A Preliminary Study on the Relationship Between the Indica-Japonica RAPD Differentiation of Parents and Heterosisin Dian Type Hybrid Rice

The relationship between the indica-japonica differentiation of parents and heterosis of hybrid in rice was studied with 10 sterile lines, 10 maintainer lines of the sterile lines, 38 restorer lines of Dian type hybrid rice and 40 hybrids derived from the sterile lines and restorer lines. The results indicated that there was a parabolic correlation between the indica-japonica differentiation of parents detected by RAPD markers and heterosis of hybrid rice. When certain indica-japonica differentiation of parents exists, the percentage of combinations with positve heterosis and the mean heterosis of hybrids were high. But that didn't mean too much difference of parents could lead to stronger hetesosis, that meant overdiffernt parents seldom bring positve het-erotic hybrids. Suitable difference of percent of indica alleles of parents of stronger heterotic hybrid was 12 -16%.

Suitable growing zone and yield potential for late-maturity type of Yongyou japonica/indica hybrid rice in the lower reaches of Yangtze River, China

Late-maturity type of Yongyou japonica/indica hybrids series （LMYS） have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone and evaluation of yield advantage is of practicall importance for LMYS in this region. Fifteen LMYS, two high-yielding inbred japonica check varieties （CK-J） and two high-yielding hybrid indica check varieties （CK-I） were grown at Xinghua （119.57°E, 33.05°N） of Lixiahe region, Yangzhou （119.25°E, 32.30°N）of Yanjiang region, Changshu （120.46°E, 31.41°N）of Taihu Lake region, and Ningbo （121.31°E, 29.45°N） of Ningshao Plain in 2013 and 2014. The results showed that maturity dates of the 15 were later than the secure maturity date at Xinghua and 6, 14 and 15 LMYS were mature before the secure maturity date at Yangzhou, Changshu and Ningbo, respectively. One variety was identified as high-yielding variety among LMYS （HYYS） at Yangzhou, 8 HYYS in 201：3 and 9 HYYS in 2014 at Changshu, 9 HYYS at Ningbo. HYYS here referred to the variety among LMYS that was mature before the secure maturity date and had at least 8% higher grain yield than both CK-J and CK-I at each experimental site. Grain yield of HYYS at each experimental site was about 12.0 t ha-1 or higher, and was significantly higher than CK varieties. High yield of HYYS was mainly attributed to larger sink size due to more spikelets per panicle. Plant height of HYYS was about 140 cm, and was significantly higher than check varieties. Significant positive correlations were recorded between duration from heading to maturity stage and grain yield, and also between whole growth periods and grain yield. HYYS had obvious advantage over check varieties in biomass accumulation and leaf area duration from heading to maturity stage. Comprehensive consideration about safe matudty and yield performance of LMYS at each experimental site, Taihu Lake region （representative site Changshu） and Ningshao Plain （representative site Ningbo） were thought suitable growing zones for LMYS in the lower reaches of Yangtze River. The main factors underlying high yield ofHYYS were larger sink size, higher plant height, longer duration from heading to maturity stage and whole growth periods, and higher biomass accumulation and leaf area duration during grain filling stage.

Higher leaf area through leaf width and lower leaf angle were the primary morphological traits for yield advantage of japonica/indica hybrids

The yield potential of japonica/indica hybrids(JIH)has been achieved over 13.5 t ha–1 in large-scale rice fields,and some physiological traits for yield advantage of JIH over japonica inbred rice(JI)and indica hybrid rice(IH)were also identified.To date,little attention has been paid to morphological traits for yield advantage of JIH over JI and IH.For this reason,three JIH,three JI,and three IH were field-grown at East China(Ningbo,Zhejiang Province)in 2015 and 2016.Compared with JI and IH,JIH had 14.3 and 20.8%higher grain yield,respectively,attributed to its more spikelets per panicle and relatively high percentage of filled grains.The advantage in spikelets per panicle of JIH over JI and IH was shown in number of grains on the upper,middle,and lower branches.Compared with JI and IH,JIH had higher leaf area through leaf width and lower leaf angle of upper three leaves,higher leaf area index and leaf area per tiller at heading and maturity stages,higher stem weight per tiller and K and Si concentrations of stem at maturity,higher dry matter weight in leaf,stem,and panicle at heading and maturity stages,and higher biomass accumulation after heading and lower biomass translocation from stem during ripening.Leaf width of upper three leaves were correlated positively,while leaf angle of upper three leaves were correlated negatively with biomass accumulation after heading,stem weight per tiller,and per unit length.Our results indicated that the grain yield advantage of JIH was ascribed mainly to the more spikelets per panicle and relatively high percentage of filled grains.Higher leaf area through leaf width and more erect leaves were associated with improved biomass accumulation and stem weighing during ripening,and were the primary morphological traits underlying higher grain yield of JIH.

