direct sowing machine was used for the promotion test in field of several cities and counties in Jiangsu Province,and artificial rice planting and mechanization rice planting were compared to explore the production and economic situation. [Result] 2BDQ-8 rice direct sowing machine had advantages such as high efficiency and low cost,the rice direct sowing machine saved about 30% compared to the artificial rice planting and mechanization rice planting,and the overall efficiency was significant. [Conclusion] 2BDQ-8 rice sowing machine was a production technology that had low cost and high efficiency,which should be widely applied.

Effect of Rice Sowing Date on Occurrence of Small Brown Planthopper and Epidemics of Planthopper-Transmitted Rice Stripe Viral Disease

To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RSV） disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics （AUCPD or planthopper-day accumulation） or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.

Effect of Different Sowing Dates in South Henan 's Rice-growing Areas on the Growth and Yield of Ratoon Rice

In order to determine the optimal sowing date of ratoon rice in South Henan's rice-growing areas,this paper performs a comparative analysis of rice growth process,seedling quality and yield of first season rice and ratoon rice under different sowing date treatments. The results show that under climatic conditions( 2014),by using dry seedling cultivation in a small plastic shed,the growth of seedling sown on February21 was affected,while the sowing treatments from March 1 to April 11 can breed normal seedlings,and in this period,the maturity period of first season rice was delayed with prolonged sowing date,and ratoon rice yield declined with prolonged sowing date( total production of rice sown on 11 March reaching a peak). Thus,it is considered that the optimal sowing date of ratoon rice in South Henan's rice-growing areas is mid-March.

Effects of Late Sowing on Differentiation and Degeneration of Branches and Spikelets of <i>Indica</i>Rice under Different Ecological Conditions

In rice (Oryza sativa L.), yield is related to characteristics of branches and spikelets. To investigate the effects of late sowing date on differentiation and degeneration of spikelets in rice, field experiments were conducted in Chongzhou and Hanyuan, China. Differentiation and survival of branches and spikelets in Hanyuan were lower than that of Chongzhou, whereas degeneration was greater than that of Chongzhou. In Chongzhou, sowing date affected differentiation and survival of primary, secondary, and total branches, as well as differentiation and degeneration of secondary and total spikelets. In Hanyuan, sowing date affected degeneration of secondary and total branches, and the survival and degeneration of primary spikelets. Late-sown plants experienced higher temperatures in the jointing to heading period, and there were higher sunshine hours. Rainfall and humidity were higher in Chongzhou, but lower in Hanyuan. Late sowing increased differentiation, degeneration, and survival number of branches and spikelets in Chongzhou. However, in Hanyuan, late sowing increased differentiation and degeneration of branches, but decreased survival of branches, which reduced spikelet differentiation and degeneration, resulting in fewer branches. Thus, the key to higher yield in Chongzhou was to increase differentiation of spikelets, whereas in Hanyuan, it was to reduce degeneration of branches and spikelets.

Relationship between “Two Insects and One Spider” and Their Occurrence and Damage Regularity during Different Sowing Periods in Single Cropping Hybrid Rice

[Objective]The paper was to study the relationship between rice leaf roller,rice planthopper and spider and their ecological regulation ability in the field.[Method]The population dynamics of rice leaf roller,rice planthopper and spider at three different sowing and transplanting periods of single cropping hybrid rice in the treatment area with combination of 3 drug formulations and untreated area were monitored.[Result]There were significant or extremely significant positive correlations among rice leaf roller,rice planthopper and spider in single cropping hybrid rice.However,with the delay of planting and transplanting period,the population fluctuation crest of rice leaf roller and rice planthopper decreased,but the intensity increased with the advance of time,and the natural ecological regulation ability was relatively improved.[Conclusion]The sowing period of single cropping hybrid rice is delayed 5-10 d compared with conventional rice,that is,sowing in late May and early June.The seedling age of 20-30 d is beneficial not only to reduce the initial population quantity of rice leaf roller and rice planthopper in the field,but also to increase the population quantity of spiders.

