Relationship of Parental Indica-Japonica Indexes with Yield and Grain Quality Traits of Japonica Hybrid Rice in Northern China

Taking the main parents （10 male sterile lines and 10 restorer lines） and their 100 combinations of japonica hybrid rice in northern China as materials, the relationships of parental indica-japonica indexes determined by the methods of the Cheng’s index as well as simple sequence repeat （SSR） markers with yield and grain quality traits of hybrid rice were studied. For the parents, the Cheng’s index （Chi） ranged from 13.5 to 19.3 and the indica index in SSR markers （ADi） were from 0.12 to 0.38. The classification of parents by Chi was not completely consistent with that by ADi. The Chi of male parent was more closely related to hybrid traits than that of female parent, as contrasted to ADi. At the same time, the difference between parents （PD） in Chi was more closely related to hybrid traits than that in ADi. The indica-japonica indexes of parents and their difference between parents appeared quadratic relationship to hybrid traits with the critical extremum. The directions of the correlation of indica-japonica indexes of parents and their differences with hybrid yield traits were on the opposition to those with hybrid grain quality traits. Therefore, the female parent should match the male parent moderately in indica-japonica index to obtain the optimum of hybrid traits, high yield as well as good quality.

Irrigating with cooler water does not reverse high temperature impact on grain yield and quality in hybrid rice

Rice grain yield and quality are negatively impacted by high temperature stress.Irrigation water temperature significantly affects rice growth and development,thus influencing yield and quality.The role of cooler irrigation water in counteracting high temperature induced damages in rice grain yield and quality are not explored.Hence,in the present study two rice hybrids,Liangyoupeijiu(LYPJ)and IIyou 602(IIY602)were exposed to heat stress and irrigated with water having different temperatures in a splitsplit plot experimental design.The stress was imposed starting from heading until maturity under field-based heat tents,over two consecutive years.The maximum day temperature inside the heat tents was set at 38℃.For the irrigation treatments,two different water sources were used including belowground water with cooler water temperature and pond water with relatively higher water temperature.Daytime mean temperatures in the heat tents were increased by 1.2–2.0℃ across two years,while nighttime temperature remained similar at both within and outside the heat tents.Cooler belowground water irrigation did have little effect on air temperature at the canopy level but decreased soil temperature(0.2–1.4℃)especially under control.Heat stress significantly reduced grain yield(33%to 43%),panicles m^(-2)(9%to 10%),spikelets m^(-2)(15%to 22%),grain-filling percentage(13%to 26%)and 1000-grain weight(3%to 5%).Heat stress significantly increased chalkiness and protein content and decreased grain length and amylose content.Grain yield was negatively related to air temperature at the canopy level and soil temperature.Whereas grain quality parameters like chalkiness recorded a significantly positive association with both air and soil temperatures.Irrigating with cooler belowground water reduced the negative effect of heat stress on grain yield by 8.8%in LYPJ,while the same effect was not seen in IIY602,indicating cultivar differences in their response to irrigation water temperature.Our findings reveal that irrigating with cooler belowground water would not significantly mitigate yield loss or improve grain quality under realistic field condition.The outcome of this study adds to the scientific knowledge in understanding the interaction between heat stress and irrigation as a mitigation tool.Irrigation water temperature regulation at the rhizosphere was unable to counteract heat stress damages in rice and hence a more integrated management and genetic options at canopy levels should be explored in the future.

