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10 October 1998, Volume 12 Issue 4 Previous Issue    Next Issue
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研究报告
综述与专论
研究简报


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研究报告

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Genetic Difference of Parents and Its Relation to Heterosis in Hybrid Rice Liao Fuming,Zhou Kunlu,Yang Hehua,Xu Qiusheng 1998, 12(4): 193-199 .  Abstract ( )   PDF (317KB) ( )   Using 7 maintainer lines and 9 restorer lines as the materials, the genetic difference of hybrid rice parents and its relation to F1 heterosis were studied through principal component analysis and cluster analysis of 11 major agronomic characters. The results showed that among all of the 120 genetic distances of the 16 parents, morethan 80% was below 2; the average genetic distances among the 9 restorers and among the 7 maintainers except Xiangxiang 2B were 0. 4793 and 0. 7723, respectively, which indicates that the genetic difference is comparatively small in the existing hybrid rice parents, especially within restorer lines or within maintainer lines. The analysis of Correlation between the genetic distance of both parents and heterosis of their F1 hybrids showed that there was not correlation between them among the existing hybrid rice parents. However, it was found that the grain yield of F1 hybrids was closely related to that of both parents, especially to the mean grain yield of both parents, indicating thatparental improvement is of great importance to increase hybrid rice yield. Furthermore, the relation between parental improvement and heterosis, the approaches to the improvement of parents and the principle of choice of pareals for developing hybrids were also discussed.

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Fertility Stability of P(T)GMS Lines in Rice and Its Identification Techniques Deng Qiyun,Yuan Longping 1998, 12(4): 200-206 .  Abstract ( )   PDF (337KB) ( )   The phenomena, intrinsic character, and workable controlling ways as well as identification methodology of fertility stability of P(T)GMS lines have been studied by surveying and analyzing more than 90 P(T)GMS accessions under artificially controlled climatic conditions. Main results are as follows: (1) Both photoperiod and temperature are important factors conditioning fertility alteration of P(T)GMS materials, none of which is of solely photoperiod-sensitive type; (2) There are 3 different types of P(T)GMS lines with regard to their most sensitive stage to temperature for fertility alteration (MSST); (3) The key technique criterion of practical P(T)GMS lines is that the critical temperature inducing male sterility (CTIMS) must be relatively lower and the specific CTIMS should be designed based on the historical meteorological data in local areas; (4) CTIMS will inherently drift up if parent seed multiplication is normally conducted without any artificial selection. The appropriate criterion of CTIMS of practically usable P(T)GMS lines incentral China rice-growing area and the possibility of controlling drift of CTIMS are discussed. And themost effective way to control the drift of CTIMS within the permission of commercial seed production is the procedure of core seed and foundation production.

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Discrimination of Indica and Japonica Rice Based on Morphological Characters of Silica Bodies from Motor Cells Wang Cailin,T Udatsu,Tang Linghua,Zou Jiangshi,Y Isato,H Fujiwara 1998, 12(4): 207-214 .  Abstract ( )   PDF (551KB) ( )   The differences between the shapes of silica bodies in indica and japonica rice were investigated for the native and improved varieties from China and other countries of Asia. A discriminant function based on the four morphological characters of silica bodies (vertical length, VL; horizontal length, HL; lateral length, LL and shape coefficient b/a) was developed on the basis of principal analysis and discrimination analysis. i. e. Z=0. 4947 VL0. 2994 HL+ 0. 1357LL - 3. 8154b/a - 8. 9567, Z<0, variety belongs to indica; Z>0, variety belongs to japonica. The probability of correct discrimination based on the shape of the silica bodies was about 90%, a value higher thanthat based on the grain shape(74%). The discrimination results based on the shape of the silica bodies were almost the same as those obtained by Sato's discriminant function based on phenol reaction of the hull (PR), potassium chlorate (KCIO3) resistance of seedlings (KC) and apiculus hair length (AH) (Z= PR+ 1. 313KC - 0. 82AH -1. 251 ). It is considered that for studies of the origin and dissemination of rice due to the largely remaining property and stability of plant opal, discrimination of indica and japonica rice based on the shape of plant opal is more suitable than that based on the shape of carbonized rice.