化肥优化减施对麦茬旱直播稻强、弱势粒食味与营养品质的影响

以常规施肥处理(F0,施N 350 kg/hm^(2)、P_(2)O_(5)135 kg/hm^(2)、K_(2)O 135 kg/hm^(2))为对照,研究不同化肥优化减施处理(F1:施N 280 kg/hm^(2)、P_(2)O_(5)108 kg/hm^(2)、K_(2)O 135 kg/hm^(2);F2:施N 210 kg/hm^(2)、P_(2)O_(5)81 kg/hm^(2)、K_(2)O 135 kg/hm^(2);F3:施N 140 kg/hm^(2)、P_(2)O_(5)54 kg/hm^(2)、K_(2)O 135 kg/hm^(2))对麦茬旱直播稻强、弱势粒食味与营养品质的影响,以期为直播稻优质高产施肥管理提供参考。结果表明,各化肥优化减施处理总体上均显著提高了直播稻强、弱势粒崩解值和峰值黏度,改善了食味品质,F1、F2、F3处理强势粒的崩解值分别比F0处理显著提高8.35%、7.65%、9.78%,F1、F3处理弱势粒的崩解值分别比F0处理显著提高13.25%、11.13%。各化肥优化减施处理总体上均显著降低了强、弱势粒中组氨酸、脯氨酸及锰含量,总体上均显著提高了强、弱势粒中酪氨酸、精氨酸、赖氨酸含量和弱势粒中铜、锌含量,另外,F1处理还显著提高弱势粒中铁含量,F2处理显著提高强势粒中铁、铜含量及强、弱势粒中钙含量。与F0处理相比,F1、F2、F3处理强势粒的酪氨酸含量分别显著提高100.28%、44.76%、41.08%,弱势粒的酪氨酸含量分别显著提高85.21%、61.64%、22.47%;F1、F2、F3处理强势粒的赖氨酸含量分别显著提高28.87%、27.32%、70.62%,F1和F3处理弱势粒的赖氨酸含量分别显著提高27.23%、39.44%;F1、F2、F3处理强势粒的精氨酸含量分别显著提高6.54%、11.84%、2.18%,弱势粒的精氨酸含量分别显著提高32.83%、33.59%、23.02%。与F0处理相比,F1处理弱势粒铁含量显著提高27.16%,F1、F2、F3处理弱势粒锌含量分别显著提高18.86%、6.56%、3.39%,F1、F2、F3处理弱势粒铜含量分别显著提高2.49%、2.95%、3.11%。综上,化肥优化减施在提高强、弱势粒食味品质的同时,可以改善营养品质,总体上以F1处理最优。

播期和密度对精量穴直播水稻产量和抗倒伏性的影响

为探究渝西地区播期与密度互作对精量穴直播水稻产量和抗倒伏的影响,以渝香优8133和泰优粤禾丝苗为试验材料,设置2个播期(B1:3月29日、B2:5月25日)和5个播种密度(D1:每1 hm^(2)1.50×10^(5)穴、D2:每1 hm^(2)1.95×10^(5)穴、D3:每1 hm^(2)2.40×10^(5)穴、D4:每1 hm^(2)2.85×10^(5)穴、D5:每1 hm^(2)3.30×10^(5)穴),分析茎秆力学、茎秆形态及器官干物质积累与茎秆抗倒伏性和产量的关系。结果表明,与早播处理(B1)相比,迟播处理(B2)可显著提高精量穴直播水稻产量水平;同时,B2播期处理较高的叶面积指数(LAI)和有效穗数导致茎秆倒伏指数显著提高。随着播种密度增加,2个水稻品种的产量均呈先增加后降低趋势,B1播期下D3处理产量最高,B2播期下D4处理产量最高,但与D3处理差异不显著;而倒伏指数呈持续增加趋势,2个水稻品种趋势一致。与D1处理相比,B1和B2播期的D2、D3处理倒伏指数增幅较小,D4、D5处理显著升高,以渝香优8133表现明显。在B1和B2播期下,D2、D3处理的单株茎鞘干重、基部节间茎粗、壁厚及茎鞘充实度与D1处理相当,而D4、D5处理大幅降低。综合分析认为,在B1和B2播期下,D3处理是精量穴直播水稻产量、抗倒伏协同较好的适宜播种密度。

