Manure substitution improves maize yield by promoting soil fertility and mediating the microbial community in lime concretion black soil

Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.

Production traits and fertility of reciprocal hybrids between Argopecten irradians irradians and A.i.concentricus

The two bay scallop subspecies,Argopecten irradians irradians(NN)and A.i.concentricus(SS),are fast growing and major cultured bivalves in China.However,their relatively small sizes and decreasing production traits caused by long-term inbreeding have been major concerns to the industry in the last two decades.Hybridization between the two bay scallop subspecies may provide a new approach to breed a new variety with superior production traits for the industry.For this end,in this study,we hybridized the two bay scallop subspecies in order to obtain a new strain that incorporates the genes of both subspecies.No significant difference was found in fertilization rate,hatching rate and metamorphosis rate between the purebred and crossbred cohorts(NN♀×SS♂,denoted as NS;SS♀×NN♂,denoted as SN).Both mating strategy(intra-vs.inter-population crosses)and egg origin had significant effects on growth and survival at the larval stage.Heterosis was observed in the crossbred and was more pronounced in older stages.Genetic diversity of the reciprocal hybrids,especially that of SN,was increased compared with the purebred cohorts.Almost all hybrids were completely fertile and able to reproduce by selffertilization or by backcrossing with either parent.Apparently,male sterile individuals whose gonads were fully occupied by the ovary part at mature stage were found in the hybrids for the first time.The hybrids,especially SN,may provide precious germplasm resources for the production of ternary hybrids with the Peruvian scallop,A.purpuratus.

Sperm function, mitochondrial activity and in vivo fertility are associated to their mitochondrial DNA content in pigs

Background Despite their low abundance in sperm, mitochondria have diverse functions in this cell type, includ-ing energy production, signalling and calcium regulation. In humans, sperm mitochondrial DNA content(mtDNAc) has been reported to be negatively linked to sperm function and fertility. Yet, the association between mtDNAc and sperm function in livestock remains unexplored. For this reason, this study aimed to shed some light on the link between mtDNAc and sperm function and fertilising potential in pigs. A qPCR method for mtDNAc quantification was optimised for pig sperm, and the association of this parameter with sperm motility, kinematics, mitochondrial activity, and fertility was subsequently interrogated.Results First, the q PCR method was found to be sensitive and efficient for mtDNAc quantification in pig sperm. By using this technique, mtDNAc was observed to be associated to sperm motility, mitochondrial activity and in vivo, but not in vitro, fertility outcomes. Specifically, sperm with low mtDNAc were seen to exhibit greater motility but decreased mitochondrial activity and intracellular reactive oxygen species. Interestingly, samples with lower mtD-NAc showed higher conception and farrowing rates, but similar in vitro fertilisation rates and embryo development, when compared to those with greater mtDNAc.Conclusions These findings enrich our comprehension of the association of mtDNAc with sperm biology, and lay the foundation for future research into employing this parameter as a molecular predictor for sperm function and fer-tility in livestock.

Marriage-Age and Fertility Pattern among Reproductive Age Women in Abakaliki, Ebonyi State, South East Nigeria

Introduction: In Nigeria, one of the major reasons for marriage is procreation and married couples look forward to having children within a year or two of marriage. The age of marriage is on the increase in this part of the world. Many women are now increasingly getting engulfed in career and academic pursuits at the detriment of early marriage. Many men are also not interested in marrying women who have no job. There is age-related acceleration of primordial follicle depletion which is of great clinical importance because it is associated with a significant decrease in fecundity. Objective: This study assessed the ages of the marriage of women who attended Fertility and Antenatal clinics at the National Obstetric Fistula Centre and Smile Specialist Hospital, Abakaliki, and their relationship with the fertility pattern of these women. Methods: This was a cross-sectional study of 352 consenting married women who sought and received fertility and Antenatal care at the National Obstetric Fistula Centre and Smile Specialist Hospital Abakaliki, South-East Nigeria between February 1, 2022 and January 31, 2024. Semi-structured questionnaires were administered to the participants over a two-year period. Data was analyzed using IBM SPSS version 20. A test of statistical significance was done using Chi Square. Results: The age group with the highest education was 26 - 30. This was statistically significant (X2 = 90.893, P-value 2 = 294.555, P-value 2 = 173.007, p-value 2 = 129.494, P-value 2 = 169.300, p-value 2 = 279.230, p-value Conclusion: There is increased difficulty at conception at marriage age above 25 years. The major reasons for delayed marriage were academic pursuit and lack of gainful employment. Education of the masses and inclusion of biological dynamics of the female reproductive behaviours as part of the core school curriculum will help enlighten the female and the male folks alike to enable them to make informed decisions with regard to the timing of marriage and commencement of procreation. This will help reduce infertility and save millions of couples the agony associated with infertility.