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Differential Display of mRNAs from Anthers at Different Developmental Stages in Cytoplasmic Male Sterile Rice and its Maintainer Lines Guan Hexin,Jing Runchun,He Yuqing,Zhu Yingguo 1998, 12(4): 215-218 .  Abstract ( )   PDF (300KB) ( )   Anther mRNAs of cytoplasmic male sterile (CMS) rice and its maintainer lines of Yuetai were studied by DDRT-PCR. The cDNA bands showed very little difference between CMS rice and its maintainer lines. Similar results had been obtained at different developmental stages of both CMS and its maintainer lines. These resultsindicated that most of the genes were constitutively expressed. About 24 differential bands were found, AGCK-20 only existed in CMS when hybridized with total RNA by means of dot blotting.

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In vitro Regulation of Haploid Somaclonal Micro-Buds in Indica Rice Yang Changdeng,Wu Lianbin,Zhao Chengzhang 1998, 12(4): 219-222 .  Abstract ( )   PDF (283KB) ( )   The effects of hormone and colchlcine on the induction, differentiation, propagation and chromosome doubling of haploid somaclonal micro-buds of indica rice were studied. The results indicated that: 1)2 mg/L of 2,4-D can enhance the culture ability of haploid indica rice. Higher or lower concentration of 2, 4-D can enhance the frequency of induction or differentiation, but reduce the ratio of micro-buds. 2)NAA has distinct effect on the propagation of indica haploid micro-buds. 0.5 mg/L of NAA can propagate micro-buds quickly, the number of micro-buds is 46.21 times of original ones after 35 days, which is 2.8 times of control without NAA, and the weight per micro-bud is only 0.079 mg. The acceptable culture medium to propagate micro-buds is N6 appended with 2.5 mg/L MET, 0.5 mg/L NAA and 2 mg/L 6-BA. 3) Indica haploid micro-buds treated for 48 h with colchiclne at 500mg/L can obtain higher diploid ratio. Its green plantlets ratio and diploid plantlets ratio is 42.9% and 60.0% respectively. Treatment of colchicine is uncalled-for to the callus. Although the treatment of colchiclne can enhance the diploid plantlets ratio from haploid micro-buds, but the total diploid plantlets ratio is lower than the control because of decreasing of differentiation frequency from callus.

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Characteristics of Dry Matter Production of Rice Grown in Floating Beds on Waters Wu Weiming,Song Xiangfu,Ying Huodong,Zhu Min,Lu Yongliang 1998, 12(4): 223-228 .  Abstract ( )   PDF (424KB) ( )   The characteristics of dry matter production of rice grown on the natural waters with that of rice grown in the paddy field were investigated. The results showed that: (1) the yield of rice grown on waters increasedby 12 percent compared with that in paddy fields; (2) the total dry matter production was similar with that of paddy rice at the early stage, while higher at the middle and later stage, the percentage of dry matter accumulated after tillering increased by 3.4 percent points; (3) the dry matter of green leaves was similar with that of paddy rice at the early stage, and increased by 30 percent at the middle and late stage; (4) the dry matter of stem and sheath was higher than that of paddy rice at the early and middle stage, but lower at the later stage. The contribution of stem and sheath to the yield was less than that of paddy rice.

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Succession Regularity of Arthropod Community in Single-Cropping Paddy Fields Hu Yang,Tang Qiyi,Tang Jian,Hu Guowen 1998, 12(4): 229-232 .  Abstract ( )   PDF (291KB) ( )   The arthropod community's succession in the paddy fields in Fuyang, Zhejiang Province, during July-October 1995 were investigated by means of the indices such as species richness, number and Shannon index. The results indicate that the whole succession could be divided into three phases: expanding, fluctuation and declining. The arthropod community can also be divided into three sub communities, i. e. natural enemy, insect pests and neutral insects subucommunity, based upon their effects on rice plants. The three sub-communities' succession are asynchronous. The sub-community of natural enemy had the highest species richness and diversity with a contribution approximate to 50%. The weekly accumulative value of neutral insects and insect pests sub-community possessed similarity. However, their quantity succession is negatively correlated.

综述与专论

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Recent Development of Genetic Studies of Varietal Resistance to Insect Pests in Rice Jiang Renchun 1998, 12(4): 233-237 .  Abstract ( )   PDF (358KB) ( )   The fundamental methods of genetic studies on the varietal resistance to insect pests of rice are described, and the recent development of inheritance of varietal resistance to the brown planthopper (Nilaparvata lugens), white-backed planthopper (Sogatella furcifera), green leafhopper (Nephotettix virescens), gall midge (Orseolia oryza), zigzag leafhopper (Recilla dorsalis), striped stem borer (Chilo suppressalis) and yellow stem borer (Scirpophaga incertulas) in rice are summarized. The present problems and prospects of genetic studies were also discussed.