播种量对滨海稻区水稻机械旱直播产量、米质及经济效益的影响

为了完善滨海稻区水稻机械旱直播稻高产栽培技术体系,保证产量米质同时尽量降低农业成本、降低劳动强度,提高农业生产效率、经济效益,为直播稻未来在滨海稻区发展提供理论依据。采用田间对比试验方法,研究了不同播种量对滨海稻区水稻机械旱直播产量、米质及经济效益的影响,探索滨海稻区水稻机械旱直播最佳播种量。结果表明,播种量为97.5 kg/hm^(2)机械旱直播产量最高,加工品质较好,但稻米营养品质及食味值略低于播种量为120 kg/hm^(2);水稻机械旱直播比机插秧分别减产2.13 t/hm^(2)、1.76 t/hm^(2)、2.05 t/hm^(2),但效益比机插秧分别增加了0.144万元/hm^(2)、0.218万元/hm^(2)、0.118万元/hm^(2),处理2比处理1、3分别增加0.074万元/hm^(2)、0.100万元/hm^(2)。

气象因子与播期调控水稻籽粒灌浆关系的研究

为研究东北地区适宜的水稻播种日期,以通禾822水稻品种为供试材料,设置6个播期处理:4月10日(S1)、4月20日(S2)、4月30日(S3)、5月10日(S4)、5月20日(S5)、5月30日(S6),探讨了气象因子与齐穗后的水稻产量构成因子、籽粒灌浆特性之间的关系。结果表明:(1)播期从4月10日推迟到5月30日,水稻生育进程加快,生育时期缩短,千粒重显著降低;产量下降主要是由结实率和千粒重引起的,而结实率和千粒重的降低主要与活跃灌浆期、最大灌浆速率和平均灌浆速率有关,而活跃灌浆期、灌浆速率受齐穗后有效积温、日最高温度和降雨量的影响显著。(2)在播期内,水稻的结实率、千粒重、最大灌浆速率随着有效积温的增加和日最高温度的升高而呈增加的趋势。(3)播期的延迟导致水稻在灌浆期遭遇大量降雨,从而造成水稻灌浆速率下降、产量减少;影响籽粒灌浆和千粒重的主要气象因子是积温。在当地气候条件下,4月20日播种处理的水稻灌浆性能较好,有利于获得较高的产量和提高有效积温的生产效率。

肥密措施对水直播稻苗期杂草发生及产量的影响

为明确水分管理方式、施氮量和用种量对水直播稻生长发育特性、产量和苗期稻田杂草发生的影响,于2021年以卓两优1126为试验材料,采用再裂区试验设计,在湖南省浏阳市开展大田试验。以水分管理方式为主区,施氮量为副区,播种量为再副区。水分管理(播种至3叶1心期)设淹水(W1)和湿润(W2)2个处理;施氮量设0 kg/hm^(2)(N0)、150 kg/hm^(2)(N1)和195 kg/hm^(2)(N2)3个处理;播种量设15.0 kg/hm^(2)(D1)、22.5 kg/hm^(2)(D2)和30.0 kg/hm^(2)(D3)3个处理。结果表明,不同水分管理方式间苗期稻田杂草总数差异极显著,而不同施氮量和用种量处理间杂草总数差异不显著。W1处理水稻平均产量为8.5 t/hm^(2),显著高于W2处理;N1和N2处理间水稻平均产量差异不显著,但均显著高于N0处理;水稻产量随着用种量的增加而增加,但不同用种量处理间差异不显著。综上,水稻淹水直播条件下,施氮量为150 kg/hm^(2),播种量为15.0 kg/hm^(2),并于3叶1心期除草1次,可在减少除草剂用量的同时实现水稻增产。

