Why are There Indica Type and Japonica Type in Rice?——History of the Studies and a View for Origin of Two Types

On the bases of archaeological discoveries, the earliest domestication of rice has been confirmed in the middle and lower Changjiang River basin, while in the region wild rice populations are found in shallow swamps under a climate with freezing winter cold. These findings lead us to-examine the past ideas about domestication and differentiation of rice. Historically, in 1930s two sub-species, indica and japonica, were proposed on the basis of sterility in F1 hybrids between them. Soon after that, the two types were classified by the associations of a number of genetically independent traits. The characteristic associations of traits have been explained by the hybrid sterility or reproductive barriers which were assumed to comprise a set of duplicate recessive lethal genes and to be an inner genetic mechanism to lead to the varietal differentiations In 1980s, the hybrid sterility between Indica and Japonica types was analyzed, and Indica, Japonica, and wide-compatibility type which gives fertile hybrids when cross to Indica and Japonica types, are proved to contain an allele, S5＇, S5＇ and S5^n, respectively at a locus on chromosome 6. And those gametes having Sj allele are found to be partially aborted in the hybrid genotypes of S5＇/S5＇ while no gamete abortion occurs in S5＇/S5^n and S5＇/S5^n genotypes. Since then, the gene S5^n has been used in hybrid rice breeding to obtain fertile and vigorous hybrids between subspecies, and the long-disputed problem of hybrid sterility has been solved. Also in such studies the characteristic association of traits found in each of vadetal groups is better explained by founder effects. On the other hand, a large number of native cultivars of rice were surveyed with enzyme polymorphism in 1980s and later with molecular markers. As a result, profound genetic diversity is found in cultivated rice as well as in wild rice. These findings seem to lead us to the idea of multiple independent domestications of rice. However, before reaching such a conclusion, at least two factors, i.e., long-distance-dissemination of some genotypes and the possibilities of introgression by local wild rice to primitive cultivars need to be examined. Taking the two factors as well as the historical events into consideration, it is considered here that the perennial japonica cultivars which are close to wild rice in the Changjiang River basin were disseminated to East India through Assam or along the Bengal Bay, where they were transformed under the introgressions of local wild rice and formed a secondary center, from which some genotypes seem to be disseminated to colonies in Southeast Asia under the influence of Hinduism. Later some of the genotypes were introduced into China and constituted so called Indica type. This may be a reasonable picture for the varietal differentiation.

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.

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.

育苗容器对紫叶紫薇容器苗生长、开花及生理的影响

【目的】探讨育苗容器类型和规格对紫叶紫薇容器苗生长、开花及生理的影响,筛选出培育紫叶紫薇容器苗的适宜育苗容器,为高效培育紫薇容器苗提供理论依据。【方法】以紫叶紫薇优良新品种‘丹红紫叶’2年生苗木为研究材料,选用黑色塑料营养杯(C1)、白色无纺布美植袋(C2)、黑色控根容器(C3)3个类型以及16×16(D1)、21×21(D2)、25×25(D3)3种规格(直径×高,cm),组成9种容器组合处理,测定不同处理容器苗生长、开花及生理指标。【结果】(1)不同育苗容器处理对紫叶紫薇容器苗的生长、开花及生理指标均影响显著,同一容器类型苗木的生长、根系、生物量、花期、花径、花序、可溶性蛋白含量、可溶性糖含量、相对叶绿素含量、净光合速率、气孔导度、蒸腾速率等指标均随着育苗容器规格的增大而显著增加。(2)地径生长量、总根长、总根表面积、总根体积、根尖数、地上部干质量、地下部干质量、总干质量、花期均以C3D3处理最大,比最小的C1D1处理分别显著提高817.12%、108.12%、94.60%、75.66%、144.14%、135.67%、228.45%、164.65%、34.48%;苗高生长量、冠幅生长量、叶面积、花序长和宽均以C1D3处理最高,比最低的C1D1处理分别显著提高116.05%、81.39%、114.95%、70.44%和65.79%;相对叶绿素含量、水分利用效率均以C3D3处理最大,可溶性蛋白和可溶性糖含量、净光合速率、气孔导度均以C1D3处理最高;胞间CO_(2)浓度、水分利用效率在各处理之间无显著差异。(3)各处理隶属函数法综合评价得分排序为:C3D3>C1D3>C2D3>C3D2>C2D2>C1D2>C2D1>C3D1>C1D1。【结论】黑色控根容器在地径生长量、根系生长指标、生物量、花期和花径、叶绿素相对含量及净光合速率方面表现最佳;紫叶紫薇2年生苗的最适宜育苗容器是直径25 cm、高25 cm的黑色控根容器。

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。

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.

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。

水稻杂种优势与遗传分化关系的研究

以培矮 64s、 10 8s、N4 2 2 s、L S2 s等 4个两系不育系为母本 ,以韩国籼、中国南方的早中籼 (简称中国籼 )、东北粳 (分东北普通粳和粳杂恢复系 )、华北粳、非洲粳、美国粳等 6个生态型的 4 7个育成品种为父本 ,按照 NC- 设计 ,配制 188个组合。在所配的组合类型中 ,N4 2 2 s/中国籼单株粒重最高 ,其次是 N4 2 2 s/韩国籼、培矮 64s/东北粳、 10 8s/中国籼 ,这些组合类型均为籼粳亚种间的组合 ,说明亚种间巨大的杂种优势。不同组合类型的产量构成因素分析表明 ,与中国南方的早中籼和韩国育成籼稻品种配组的 F1在穗数上具有明显的优势 ,与东北粳杂恢复系、美国稻配组的 F1在穗粒数上具有明显的优势 ,而与非洲粳配组的 F1在千粒重上具有明显的优势 ,华北粳在穗数和穗粒数上处于中间型 ,推测中国籼和韩国籼可能具有穗数上的优势基因 ,美国稻和东北粳具有粒数的优势基因 ,非洲粳具有粒重上的优势基因。比较 4个不育系配组的产量及产量构成因素发现 ,培矮 64s在穗数上具有明显的优势 ,培矮 64s、 N4 2 2 s和 10 8s在穗粒数上均具有优势 ,而 LS2 s在千粒重上明显的优势。杂种优势与双亲籼粳分化的相关关系分析表明 ,超亲优势与双亲的籼粳分化关系明显 ,且

