【作者】 张强；

【导师】 刘立军； Jianchang Yang；

【作者基本信息】 扬州大学 ， 作物栽培学与耕作学， 2022， 博士

【摘要】 再生稻能实现一种两收,是我国南方稻区提高稻田复种指数、增加单位面积粮食产量的有效途径。因其具有省时、省工、节本增效等特点,能够有效解决我国农业生产面临的生产成本不断增加和劳动力日益短缺等问题,近年来再生稻种植面积不断扩大。但目前再生稻生产仍存在因缺乏两季高产再生稻品种和无法较好协调头季与再生季生长之间的矛盾,而导致再生稻产量不稳定、难以实现两季均衡增产等问题,限制了再生稻生产的进一步发展。针对上述突出问题,于2018-2021年在河南省信阳市农业科学院试验基地开展了以下研究。(1)以14个头季产量差异小而再生季产量差异较大的水稻品种为试验材料,比较分析了两季高产再生稻品种的农艺与生理特征。(2)以两季高产再生稻品种两优6326为试验材料,研究了 100 kg hm-2、250 kg hm-2和400 kg hm-2三个氮肥水平以及基蘖肥:穗肥7:3、6:4、5:5和4:6四种施氮比例对头季和再生季产量、再生芽生长发育以及再生力的影响。(3)以两优6326和信粳1501为供试材料,研究了头季稻结实期常规水层灌溉(CI)、轻度干湿交替灌溉(WMD)和重度干湿交替灌溉(WSD)对头季和再生季水稻产量的影响。(4)以两优6326为试验材料,在头季稻齐穗后15 d和收割后当天叶面喷施赤霉素(GA3)、6-苄氨基嘌呤(6-BA)、复配剂(GA3+6-BA)和CK(清水),并设置三个头季收割留桩高度20 cm、30 cm和40 cm,研究了外源激素对不同留桩高度再生稻生长和产量的影响。(5)以两优6326和桃优香占为试验材料,设置再生稻和单季中稻两种种植模式,比较分析了头季稻、再生季和单季中稻的产量与稻米品质的差异。通过上研究,以期明确高产再生稻品种的农艺与生理特征,提出再生稻高产优质栽培技术途径,为豫南地区再生稻高产高效优质栽培提供理论与科学依据。主要结果如下:1.高产再生稻品种头季具有齐穗期粒叶比适宜;齐穗后群体光合势、净同化率、群体生长率、地上干物质积累量、剑叶光合速率和根系氧化还原力(ROA)高;成熟期叶面积指数和地上干物质量高,叶面积指数衰减率、收获指数以及营养器官干物质转运量和转运率低等特征。相关分析表明,再生季水稻产量与齐穗到成熟期群体生长率、群体净同化率、地上干物质积累量和成熟期地上干物重及根系活性呈显著或极显著正相关,与收获指数、粒叶比和营养器官干物质转运率呈显著或极显著负相关。这些可作为筛选高产再生稻品种的农艺和生理指标。2.头季稻施氮量过高或穗氮肥比例过大均不利于头季稻和再生季水稻产量的提高。不同施氮方式下,再生率的提高是再生季产量增加主要原因,不同施氮方式主要通过改变头季稻根系活性和茎鞘非结构性碳水化合物(NSC)浓度来影响再生率。头季稻齐穗后茎鞘和叶片NSC浓度和根系活性与再生率呈非线性正相关,适当提高穗肥施氮量后,根系活性和NSC浓度增加,有利于促进再生芽萌发和生长,提高再生率。穗肥施氮量过高后,较高的NSC浓度和ROA导致再生芽萌发数量过多,再生芽个体发育质量下降,再生率降低。表明头季稻合理的施氮量和比例能提高头季稻齐穗后根系活性、茎鞘和叶片以及稻桩NSC浓度,促进再生芽的萌发和生长,进而提高再生率和再生季水稻产量。在本试验条件下,头季稻施氮量为250 kg hm-2,穗氮肥占比50%时,再生稻两季总产最高。3.与CI相比,头季稻结实期WMD使头季稻的千粒重、结实率和产量分别提高了 3.4%～4.7%、1.2%～2.1%和6.04%～6.46%,WMD对再生季水稻穗粒数、结实率和粒重无明显影响,但使其单位面积穗数提高了 9.6%～11.8%,导致再生季水稻产量提高了 13.3%～14.6%。头季稻结实期WSD对头季稻产量无明显影响,但显著降低了再生季单位面积穗数,使其产量明显降低。WMD通过提高头季稻结实期叶片光合速率、叶面积指数、根系生理活性、干物质积累量和茎鞘非结构性碳水化合物转运量来提高头季稻千粒重和结实率。WMD提高了头季稻结实期茎鞘中淀粉水解酶活性,使可溶性糖含量增加,同时提高了茎鞘中玉米素及其核苷(Z+ZR)含量,导致再生芽数量和再生季穗数增加。WSD虽然提高了茎鞘中淀粉水解酶活性,但茎鞘NSC转运量过多,使其可溶性糖含量降低,导致再生芽数量和再生季穗数降低。上述结果表明,头季稻结实期不同灌溉方式对再生稻两季产量都有较大影响,头季结实期采用轻度干湿交替灌溉能够优头季稻结实期地上和地下相关指标,提高头季和再生季水稻产量。4.与CK相比,外源激素GA3、6-BA和GA3+6-BA处理后,头季稻产量提高2.8%～5.0%;再生季产量分别提高10.3%～48.3%(20 cm留桩),15.6%～59.4%(30 cm留桩)和9.1%～29.5%(40 cm留桩)。喷施外源激素后,头季稻籽粒灌浆后期叶面积指数、叶片光合速率、根系活性和干物质积累量增加,导致头季稻结实率和千粒重均有不同程度提高。同时头季收割后的稻桩干物重、再生季齐穗后叶面积指数、根系活性和叶片光合速率增加,提高了再生季水稻再生率、结实率和千粒重。但不同外源激素对两季水稻的增产效果有所差异,表现为GA3+6-BA＞6-BA>GA3。表明豫南地区种植再生稻,留桩高度为40 cm(大部分品种的稻桩能够保留4个节间),结合茎叶喷施GA3 12 ghm-2+6-BA9ghm-2,可增加两季水稻产量。5.与单季中稻相比,头季稻产量提高6.2%～6.4%,再生季产量降低57.4%～57.7%,头季稻较高的穗粒数和较长的生育期是其高产的主要原因。与单季中稻相比,头季稻稻米外观、加工和蒸煮食味品质变差;再生季稻米的加工品质与单季中稻无明显差异,但外观和蒸煮食味品质明显提高。齐穗后的日平均温度、最高温度和最低温度对稻米品质的影响较大,再生季齐穗后较低的日平均温度、最高温度和最低温度是其稻米品质优于头季稻和单季中稻的主要原因。更多还原

【Abstract】 Ratoon rice can realize one seeding and two harvests,which is an effective way to improve the multiple cropping index of paddy fields and increase the grain yield per unit area in southern China.Since it has the advantages of time-saving,labor-saving and costsaving which can effectively solve the problems of increasing production costs and labor shortages faced by rice production,the planting area of ratoon rice has continued to expand in recent years.However,the contradiction between the growth of main and ratoon season is still faced in the ratoon rice production,resulting in unstable yield in the ratoon season and difficulty achieving high yields in both seasons,which limits the further increase in the yield and planting area of ratoon rice.In order to solve the above problems,the following experiments were carried out in Xinyang Academy of Agricultural Sciences from 2018 to 2021.(1)14 rice varieties with small differences in grain yield of main crop and large diferences in grain yield of ratoon crop were used as experimental materials to clarified the agronomic and physiological characteristics of ratoon rice varieties with high yield in both seasons.