机插种植均匀度对水稻产量构建及品质形成的影响

水稻种植均匀度对产量和品质有显著的影响,本试验旨在明确均匀度的提高协同产量和品质提升的机理。试验选用籼粳杂交稻甬优1540,常规粳稻浙禾香2号,杂交籼稻华浙优210为供试品种,设置4种不同种植均匀度处理:T_(1)(条播机插,种植均匀度65%~75%)、T_(2)(撒播机插,种植均匀度45%~55%)、T_(3)(人工模拟机插,种植均匀度100%)、T_(4)(人工模拟机插,种植均匀度50%),比较不同种植均匀度群体的分蘖动态变化、叶面积光合效能、干物质积累与转运、产量形成及稻米品质的变化。结果表明:(1)种植均匀度提高通过促进分蘖增加了群体有效分蘖数,3个品种平均分蘖高峰苗数表现为T_(3)>T_(1)>T_(2)>T_(4),不同品种在处理间变化趋势一致。(2)种植均匀度的提高增加了群体叶面积指数,同时显著提高了抽穗期上三叶高效叶面积指数。而且,增加均匀度显著提高了干物质积累并促进了植株干物质转运,成熟期干物质积累量表现为T_(3)>T_(1)>T_(2)>T_(4),品种间趋势一致,但是T_(2)跟T_(4)差异不明显。均匀度提高对灌浆期茎鞘物质运转有一定促进作用,品种间存在差异,T_(1)、T_(2)和T_(4)间差异不明显。(3)不同均匀度处理下每穗粒数无显著性差异,但高均匀度下一次枝梗和二次枝梗的着粒分布更均匀。(4)高均匀度群体主要通过有效穗数提高产量,品种间趋势一致,T_(3)比T_(1)、T_(2)、T_(4)平均产量分别高8.16%、15.41%、15.61%。(5)提高种植均匀度提高了稻米糙米率、精米率、整精米率和蛋白质含量,降低了稻米垩白米率和垩白度。以上结果表明,提高种植均匀度能够促进群体分蘖,增加群体叶面积指数和干物质积累,提高有效穗数,从而提升了稻谷产量和出米率,并一定程度上改善了稻米品质。试验结果明确生产上采用精准条播育秧机插能够通过提高种植均匀度协同提升稻谷产量和稻米品质。

播期对籼粳杂交稻甬优1540产量、品质的影响及其与气候因子的相关性

以杭嘉湖稻区生产上大面积推广的优质水稻品种甬优1540为材料,研究甬优1540稻米品质、产量、产量构成因子对不同播期(4月30日、5月10日、5月20日)的响应,及其与气候因子的关系。结果表明,播期适当推迟,可显著提高甬优1540产量(产量峰值出现在播期5月10日和5月20日),增产主要源于除有效穗外产量构成因子不同程度提高;甬优1540的加工、外观和蒸煮品质随着播期延迟亦不同程度提升,但营养食味品质有所不同。由此可见,杭嘉湖稻区优质稻甬优1540在5月10日左右播种能一定程度上实现产量与米质的协同变优。分析不同播期播种水稻,穗发育、籽粒灌浆阶段的气候因子与产量及米质指标相关性发现,日均日照时数、日均气温、日最高温度、日最低温度与每穗粒数(R=-0.25~-0.82,P<0.001)、加工品质(R=-0.28~0.90,P<0.001)负相关;而灌浆期昼夜温差与千粒重(R=0.6,P<0.001)、碱消值(R=0.50,P<0.001)、胶稠度(R=0.87,P<0.001)和蛋白质含量(R=0.74,P<0.001)正相关,与稻米直链淀粉含量(R=-0.83,P<0.001)显著负相关,表明适度缓解穗发育期和籽粒灌浆期高温胁迫,提高灌浆期昼夜温差,有利于提高水稻加工和蒸煮食味品质,是通过播期调整协同优化稻米产量和品质的关键。

