增香栽培对优质香稻品质和产量的影响

为了探明增香栽培对优质香稻品质和产量的影响,以4个优质常规香稻、 4个优质杂交香稻品种为试验材料,以常规和增香两种栽培措施进行大田对比试验,测定各优质香稻的脯氨酸质量分数、品质、理论产量及产量构成因素.结果表明:与常规栽培相比,供试香稻的脯氨酸质量分数和整精米率、杂交香稻的蛋白质质量分数与胶稠度显著提高,杂交香稻的垩白度与垩白粒率以及供试香稻的直链淀粉质量分数显著降低;供试香稻的淀粉黏滞性RVA谱特征值整体呈下降趋势,下降程度不等,其中杂交香稻的起浆温度显著上升,而常规香稻的冷胶黏度、起浆温度以及峰值时间变化无统计学意义;常规香稻的食味值显著下降,而杂交香稻的食味值变化无统计学意义.除此之外,增香栽培对理论产量及产量构成有不同影响,其中杂交香稻的产量及有效穗数显著升高,穗粒数和千粒质量变化无统计学意义.

Enriching Iodine and Regulating Grain Aroma,Appearance Quality,and Yield in Aromatic Rice by Foliar Application of Sodium Iodide

Applying iodine fertilizers to cultivate iodine-rich crops for daily intake is an effective approach for iodine supplementation,especially for aromatic rice.Field experiments were conducted during the early growing seasons of 2021 and 2022 to evaluate the impacts of foliar application of iodine fertilizer on aromatic rice and to explore the optimal iodine fertilizer concentration.At the full heading stage,six different concentrations of sodium iodide solutions of 0%(CK),0.010%(T1),0.025%(T2),0.050%(T3),0.075%(T4),and 0.100%(T5)were applied to indica aromatic rice cultivars Meixiangzhan 2 and Xiangyaxiangzhan.The results showed that sodium iodide treatments significantly increased the iodine and sodium contents in both leaves and grains.Compared with the CK,the T1 and T2 treatments increased the 2-acetyl-1-pyrroline(2-AP)content in mature grains by 8.41%-101.66%and 13.58%-74.60%,respectively.Improvements in the contents of 1-pyrroline-5-carboxylic acid,proline,1-pyrroline,and methylglyoxal,as well as the activity of proline dehydrogenase were also detected.Additionally,sodium iodide treatments remarkably decreased the chalky grain rate,chalkiness area,and chalkiness degree of aromatic rice,with the T2 treatment exhibiting a 17.79%-47.42%decrease in chalkiness degree compared with the CK.Meanwhile,T1 and T2 treatments showed beneficial impacts on chlorophyll content,photosynthetic characteristics,and yield components,while T3,T4,and T5 treatments exhibited adverse effects on leaf and grain yields.The linear discriminant analysis revealed significant differences between treatments.The correlation analysis and piecewise structural equation modeling showed that the iodine and sodium influenced the photosynthetic characteristics and chlorophyll content of the leaves,thereby regulating the 2-AP biosynthesis and yield components,ultimately affecting the 2-AP content and yield.Overall,this study suggests that foliar application of 0.025%sodium iodide is an effective method to enrich the iodine content in rice grains,improve the grain aroma and appearance quality of aromatic rice,without detrimental effects on grain yield.

轻简氮肥管理对华南双季稻产量和氮肥利用率的影响

【目的】针对当前我国水稻种植中面临劳动力短缺、用工成本高、肥料利用率低等突出问题,探索在保障水稻高产高效的前提下更为简化的"一基一追"轻简施氮模式,减少施肥次数,提高种稻效率,为水稻轻简化栽培提供理论依据。【方法】以常规籼稻五山丝苗为试验材料,采用随机区组设计。2018年晚季设置不施氮(N0)、三控施肥(TC)、三控减氮(RTC)和3个轻简施氮(SNM1、SNM2、SNM3)6个处理,2019年早季设置N0、TC、农民习惯施肥(FP)和3个轻简施氮(SNM2、SNM4、SNM5)6个处理,研究不同氮肥管理对华南双季稻产量及其构成、物质生产、氮肥利用效率以及稻米品质的影响。【结果】2018年晚季,SNM2处理与TC处理的产量无显著差异,但二者均显著高于RTC、SNM1和SNM3处理;2019年早季,SNM2、SNM4和SNM5处理的产量与TC处理无显著差异,但比FP处理增产7.36%—7.51%,主要是由于每穗粒数增加。SNM2处理的有效穗数、每穗粒数、结实率和千粒重与TC处理无显著差异(2019年早季千粒重除外),但2个处理的产量构成不同,SNM2处理的单位面积颖花数多,主要通过扩大库容量保持高产。2018年晚季,SNM2处理的氮肥吸收利用率(RE)、氮肥农学利用率(AE)、氮肥生理利用率(PE)和氮素收获指数(NHI)与TC处理相比无显著差异,但氮肥偏生产力(PFP_N)显著增加;SNM1和SNM3处理的RE、AE和PFP_N显著低于SNM2处理。2019年早季,3个轻简施氮处理的5项氮肥利用率指标均与TC处理无显著差异,4个轻简处理的RE、AE和PFP_N显著高于FP处理。SNM2、SNM4、SNM5和TC处理的单位面积颖花数、总生物量和总吸氮量均高于FP处理。2018晚季,SNM2处理的垩白粒率较TC处理显著降低,其他指标与FP和TC处理无明显变化。【结论】采用"一基一追"的轻简氮肥管理SNM2处理,在减少氮肥10%、减少2次施肥的情况下,其水稻产量和氮肥吸收利用率与TC处理无显著差异,但显著高于FP处理,外观品质有所改善,碾磨品质和蒸煮食味品质没有明显变化。因此,在劳动力紧缺问题突出的情况下,采用轻简氮肥管理技术,既可以节约劳动力成本,又可实现水稻的高产和氮肥高效利用,该研究结果对水稻轻简化栽培具有指导意义,具有良好的应用前景。