Dry matter production and panicle characteristics of high yield and good taste indica hybrid rice varieties

Indica hybrid rice(Oryza sativa) production aims to achieve two crucial targets: high yield and good taste. This study selected three types of indica hybrid rice according to grain yield and taste value, including high yield and good taste(HYGT), low yield and good taste(LYGT), and high yield and poor taste(HYPT), to analyze yield components,corresponding growth characteristics, and rice taste quality. When values were averaged across varieties and years,there were almost no differences in taste value between HYGT and LYGT;HYGT showed a significant increase in yield,owing to a higher number of panicles and spikelets per panicle, with a respective increment of 16.2 and 20.6%. The higher grain yield of HYGT compared with LYGT was attributed to three key factors: a higher leaf area index(LAI) during heading, a higher ratio of grain to leaf, and a higher biomass accumulation at maturity. HYGT and HYPT achieved similar high yields;however, HYGT had more panicle numbers and lower grain weight. In addition, HYGT showed a significantly higher taste value than HYPT, attributed to its significantly lower protein and amylose contents, with reductions of 8.8and 15.7%, respectively. Lower protein and amylose contents might be caused by a proper matter translocation from vegetative organs to panicle. This study suggested that reasonable panicle characteristics and translocation efficiency from vegetative organs to panicle during heading to maturity are the key factors in balancing yield and rice taste quality.These results will provide valuable insights for rice breeders to improve the grain yield and quality of indica hybrid rice.

Breeding of Yujingyou 50,a New Late Hybrid Rice Combination with Good Quality

Yujingyou 50 is a new high-quality late indica hybrid rice combination selected by Institute of Grain and Oil Crops,Nanchang Academy of Agricultural Sciences and Hunan Zhonglang seed Industry Co.,Ltd.The combination matured 3 d earlier than Tianyouzhan.It has the characteristics of moderate plant type,broad and long flag leaves,general tillering ability,colorless palea tips,large panicles with many grains,high seed setting rate,average 1000-grain weight,good color change at maturity,and rice quality reaching grade 2 of ministry standard.It was approved by the Jiangxi Provincial Crop Variety Approval Committee on March 18,2021.This paper introduced the breeding process,characteristics,cultivation techniques and key points of seed production of this variety.

Preliminary studies on rice quality of japonica-indica hybrid rice

It has been proved that high yield combina-tions can be obtained via hybridization betweenindica and japonica rice. However, people haveworried about the quality of this kind of ricefor a long time. Our researches were mainlybased on the mating pattern of "japonica malesterile line/indica restorer line" to generateand select elite japonicalinous crosses. Ricequality is shown in table 1 and 2. The scores of rice quality of 7 crossesranged from 56-59, and met the high quality

Analysis of seed and maternal genetic effects on cooking quality characters in indica hybrid rice

We analysed seed and maternal genetic effects on characters of cooking quality in indica hybrid rice by using the model for quantitative characters of seeds of cereal crops. Incomplete diallel crosses were made by using six male sterile lines (Zhenshan 97A, Erjiuqing A, Erjiunan 1A, V20A, Zhe’nan 1A and Zhe’nan 3A)as females and three restorer lines(Cezao 2-2, T49 and 26715)as males. Sampled seeds were used to measure the cooking quality characters, including amylose content(%), gelatinization temperature(alkali spreading score)and gel consistency(mm). Results indicated that some rice cooking quality characters were controlled by both seed genes and maternal genes (see table). Gel consistency was mainly controlled by maternal effects, but also

Discussion on strategy of grain quality improvement for super high yielding japonica rice in Northeast China

japonica rice is mainly distributed in Northeast China and accounts for 44.6% of the total cultivated area of japonica rice in China. The comprehensive using of inter-subspecies heterosis is the main breeding mode of super japonica rice varieties in this region. Improving rice quality at relative high yielding level is the current research focus. Performing crosses between indica and japonica lines allows for the recombination of regulatory genes and genetic backgrounds, leading to complicated genetic rice quality characteristics, which can be used to explore patterns of quality improvement. In the present study, we utilize recombinant inbred lines （RILs） derived from indica-japonica hybridization to analyze the effect factors of rice quality derived from genetic factors, which contain both regulatory genes concerning rice quality and genetic backgrounds＇ random introduction frequency coming from indica （Di value）, and the improvement strategy was further discussed. The regulatory genes involved in amylase content （Wx） and nitrogen utilization efficiency （NRT1.1B） were the major factors affecting the amylose content （AC） and protein content （PC） in RILs, respectively. Both the Di value and the major grain width gene （GS5） had regulatory effects on milled rice width （MRW） in RILs, and their interaction explained the major variance of MRW in the RILs. With the mediation of MRW and chalkiness degree （C）, Di value had a further impact on head rice rate （HR）, which was relatively poor when the Di value was over 40%. In Northeast China, the Di value should be lowered by backcrossing or multiple crosses during the breeding of indica-japonica hybridization to maintain the whole better HR and further to emphasize the use of favorable genes in individual selection.