成都平原不同播期水稻生育期气候资源及干旱特征分析——以广汉为例

作为西南地区主要的水稻产区,成都平原近年来面临日益严重的干旱问题。为确定该地区水稻最适宜的播种时期,提高抗旱能力,本文以广汉地区为例,采用气候倾向率法分析1991—2020年不同播期水稻生育期的气候资源特征,并通过作物水分亏缺指数(Crop Water Deficit Index,CWDI)评估水稻生育期的干旱程度。结果表明,近30 a来研究区各播期水稻的气候特征均表现为日照减少、日均温上升、降水量增加的趋势。随播期推迟,水稻全生育期日照时数整体减少,日均温、降水量均呈上升和增加趋势。CWDI随水稻发育逐渐减小,各播期水稻在生育前、中期缺水率较高。不同播期水稻生长期内均以轻旱、中旱为主,其次是重旱,特旱最少。研究区3月下旬至4月初的气候资源配置最优,是最适宜水稻播种的时期;3月上旬及中旬播种应选择抗旱品种,而4月中下旬播种则需防范重旱对作物需水期的影响。

RITSD Analysis of the Agronomic Traits of Somaclonal in Rice

[Objective]The aim was to study the sensitive response characteristics of the main agronomic traits of somaclonal and the variation of sensitive response of the lines of somaclonal to sowing date. [Method]The RITSD changing of agronomic traits was studied by using 24 rice somaclonal and its donor parent under two sowing dates. [Result]The average values of RITSD were higher （over one） for the traits of pant height （PH）,density of spikelets （DS）,filled spikelets per panicle （FSP）,spikelets per panicle （SP） and grain weight per plant （GWP）,but lower for days of sowing to heading （DSH）,effective panicles （EP）,panicle length （PL）,seed setting rate （SS） and 1 000-grain weight （1 000-GW）. These showed that PH,DS,FSP,SP and GWP were easily affected by sowing date and tended to higher with the later sowing; the RITSD of somaclonal changed with the agronomic traits. The frequency of RITSD＇ variation of DSH and PH was higher than that of PL. The RITSD＇ value of EP,PL,DS,FSP,SP and SS became higher,and higher or lower for DSH and GWP in different somaclonal; compared with the donor,20 of 24 was significantly different,and the frequency of RITSD variation was over 83. 3%,however,RITSD of the most lines （75%） changed only for 1-2 characters; cluster analysis showed that the RITSD of agronomic traits belonged to different combinations of somaclonal in rice. [Conclusion]the study had provided a theoretical basis for the screening and using of the somaclonal.

水稻机械育插秧技术研究进展

比较了我国水稻生产中不同水稻机插秧方式、机插播种育秧方式的优缺点,分析了传统杂交稻机插技术存在的问题,进而创新提出杂交稻精准播种机插技术,并展望了水稻绿色机插技术的发展。

紫云英与油菜混播对水稻产量、土壤活性有机碳及其组分的影响

“绿肥-双季稻”是一种绿色高产高效、培肥地力的种植模式,绿肥具有提供养分、改善生态环境以及节能减排等作用。研究紫云英与油菜混播对水稻产量、土壤活性有机碳及其组分、碳素有效率、碳库管理指数的影响,并筛选最佳的混播比例,为我国南方地区推广绿肥种植和合理利用土地资源提供科学依据。本试验以紫云英、油菜单播为对照,共设计5个处理(单播紫云英-早稻-晚稻;3/4紫云英+1/4油菜-早稻-晚稻;1/2紫云英+1/2油菜-早稻-晚稻;1/4紫云英+3/4油菜-早稻-晚稻;单播油菜-早稻-晚稻)。研究结果表明:紫云英与油菜混播处理的水稻产量和有效穗数均高于两个对照,且处理1/2紫云英+1/2油菜最高,有效穗数与水稻产量呈显著正相关。混播处理土壤微生物量碳、易氧化有机碳和活性有机碳含量较对照处理高,其中微生物量碳含量差异最为显著。土壤活性有机碳含量与碳库管理指数、碳素与碳素有效率间和各碳库管理指数间的呈显著或极显著相关。通过主成分分析发现,紫云英与油菜不同比例混播对土壤活性有机碳库影响显著。紫云英、油菜混播可以显著提高早稻产量和提升土壤活性有机碳库含量,其中以处理1/2紫云英+1/2油菜-早稻-晚稻效果最好。