不同香稻品种苗期耐高温的形态生理响应

【目的】本研究旨在分析不同香稻品种苗期耐高温的形态生理响应特征,筛选出耐热性较好的香稻品种。【方法】在盆栽条件下,于光照培养箱内,以超级常规香稻玉香油占为对照,研究了常规香稻品种巴斯马蒂、桂香占、农香18、湘晚籼13、象牙香占、中香1号、美香占2号在苗期高温处理下的形态生理响应特征。于高温处理前后测定了8个香稻品种苗期各项形态生理指标。【结果】与玉香油占相比,高温胁迫下,巴斯马蒂的株高、单株鲜质量、单株干质量增幅更大,成活率和过氧化物酶活性更高,丙二醛含量反而下降了33.39%,表明巴斯马蒂的耐高温胁迫能力较好。湘晚籼13在高温处理下的单株干质量增幅与玉香油占相近,株成活率较玉香油占低,胞间二氧化碳浓度变幅较小,SOD活性和丙二醛含量的变幅在8个品种中均为最低,说明其耐高温胁迫的能力略低于玉香油占。农香18、象牙香占和美香占2号的成活率分别为13.33%、12.67%和16.00%。桂香占(4.33%)、中香1号(1.33%)在高温处理后的成活率最低,表明两者的耐高温能力均较差。【结论】8个品种耐热性从强到弱依次为巴斯马蒂、玉香油占、湘晚籼13、农香18、象牙香占、美香占2号、桂香占和中香1号。

香稻分蘖期减氮侧深施液体肥对产量和氮素利用的影响

【目的】研究液体肥分蘖期减氮侧深施用和常规全量撒施固体肥对香稻关键生育期氮素吸收利用、干物质积累和氮代谢生理影响及其与香稻产量形成的关系,以期为今后华南香稻种植区分蘖期机械化侧深施液体肥提供理论指导和依据。【方法】2019—2020年连续进行2年大田试验,以华南地区种植面积较大的香稻品种玉香油占和象牙香占为供试材料,采用随机区组排列设计。设置了全程不施肥处理(T1)、常规全量撒施肥固体肥处理(T2,总施氮量为150 kg N·hm^(-2))、液体肥分蘖期减氮10%侧深施处理(T3)和液体肥分蘖期减氮20%侧深施处理(T4)4个处理。研究了不同施肥处理对香稻的产量及其构成因素、氮素吸收利用、干物质积累和氮代谢生理的影响。【结果】(1)2年大田试验中,2个香稻品种均在T3处理下产量最高,且显著高于T1处理。与T2处理相比,T3处理下玉香油占2019年和2020年的产量分别提高1.84%和15.20%,象牙香占2019年和2020年的产量分别提高0.65%和3.71%。这主要与T3处理下具有最高的有效穗数有关。(2)2年大田试验中,在幼穗分化期和抽穗期,2个香稻品种的总干物质积累量、叶面积指数和总氮素积累量普遍在T2处理下最高,T3处理和T2处理间的总干物质积累量和总氮素积累量差异不显著。在成熟期,2个香稻品种的总干物质积累量、叶面积指数和总氮素积累量均在T3处理下最高;对玉香油占而言,2019年成熟期T3处理下的总干物质积累量、叶面积指数和总氮素积累量分别较T2处理增加25.14%、26.57%和21.31%,2020年的相应增幅分别为5.83%、21.80%和46.47%;对象牙香占而言,2019年成熟期T3处理下的总干物质积累量、叶面积指数和总氮素积累量分别较T2处理增加19.95%、3.73%和13.41%,2020年相应增幅为21.17%、1.78%和14.37%。此外,2个香稻品种的氮素吸收利用率和氮素农学利用率也均在T3处理下最高。(3)在幼穗分化期和抽穗期,2个香稻品种在T2处理下较其他处理相比有较高的氮代谢相关酶活性,而成熟期T3处理下2个香稻品种的氮代谢相关酶活性最高。【结论】综合2年大田试验表明,液体肥分蘖期减氮10%侧深施处理较常规全量撒施固体肥处理,在减少氮肥使用的同时能维持生育前期生长发育,提高生育后期总干物质积累量、叶面积指数、氮素利用和氮代谢相关酶活性,最终实现香稻增产。