Breeding of High Quality Indica CMS Line Xinlong A

Xinlong A was a high quality indica CMS line developed with early rice intermediate material 05Zao20(Zhouyou 903/Zhong9B F6)as female parent and IR58025B/Q96 F4 as male parent,Jin23A was then used as female parent for test crossing with BC,and backcrossed and bred with complete fertility and abortion lines.The male sterile line had the characteristics of good agronomic characters,strong combining ability,good resistance,high yield and good quality which reaches gradeⅡstandard of national high quality rice.It showed broad prospects and was technically identified in Jiangxi Province in 2017.

Breeding of New Japonica-indica Hybrid Rice Combination Chunyou 284

Chunyou 284 is a medium- japonica hybrid combination,as well as an indica-japonica subspecific hyrbid with super-high yield,which was developed from Chunjiang 23A,a thermo-sensitive CMS line with very early anthesis time,and C84,an indica-japonica intermediate type restorer line with wide compatibility.This combination has the advantages of high yield potential,early maturity,excellent comprehensive agronomic traits and wide adaptability.It was approved by Jiangsu Provincial Crop Variety Approval Committee in June,2018.The breeding process,main characteristics,cultivation techniques and seed production points of the combination were introduced.

Genetic Analysis of Leucine Content in Indica-Japonica Hybrid Rice (Oryza sativa L.)

Genetic control of leucine content in indica-japonica hybrid rice (Oryza sativa L.) was studied in 35 crosses of F1 and F2 generations, which were derived from crossing 7 male sterile indica rice lines with 5 restorer japonica rice lines along with their parents. Two genetic models and their corresponding statistical methods for quantitative traits of triploid seeds in cereal crops were used for the analysis. The first was the unconditional genetic model, which refers to the analysis of cumulative measurements (from flowering to a specific time) along the developmental stages, while the second was the conditional genetic model, which relates to analysis from one developmental stage to another stage (t - 1→t). The results showed that leucine content of indica-japonica hybrid rice was controlled by the expression of triploid endosperm effect (endosperm additive effect and endosperm dominant effect), cytoplasm effect, diploid maternal plant effect (maternal additive effect and maternal dominant effect) and their environmental interaction effects. Of these effects, endosperm dominant effect and maternal dominant effect were more important at the earlier stages, while endosperm additive effect and maternal additive effect were more important at the later stages of rice grain development under both unconditional and conditional genetic analyses. Due to the high heritabilities, which came from endosperm, maternal and cytoplasm effects for leucine content at different developmental stages, selection for leucine content of indica-japonica hybrid rice would be more efficient at early generations in breeding programs.

