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    10 April 1998, Volume 12 Issue 2 Previous Issue    Next Issue

    研究报告
    综述与专论
    研究简报
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    研究报告
    Genetic Effects of Sterile Cytoplasm of Isonuclear Alloplasmic CMS Lines in Hybrid Rice (Oryza sativa L. subsp. japonica )
    Wang Cailin,Tang Shuzhu,Tang Yugeng
    1998, 12(2): 65-71 . 
    Abstract ( )   PDF (359KB) ( )  
    Genetic effects of sterile cytoplasm on twelve agronomic characters of F1 rice hybrids (Oryza sativa L. subsp. japonica ) were investigated. Two sets of isonuclear alloplasmic CMS lines (A lines) of Nanjing 11A and Nanjing 34A with four different cytoplasms of Chinsurah Ⅱ(BT), Eshandabagu (D), wild abortion(WA) and wild rice species/cultivars (WC) and their maintainer lines (B lines ), four restorer lines (R lines ) of 77302-1, Ninghui 3-2, C57 and C Bao were used to make hybrids of A lines × R lines (aF1 )and B lines X R lines(bF1 ). Cytoplasmic effects were determined by the difference of aF1-bF1. Significant negative effects on plant height, exserted panicle neck length, number of grains per panicle, seed setting rate, harvest index, and grain yield per plant and significant positive effects on 1000-grain weight were observed. Cytoplasmic effects significantly varied with different CMS cytoplasms, in which D and BT type cytoplasms had the advantages of WA and WC types for most of the characters. Cytoplasmic effects significantly varied with different nuclear backgrounds of B and R lines and the interaction of B × R.
    Identification of QTL for Salt Tolerance in Rice Via Molecular Markers (in English)
    Lin Hongxuan,Yanagihara S,Zhuang Jieyun,Senboku T,Zheng Kangle,Yashima S
    1998, 12(2): 72-78 . 
    Abstract ( )   PDF (321KB) ( )  
    The recombinant inbred (RI) lines (F7) were developed by single seed descent procedure from acombination, Tesanai 2/CB. The RI population was used to map QTLs controlling salt tolerance in rice. The 142 lines were genotyped at 60 RFLP markers and evaluated for seedling survival days (SD) in culture solution with EC= 12 dS/m by adding NaCl. Transgressive segregations were observed for salt tolerance in the RI population. Alinkage map consisting of 52 marker loci from 11 linkage groups was constructed. Of 60 marker loci, only one marker locus RG13 on chromosome 5, which associated significantly with salt tolerance was detected and this locus explained 11. 6 % of the observed phenotypic variance for SD. The allele from Tesanai 2 increased salt tolerance. Among 59 pairs of loci between RG13 and all other 59 marker loci, significant epistatic interactions were detected in three pairs which were RG13 and RG104 on chromosome 3 (P= 0. 0004), RG13 and RG143 on chromosome 4 (P= 0. 0028) , RG13 and RG716 on chromosome 6 (P = 0. 0063). The interactions between RG13 allele from Tesanai 2 and RG104 or RG143 from CB significantly increased salt tolerance level. The interaction between RG13 and RG716 alleies from Tesanai 2 also increased tolerance level. These gene interactions provided clear genetic evidence of transgression.
    Direct and Maternal Genetic Effects on Grain Quality Characters in Early Hybrid Rice
    Chen Jianguo,Song Guoqing,Zhai Shaohong,Zhou Yong
    1998, 12(2): 79-84 . 
    Abstract ( )   PDF (433KB) ( )  
    Genetic studies were conducted for seven grain quality characters using genetic models with genotype×environment interactions for seed traits in early hybrid rice. The results indicated that the seven characters were controlled by seed direct genetic effects and maternal effects simultaneously. The genetic variations of the percentage of brown rice, milled rice recovery, grain length and alkali digestion value(ADV) were mainly attributable to maternal additive and direct additive effects, with maternal additive effects predominating for the former three characters, and direct additive effects for ADV. Significant negative genetic covariances between direct additive and maternal additive effects were also detected for these four traits. Chalkiness score was mainly governed by maternal additive effects, but direct dominant effects also operated. The genetic variations of grain width and length/width ratio were mainly assigned to maternal additive × environment and direct additive ×environment effects, with maternal additive ×environment effects predominating, and direct dominant effects also existed. Predicted values of genetic effects indicated that the restorer line Huda 242 appeared to be more useful for the improvement of grain qualities ofearly hybrid rice.
    Effect of the Paddy-Upland Yearly Rotation on the Soil Fertility
    Wang Renmin,Ding Yuanshu
    1998, 12(2): 85-91 . 