Subsequent pregnancy outcomes and fertility rates in the case series that underwent bilateral hypogastric artery ligation(BHGAL)due to severe postpartum hemorrhage

Objective:To evaluate the effect of bilateral hypogastric artery ligation(BHGAL)on women's pregnancy outcomes and fertility rates in cases with severe postpartum hemorrhage.Methods:Patients hospitalized in a tertiary care center between 2007 and 2018 were included in the study.The records of cases were obtained from the hospital database,retrospectively.Maternal demographic data,morbidities or complications associated with BHGAL surgery,any additional haemostatic interventional or surgical procedures,preoperative admission and lowest postoperative haematocrit-hemoglobin values,blood products given,type of anaesthesia,intensive care unit(ICU)and length of hospital stay were recorded.In cases without surgical sterilization,future fertility and subsequent pregnancy outcomes were assessed for at least two years after operation.Information was obtained through face-to-face or telephone interviews with patients whose long-term fertility and subsequent pregnancy outcomes were assessed.Results:Sixty-eight patients with BHGAL surgery history were included in the study.26 Of 37 cases(70%)that did not undergo surgical sterilization had a desire for pregnancy after the surgery.Six of these cases(23%)were diagnosed with secondary infertility.The fertility rate of these cases was 77%,and subsequent pregnancy was detected in 20 women.A total of 25 pregnancies,including first and second pregnancies,developed,and 15 of these pregnancies resulted in term delivery,six preterm births,one stillbirth,and three abortions.Conclusions:The postoperative pregnancy rate was found to be higher than the rate of women with infertility problems,and this surgery does not seem to adversely affect pregnancy outcomes.This is a tertiary center experience and cohort studies with large patient series are needed.

Effect of Soil Fertility and Planting Density on the Partitioning of the Above-Ground Biomass of Eucalyptus in a Plantation (Pointe-Noire, Republic of Congo)

Afforestation and reforestation are useful approaches to improve carbon sequestration. With the advent of forest plantations, growing environment conditions have become increasingly restrictive for light, soil nutrients, and interactions between trees to acquire available resources. Tree biomass data are essential for understanding the forest carbon cycle and plant adaptations to the environment. The distribution of tree biomass depends on the sum of multiple stand conditions. The data are from a dedicated experiment with two very contrasting areas of fertility, and two planting densities, including a high density at planting in order to achieve thinning. The plant material consists of the high-performance clones of Eucalyptus urophylla × E. grandis and the reference clone E. PF1. We hypothesize that the distribution of biomass changes as the intensity of competition changes and that this is accelerated by the fertility of the sites in time. The results indicate that fertilization, planting density and clones have an impact on biomass partitioning.

Exploring the relationship between Hashimoto's thyroiditis and male fertility:A meta-analytic and meta-regression perspective on hormonal and seminal factors

Objective:To explore the relationship between Hashimoto's autoimmune hypothyroidism(HT)and male fertility,focusing on hormonal and seminal factors.Methods:A systematic literature search was conducted across databases such as PubMed,Web of Science,EMBASE,Scopus,Cochrane,and Google Scholar,covering studies published from January 2000 to March 2024.Studies investigating the impact of HT on semen quality parameters and reproductive hormones were included.Pooled effect estimates were calculated using standard mean difference(SMD)and 95%confidence intervals(CI).Results:A total of 8 studies with 8965 participants were included.HT significantly affected semen quality and reproductive hormone levels.Specifically,there was a notable decrease in progressive morphology(SMD=-0.78;95%CI:-1.40 to-0.17;P=0.01)and sperm motility(SMD=-1.151;95%CI:-1.876 to-0.425;P=0.002).In addition,there were no significant changes in reproductive hormones,although there were elevated levels of luteinizing hormone(SMD=0.437;95%CI:0.000 to 0.874;P=0.050)and follicle-stimulating hormone(SMD=0.293;95%CI:-0.171 to 0.758;P=0.216),with a slight impact on testosterone levels(SMD=-1.143;95%CI:-2.487 to 0.200;P=0.095).Conclusions:This systematic review and meta-analysis provides robust evidence of the detrimental effects of HT on semen quality and reproductive hormones,underscoring the necessity for thorough evaluation and management of thyroid function in male infertility assessments.