施氮量对优质稻G优325氮肥利用率和产量的影响

【目的】探明优质杂交籼稻新品种G优325的适宜施氮量。【方法】设5个施氮量处理(0、60、120、180和240 kg/hm^(2),分别记为N0、N60、N120、N180和N240)进行田间试验,研究不同施氮量对G优325主要生育时期茎糵数、干物质积累与转运能力、氮肥吸收利用率和产量及其构成因素的影响。【结果】适当增加施氮量能显著提高G优325的产量,且在N180处理下产量最高。施氮量对产量构成因素、茎蘖数和干物质积累总量影响显著,随着施氮量增加,G优325成熟期的有效穗数、每穗总粒数和干物质积累总量均表现为先增加后降低的趋势,且有效穗数和干物质积累总量均在N180处理达到最高值,而每穗粒数在N120处理最多。随着施氮量增加,抽穗前后的干物质积累向籽粒的转运量均表现为处理N180>N240>N120>N60>N0;拔节期、抽穗期和成熟期的氮素积累总量均表现为先增加后降低的趋势,且均在N180处理下最高;氮素干物质生产效率、氮素稻谷生产效率、氮素收获指数、氮肥吸收利用率、氮肥农学利用率、氮肥偏生产力和氮素生理利用率均表现为处理N0>N60>N120>N180>N240。【结论】适宜提高施氮量(180 kg/hm^(2)),可协同实现优质杂交籼稻新品种G优325高产与较高氮肥利用效率。

香型优质高产杂交稻新品种野香优669的选育与应用

【目的】选育产量、米质和抗性相协调的香型优质水稻新品种。【方法】利用亲本间的遗传多样性和农艺性状的互补性,以高产、高配合力的父本福恢669与香型、优质、抗病的不育系野香A杂交,结合多生态点抗性鉴定、高温逼熟后品质分析、多年多点品比试验等相结合。【结果】选育出优质、高产、抗病,株叶态协调的杂交稻品种野香优669。2019–2020年参加福建省中稻区域试验,全生育期两年平均139.8 d,比对照II优3301早熟1.1d,产量平均9363 kg·hm^(-2),比对照增产2.24%,未达显著水平。两年稻瘟病抗性鉴定综合评价为抗稻瘟病,稻米品质达部颁一等优质食用稻品种品质标准,2021年通过福建省农作物审定委员会审定(闽审稻20210014)。野香优669聚合了来自双亲的22个有利基因,其中6个为单方携带,16个为双亲均携带。【结论】野香优669产量高、抗性强、品质好、口感佳,在生产上大面积推广应用,是福建省农业主推品种之一。

部标1级优质稻新品种黄丝粤占的选育

在保障粮食安全和消费者对稻米品质要求日益提高的双重背景下,为了培育高产、优质、广适性大品种,笔者在核心种质育种理论指导下,通过将传统系谱法、分子标记辅助选择技术和运用先进仪器设备鉴定相结合的方法,选育出部标(NY/T 83—2017)1级优质稻新品种黄丝粤占。黄丝粤占在不同年度和不同区域试验中表现出株型理想、丰产性好、适应性广、抗稻瘟病、食味品质优异的特性,实现了高产、优质和抗病等优良基因的有效聚合。2023年黄丝粤占通过广东省农作物品种审定委员会审定,适宜广东粤北以外稻作区作早、晚稻种植,具有很大的推广潜力。

绿色优质节水抗旱稻新组合‘旱优640'的选育及制繁种技术

‘旱优640‘是以沪旱5A为母本、旱恢1640为父本,由上海市农业生物基因中心选育而成的绿色、优质、节水、适应性广的抗旱新品种。2021年通过上海市审定(沪审稻2021009)。本文详细介绍了‘旱优640’的选育过程、特征特性、繁种与制种技术,为‘旱优640’的大面积推广应用提供参考。

广西优质香稻育种创新成效、困境与对策

香味是影响大米品质的关键指标之一,也是优质稻品种选育的重要目标之一。广西丰富的香稻种质资源、优良的稻作气候生态条件为稻米品质的提高及香稻品种的创新奠定了良好的基础。近年来,在系列政策的大力支持及市场需求的迫切推动下,广西加大了优质香稻品种的选育力度。为及时了解广西优质香稻品种的研发情况,跟踪广西优质香稻育种水平变化趋势,分析广西优质香稻育种创新能力及水平,以2019—2022年通过广西审定的优质香稻品种的审定信息及推广应用数据为基础,研究广西审定优质香稻品种在品质、抗性方面的进展及主要创新主体研发情况,分析广西香稻品种开拓本地市场的成效,剖析制约广西香稻育种的主要因素,并提出加快广西香稻种业发展的对策建议。

