Morphological Deformities in the Wild Population of C. gariepinus in Ado-Ekiti,Nigeria

Clarias ganepinus from wild population, which was purchased from fish mongers in Ado-Ekiti, Nigeria, were examined for possible deformities in their body. Eighty individuals were collected. Various types of deformities observed were recorded and later photographed. The present study reported for the first time the occurrence of morphological deformities in C. gariepinus natural ecosystem in Ado-Ekiti, Nigeria. The rivers, where the fish were collected, were found to have been exposed to persistent human activities. The possible causes of the deformities may be pollution from human activities or other factors such as poor nutrition, heredity, diseases. The etiology of the deformities in Clarias under this condition is recommended to be studied in detail.     

Study on the Relationship Between Sex Differentiation and Ethylene in Ramie

To explore the role of ethylene in sexual determination in ramie, the ethylene release rates in ramie stem apex of different sex, bud of the same node in female and hermaphrodite ramie in the second crop, and single inflorescence of different sex in hermaphrodite ramie were measured by gas chromatography. Effects of two ethylene inhibitors on sex expression in ramie were investigated. The ethylene release rate of stem apex was higher in the second crop or female ramie than that in the third crop or hermaphrodite ramie during growth. Although ethylene release rates between lower nodes and higher nodes were little different, it was lower in the middle nodes in hermaphrodite ramie. The ethylene release rates were higher in the higher nodes of female ramie at the second crop. At the third crop, the ethylene release rates were higher in lower nodes, lower in middle nodes and then highest in higher nodes in female ramie. However, an opposite ethylene release pattern was observed in hermaphrodite ramie. The ethylene release rate was higher in female flower than male flower and mixed inflorescence in hermaphrodite ramie. The male flower could be distinctly induced by AVG （aminooethoxyvinylglycine）. The node of the first male flower, percentage of female flowers and ratio of female flowers to male in ramie were evidently depressed by AVG in contrast to water. The percentage of mixed male and female flowers was also increased and the percentage of female flower decreased by spraying AgNO3. There was a close relationship between sexual differentiation and ethylene release rate in ramie. The female ramie could be induced by high ethylene release rate. The female flower could be inhibited by AVG and AgNO3. AVG at a concentration of 300 mg L^-1 was most effective.     

孑遗植物银杏(Ginkgo biloba L.)雌雄株水分生理特征研究(英文)

[Objective] The experiment aimed to study the difference of water physiology of male and female Ginkgo biloba L. for discussing the strategy of water utilization as well as the important role of this difference during evolution process. [Method] The stem sap flow, stomatal conductance(Gs), transpiration rate(Tr) and water use efficiency (WUE) of male and female Ginkgo biloba L. were comparatively studied. [Result] The day-night processes of flow on male and female Ginkgo biloba L. were similar. The flow on male and female Ginkgo biloba L. in day were almost same while the flow at night on male Ginkgo biloba L. was bigger than that on female Ginkgo biloba L. The Tr and Gs of male and female Ginkgo biloba L. were high in morning and at night but low at noon ,while Tr and Gs of female Ginkgo biloba L. in morning and at night were higher than these of male Ginkgo biloba L. at the same time point. However, these indexes of female plant were lower than these of male plant from 11:00 to 14:00. WUE changing trends of male and female Ginkgo biloba L. were similar, while average water utilization rate of female Ginkgo biloba L. was slightly lower than that of male Ginkgo biloba L. [Conclusion] Compared with other companion plants, water physiology of male and female Ginkgo biloba L. had strong homoplasy. The phenomenon might be a survival strategy of dioecious plants under long term evolutionary pressure.     

Cytological Analyses on Development of Male and Female Gametophytes in an Interspecific Hybrid F1 from Cucumis hystrix Chakr. x Cucumis sativus L.