低温下不同香稻品种苗期的形态生理响应

对不同香稻品种苗期的耐冷性进行初步鉴定和评价,以筛选出耐冷性较强的香稻品种,为香稻苗期的低温伤害机理提供依据。以超级常规香稻玉香油占为对照,研究了低温对7个常规香稻品种(巴斯马蒂、桂香占、农香18、湘晚籼13、象牙香占、中香1号、美香占2号)苗期的幼苗素质、幼苗光合生理特性、幼苗叶片叶绿素荧光、幼苗抗氧化酶活性及丙二醛含量等生理指标的影响。结果表明,桂香占、农香18、湘晚籼13、中香1号及美香占2号的成活率与对照无显著差异,而巴斯马蒂和象牙香占的成活率则比对照显著降低;香稻品种干质量增长变化幅度为14.84%～39.84%,鲜质量增长变化幅度为2.17%～28.34%,农香18、湘晚籼13及中香1号的干质量和鲜质量受低温影响较小。此外,低温处理后,株成活率较高品种幼苗在光合生理特性、荧光特性、抗氧化酶活性等方面表现出一定优势。桂香占、农香18、湘晚籼13、中香1号及美香占2号在苗期有较强的耐低温能力,而巴斯马蒂和象牙香占的耐低温能力则较差。

广东省水稻保护性耕作技术研究

广东是农业大省,近年来随着人口增加和农村经济快速发展,农业面源污染形势十分严峻。广东省承担的世界银行农业面源污染治理项目中的水稻保护性耕作项目,设计免耕和少耕机插秧、免耕和少耕直播4种主要模式,投入50多台(套)农业机械,经过7个试验点5年的试验,结果表明,在全程机械化条件下的保护性耕作,通过采用先进适用的农业机械,农机农艺结合,合理使用化肥农药,减少作业量、人工以及化肥农药等物资投入,可达到减少面源污染的目的,提高农业生产效益。广东开展水稻保护性耕作有重要意义。

Nitrogen Deep Placement Combined with Straw Mulch Cultivation Enhances Physiological Traits,Grain Yield and Nitrogen Use Efficiency in Mechanical Pot-Seedling Transplanting Rice

To assess the effects of straw return coupled with deep nitrogen(N)fertilization on grain yield and N use efficiency(NUE)in mechanical pot-seedling transplanting(MPST)rice,the seedlings of two rice cultivars,i.e.,Yuxiangyouzhan and Wufengyou 615 transplanted by MPST were applied with N fertilizer at 150 kg/hm2 and straw return at 6 t/hm2 in early seasons of 2019 and 2020.The experiment comprised of following treatments:CK(no fertilizer and no straw return),MDS(deep N fertilization and straw return),MBS(broadcasting fertilizer and straw return),MD(deep N fertilization without straw return),MB(broadcasting fertilizer without straw return).Results depicted that the MDS treatment significantly increased the rice yield by 41.69%-72.22%due to total above-ground biomass,leaf area index and photosynthesis increased by 54.70%-55.80%,38.52%-52.17%and 17.89%-28.40%,respectively,compared to the MB treatment.In addition,the MDS treatment enhanced the total N accumulation by 37.74%-43.69%,N recovery efficiency by 141.45%-164.65%,N agronomic efficiency by 121.76%-134.19%,nitrate reductase by 46.46%-60.86%and glutamine synthetase by 23.56%-31.02%,compared to the MB treatment.The average grain yield and NUE in both years for Yuxiangyouzhan were higher in the MDS treatment than in the MD treatment.Hence,deep N fertilization combined with straw return can be an innovative technique with improved grain yield and NUE in MPST in South China.

Epoxiconazole Improved Photosynthesis,Yield Formation,Grain Quality and 2-Acetyl-1-Pyrroline Biosynthesis of Fragrant Rice

Epoxiconazole is a triazole compound.However,the effects of epoxiconazole on crop productivity and quality were rarely reported.In this study,we investigated the effects of epoxiconazole application on yield formation,grain quality attributes,and 2-acetyl-1-pyrroline(2-AP)content in fragrant rice.A three-year field experiment was carried out with a fragrant rice variety,Meixiangzhan 2.At the heading stage,0,0.02,0.04,0.08,0.16 and 0.32 g/L epoxiconazole solutions were foliar applied to fragrant rice plants,respectively.The results showed that epoxiconazole application significantly increased grain yield,seed-setting rate and 1000-grain weight.Chlorophyll content and net photosynthetic rate of fragrant rice during the grain-filling stage significantly increased due to epoxiconazole application.Foliar application of epoxiconazole at 0.08 g/L increased grain protein content and decreased both chalky rice rate and chalkiness area ratio of fragrant rice.Epoxiconazole also substantially increased grain 2-AP content by inducing the regulation in contents of related synthetic precursors,including proline,pyrroline-5-carboxylic acid,Δ1-pyrroline and methylglyoxal.Overall,foliar application of epoxiconazole could be used for the improvement in grain yield,grain quality and 2-AP content in fragrant rice production when applied concentration at 0.08-0.32 g/L.Our findings provided the new roles of epoxiconazole in crop production.