Pro-fertility effect of Ficus carica fruit extract in streptozotocin-induced male rats

Objective:To explore the impact of Ficus carica fruit aqueous extract on fertility parameters in streptozotocin(STZ)-induced male rats.Methods:Twenty-four male Sprague-Dawley rats were divided into four different groups.All groups except a normal control group were induced with 50 mg/kg of streptozotocin(STZ)intravenously to induce diabetes.A positive control group was treated with an antidiabetic drug,metformin(500 mg/kg)whereas a negative control group remained untreated throughout the experiment.Meanwhile,another diabetic rat group received treatment with 400 mg/kg of aqueous Ficus carica fruit extract.Rats in the treatment group were administered Ficus carica fruit aqueous extract daily through forcefeeding via oral gavage for a 21-day period.Assessments included the sperm quality(count,motility and morphology),histology of the testes,serum testosterone and fasting blood glucose(FBG)level.Results:The FBG level of the Ficus carica-treated rats exhibited a significant decrease compared to the negative control group(P<0.05).Sperm quality analysis also indicated that the aqueous Ficus carica extract had significant positive effects on sperm count and motility(P<0.05).The histology of the testes in Ficus caricatreated rats revealed an improved cell arrangement in the germinal cell layer.Furthermore,serum testosterone level showed an increment in the Ficus carica treatment group in comparison to the negative control group.Conclusions:Our findings provide compelling evidence for the profertility and anti-hyperglycemic properties of aqueous Ficus carica fruit extract in diabetic-induced male rats.

Bulked Segregant RNA-Seq Analysis of Pollinated Pistils Reveals Genes Influencing Spikelet Fertility in Rice

Prezygotic isolation is important for successful fertilization in rice, significantly affecting yield. This study focused on F_(5:6) generation plants derived from inter-subspecific crosses(Nipponbare × KDML105) with low(LS) and high seed-setting rates(HS), in which normal pollen fertility was observed. However, LS plants showed a reduced number of pollen grains adhering to the stigma and fewer pollen tubes reaching the ovules at 4-5 h post-pollination, compared with HS plants. Bulked segregant RNA-Seq analysis of pollinated pistils from the HS and LS groups revealed 249 and 473 differentially expressed genes(DEGs), respectively. Kyoto Encyclopedia of Genes and Genomes analysis of the HS and LS-specific DEGs indicated enrichment in metabolic pathways, pentose and glucuronate interconversions, and flavonoid biosynthesis. Several of these DEGs exhibited co-expression with pollen development genes and formed extensive clusters of co-expression networks. Compared with LS pistils, enzyme genes controlling pectin degradation, such as OsPME35 and OsPLL9, showed similar expression patterns, with higher levels in HS pistils pre-pollination. Os02g0467600, similar to cinnamate 4-hydroxylase gene(CYP73), involved in flavonoid biosynthesis, displayed higher expression in HS pistils post-pollination. Our findings suggest that OsPME35, OsPLL9, and Os02g0467600 contribute to prezygotic isolation by potentially modifying the stigma cell wall(OsPME35 and OsPLL9) and controlling later processes such as pollen-stigma adhesion(Os02g0467600) genes. Furthermore, several DEGs specific to HS and LS were co-localized with QTLs and functional genes associated with spikelet fertility. These findings provide valuable insights for further research on rice spikelet fertility, ultimately contributing to the development of high-yielding rice varieties.