An interspecific hybrid F1 of Cucumis hystrix Chakr. x Cucumis sativus L. （NC4406） was used to establish the developmental sequence and to characterize the male and female gametophytes at cytological level for further understanding of the phylogenic relationship and the mechanism of fertility or sterility in the interspecific hybrid F1 The development of male and female gametophytes was studied through meiotic analysis and paraffin section observation technique, respectively. Meanwhile, the fertility level was assessed through hybrid F1 backcrossing to cultivated cucumber 4406. Variable chromosome configurations were observed in the pollen mother cells （PMCs） of hybrid F1 at metaphase Ⅰ , e.g., univalents, bivalents, trivalents, quadravalents, etc. At anaphase Ⅰ and Ⅱ, chromosome lagging and bridges were frequently observed as well, which led to the formation of polyads and only a partial number of microspores could develop into fertile pollen grains （about 23.3%）. Observations of the paraffin sections showed numerous degenerated and abnormal embryo sacs during the development of female gametophytes, and only 40% of the female gametophytes could develop into normal eight-nuclear megaspore. On an average, 22.8 and 6.3 seeds per fruit could be obtained from the reciprocal backcross. The interspecific hybrid F1 of C. hystrix x NC4406 was partially fertile; however, the meiotic behaviors of hybrid F1 showed a high level of intergenomic recombination between C. hystrix and C. sativus chromosomes, which indicated that it plays an important role for introgression of useful traits from C. hystrix into C. sativus.     

Effects of Pawpaw Seed Powder as an Additive on Growth of Catfish Fingerlings Reared in an Indoor Tanks

Since the demand of African Catfish (Clarias gariepinus) is on increase there is need to increase its production so as to meet the protein requirement of the populace. An investigation was conducted for six weeks feeding trial to determine the performance of African catfish (Clarias gariepinus) fingerlings feed diets containing varying replacement level of fish meal with pawpaw seed powder meal (Carica papaya). Fingerlings of Clarias gariepinus were subjected to five different dietary treatments with varying levels of pawpaw seed powder meal. The diets I-V contained 0, 20%, 40%, 60% and 80% replacement levels, respectively. The experiment was carried out in an 80 litres circular plastic bowls, the treatments were in triplicate. Each bowl contained 12 fingerlings. Feeding was done at 3% body weight per day and fishes were weighed every week. Growth parameters such as specific growth rate (SGR), weight gained (WG), food conversion ratio (FCR), protein efficiency ratio (PER) and mortality were determined. Therefore, it could be concluded that fish meal could be replaced up to 80% with pawpaw seed powder meal in the diet of Clarias gariepinus fingerlings to encourage growth, while at 40% pawpaw seed powder meal inclusion mortality was reduced.     

Genetic Analysis on Plant Type of Northern Japonica Hybrid Rice

This study was designed to analyze the genetic relationship of the morphological traits of the northern japonica hybrid rice. The genetic relationship of the morphological traits of the 100 cultivars combined by the 10 sterile lines and the 10 restore lines was studied by using the principle component analysis and the SAS and QGA. The results showed that compared with the female parent, most of the morphological traits related closely to their father. The additive genetic effect and the dominant genetic effect appeared significantly, and the former was more significant than the latter. Genetic correlation analysis indicated that high plants or high plants with more leaves were in favor of improving the number and the weight of the spike and producing the hybrid vigor. The important factors influencing the plant type of the northern japonica hybrid rice were the plant height （PH）, the angle of the flag leaf （FLA）, flag leaf length （FLL）, and the weight of the shoots and leaves （SLW）, respectively. The morphological traits system of the northern japonica hybrid rice was very complex, and the restore line should be given more importance compared with the sterile line, and PH, FLA, FLL, and SLW should be considered first in the plant type breeding.     

苯达松敏感基因在杂交水稻制种技术上的应用研究（英文）

The seed production of male and female parent of 'Hunzhi 1' contained bentazon susceptible gene was studied.The result showed that spraying 3.375 L/hm2 48% bentazon aqua could control the self-pollinated fertilization rate below 1.0% and survival plant rate was 0.The spray of bentazon would not influence MC526 pollen vitality.Seed setting rate of female parent was not obvious different from that of control group with spraying bentazon aqua more than 3.375 L/hm2 from the sprouting appearing period to full heading stage.This demonstrated that bentazon aqua had no influence on seed setting rate during florescence of female parent.The weight ratio between male parent seeds and female parent seeds was 1 to 5,then seeds from parents with that weight ratio would be mixedly planted for seed production.With this weight ratio,relative proper structure of panicle and grain would be obtained,panicle ratio was 1 to 4.3,glumous flowers ratio was 1 to 3.5.Cross seed-setting rate of female parent was 72.6% and seed production per hm2 was 66 000 kg.     

Heterosis of Double Low Self-incompatibility in Oilseed Rape (Brassica napus L.)