Relationships of Panicle Type Index with Subspecies Characteristics and Yield Traits in Filial Generation of Crosses between Indica and Japonica Rice

Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica）, were grown in Liaoning and Sichuan Provinces, China, to study the panicle type index （PTI, the ratio of a number of node position on panicle axis where the secondary branch with the most numerous secondary branch grains is located to the number of primary branches） and its relationships with subspecies characteristics and yield traits. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be a method for breeding cultivars with ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI varied remarkably with different subspecies types. As a whole, it showed a trend of indica （H）〉indicalinous （H＇）〉japonicalinous （K＇）〉japonica （K） However, it is not appropriate to regard PTI as a parameter for subspecies classification in rice because it was recombined in the filial generations of cross between indica and japonica rice. The negative correlations were found between PTI and most of panicle characteristics, as well as yield-related traits. Based on PTI, most of lines from the two populations were middle dominant panicle type （the number of grains on the secondary branch is numerous in middle position of the panicle） and lower dominant panicle type （the number of grains on the secondary branch is numerous in lower position of the panicle and becomes less towards the top of panicle） with significant yield advantages.

氮素水平对籼粳杂交稻产量和贮藏蛋白的影响

氮素对稻米蛋白质含量的影响研究颇广,但籼粳杂交稻强弱势粒蛋白组分的积累动态、蛋白质分布及其对氮素的响应鲜有报道。以两个籼粳杂交稻(甬优12和甬优17)为材料,设置4个氮肥水平,即N0(不施氮)、低氮(100 kg·hm^(-2))、中氮(200 kg·hm^(-2))和高氮(300 kg·hm^(-2)),比较了产量、粒型、强弱势粒干物质积累与贮藏蛋白的积累特征。结果显示,施氮显著提高两品种的产量以及蛋白质含量,但品种间对氮素响应存在差异。甬优12在低氮下就能获得较高产量,且其蛋白质积累对氮素响应也较稳定,能实现高产优质的平衡。低氮对粒型无显著影响,高氮显著降低长宽比,导致粒重轻微下降。醇溶蛋白和谷蛋白积累过程存在此起彼伏的现象,从而维持总蛋白的相对平衡。弱势粒蛋白质含量高于强势粒,但因其粒重小导致总积累量仍然低于强势粒。贮藏蛋白主要富集在籽粒外层胚乳中,甬优17对氮素响应较甬优12更敏感。研究结果可为籼粳杂交稻的高产优质栽培技术提供理论依据。

紫薇种内杂交可配性与抗白粉病种质筛选

以红火箭、红火球和红叶3个美国紫薇品种和四川粉花紫薇、四川白花紫薇两个四川本地紫薇品种为亲本进行种内杂交,调查坐果率、结实率和种子萌发率等3个种实性状,测定了3个种实性状的遗传力,性状之间的相关遗传力和相关系数;采用孢子悬浮液侵染法对子代进行了病菌接种,根据子代病情分级筛选抗白粉病的杂交组合。结果表明:(1)杂交组合子代的种实性状均在显著性差异,且均显著低于自由授粉子代。(2)12个杂交组合收获了种子,其中只有8个杂交组合种子能萌发,因此紫薇杂交设计需充分考虑亲本搭配。(3)三个种实性状的遗传力均在0.99以上,坐果率与结实率、萌芽率的相关遗传力均在0.8以上,采用坐果率性状提前选择结实率和萌芽率性状的效率分别达88.37%、84.47%。(4)8个杂交组合子代白粉病抗性试验发现,部分“美中”组合杂交子代的抗性表现好,而部分表现很差,其中“红火箭×四川粉花紫薇”杂交组合F1代抗性表现最佳,参试子代均为抗病类型,抗性表现次佳的为“红火箭×四川白花紫薇”杂交组合,而“四川粉花紫薇×美国红叶紫薇”杂交组合F1代抗性表现最差。本地品种杂交子代表现均衡。(5)初步筛选出8株免疫株,25株高抗株。相关研究发掘的抗白粉病杂交组合和抗病类型为紫薇抗性育种提供材料基础。

