The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.

The presence of facultative apomixis In line 296B was proved by the embryologicalstudy.The twin embryosacs were observed at florescence.The autonomous development of em-bryo was confirmed by multiple cell proembryo existing with undeveloped polar nuclei In one embryosac.Cell structure and size of apomictic proembryo were different from sexual proembryo.The structural feature of proembryo can be used to distinguish apomictic proembryo with devel-oped endosperm from sexual embryo.The apomictic development in this line is attributed toaposporous type.The frequency of apomixis Is at least 16—21%.The apomictic characters andthe potential for fixing heterosis in line 296B was dlscussed in the present paper.

Eighteen cultivars representing five botanical types of Arachis hypogaea L.were se-lected as female parents to cross with A.sp.9990,an Erectoides accession with resistance to mul-tiple diseases and pests.All the crosses failed to produce viable seeds mainly due to embryo abor-tions.Three morphologically different types of embryo abortion were recorded.Marked differ-ences were observed between subspecies,and among botanical types and genotypes in hybrid podproduction and embryo development.In terms of pod production per 100 pollinations,subspeciesfastigiata was superior to subspecies hypogaea,and Valencia and Virginia types performed betterthan Spanish and Peruvian types.Fengqiu Yibazhua and Silihong were among the most acceptablegenotypes by showing higher pod productions and delayed embryo abortions.These results sug-gest that through extensive screenings,particular genotypes with higher crossability or lessincompatibility with A.sp 9990 can be obtained,and the use of such genotypes in hybridizationprog.

The difference in protein content, MDH,POD and COD isozymes have been seenbetween lowland rice roots and upland rice roots during root growth and development. High pro-tein content has been examined in upland rice roots,but isozyme bands in lowland rice roots aremore than that in upland rice roots.Total area of POD isozyme bands at seedling and tilleringstages of upland rice is larger than that of lowland rice.The POD isozymes zymogram in the rootof upland rice is more stable compared with that of lowland rice.More COD isozyme numbershave been showed in roots of upland rice,but the relative activity of COD isozyme in roots of up-land rice at the seedling and tillering stages is lower than that of lowland rice.COD₇ band can beshown in upland rice root at flowering stage,but it is absent in lowland rice.Therefore,COD₇,band can be taken as an index for resistance of the upland rice to drought environment.

Eight F₁-hybrid cultivars of broccoli were studied.We obtained cell division,celled colonies and p-calli in 5 cultivars,roots and shoots regeneration in one cultivar.The leavesof propagated plantlets in vitro were cut into 1—2mm pieces,isolated with an enzyme solutioncontaining 2% cellulase and 1%macerase on a rotary shaker（50 rpm,21℃,3h,2500 lux light）,and purified with a 0.5M sucrose solution.The purified protoplasts were placed on a drop of 1%agarose.2—3 ml liquid medium was added around the agarose drops,and all of the cultures wereincubated at 25℃ under light（4000 lux）for 16 hours.3—5 days after isolation the cell divisionwas found.About 7 days after incubation 4 multicellular colonies were formed.After 3—5 wksome p-calli were developed.When the p-calli were 2—3 mm in diameter it was transferred to asolidified medium.Once they were developed to 1 cm in diameter they were transferred on a re-generation medium.About 5 months after incubation some roots and shoots grown from the calliwere regen.

Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann't be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M₁,M₂ and M₃ media successively and altering these media compo-sitions.The loosened calli can be selected from the regulation and used for protoplast isolationsuccessfully.Rate of protoplast division in KM₈P medium was 12.3—33.5%.Calli derivedthrough protoplast division are loose and cann't be used directly for plan regeneration because ofits soft physical structure.When they were subcultured in N₆—1,N₆—2,N₆—3 and N₆—4 media,in which the media compositions were changed,the compact calli were obtained and 129 plantletswere regenerated from them.101 plants,which grew to maturity after transplanting the plantletsinto field,exhibited sterility in some degree.Most of the subsequent lines derived from the regen-erated plants were sterile and only two lines could get normal reproduction.