    Abstract ( )   PDF (289KB) ( )  
    With 6-year (from 1987 to 1993) long-term experiment, the effect of barley-rice-rice(BRR,CK) andbarle y-corn-rice (BCR ) cropping s ys tern on the soil fertility in Zhejiang Province were studied. The resulis showedthat the contents of organic matter, total N, total P, hydrolytic N, available P, and exchangeable K of paddy soil were significantly increased both in BRR and BCR treatment with cultivation year after year. Meanwhile, the soil physical properties were also improved. Compared with BCR treatment, BRR treatment is more benificial to increasing the contents of soil organic matter, total N and total P, but the contents of soil available P and exchangeable K were significantly higher in BCR treatment than those in BRR treatment. In additional, BCR treatment is more beneficial to improving soil physical properties than BRR treatment is. Therefore, compared with BRR treatment, BCR treatment could enhance the amount of aerobic microorganism and decrease the amount of anaerobic microorganism and the reductive matter. The result also showed that BCR treatment is more evidently in increasing the content ofquick active nutrients, N, P, K in late rice season than BRR treatment, then the late rice in BCR treatment grows quicker and better than in BRR treatment.
    Application of High-Hydroscopicity Seed-Coating Material in Dry-Raised Scattered-Transplantation Rice
    Xu Maolin,Zhang Hongxi,Huang Niansheng,Liu Xiaojing,Dai Zhengyuan,Kong Xiangdou,Zhao Buhong,Tan Changle
    1998, 12(2): 92-98 . 
    Abstract ( )   PDF (469KB) ( )  
    Rice seeds were coated with high-hydroscopicity seed coating material and sowed in dry-raisingseedling bed without seed-soaking and pregermination. The treatment of high-hydroscopicity resin seed-coatingmaterial can fornl a water-stored ball of about 1. 8 cm × 1. 5 cm × 1. 2 cm around seed and root, the ball has the abilities of absorbing, keeping and providing water. As the ball containing pesticide, germicide and plant regulatorand releasing slowly, it may afford a suitable surroundings for germination and seedling growth. The procedure cannot only enhance emergence and seedling rate, prevent diseases, pests and died seedlings, strengthen root system, improve seedling qualities, but also can scatter dry-raised seedlings with more soil, improve seedling-standing speed and resist to planting injury, increase the yield of dry-raised scattered-transplantation rice.
    The Relationship Between IAA and Grain Development of Indica-Japonica Hybrid Rice and Regulation with S-07
    Tiao Shulan,Wang Xi
    1998, 12(2): 99-104 . 
    Abstract ( )   PDF (443KB) ( )  
    Shanyou 4I3, an indica-japonica hybrid rice combination, and its male parent Zhong 413 were selected to investigate the effects of plant growth retardant S-07 on the grain filling of vigorous and weak spikelets, and also to clarify the role of exdogenous and endogenous IAA in grain development. The suppression of vigorous spikelet on weak spikelet during the early grain-filling period can also be realized by the use of exdogenous IAA. Differential change patterns were detected for endogenous IAA content between vigorous and weak spikelets during the grain filling period, where IAA content increased sharply from the beginning of grain-filling and reached its maximum about eight days after flowering for vigorous spikelet, but was rather low during the initial 12 days and increased gradually to the top about 8 days afterwards for weak spikelet. The application of S-07 solution at the booting stage could decrease the IAA content of vigorous spikelet, but increased that of weak spikelet. The vigorous ones had higher transformation efficiency from 3 H-Try to 3 H-IAA and stronger competition for 3 H-IAA from otherparts, which may partially contribute to the different level of endogenous IAA between vigorous and weak spikelets. The results indicated that the application of S-07 solution at the late booting stage had different effects oil spikelet to a certain extent, but as expected, increased the seed weight of weak spikelet by stimulating and accelerating its grain filling.
    Major Factors on Diurnal Changes of Photosynthetic Rate
    Wen Xiaoyan,Jiang Dean,Lu Qing,Rao Lihua
    1998, 12(2): 105-108 . 
    Abstract ( )   PDF (257KB) ( )  

    The rice cultivar Erjiufeng grown in pots were used to determine the diurnal changes of photosynthetic rate (Pn) and its major affecting factors, i. e. photosynthetic photon flux (PPF) , temperature, intercellular CO2 concentration (Ci), stomatal conductance (SC), transpiration, and relative humidity (RH). The relation between photosynthetic rate and its factors were analysed by the correlation analysis and path analysis. The PPF is the major factor which affected Pn before 8: 30 am; The Pn reached the maximum values at 8: 30 am, and the midday depression of Pn was caused by the lowering of stomatal conductance. The change of Pn from 14: 30 to 18: 00 were negative correlation with Ci, significantly possitive correlation with PPF, SC, transpiration, leaf temperature and RH.