籼型杂交水稻稻米蒸煮品质、碾米品质及营养品质的细胞质遗传效应

有关杂交水稻品质性状的研究,国内外学者已做了一些工作,主要注重于现有杂交稻米质的表现,或者是稻米品质的核遗传效应,作者在前文中已报道细胞质对稻米外观品质及氨基酸含量的影响,发现细胞质效应是显著的,但主要是通过核质互作进行表达。本文就稻米蒸煮品质、碾米品质及营养品质的细胞质影响作一探讨。

不同籼型杂交水稻的干物质积累、分配及产量形成特性

为探讨不同籼型杂交水稻干物质积累、分配及产量形成特性,以实现水稻超高产栽培和培育超高产水稻新品种,试验以6个籼型杂交水稻品种为材料,对籼型杂交水稻干物质积累、分配、转运和群体生长率等生理特性进行研究。结果表明:1)拔节期叶面积指数最低,孕穗期除Q优6号外,其余各品种均达最高,随后各品种叶面积指数降低。2)生育前期Q优麻恢1号干物质积累最高,生育后期除湘优109外,其余各品种均达最高。3)6种籼稻在成熟期各器官的干物质分配比例均以籽粒的最大,依次分别为Q优6号(64.64%)>中优608(63.55%)>Ⅱ优838(62.98%)>Q优麻恢1号(62.85%)>湘优109(62.56%)>T优300(61.54%),其实收产量大小顺序为Ⅱ优838>Q优麻恢1号>中优608>湘优109>T优300>Q优6号;其中Ⅱ优838产量最高,为12 353.20 kg/km2,显著高于湘优109、T优300和Q优6号,但与Q优麻恢1号和中优608差异不显著。

籼型杂交中稻高产组合的植株性状及其分类

以21个籼型杂交中稻组合为材料,对产量性状组与根系及地上部植株性状组进行基因型值相关分析和典型相关分析。结果表明:籼型杂交中稻高产组合性状的典型变量有两组达到显著水平,第一组以分蘖力,4叶期假茎基宽,有效穗数和结实率起主要作用;第二组以着粒数和齐穗期叶面积指数为主的相关。高产组合可分为强分蘖力、穗数多、高结实率类型,物质生产能力强的大穗型和穗粒兼顾的中间类型三种,在育种实践中的选择方向应多样化。分蘖力强、着粒数偏少可作为选择强发根力组合(材料)的参考指标。

籼型杂交水稻F_1优势与高产恢复系关系的研究

籼型杂交水稻的优势是普遍存在的，不同性状有明显差异。在研究的２０个组合１９个性状中，以产量的正向优势最强，其次是单穗谷重，再次按粒重、穗长、顶３叶叶面积、每穗实粒数、株高、成穗数、结实率、每穗总粒数的顺序递减，而全生育天数为负向优势。杂种Ｆ１的全生育天数、穗长、顶３叶叶面积、穗数、粒数、粒重、单穗重及产量与对应恢复系呈显著或极显著相关。随着恢复系产量的提高，杂种Ｆ１亦随之提高。当恢复系产量达到一定水平后，品种间的杂种Ｆ１产量超父优势不强；但籼粳交后代的恢复系，其Ｆ１的产量超父优势明显。恢复系产量结构类型的差异对杂种Ｆ１产量优势的影响不明显。

不同穗型杂交籼稻物质积累、氮素吸收利用和产量的差异比较

以18个杂交籼稻组合为材料,在2种氮肥条件下测定了其产量、干物质及氮素积累指标,并按单穗重量对18个组合进行聚类分析,研究了不同穗型水稻产量、干物质积累与转运及氮素吸收利用的差异。结果显示,18个组合可分为大穗型(A类)、中等偏大穗型(B类)、中等偏小穗型(C类)和小穗型(D类)四类。施氮使单穗重增加,但2种氮肥条件下各组合的从属类别保持不变。随着穗型变大,水稻产量逐渐增加,两种氮肥水平下大穗型组合产量均最高。大穗型组合物质积累总量上优势明显。亏氮条件下花后干物质积累比例较高,丰氮条件下花前花后干物质积累均衡。茎鞘物质转运与水稻穗型和氮肥条件均有关,施氮可以有效促进A、B类水稻茎鞘物质输出。两种氮肥条件下偏大穗型(A、B类)水稻较偏小穗型(C、D类)水稻在N积累总量上优势更大,B类组合总吸氮量最大,但其N素利用能力较差;A类组合花前花后N素积累比例适宜,花后营养器官N素输出能力强,因而N素干物质生产效率及产谷效率均最高。