66 F1 hybrids, produced by 3 double low self-incompatible lines and 22 varieties with a North Carolina Ⅱ (NCⅡ) crossing design, were tested for their heterosis in Wuhan, China during two growing seasons from 1999- 2001. The results showed that significant differences were found between F1s and their parents for yield per plant and seed oil content. Mid-parent heterosis of these two characters ranged from 5.50%-64.11% and from 1.55% -7.44% respectively. Heterosis for seed yield per plant was greater than that of seed oil content. For yield components, heterosis of total number of siliques per plant was the highest, followed by seed number per silique and 1 000 seeds weight. Significant genotype-by-year interaction was found for seed yield per plant. Results from correlation and combining ability analysis indicated that parental effects on its F1 hybrid depended on characters, seed yield per plant was affected by both additive and non-additive effects, and seed oil content was affected mainly by additive effect. When designing hybrid programme, parents might be selected by GCAs and variances of SCAs of parents for the characters affected by both additive and non-additive effects, and by the sum of GCAs of female and male parents for the characters mainly affected by additive effects.     

Comparisons of Photosynthetic Characteristics in Relation to Lint Yield Among F_1 Hybrids,Their F_2 Descendants and Parental Lines of Cotton

We compared the photosynthetic characteristics in relation to yield of two F1 cotton hybrids（Shiza 2-F1 and Xinluzao 43-F1）, their parental lines（NT2, H2 and 4-14） and their F2 descendants at different growth and development stages. The two F1 exhibited heterobeltiosis in net photosynthetic rate（Pn） by 8.1-52.1%, canopy apparent photosynthetic rate（CAP） by 8.2-57.6% and canopy respiration rate（CR） by 3.0-78.7% during the growing season. They also exhibited mid-parent heterosis by 2.0-5.2% in leaf chlorophyll content（SPAD） during the late growth and development stages. Regression analysis showed that both parents contributed to increase in Pn, SPAD and CAP in the F1. A low CR in the F1 matched a low CR of the parental line. Photosynthetic characteristics in the F2 were mainly dependent upon the magnitude and degeneration rate of the F1. Mid-parent heterosis in CAP and in CR during the late growth and development stage reduced the degeneration of the F2. Average dry matter accumulation was 10.7-34.7% higher in the parental lines of Xinluzao 43-F1 than in the parental lines of Shiza 2-F1. Heterobeltiosis in dry matter accumulation was 7.0-23.1% greater for Xinluzao 43-F1 than for Shiza 2-F1. Dry matter accumulation in the F1 was affected by either the dry matter accumulation of parents or heterobeltiosis. Dry matter accumulation in the F2 was mainly influenced by dry matter accumulation in the F1. The yields of the two F1 were 39.1-46.3% higher than their respective parents and 26.4-45.9% higher than that of the conventional cultivar Xinluzao 33. The yields of the two F2 were 9.2-12.8% higher than the parents and 14.9-27.4% higher than that of Xinluzao 33. The photosynthetic production and yield of the F1 and F2 were higher than that of their parents. The increases in Pn and CAP of the F1 and F2 were dependent on the photosynthetic characteristics of their parents. It is thus concluded that the photosynthetic performance, light use efficiency and yield of the F1 can be improved by using at le     

Differential Gene Expression Between Hybrids and Their Parents During the Four Crucial Stages of Cotton Growth and Development

The study aims to clarify the differential gene expression between cotton hybrids and their parents in order to better understand the molecular basis of cotton heterosis. The research focused on cotton heterotic and lower heterotic hybrids and their parents during the four crucial stages, which were analyzed using a differential display technique. The results indicated that there were both quantitative and qualitative differences in gene expression amongst them. The quantitative differences include over- and under-expression of parental genes and the dominant expression of highly-expressed parental genes in hybrids. In contrast, the qualitative differences are the following： （i） Bands were observed in both parents but not in the F1 hybrid （BPnF1）; （ii） bands occurred in either of the parents but not in the F1 hybrid （UPnF1）; （iii） bands presented only in the F1 hybrid but not in either of the parents （UF1nP）; and （iv） bands were detected in either of the parents and the F1 hybrid （UPF1）. Overall, the major differences of gene expression occurred in the qualitative level and four related differential patterns were observed. Furthermore, the amount of differential patterns during the flowering stage was relatively higher than those of other stages. At this juncture, both the amount of hybrid-specific expression patterns at flowering stage and the silenced expression patterns at boll-forming stage in highly heterotic hybrids were found higher than those in the lower heterotic ones. It was concluded that significant differences of gene expression in leaves were present between cotton hybrid and its parents during the whole growing stages. Hence, these differences might be responsible for the observed cotton heterosis.     

Nectar secretion of RN-type cytoplasmic male sterility three lines in soybean [Glycine max (L.) Merr.]