(2)Using rice variety with high yield in both seasons named Liangyou 6326 as material,three nitrogen(N)fertilizer levels(100 kg hm-2,250 kg hm-2 and 400 kg hm-2),and four different ratios of basal tillering fertilizer to panicle fertilizer(7:3,6:4,5:5 and 4:6)applied to the main crop were designed to investigate their effects on growth and development of regenerated buds,and grain yield of main and ratoon crop.(3)Two rice varieties named Liangyou 6326 and Xingeng 1501 were used as materials,and three irrigation regimes,i.e.,conventional flooding irrigation(CI),alternate wetting.and moderate soil drying irrigation(WMD)and alternate wetting and severe soil drying irrigation(WSD)during grain filling in main crop were applied to investigate their effects on grain yield in main and ratoon crop.(4)Using Liangyou 6326 as material,three different hormone treatments[gibberellin A3(GA3),6-benzylaminopurine(6-BA),GA3+6BA]and CK(clear water)were sprayed at 15 days after full heading and after harvesting of main crop,conjoint three different stubble height(20 cm,30 cm and 40 cm)were set to explore the effects of hormones on the grain yield and growth of ratoon rice under different stubble heights.(5)Using Liangyou 6326 and Taoyouxiangzhan as experimental materials,two rice planting modes(ratoon rice and single season rice)were set up to compare and analyze the differences in the rice yield and quality between ratoon rice and single season rice.It is expected that the agronomic and physiological characteristics of high-yielding ratoon rice varieties will be clarified and the high yield and good quality cultivation of ratoon rice will be proposed through the above researches.So as to provide scientific guidance for high yield and good quality cultivation of ratoon rice.The main results are as follows:1.The high-yielding ratoon rice varieties have a small grain to leaf ratio at the full heading stage in the main crop.And they have higher leaf area duration,higher net assimilation rate,higher crop growth rate,higher aboveground dry matter accumulation,and higher photosynthetic rate and root oxidation activity(ROA)after full heading in the main crop.In addition,they also have higher leaf area index(LAI),higher aboveground dry matter weight,lower leaf area index decay rate,lower harvest index,and lower dry matter translocation rate at maturity stage in the main crop.Correlation analysis showed that the grain yield of ratoon crop was significantly positively correlated with the crop growth rate,crop net assimilation rate,aboveground dry matter accumulation from full heading to maturity,aboveground dry matter weight and ROA at the maturity of main crop,and was negatively correlated with harvest index,grain to leaf ratio and dry matter translocation rate.These indices can be used to screen and breed high-yielding varieties for ratoon rice production.2.High N application and panicle N application rate in the main crop is not conducive to the increase of grain yield in the main and ratoon crop.Under different N application regimes,the increase of regeneration rate was the main reason for the increase in the grain yield of ratoon crop.Different N application regimes mainly affected the regeneration rate by changing the ROA and nonstructural carbohydrate(NSC)concentration in the main crop.The NSC concentration and ROA after full heading of the main crop had a nonlinear correlation with the regeneration rate.Appropriately increasing the amount of panicle N application,the ROA and NSC concentration increased,thereby promoting the growth and development of regenerated buds and improving the regeneration rate.However,when the excess of panicle N was applicated in the main crop,the excessive NSC and ROA led to the excessive