The unstability of cytoplasmic male sterilities (CMS) of Brassica napus Lwas stud-ied from 1989 to 1992,and the results indicated: 1. The occurrence of trace-pollen plants In sterilematerials was caused by nuclear polygenes of the maintainers; 2. Progenies of partial sterility typeshowed segregation of sterile, partially sterile (with trace pollen)and fertile plants; 3. High andlow temperature CMS lines were crossed and its progenies manifested complex segregation; 4.There was a tendency to increase the fertility with successive selfing of the high temperatureCMS line.

On the MS medium supplemented with 2 ppm 2,4-D,calli were induced after 4-6weeks from the petioles of an American celery plant （Apium graveolens var.Dulce pers.cv.Florida）.Suspension culture was started from the calli in a hormone-free liquid MS medium on agyratory shaker at 110 rpm,and kept at 26℃.To stimulate cell division and dedifferentiation,thesubcultures were conducted for 7 days each on the same medium.The liquid suspension containingsingle cells,cell aggregates,and somatic embryos in different stages were screened 2-3 weekslater and 1.0-1.5mm somatic embryos were obtained.These embryos were encapsulated withsodium alginate by dropping-bead method and solidified with 0.1mol CaCl₂,.These synthetic seedsgerminated and developed well into seedlings in the sterilized vermiculite substrate.

The inhibitory effect of lead on the seed germination and seedling growth was obvi-ously seen in barley,sorghum and wheat.Their differential reactions on the lead solution werefound under the lead stress during the seed germination and seedling growth stages.Wheat ismore sensitive to lead than the other three plants.This can be used to select new crops which canresist lead damage.The changes of the peroxidase and polyphenol oxidase isozymes have beenfound in individual plants which was injured by a lead solution at the seedling and root develop-ment stages.The authors suggest that these isozymes,which have been changed in patterns andnumbers,may be adaptive isozymes.Adaptive isozymes are produced in plant tissue when plantsare in harmful environmental conditions.The change in environmental conditions influences theexpression of the gene which encode peroxidase,polyphenol oxidase isozymes,and promote forma-tion of the adaptive isozymes.

Choline chloride can increase the activities of Hill reaction and ATPase in isolatedchloroplast from wheat leaves. It can also increase the activities of ribulose-1, 5-bisphosphate car-boxylase (RuBPCase EC 4. 1. 1. 39) and glyceraldehyde-3-phosphate dehydrogenase(G-3-PDHEC 1. 2. 1. 13) with the method of vacuum infiltration. But higher concentrations of choline chlo-ride tends to inhibite the activities of these enzymes. As a result of choline chloride treatment theamounts of both protein and chlorophyll can be increased, and the photosynthetic rate can beraised,too. The above data suggest that the choline chloride may act on the enzymes involved inlight reaction and dark reaction in the photosynthesis.

This paper reports a new transgenic tobacco line NC89 resistant to both tobaccomosaic virus(TMV)and cucumber mosaic virus(CMV).It deals with the details of field experi-ments of the whole process of segregation and selection of the progenies of transgenic plant popu-lation.By using the gene transfer technics,some transgenic plants resistant to mosaic disease froma flue-cured tobacco cultivar NC89 were obtained in green house in 1989.Thereafter,throughfield inoculation and selection from the 2nd and 3rd generations,a homozygous line resistant toboth viruses and with good qualities was bred out.The inheretant stability of the resistance of thenew line was confirmed through the 4th to 6th generations.In 1992,the transgenic resistant linewas planted about 7000 hectares in Henan province.The relative effect of controlling mosaic dis-eases of tobacco was 50—70%.The out-put value increased 30—50% per unit area.This is a newexample of growing a transgenic virus-resistant Plant in large scale in China.

Water stress treatment at different developmental stages of a winter wheat varietywas made in outdoor pot experiments from 1987 to 1988.It was found that the most sensitivestage was the booting stage and the second most sensitive stage was the flowering stage.Waterstress at most development stages affects the number of grains.Wheat water stress can be diag-nosed effectively and quickly by means of leaf temperature difference between the drought fieldand the well watered control plot measured by an infra-red thermometer.