Significant progress has been achieved in the use of heterosis in soybean and several soybean hybrids have been released in China. However, broad use of hybrid soybean seed is limited due to low seed setting of female parents. Breeding cytoplasmic male sterile(CMS) lines with high out-crossing rate is necessary to solve the problem. The objective of this study was to determine the relationship between out-crossing rate of CMS lines and their nectar secretion. The daily nectar secretion rhythm, meteorological effect on nectar secretion, and differences in nectar secretion among genotypes and years were investigated in 27 soybean CMS lines(A-lines) with their maintainers(B-lines) and restorers(R-lines). The correlation between out-crossing rate of CMS lines and nectar production was also evaluated. Nectar secretion had diurnal variation. Secretion initiated at about 06:00 for most materials and reached a peak at 07:00–08:30 after flower opened, then the nectar secretion decreased gradually. A sub-peak appeared at about 13:00, while the nectar could not be detected at 17:00. Nectar secretion was greatly influenced by the weather conditions. The amount of nectar secretion increased gradually over time during periods of high temperature and no rainfall for several days. Rainy weather and low temperatures inhibited nectar secretion. There were obvious variations of nectar amount among different genotypes tested. Significant nectar variation within a genotype among years was also observed, and the highest nectar secretion was 3-fold higher than the lowest. The amount of nectar secretion from R-lines was significantly higher than that of A-and B-lines. There was no significant difference in nectar secretion between A-and B-lines. A-and B-lines with higher out-crossing rates secreted more nectar. The amount of nectar secretion of A-and B-lines were significantly positively correlated with the out-crossing rate of A-lines.     

Muscle hypertrophy in transgenic mice due to over-expression of porcine myostatin mutated at its cleavage site

Myostatin, a member of the transforming growth factor beta(TGF-β) superfamily, is a dominant inhibitor that acts to limit skeletal muscle growth and development. In this study, we generated transgenic mice that express porcine myostatin containg mutations at its cleavage site(RSRR) to evaluate its effect on muscle mass. Results showed that the weight of four skeletal muscles including gastrocnemius, rectus femoris, tibialis anterior, and pectoralis increased by 17.83 and 28.39%, 21.76 and 28.70%, 34.31 and 41.62%, 53.21 and 27.54% in transgenic male and female mice, respectively, compared to their corresponding non-transgenic control mice. Measurement of muscle fiber size and number indicated that the mean myofiber size increased by 50.73 and 61.30% in transgenic male and female mice respectively compared to the non-transgenic controls. However, there was no difference in the number of myofiber between transgenic and non-transgenic male mice. These results clearly demonstrated that the increase in skeletal muscle mass in transgenic mice is caused by hypertrophy instead of hyperplasia.     

Identification of the Sex of Earlier Embryos from Generic Hybrids of Chicken-Quail by Wpkci

In this study, a protocol was developed to identify the sex of earlier embryos of chicken （♂）-quail （♀） hybrids and successfully tested the sex proportion of each period （66-120 h）. We acquired cross bred eggs by artificial insemination, hatched them in the same batch according to the standard hatching condition of chicken, and collected earlier living embryos at 66, 72, 78, 84, 90, 96, 102, 108, 114, and 120 h randomly. We adopted RT-PCR protocol and multiple PCR, made the known sex quail as the external control, employed fl-actin as the internal control, and used primers that were designed according to conservative area of gene Wpkci of quail to identify the sex of earlier hybrid embryos. The results indicated that the primer of Wpkci can be used to identify the sex of hybrid embryos accurately; there were more male than female in earlier embryos, the sex proportion of earlier embryos compared with academic numerical value was significantly different （P〈0.01）, and there was no difference between different periods （P〉0.05）. In the present study, we concluded that a simple, fast, credible and stable protocol to identify the sex of earlier hybrids embryos had been established by using primer of Wpkci; in earlier embryos, the death rate of female was higher than that of male and there was no fluctuant peak.     

Inheritance of Fertility Restoration for Cytoplasmic Male Sterility in a New Gossypium barbadense Restorer

In order to clarify inheritance mechanism of fertility restoration for cytoplasmic male sterility （CMS） in a new Gossypium barbadense restorer line Hai R which was found in the fertility test crossing of G. hirsutum CMS lines with G. barbadense germplasms. 23 fertility segregation populations of F2 and backcross were used to analyze the inheritance of fertility restoring gene（s） of Hai R. The result showed that Hai R had one major dominant gene （RfB） to control the CMS fertility restoration and this fertility restoration gene functioned at the sporophytic level. The sterile cytoplasm background might not only influence the transmission rate of male gamete but also that of female gamete when the restorer gene was recessive. It could be deduced that this fertility restoration gene might come from G. harknessii cotton, Hai R is of value in the application of cotton interspecific hybrid breeding.     