germination of regenerated buds,resulting in the decline of the development and growth of regenerated buds and the regeneration rate.The results indicated that reasonable N regime in the main crop could improve ROA and NSC concentration of the main crop,thereby promoting the growth and development of regenerated buds and then improving the regeneration rate and grain yield of ratoon crop.Under the conditions of this experiment,when the N application rate was 250 kg hm-2 and the proportion of panicle N fertilizer was 50%in the main crop,the total yield of both seasons in the ratoon rice was highest.3.Compared with CI,WMD increased grain yield by 6.0%～6.5%in the main crop by increasing 1000-grain weight and filled grain rate,while the ratoon crop grain yield increased by 13.3%～14.6%via increased panicle number.WSD had no significant effects on the grain yield of main crop but significantly decreased the grain yield of ratoon crop by decreasing panicle number.Higher leaf photosynthetic rate,leaf area index,ROA,dry matter accumulation and NSC translocation under WMD primarily drove the increased 1000-grain weight and filled grain rate in the main crop.Under WMD,higher soluble sugar contents catalysed by high amylase activity and higher zeatin+zeatin riboside in stems of main crop promoted the growth of regenerated buds and increased the ratoon crop panicle number.WSD reduced the stem soluble sugar contents via excessive translocation of NSCs to grains in the main crop,leading to a decrease in ratoon crop regenerated buds.Thus,high-yielding and water-saving can be achieved in ratoon rice production by using WMD during grain filling in main crop.4.Compared with CK,after treatment with exogenous hormones GA3,6-BA and GA3+6-BA,the grain yield of main crop was increased by 2.8%～5.0%,and the grain yield of ratoon crop increased by 10.3%～48.3%(stubble height was 20 cm),15.6%～59.4%(stubble height was 30 cm)and 9.1%～29.5%(stubble height was 40 cm),respectively.After hormone application,the LAI,leaf photosynthetic rate,ROA and dry matter accumulation increased at the later stage of grain filling in the main crop,resulting in the increase of filled grain rate and 1000-grain weight in main crop.And the dry matter weight of stubble,LAI,ROA and leaf photosynthetic rate were increased after full heading of ratoon crop,resulting in an increase in the regeneration rate,filled grain rate and 1000grain weight in the ratoon crop.However,the effect of different hormones on rice yields of main and ratoon crop was different,which showed the order 6-BA+GA3>6-BA>GA3.The above results showed that when the stubble height was 40 cm(stubble could retain 4 internodes)and the stems and leaves were sprayed with GA3 12 g hm-2+6-BA 9 g hm-2,the ratoon rice could obtain a high yield in both seasons in southern Henan.5.Compared with signal season rice,the yield of main crop increased 6.2%～6.4%,and the yield of ratoon crop decreased 57.4%～57.7%.The higher spikelet per panicle and longer growth period in main crop were the main reasons for its higher yield.Between the different rice planting patterns,the rice quality in main crop was worst.And there was no difference in the rice processing quality between the ratoon crop and the signal season rice,but the appearance,cooking and eating quality in the ratoon crop were better than those in the signal season rice.The daily average temperature,maximum temperature and minimum temperature after full heading of rice had great influence on rice quality.And the lower daily average temperature,maximum temperature and minimum temperature after full heading in the ratoon crop were the main reasons for its better rice quality than that of main crop and single season rice.更多还原