北方粳型超级稻中籼粳杂交优势贡献的分子基础

在"理想株型与优势利用相结合"育种理论指导下,亚种间杂交为中国北方粳型超级稻增产做出了巨大贡献。以中国北方栽培粳稻品种为试材,利用籼粳特异性标记Indel与SSILP分析了不同年代与地区北方粳稻品种的籼型血缘的相对含量,结果表明,20世纪90年代以后育成品种籼型基因型频率显著增加。相关分析表明,籼稻血缘含量与每穗粒数存在显著的正相关性,与有效穗数存在显著的负相关性。进一步对籼粳杂交育成品种的8个产量与品质相关基因进行检测发现,育种家通过"选择"将控制穗粒数与粒重的籼稻增产基因GN1a、GS3部分固定于北方粳稻基因组中,淘汰了适口性差的籼稻高直链淀粉基因Waxy以及不符合北方农民收获习惯的籼稻落粒基因qSH1,同时保留了北方粳稻原有的理想株型基因DEP1,宽粒基因qSW5。本研究进一步明确了"籼粳杂交优势利用理论"的分子基础。

我国杂交粳稻的发展及其技术策略

阐述了北方杂交粳稻的生态优势和杂种优势及人们喜粳嫌籼食味的变化 ,介绍了杂交粳稻“北上”、“南下”取得的进展和存在问题 ,提出当前杂交粳稻进一步发展应采取“籼粳架桥”

滇型杂交稻亲本籼粳分化与杂种优势关系的初步研究

以滇型杂交稻不育系 10个、相应的保持系 10个和恢复系 38个 ,以及由上述不育系和恢复系组配的 4 0个杂交种为试材 ,研究了亲本材料的RAPD籼粳分化程度与杂种优势的关系。结果表明 ,亲本籼粳差异与产量杂种优势存在抛物线的关系。利用籼粳分化存在一定差异的亲本杂交 ,易得到正向优势组合 ,平均杂种优势较强 ;但并非双亲籼粳分化差异越大越好 ,双亲差异过大则不易获得正向优势组合 ,使杂种优势减弱 ,甚至为负。双亲籼稻成分差值以 12 %～ 16

栽培稻中间型品种和籼粳交DH株系的亲和性鉴定

以籼、粳标准测验种为母本 ,对栽培稻一些中间型材料、籼粳交DH株系及籼粳对照品种在内的共 95份材料进行杂交亲和性鉴定 ,结果显示 :全部材料的亲和性分化呈连续分布 ,可分为亲籼 (ICV)、亲粳 (JCV)、广亲和 (WCV)及非亲和 (NCV) 4种类型 ;共鉴定到 5 5份广亲和性材料 ,主要为中间型 (18份 )和籼粳交DH株系 (3 4份 ) ;亲本具有广亲和性的籼粳交DH株系几乎全部具有广亲和性 (占 96.2 % ) ,且广亲和性强于对照品种零轮 ,而亲本不具有广亲和性的籼粳交DH中也能产生广亲和株系 (占 2 5 .0 %～5 7.1% ) ,但广亲和性略差。认为水稻广亲和性的产生可能是由籼粳分化决定的 ,选育中间型广亲和系是广亲和品种选育的主要方向。

籼粳交后代中的穗型指数与亚种特性及产量性状的关系

以两个典型的籼粳交重组自交系F6群体(RILSA:中优早8号/丰锦;RILSB:七山占/秋光)为试材,分别在四川和辽宁种植,研究穗型指数(PTI)与亚种特性及产量性状的关系。结果表明,PTI在籼粳交后代中表现连续变异,籼粳交可以创造大量具不同PTI的株系,可以作为理想穗型选育的来源。生态环境对PTI有显著影响,从辽宁到四川,PTI显著变小。PTI与大多数亚种特征性状呈显著负相关。PTI在不同亚种类型间有明显差异,总体上有籼(H)>偏籼(H′)>偏粳(K′)>粳(K)的趋势,但PTI不可以作为判别亚种类型的依据,因为籼粳交后代中的PTI在不同亚种类型间交错重叠。PTI与穗部性状和产量性状大多呈负相关,两群体中绝大多数株系的PTI为中下部优势型,在产量上具有明显优势。