Effects of High-Quality Aromatic Rice Varieties on the Fitness of the Striped Stem Borer, Chilo suppressalis （Walker） in Central China

The striped stem borer (SSB), Chilo suppressalis (Walker) (Lepidoptera: Pyralidae), is a major pest of rice in China. Variation in host-plant quality may affect the body size of herbivorous insects, which in turn, can determine their life-history parameters such as survival, fecundity and fitness. In this study, we tested the effects of high-quality aromatic rice varieties on the fitness of SSB in China. Results showed that 1st instar larvae had higher penetrating rates and survival rates on the high-quality aromatic rice varieties (EX-1 and WX-988) than that on the non-aromatic rice varieties (EZ-5 and LYP-9). In addition, shorter developmental periods, greater female pupal weights and higher of other life-history parameters (hatching rate, pupation rate, eclosion rate and increase index) were found on the high-quality aromatic rice varieties, although only female pupal weight showed a significant difference between the two varieties. The highest dead heart rate was found on the aromatic rice variety of EX-1. These results indicate that SSB sustains a lower fitness cost when consuming the high-quality aromatic rice varieties (EX-1 and WX-988) than on the non-aromatic rice varieties (EZ-5 and LYP-9) in Central China.     

Determination and Difference Analysis of DNA Methylation Content Both in Blood and Muscle Tissue of Pigs

In this experiment, DNA samples from parental lines Large White, Landrace, and Meishan pigs, and their hybrids Large White × Landrace, Landrace × Large White, Large White × Meishan, and Meishan × Large White pigs were used for the determination of DNA methylation content in both blood and muscle tissue. The differences about DNA methylation content between parental lines and their hybrids were analyzed. These will offer theoretical support from molecular level for heterosis. High performance liquid chromatography （HPLC） was firstly used to detect DNA methylation content. The average DNA methylation content in 163 DNA samples of muscle tissue was 16.92%, whereas, the average DNA methylation content in 182 samples of blood was 6.49%, the difference between which was especially prominent （P 〈 0.01）. In blood, the methylation content was lower than 10%, with the highest level of 9.93% in Landrace x Large White and the lowest of 2.97% in Landrace. The difference between Large White and Landrace was highly significant （P 〈 0.01）, but not significant between Large White and Meishan; and the differences between reciprocal cross hybrids in both hybrid systems were significant （P 〈 0.05）. In muscle tissue, the differences in methylation content among three parents were not significant （P 〉0.05）; and the differences between reciprocal cross hybrids in both hybrid systems were not significant （P 〉 0.05）, but between different hybrid systems, the hybrids had a significant difference （P 〈0.05）. The average methylation content in muscle samples was higher than that in blood samples, and the methylation in different tissues was different.     

Sex-Related Larval Susceptibility of Diamondback Moth,Plutella xylostella （Lepidoptera：Plutellidae） to some Reduced-Risk Insecticides

Five reduced-risk insecticides were compared for their toxicities to male and female third instar larvae of diamondback moth （DBM）, Plutella xylostella L. （Lepidoptera：Plutellidae） obtained from a laboratory colony. Leaf-dip bioassays were used to assess larval mortality at different insecticides rates （ranging from 0.01 mg AI/L to 100 mg A1/L） and exposure times （24, 48 and 72 h after treatment）. Toxicity of the insecticides generally increased with rate and exposure time. At 72 h after treatment, median lethal concentrations （LCs0s） of methoxyfenozide, spinosad, novaluron, indoxacarb and Bacillus thuringiensis （Bt） against the male third instar larvae of P, xylostella were 0.0524, 0.1117, 0.9149, 1.1939 and 4.4983 mg AI/L, respectively, and were 0.1008, 0.2583, 1.0649, 0.2850 and 5.3053 mg AI/L against female third instar larvae, respectively. At 0.1% of the approximate recommended field rates, methoxyfenozide （60%-75%） and spinosad （53%-57%） were the most toxic, while Bt （30%-45% mortality） was the least toxic to male and female P. xylostella larvae. Spinosad was the fastest acting and the only insecticide that caused significant larval mortality （17%） at 24 h after exposure. Significant sexual differences were recorded in the susceptibility of P. xylostella larvae to two of the insecticides： spinosad and indoxacarb. Male larvae were two-fold more susceptible to spinosad but 10-fold more tolerant to indoxacarb than female larvae.     