There is evindence showing that stress susceptibility index(SSI)(1一Yd/Yp)/(1—(?)d/(?)p)used as a measure of drought resistance of crop on the field is an altered form of droughtresistance coefficient(DRC)(Yd/Yp).The correlative coefficient SSI and DRC is r=-1.Therefore,the SSI doesn't improve the defect of the DRC.After two years experiments per-formed by using thirty winter wheat varieties as trial materials,the concept of drought resistanceindex in crops was put forward.Its expressing equation is:the yield in drylan×drought resis-tance coefficient/average yield in dryland.It makes the drought resistance coefficient(physicalindex)correlate well with the yield in dryland(agronomy index)and is suitable for breeder.

Three new genus and thirteen new specides published during 1988—1991 are de-scribed in this paper.They are:Fulgoridae——Neoalcathous huangshanana,N.wuyishanana,Kalidasa lui;Achilidae——Ganachilla zhenyuanensis,Haicixidia jianfegensis,Magadha yadon-gensis,M.gyirongensis,M.taibaishanensis,Catonidia tibetensis,C.guadunensis,C.wuyi-shanana,C.fujianensis;Cixiidae—Oliarus zaonensis.They all are collected from China.Thetype specimens of them are deposited in the Shijiazhuang Pomology Institute,Northwestern Agri-cultural University and Institute of Zoology,Academia Sinica.

Calli derived from tomato leaves were treated with different γ ray doses and cul-tured in medium with and without early blight fungitoxin.The experiment indicated that γ rayhad obvious influence on the growth of tomato calli,with a stronger inhibition at 3000 rad dose.The fungitoxin could be used as selection pressure in the screening of disease resistant mutant.

"8407"is a disease resistant germplasm of Chinese cabbage which is highly resis-tant to turnip mosaic virus (TuMV),selected by the Vegetable Institute,Hebei Academy of Agri-cultural and Forestry Sciences.In 1985 and 1989,it was approved and accepted as one of the na-tional disease resistant germplasm of Chinese cabbage by the National Expert Group.The identifi-cation in 1989 showed that"8407"was highly resistant or immune to 19 TuMV strains from 10provinces/cities across the country.Therefore,it was regarded as the best germplasm both verti-cally and horizontally resistant to TuMV of Chinese cabbage.This germplasm was selected fromChang Paodan (Inner Mongolia)of Qingmaye system after 6 generations of successive self cross.Using the disease resistant germplasm of"8407",we developed new multi-resistant varieties of"8361"and"8612"in 1983 and 1986 respectively,which was highly resistant to TuMV and downymildew and soft rot.These varieties have been extended to an areas of over 20000 ha.

The results of pot and pond trials are as follows.On equal amount of nitrogen(N)applied,the wheat nitrate reduction activity(NRA)and photosynthesis strength and other phy-siological properties are stronger and yields are higher at normal soil moisture than those atdrought.At the same soil moisture,in a certain range of N applied,these properties of wheat in-crease with the increasing of N applied,but they descend when the amount of N applied exceedsa certain range.

This paper reports the diagnosis studies of soil nutrient status and deficiency of 12nutrients elements by using the systematic approach of soil nutrient status.The characteristicsof vegetable soils,the nutrient balance of different vegetable soils and the limiting factors andtheir extent to reducing yield in developing and developed vegetable soils were studied.And thebalance fertilization for further yield-increasing and quality improving was recommended.

The ideal reducing reagent in testing available nitrogen of soil by Conway Methodis Devard's alloy.The optimum ratio of soil:Devard's alloy:1.0N NaOH solution is 5.0g:0.2g:5ml.When reaction goes on at 30℃ for 4 hours,the rate of soil NO₃-N reduction is about 90%,and the recovery rate of soil NH₄-N is about 95%.Some organic nitrogen can be measured at thesame time.This method is defined as the Modified Conway Method and the soil N-min is r=0.982（n=10）.In predicting soil nitrogen supplying power,the Modified Conway Method takesonly 1/6 of time needed by Conway Method.The Modified Conway Method can also be used forthe measure of soil N-min.