Improvement of Wolfberry(Lycium barbarum L.)Fruit Yield and Quality and Enhancement of Soil Fertility by Nitrogen Reduction Combined with Organic Fertilizers

Excessive amounts of nitrogen(N)fertilizers are applied during wolfberry production,resulting in some soil problems as well as potential environmental risks in the Qinghai-Tibet Plateau.In this study,organic fertilizers were used to replace part of the N fertilizer in wolfberry fields with different fertility levels.N fertilizer rates had 0,50,100,150,200,and 250 g N/plant.Organic fertilizer rates had 0,2,4,6,8,and 10 kg organic fertilizer/plant.The experimental treatments included 6 combinations of N0M10,N50M8,N100M6,N150M4,N200M2,and control was N250M0.The results showed that in the high-fertility soils,combinations of N150M4,N100M6 and N50M8 treatments were increased in yields,fruit shape index,flavonoid content,total phenol content,mineral nutrient content,and antioxidant activity of wolfberry fruits.Also they were improved in soil fertility and decreased in residual nitrate through the soil depth of 0-300 cm.In the soil with less fertility,fruit yield,amino acid contents,flavonoids,total phenols,mineral nutrients and antioxidant activity of fruits were increased by the N200M2,N150M4 and N100M6 treatments and soil fertility was improved as well.Also more residual nitrate was found in the depth of 0-100 cm of soil with both chemical and organic fertilizer compared with the control.Therefore,in the Qinghai-Tibet Plateau,combining decreased N fertilizer with organic fertilizer rather than chemical fertilizer alone could help farmers achieve satisfactory yields and quality of wolfberry fruits and reduce the risk of nitrate leaching.In conclusion,50-150 g/plant of N fertilizer combined with 4-8 kg/plant of organic fertilizer in high-fertility gardens and 100-200 g/plant of N fertilizer combined with 2-6 kg/plant of organic fertilizer in low-fertility gardens are recommended for wolfberry cultivation.

Fertility preservation in patients with gynecologic cancer

In this editorial we comment on the article by Gu et al.We focus and debate the necessity of fertility sparing surgery in young women’s with gynecologic cancers,specifically on those patients with the desire to conceive.This type of individu-alized treatment options is often very difficult,due to the risk of disease evolution and multiple disparities in fertility preservation services among women in di-fferent countries and societies.For this reason national policy interventions are mandatory in order to ensure equitable access this procedures,in women with cancer.

Pharmacological methods for ovarian function and fertility preservation in women with cancer:A literature review

Oncofertility is an extremely significant topic that is increasingly being discussed owing to increased evidence indicating that fertility preservation does not affect the treatment outcomes of patients with cancer but significantly contributes to preserving life quality.The effect of chemotherapy can range from minimal effects to complete ovarian atrophy.Limited data are available on the effects of monoclonal antibodies and targeted therapies on the ovaries and fertility.Temporary ovarian suppression by administering a gonadotropin-releasing hormone agonist(GnRHa)during chemotherapy decreases the gonadotoxic effect of chemotherapy,thereby diminishing the chance of developing premature ovarian insufficiency(POI).At present,the concomitant administration of GnRH analogs during chemotherapy is the only accepted pharmacological method for preserving ovarian function.Notably,most randomized studies on the effectiveness of luteinizing hormone-releasing hormone agonists during chemotherapy in preventing POI have been conducted in women with breast cancer,with a considerably small number of studies on patients with hematological malignancies.Furthermore,most randomized controlled trials on breast cancer have revealed a decrease in treatment-induced POI risk,regardless of the hormone receptor status.In addition,studies on hematological malignancies have yielded negative results;nevertheless,thefindings must be interpreted with caution owing to numerous limitations.Current guidelines from the American Society of Clinical Oncology and ESMO Clinical Practice Guidelines recommend sperm,oocyte,and embryo cryopreservation as a standard practice and only offering GnRHa to patients when proven fertility preservation methods are not feasible.In this manuscript,we present a comprehensive literature overview on the application of ovarian suppression with GnRHa during chemotherapy in patients with cancer by addressing preclinical and clinical data,as well as future perspectives in thisfield that upcoming research should focus on.