研究简报

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Role of Endogenous Hormones in Tissue Culture of Mature Rice Embryo Luo Qiong,Hu Yanyu,Zhou Kaida 1998, 12(4): 238-240 .  Abstract ( )   PDF (213KB) ( )   The effect of endogenous hormones on the culture capacity in mature rice embryo culture and the possibility of increasing culture efficiency by the means of adjusting exogenous hormones of media based on endogenous hormones of rice embryo were studied. The results showed that the callus initiation and plant regeneration were related to endogenous hormones of mature rice embryo and its derived callus. Improving the balance of endogenous hormones through adjusting exogenous hormones of media is a effective means of raising culture efficiency.

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Preliminary Study on Transferring Short Root Gene srt 1 into Maintainer Lines of CMS in Japonica Rice (Oryza sativa L.)(in English) Hong Delin,Masahiko Ichii 1998, 12(4): 241-244 .  Abstract ( )   PDF (186KB) ( )

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Observation on Flowering Habits of Photo-Thermo-Sensitive Genie Male Sterile Rice He Haohua,Peng Xiaosong,Yu Qiuying,Liu Yibai 1998, 12(4): 245-248 .  Abstract ( )   PDF (237KB) ( )   The flowering habits of photo-thermo-sensitive genic male sterile rice (PTGMR) lines Anxiang S, 6442S, 165S, GD2S, 1103S, Pei'ai 64S, 0821S and restorer lines Gui 99, 102 were systematically surveyed. The flowering period of 165S and GD2S is the most concentrated, and the flourishing flowering of 165S is early, that of GD2S is late. The flowering period of 6442S, Pei'ai 64S and 0821S is comparatively concentrated, while that of Anxiang S and 1103S is relatively dispersed. The anthesis time of 165S is comparatively concentrated and these of the others are relatively dispersed. As for the spikelet opening time, Anxiang S, 6442S, 1103S is long, 165S, 0821S and Pei'ai 64S is relatively long, GD2S is the shortest. The order of distance of opened glume tips from big to smallis Anxiang S, 6442S, Pei'ai 64S, 11035, 082S, GD2S, 165S. The opening angle of spikelet of Anxilang S. 6442S and Pei'ai 64S is larger (more than 25°), while that of 165S, GD2S, 1103S and 0821S is smaller (less than 25°). The stigma exsertion rate, Pei'ai 64S is the highest, the following from high to low are 1103S, Anxiang S, 0821S, 165S, 6442S and GD2S, but that of 165S, 6442S and GD2S is less than 60%. The stigma area of 1103S, Anxiang S and 0821S is more than 1. 00 mm2, that of other PTGMRs is less than 1. 00 mm2. The stigma vitality of 165S, AnxiangS, 1103S, 0821S dropped slowly, that of 6442S, Pei'ai 64S, GD2S dropped fast.

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Characteristics of Ammonium and Nitrate Uptake in Rice He Wenshou,Li Shengxiu,Li Huitao 1998, 12(4): 249-252 .  Abstract ( )   PDF (275KB) ( )   Solution culture experiments were conducted to study N uptake kinetics and the relatively uptake of ammonium- and nitrate-N by rice (Oryza sativa) at different growth stages. The relative uptake or the ratios(NH4-N/NO3-N) of ammonium-N to nitrate-N absorbed by rice varied with its growth stages. At different stages, rice plant had different preference to either ammonium-N or nitrate-N when both NH and NO were present equally in the nutrient solution. From transplanting to initial tillering, the absorbed ratio was 1. 15 on average, and the absorbed ammonium-N accounted for 53. 48% of the total uptake nitrogen during the same period. During the tillering period, the absorbed ratio was 2. 55 on average, and the absorbed ammonium-N accounted for 71. 8% of the total at this stage. This phenomenum that rice preferred ammonium-N to nitrate-N during the vegetative growth period could be explained by kinetic parameters(Vmax and K) of absorption. During the reproductive period from elongation to maturity, the absorbed ratios tended more or less towards 1, and either of the nitrogen forms could be taken up efficiently by the crop. For the whole growth duration, the absorbed ratios ranged from 0. 98 to 2. 62 with 1. 28 on average, the accumulated ammonium-N absorbed being 56. 1 % of the total nitrogen.