The Sublethal Effects of Chlorantraniliprole on Helicoverpa armigera (Lepidoptera: Noctuidae)

Sublethal effects of chlorantraniliprole to Helicoverpa armigera (Hübner) larvae were evaluated through exposure of third instar larvae to the insecticide incorporated into an artificial diet. When larvae were fed on the insecticide-containing diet for 7d, the LC10 , LC20 , LC40 , and LC50 values were 3.790, 7.977, 21.577, and 33.121 μg active ingredient L-1, respectively. Chlorantraniliprole at sublethal concentrations significantly reduced the larval body mass, emergence ratio, adult longevity and egg hatching rate in both the parental and offspring generations. The pupation and copulation rate in the parental generation and the pupal mass in the offspring also strongly decreased. Reproduction was seriously disturbed in both the parental and offspring groups even when only one of the partners was exposed to chlorantraniliprole at larval stages. However, at the lowest concentration of exposure (LC10 ), offspring fecundity was strongly reduced only when both partners were exposed. The net reproductive rate (R0 ), intrinsic rate of increase (rm ), and gross reproduction rate (GRR) at LC20 , LC40 concentrations were significantly lower than that of the control. Post-exposure effects also included an extended larval developmental time and increased male proportion in both generations. The doubling time (Dt) at LC20 , LC40 concentrations as well as gross reproduction rate (GRR) at LC10 concentration were also significantly increased. Chlorantraniliprole might have significant effects on H. armigera population dynamics even at sublethal concentrations on both parental and offspring generations.     

超级稻P88S/0389光合特性初探(英文)

[Objective] The aim of this study is to understand the high yield often photosynthetic mechanism of super hybrid rice P88S/0389.[Method] Chlorophyll and carotenoid contents were measured via the method of Wellburn and Lichtenthaler,and the photosynthetic rate and chlorophyll fluorescence parameters were measured using portable photosynthesis system.Through comparison of above measured indices between P88S/0389 and its parents,the photosynthetic characteristics were obtained.[Result] The pigment content of P88S/0389 lied between their parents,and detailedly was closer to its female parent at earlier growth stage and to its male parent at latter stage,respectively.The Pn,Fv/Fo,Fv/Fm and qP of the flag leaf of P88S/0389 were all higher than those of its parents,while the degradation rates of these parameters were slower than those of its parents.The qN of flag leaf was lower than those of its parents,and the increasing rate of qN of P88S/0389 was also slower than those of its parents,indicating the great heterosis of P88S/0389 to its parents in photosynthetic capacity.The data show that P88S/0389 is endowed with stronger capacities in light energy absorption,transformation and carbon fixation compared to its parents.[Conclusion] The light energy absorbed by hybrid mainly contributes to photochemical reaction,and little for heat dissipation.For ensuring high yield,the rice cultivars selected for production should synchronously possess higher photosynthetic rate and longer high value duration.     

Selection of Parents for Breeding Edible Varieties of Sweetpotato with High Carotene Content

Sweetpotato varieties with high carotene content have high value for human health. This work aims to improve the breeding efficiency of special varieties with high carotene content by combining molecular markers and agronomic traits to evaluate and screen the parents. The cluster analysis was carried out to identify and screen promising parents by utilizing phenotypic results of the agronomic and characteristic traits, and RAPD and ISSR markers of 15 parents and their offspring by group crossing. Among different parental materials, greater variations were observed in two important traits, the carotene content and the storage root yield. Negative correlation was found between the carotene content and both fresh and dried root yields. The most significant positive correlation was between the carotene content of parents and that of their offspring, with the coefficient of correlation value of 0.7932＊＊. The relationship based on the agronomic characters of the trial materials was not in agreement with the known genealogy, while that based on the molecular marker data showed better result. Each primer amplified 13.8 bands oflSSR markers on average, in which the rate of polymorphic loci was 89.6%. 9.4 bands of RAPD markers were arnplified per primer, in which the rate of polymorphic bands was 74.46%. Large genetic variation of carotene content was found among the parents. For analyzing the genetic diversity of sweetpotato, the molecular marker methods were better than morphological traits; ISSR markers were more efficient than RAPD markers. The combination of molecular markers and agronomic trait analysis may provide valuable theoretic basis for selection of parents to breed new varieties with high carotene content.