优质丰产杂交籼稻品种机直播产量构成及其群体质量研究

【目的】本研究旨在明确适宜平原(崇州)与丘陵(三台)稻区机直播优质杂交籼稻高产品种群体质量的共性特征,构建规范化的机直播优质杂交籼稻高产品种的鉴选方法和评价标准,以及为杂交籼稻机械化直播配套技术的融合提供理论及实践依据。【方法】两生态区以29个品种为试材,采用人工模拟精量穴直播(以下简称机直播),研究机直播对平原与丘陵稻区不同产量水平的优质杂交籼稻群体质量特征及产量的影响,并探讨机直播优质杂交籼稻群体质量特征与产量间的关系。【结果】依据两生态区各品种的平均籽粒产量聚类分析,将两生态区供试品种分为高产、中产、低产3种类型。其中,三台高产类型品种占17.24%,中产、低产类型品种占82.76%;崇州高产类型品种占10.34%,中产、低产类型品种占89.66%。与中产、低产类型品种相比,两生态区高产类型品种的共性特征为分蘖能力强、有效穗数多、结实率高,拔节期后叶面积指数(LAI)大,干物质累积量高;结实期顶3叶叶长、叶位、叶张角、株高及其顶部截获光能优势明显。相关分析表明,机直播条件下,除群体透光率、顶3叶叶张角、分蘖盛期LAI及干物质累积量外,各群体质量指标与籽粒产量均呈显著或极显著正相关(r=0.37~*~0.90^(**)),尤其是齐穗期高效LAI率、成熟期干物质累积量及其收获指数与产量的相关性。【结论】机直播条件下,高产类型品种能够获得较高的有效穗数和每穗实粒数,并协同提高结实率,实现生育后期群体干物质的高增长,从而获得较高产量。

籼型杂交水稻稻米糊化温度的遗传分析

以９个不育系和１０个恢复系为材料配制了１５个亲本遗传基础差异较大的籼型杂交组合，对各组合杂交稻米及相应不育系和恢复系的糊化温度进行了单粒分析。结果表明，籼型杂交稻米糊化温度的遗传受微效多基因控制，较高糊化温度对较低糊化温度存在着部分显性；籼型杂交稻米碱消值平均数与中亲值间没有显著差异，碱消值遗传方差和双亲碱消值差异间存在极显著的正相关。并对籼型杂交水稻稻米糊化温度研究方法和改良途径进行了讨论。

机械化种植对杂交籼稻F优498产量构成与株型特征的影响

为探明机械化种植杂交籼稻高产群体的株型特征,以F优498为材料,采用二因素裂区设计,研究了不同穴苗数与播期下机直播、机插、手插3种种植方式的株型特征及其与产量构成的关系。结果表明:(1)不同种植方式株型特征差异显著,机直播和机插上三叶叶长、叶宽和叶间距大,但叶基角和披垂度也较大;手插上三叶大小适宜,叶片厚而挺直;机直播和机插株高和着生高度显著大于手插,但手插比叶重、单株穗数和总叶片数显著高于机械化种植;机直播的茎蘖夹角、穗粒数和单穗重显著低于机插和手插。推迟播期和低苗处理均使叶片增大,比叶重、粒叶比、单株穗数、穗粒数和结实率随播期延迟显著降低。单穗重与上三叶长度、宽度、着生高度和株高均呈显著或极显著正相关,以机插最高,手插次之,机直播最低。(2)机直播产量显著低于机插和手插,且随播期延迟和穴苗数减少显著降低。产量及其构成与株型特征密切相关,机械化种植杂交籼稻高产株型的显著特征为适宜的株高、上三叶长度、群体LAI和茎集散度;叶宽、比叶重、叶间距大和直立性好。足穗和大穗的统一是实现水稻高产的关键,塑造个体优良的株型与优化群体结构是增产的前提,机械化种植杂交籼稻应在时间允许的条件下尽早播栽,穴苗数以3苗左右为宜。

利用SSR分析滇型杂交稻亲本籼粳分化与杂种优势的关系

以滇型杂交稻不育系4个、恢复系31个及其组配的31个杂交种为试验材料,利用SSR籼粳特异引物研究亲本籼粳分化程度及与杂种优势的关系。结果表明,在所检测的18个位点上,4个不育系均以粳稻血缘为主,31个恢复系总体上偏粳,但含有不同成分的籼稻血缘,其籼性比率Pi为0～27.8%。亲本SSR遗传距离、籼粳差异与杂种优势相关分析表明,亲本SSR遗传距离与小区产量超父优势等7个性状相关显著;亲本的籼粳分化差异与百粒重超父优势等4个性状显著相关;亲本SSR遗传距离、籼粳差异与小区产量竞争优势相关不显著,说明SSR遗传距离、亲本籼粳分化差异与产量竞争优势无线性关系,但籼粳分化差异适中的亲本杂交,容易得到正向优势极端组合,可从中筛选出杂种优势强的组合。