Based on the principles of system engineering,economics theory and local conditionof production,studies carried out by taking"quadratic-regression-orthogonal-rotational" and ran-domized complete block designs to determine the Optimal Agronomical Practices Package（OAPP）for Wheat Modelized Cultivation Management（WMCM）by system decision-makinganalysis.The OAPP was expected to meet various goals of different levels of yield and economicbenefit of middle and high fertility land in Beijing area.Taking cultivar JINGDONG-1（"JD-1"）asan example,the OAPP for grain yield≥6750 kg/ha and net benefit≥360 US （?）/ha was consist-ed as follows:density=195 plants/m²;spring irrigation times=4（stem elongation,booting,flowering,and 20 days after anthesis）;fertilization=150-188 kg N/ha,113-128 kg P₂O₅/ha.

The appropriate density of the hybrids with different plant morphotypes and grainyield of main maize hybrids in Henan province under different conditions and in different placeshave been studied for many years.The results indicalte that all the light intensity in middle andlow part of the plant,the single leaf weight(SLW) and the photosynthetic intensity decrease re-markably with the increase of plant density and leaf area index(LAI),and that all the charactersof the sirgle plant yield becorne inferior with different magnitudes.But the seriousness is slighterfor compact type hybrids than that for spread ones.Under high yield condition,the desirabledensity is 4250 to 5000 plants per mu(666. 67m~2)for compact maize hybrids and 3300 to 3500plants for spread ones.The yield differences between the two kinds of hybrid vary with the yieldlevels.

According to the production index of lint cotton yield over 100kg per mu(1/15ha)and the relationship between the climate factors and the distribution of time and space for cottonboll setting in 1985—1990,we established a model of cultural techniques of cotton leaf-age-ad-justing-controlling for enhancing early maturity.By utilizing the principle of leaf-age model andthe principle of regulating nutrient distribution with DPC(Mepiquate chloride),the plants weretreated with DPC in proper time.A new type of population plant patterns was set up.It character-ized by high population density,dwarf,high boll weight,bolls near nodes,high energy and lowconsumption,short distance transport of nutrients,high yield and good quality.We put forward aset of management measures,i.e.adjusting boll setting stage,adjusting and controlling boll set-ting structure,stably applying N,increasing P,supplementing plants with K,increasing irrigationefficiency,techniques were applied and demonstrated in large areas in high yield.

Jinyang Ⅲ strain of late-feathering Leghorn chicken has been successively selectedwith comprehensive index for 7 generations by family breeding method of mass-first and closing-late.As compared with the control,the selection result is average 7 days earlier at first laying forevery generation,more than 13 of egg number at age of 300 days and higher than 0.63% for sur-vival rate in laying period.Main laying performances are as follows:age at first laying 156±10.4days;egg number at age of 300 days 99±26.O;egg number and egg weight at 72 weeks of age 226±38.8 and 58.2±4.6g respectively.Through cross breeding selection,a series of white-shell au-tosexing chicken has been developed.More than 5.1 million commercial sex-identified chickenhave been released as well.

Preliminary study has been made to test wether three strains McAb（1B1,5D₆, 6D₈）are against the same antigen determinant.Througn ELISA additive and competition expeiments,itproved that these three strains are against different antigen determinant.The result of positiveserum antigen component analysis with 2 strains IBDV McAb showed that sample IBD positiveserum had obvious inhibition against combination of 5D₆ McAb with corresponding antigen.Theresults of substitution of corresponding component in ELISA inhibition experiment and compari-son of non-IBD serum （SPF chicken serum,ND,MD,IA positive serum）proved that IBD anti-serum was the only one showing inhibition against 5D₆ McAb.Comparison with AGP and electro-microscope observation showed that ELISA inhibition experiment was characterised by high-specificity,rapidity and sensitiveness.799 serum samples were tested with ELISA inhibition anddouble immunodiffusion（AGP）experiments.