超高产优质早熟籼粳杂交稻浙优915的选育与栽培技术

高产与优质是水稻产业的关键性目标,然而这2个性状存在明显的矛盾,运用常规育种技术在同一品种上集聚2个性状非常困难。本研究团队采用分子育种技术与籼粳杂种优势利用方法相结合,成功选育出超高产优质早熟籼粳杂交稻浙优915。该品种在区域试验和生产试验中,表现出超高产潜力。稻米品质符合食用稻部标三等,评价指标中除碱消值外,其余指标符合部标一等。全生育期为146.5~156.5 d,比嘉优5号早熟0.3~0.9 d。2023年通过国家品种审定,适宜在浙江、上海、安徽、湖北、苏南等南方粳稻种植区推广应用。根据浙优915品种特性,提出提高有效穗数和增加每穗粒数的关键性高产栽培技术。

粤稻百年主要水稻科技创新成就概述

回顾和简要概述了广东省农业科学院水稻研究所百余年来在稻作科学方面取得的主要成就。在稻种资源方面,作为最早开展稻种资源研究的单位,已收集保存栽培稻和野生稻资源24000多份,鉴评筛选出外选35等大批优异种质,创制出稻瘟病持久抗性、优质的育种亲本三黄占2号、28占和香丝苗126等广泛应用于新品种培育。在水稻育种方面,开创了栽培稻与野生稻杂交育种先河;通过人工杂交育成最早在生产上大面积应用的籼稻矮秆品种广场矮,从而开辟了水稻矮化育种新途径,进而培育出珍珠矮、广陆矮4号、桂朝2号、双桂36、特青等大品种,为农业史上的第一次绿色革命发挥了重要推动作用;作为最早开展籼型优质稻育种单位,先后育成了双竹占、黄华占、粤农丝苗、美香占2号、泰丰优208等大面积种植的优质新品种;在杂交稻育种方面,创制出野败型、红莲型高配合力、高异交率和细长粒型优质三系不育系天丰A、五丰A、荣丰A、丛广41A、粤泰A、粤丰A、泰丰A和广8A等,创制出感温与感光型恢复系广恢3550、广恢998、广恢122等,广泛应用于杂交稻育种与生产;主持和合作育成累计推广面积超千万亩的水稻品种(组合)45个。在水稻栽培方面,从20世纪50—60年代农民水稻高产经验——“潮汕经验”的总结,到80年代的水稻高产栽培技术规程研究、90年代的水稻抛秧技术和21世纪的水稻“三控”施肥技术等,这些栽培技术的研发,实现了广东省水稻生产良种良法配套,为水稻高产稳产和国家粮食安全发挥了极其重要的作用。

灌浆期高温胁迫对早籼稻品质性状的影响

【目的】研究灌浆期高温胁迫对早籼稻碾磨、外观和蒸煮食味品质的影响,揭示早籼稻品质性状对灌浆期高温胁迫的响应规律。【方法】以R996、湘早籼45号和6个新育成的早籼稻品系为试验材料,以分期播种方式利用自然高温进行胁迫处理,分析了供试品系的碾磨、外观和蒸煮食味品质,筛选出对高温钝感和敏感的水稻品系,探究稻米品质性状对灌浆期高温胁迫的响应规律。【结果】稻米品质性状对灌浆期不同时段温度的敏感性不同,始穗后10 d内温度对稻米碾磨品质和蒸煮食味品质影响最显著,始穗后30 d内温度对稻米外观品质影响最显著。稻米品质对灌浆期高温胁迫的响应因性状而异,灌浆期高温胁迫显著降低糙米率、精米率、整精米率和粒长,显著提高垩白粒率、垩白度,劣化了稻米碾磨品质和外观品质;显著降低直链淀粉含量,提高米饭外观、米饭口感和米饭黏度,提升了米饭适口性。水稻品系对高温胁迫的响应因稻米品质性状而异,Q3、Q8、Q11、Q13属于碾磨品质高温钝感品系,Q3、Q4、Q5和Q11属于外观品质高温钝感品系且高温下蒸煮食味品质优。【结论】灌浆期高温胁迫会降低稻米的碾磨品质和外观品质,提高米饭适口性。水稻品系Q3和Q11碾磨品质、外观品质好且高温钝感,蒸煮食味品质优良,可望为早籼稻优质育种提供新的种质资源。