籼型温敏核不育水稻叶绿素突变体的诱变及其初步研究

用６０Ｃｏγ射线辐照粑型温敏核不育系２１７７Ｓ，获得了一批常见的叶绿素突变体。Ｍ２代按苗计，叶绿素总突变频率为０．２６２％，其中只有４．５０％可以存活并遗传，从中筛选出３３个综合性状优良的籼型温敏核不育叶绿素突变系。经鉴定，这些叶绿素突变受基因控制，比较稳定，有的只在苗期表达并逐渐转为正常，有的则在全生育期表达。与２１７７Ｓ相比，农艺性状都有不同程度变化，但温敏不育特性基本不受影响。遗传分析表明，所有的突变体与亲本正反交时，杂种Ｆ１均为绿色植株，杂种Ｆ２群体中，正常绿色株与对应叶绿素突变株分离比值符合３：１。证明这类突变是由１对隐性细胞核基因所控制。

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。

实用早籼型两用核不育系选育策略与进展

简要回顾了我国水稻两用核不育系选育的三个阶段及取得的主要成绩 ,分析了存在的主要问题 ,提出了实用早籼型两用核不育系选育策略 ,并详细介绍了作者从事实用早籼型核不育系选育所取得的主要进展。

6个籼型水稻核不育系在武昌的育性转换特性研究

以３２０４Ｓ、ＨＮ５Ｓ、８９０６Ｓ、安湘Ｓ、１１３Ｓ和９４５１Ｓ等６个籼型核不育系为材料，在武昌自然条件下，对其育性转换特性进行了观察研究。结果表明：除９４５１Ｓ外，其余５个不育系在７～８月不育性是比较稳定的；６个核不育系，９月份都有一个时段出现了一定比率的深染色花粉，育性转换明显；平均自交结实率均低于３０％。

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。

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。

4份籼粳中间型广亲和恢复系的生物学特性及其杂种优势利用

通过籼粳杂交、广亲和特性鉴定以及育性恢复能力测定等手段,选育出CH58、CH59、C18和C84四个籼粳中间型广亲和恢复系。生物学特性研究结果表明,CH58、CH59、C18和C84的程氏指数分别为11、13、13和15,其中CH58、CH59和C18的籼粳属性为偏籼,C84为偏粳。广亲和特性鉴定和育性恢复能力测定结果表明,四个恢复系具有良好的广亲和性,且都能恢复滇型、BT型、矮败型等粳稻不育系以及野败型、印水型等籼稻不育系的育性,恢复谱广。花时特性研究表明,籼粳中间型广亲和恢复系的开花高峰要明显早于粳稻不育系春江16A。粳不籼恢亚种间杂交稻在单株产量、每穗粒数、二次枝梗数、株高、一次枝梗数和剑叶宽等性状上表现出明显的中亲优势和竞争优势。利用CH58等四个籼粳中间型广亲和恢复系与粳稻不育系配组,已选育出春优58、春优658、春优59、春优618等粳不籼恢亚种间杂交稻,已通过国家、浙江省等品种审定。CH58等四个籼粳中间型广亲和恢复系广亲和性好,恢复谱广,在三系法籼粳亚种间杂种优势利用中具有良好的应用前景。

早恢R458的选育与应用

早恢R458是江西省农业科学院水稻研究所以桂朝13号为父本,IR58为母本杂交,经过多代定向选育而成的籼型三系早稻恢复系,具有恢复力强、配合力高、千粒重大、品质优、制种产量高等特点;2009年5月通过省技术鉴定;2009年7月获植物新品种保护权。利用该恢复系所配组合通过省审或国审,江Ⅱ优赣17号(江农早IIA/R458)1999年通过江西品种审定,金优458(金23A/R458)2003年3月通过江西品种审定、2008年8月通过国家品种审定、2009年被农业部认定为超级稻,优I458(优IA/R458)2005年11月通过江西品种审定。R458系列组合推广产生了巨大的经济效益和社会效益。

籼型杂交稻碾米品质配合力与播期互作的初步研究

本文研究了按４×４不完全双列杂交估算籼型杂交稻碾米品质配合力在５个播期的表现，结果表明：不育系的糙米率、精米率及恢复系的整精米率ＧＣＡ（一般配合力）×播期工作显著，精米率和整精米率ＳＣＡ（特殊配合力）×播期互作也显著。碾米品质配合力的稳定性中等偏低。糙米率和整精米率配合力的稳定性主要受加性基因与播期互作的影响，而精米率配合力的稳定性同时受加性和非加性基因与播期互作的影响。

河姆渡遗址稻的硅酸体分析

用植物硅酸体分析技术，对河姆渡遗址的稻谷堆积物和土壤中的水稻叶片运动细胞硅酸体进行了观察调查，以冀从细胞形成角度了解河姆渡稻谷的种属。结果表明，河姆渡遗址稻叶片运动细胞硅酸体以β型为主，占７３．８％；ａ型次之，占２２．１％；中间型占４．１％。平均尖度０．８６，背离系数１，是一个以粳型为主的栽培稻群体，其生物学性状与现代的热带粳稻有相似之处。