    Varietal Differences in Photochemical Efficiency of PS Ⅱ and Features of CO2 Exchange in Rice Leaves Under Photoinhibitory Conditions
    Ji Benhua,Jiao Demao
    1998, 12(2): 109-114 . 
    Abstract ( )   PDF (281KB) ( )  
    The changes of PS Ⅱ electron transport activity, D1 protein content, chlorophyll fluorescence parameter Fv/Fm, net photosynthetic rates (PN ), photorespiratory rates (PR) , activities of carbonic anhydrase(CA) and PEPC and RuBPCase/Oase, as well as the kinetic property of RuBPCase were measured in rice leaves under photoinhibitory conditions. Photoinhibition- tolerant variety 02428 showed a less net degradation of D1 protein (or maintaining higher level of D1 protein ), higher electron transport activity and primary photochemical efficiency of PS Ⅱ, and less photoinhibition after illumination under a photon flux density (PFD) of 1000 μmol photons/m2s in 21% O2 and CO2-free gas for 3 hours, as compared with photoinbibition -sensitive variety 3037. However, no difference of RuBPCase/Oase activities and values of K(CO2) and Vmax(CO2) between two varietieswere found either before or after photoinhibition. The increasing activities of CA and PEPC were induced under photoinhibitory conditions, and which were higher in variety 02428 than in variety 3037. Furthermore, the ratioof PR to PN(PR/PN) increased while the PN decreased in both varieties, but variety 3037 showed higher PR/PN value than variety 02428. According to the results mentioned above, it is proposed that D1 protein, CA and PEPC might play an important role respectively in regulating photochemical efficiency of PS Ⅱ and CO2 exchange for photoinhibition tolerance.
    综述与专论
    Progress of Molecular Biology Studies on Xa21 Gene
    Wan Bingliang,Zhang Xianlong
    1998, 12(2): 115-118 . 
    Abstract ( )   PDF (261KB) ( )  
    The progress of molecular biology researches on rice bacterial blight disease resistance gene, Xa21, were reviewed. Xa21 localizing on the chromosome 11, linked to one marker (RG103 ) and two PCR products(RAPD248 and RAPD818). With RG103 as a hybridization probe, a 9. 6 kb Kpn I DNA fragment was isolatedfrom bacterial artificial chromos ome (BAC) and cosmid libraries, this fragment contained a s ingle, large open reading frame of 3075 base pares which was interupted by a intron of 843 base pares. Xa21 encoded a receptor kinase-like protein of 1025 amino acid sequences which contained a leusine-rich repeat(LRR) domain and a serine-threonine kinase (STK) was similar to Cf-9. N and PTO. The resistance molecular mechanism of Xa21 has been unknown.
    研究简报
    The RFLP of Tagging of eui gene in Rice
    Wu Yuliang,He Zuhua,Dong Jixin,Li Debao,Lin Hongxuan,Zhuang Jieyun,Lu Jun,Zheng Kangle
    1998, 12(2): 119-120 . 
    Abstract ( )   PDF (140KB) ( )  
    A pair of near isogenic lines, 307T with eui gene, Zhenshan 97 with sdl gene, and its F1 population were used to RFLP mapping of eui gene. Sixty three RFLP probes on chromosome 5 were screened, two markers, RG435 and RG493 were found to be linked with eui gene, genetic distance between eui and RFLP markers were calculated. ReplaceFont('ChDivSummary','');ReplaceFont('EnDivSummary','A pair of near isogenic lines, 307T with eui gene, Zhenshan 97 with sdl gene, and its F, populationwere used to RFLP mapping of eui gene. Sixty three RFLP probes on chromosome 5 were screened, two markers,RG435 and RG493 were found to be linked with eui gene, genetic distance between eui and RFLP markers were calculated.
    Effect of LH422 Cytoplasm on the Expression of Wide Compatibility Genes
    Lu Jufei,Gu Minghong
    1998, 12(2): 121-124 . 
    Abstract ( )   PDF (273KB) ( )  
    Three wide compatibility rice varieties (WCVs) Aus 373, Dular, and LH422 were used to make reciprocal crosses. The spikelet fertilities of reciprocal F1 derived from Aus373 and Dular with LH422 were significantly different. The means and ranges of the spikelet fertility in F2 generations were significantly different, too. The spikelet fertility of back crosses with cytoplasm from LH422 was lower, while that with cytoplasm from Aus373 or Dular was higher. It suggested that cytoplasm influenced the expression of wide compatibility genes inthe crosses.
    Comparative Studies on Photoinhibition in Rice Cultivar Lemont and Qiguizao (in English)
    Lu Ronghe,Yu Hui,Tang Chongqin,Liu Lina,Kuang Tingyun,Tu Zengping,Clanton C. Black
    1998, 12(2): 125-128 . 
    Abstract ( )   PDF (193KB) ( )