苗期不同叶龄喷施多效唑对优质籼稻倒伏性状的影响

以优质晚籼稻‘泰优553’和‘玉针香’为材料,在水稻秧苗的1叶1心期和2叶1心期进行多效唑处理(15%多效唑1500 g兑水750 kg),以喷施清水为对照(CK),在水稻成熟期测定水稻的农艺性状与产量、茎秆的物理性状、力学和抗倒伏特性,并分析植株抗倒伏特性与主茎性状的相关性。结果表明:2个时期喷施多效唑均显著增加‘泰优553’的产量,而对‘玉针香’的增产效果不显著,其中1叶1心期和2叶1心期处理下‘泰优553’的产量较对照处理分别增加了20.63%和15.29%;2个时期喷施多效唑均可降低2个水稻品种成熟期的株高,缩短其节间长度,增加节间粗度和茎壁厚度,从而提高节间充实度和折断弯矩,提高水稻抗倒伏能力;在2叶1心期喷施多效唑较1叶1心期喷施更能提高‘玉针香’的抗倒伏能力,其中2叶1心期处理下‘玉针香’茎秆抗倒指数较对照显著增加了36.46%,而1叶1心期处理下‘玉针香’茎秆抗倒指数较对照处理差异不显著;多效唑对‘玉针香’的抗倒伏参数的影响大于‘泰优553’。总之,苗期合理喷施多效唑能够提高水稻产量和成熟期的抗倒伏能力,但不同品种的长效效果可能不一样。

机械直播杂交籼稻高产群体共性特征研究

【目的】阐明机械直播杂交籼稻高产群体的共性特征,构建规范化的机直播杂交籼稻品种鉴选方法和指标体系。【方法】以11个杂交籼稻品种为试材,研究机直播对不同杂交水稻品种群体质量及产量的影响,探讨机直播高产群体共性特征及其与产量间的关系。【结果】与中产、低产类型品种相比,高产类型品种的两年平均产量分别显著提高了2.77%~9.63%和11.19%~18.31%。高产类型品种拔节期、齐穗期及成熟期地上部干物质累积量分别显著提高27.78%~58.62%、15.38%~32.35%及18.23%~34.32%,收获指数显著提高了24.25%~34.84%,齐穗期高效叶面积指数(LAI)显著提高了37.92%~85.43%,上三叶片较长(剑叶34.17~42.17 cm、倒2叶46.23~50.30 cm、倒3叶55.17~59.23 cm),倒2叶(1.67~1.93 cm)、倒3叶(1.40~1.53 cm)较宽,N1、N2、N3(基部至穗顶第1、2、3节间)节间长度分别缩短了12.06%~47.34%、14.02%~15.85%、1.97%~14.21%,而N4、N5(基部至穗顶第4、5节间)节间分别增加了6.86%~9.95%、6.68%~7.86%。相关分析表明,机直播条件下,各生育时期地上部干物质量、LAI、剑叶长和宽、倒2叶和倒3叶长,宽以及张角(茎秆和叶片平直部分的夹角)与稻谷产量及其构成因素密切相关。尤其以齐穗期高效LAI、倒2叶宽、剑叶长与产量相关性达极显著水平(r=0.910^(**)~0.927^(**))。【结论】增加齐穗期高效LAI(6.04~7.19),并注重协同提高剑叶长(34.17~42.17 cm)与倒2叶宽(1.67~1.93 cm),是机械直播杂交籼稻高产的共性规律。