Human circBOULE RNAs as potential biomarkers for sperm quality and male infertility

Reliable molecular biomarkers to predict fertility remain scarce.The current study investigated the potential of testis-specific circBOULE RNAs as biomarkers for male infertility and sperm quality.Using reverse transcription-PCR and real-time reverse transcription-PCR assays,we identified seven circular RNAs from the human BOULE gene in human sperm.We observed that the expression level of circEx3-6 was significantly reduced in asthenozoospermia,while the expression levels of both circEx2-6 and circEx2-7 were decreased in terato-zoospermia,compared with the controls.Furthermore,we demonstrated that the expression level of circEx2-6 was negatively correlated with the sperm DNA fragmentation index,and the expression level of circEx2-7 was correlated with both fertilization and cleavage rates in those treated with the assisted reproductive technologies.Further functional analyses in a transgenic fly model supported the roles of circBOULE RNAs in sperm development and human male fertility.Collectively,our findings support that sperm circBOULE RNAs may serve as diagnostic biomarkers for assessing sperm motility and DNA quality.Therefore,clinical application and significance of sperm circBOULE RNAs in the assisted reproductive technologies warrant further investigation.

Effect of Different Rates and Mixtures of Solid Household Waste and Faecal Sludge-Based Composts on Soil Fertility and Productivity of Sunflower (Helianthus annuus L.) in Dschang, West Cameroon

The unbalanced and inadequate use of fertilizers is one of the causes of soil degradation. Combined with the ever-increasing population, it is necessary to find sustainable agricultural production alternatives. The present work aims to determine the effect of different rates and mixtutes of organic amendments on soil fertility and the performance of Sunflower (Helianthus annuus L.). In the field, treatments consisted of solid household waste and faecal sludge in the ratios of 3/5 (V1), and a mixture of faecal sludge and household waste in the ratio of 3/5 with 900 worms (V2). At the end of the composting process, V1, V2 composts and the poultry manure (PM) were applied at rates of 4, 5 and 6 t∙ha−1 in a randomized complete block design with three replications. Soil samples were collected before and after the experiment and analyzed. The main results revealed that at the end of the composting process, there was a progressive improvement in the physico-chemical properties of V1 and V2 composts. In particular, the C/N ratio, phosphorus (P) and total nitrogen (TN) initially at 16.49 ± 0.42 (V1, V2), 21.06 ± 0.07 mg∙kg−1 (V1, V2), 0.76% ± 0.08% (V1, V2) respectively, increased after 60 days to 12.40 ± 0.41 (V1), 9.74 ± 0.28 (V2) for C/N, 21.94 ± 0.63 mg∙kg−1 (V1) and 22.04 ± 0.04 mg∙kg−1 (V2) for P, 0.96% ± 0.0% (V1) and 1.22 ± 0.04 (V2) for TN. The application of 6 t∙ha−1of PM had the greatest influence on the diameter and weight of the flower heads (27.16 ± 4.01 t∙ha−1 and 230.83 ± 2.64 t∙ha−1), while 4 t∙ha−1 of V2 gave the tallest sunflower plants (110.07 ± 73.28 cm) as well as the diameter at the crown (19.30 ± 9.07 cm). However, CEC was most influenced by 4 t∙ha−1 of V1, while 4 t∙ha−1 of PM had the greatest effect on organic carbon and phosphorus. However, 5 t∙ha−1 of PM showed the highest sunflower production and yield (1.67 ± 0.21 t∙ha−1). The combination with 900 earthworms is recommended for composting and 5 t∙ha−1 of PM is recommended to obtain a better sunflower production.

Analysis of Low Fertility Rates in Advanced Economies

In economics,opportunity cost means the maximum value of choosing one behavior over others in the situation where resources are limited(Parkin,2016).In the process of making reproductive decision,opportunity cost reveals the trade-off between time,resources,and economic benefits that individuals face when choosing to have children or not.During this process,the technological changes make the paths of career development diverse and rapidly changing,remarkably increasing the opportunity cost of childbirth and parenting.This leads to individuals more inclined to postpone or reduce childbirth when balancing their careers and families,thereby resulting in low fertility rates in developed economies.

Evaluation of Soil Fertility Quality and Environmental Driving Factors in Different Soil Types of Artificial Forests

The aim was to clarify the environmental driving factors of soil fertility indicators in artificial forests of Guangxi and comprehensively evaluate the soil fertility level.By collecting data on the current status of soil in artificial forests,the spatial distribution of major soil fertility indicators was analyzed,and the distribution map of the fertility index of artificial forests in the entire region and the comprehensive fertility index of artificial forests of different soil types were obtained.Canonical correspondence analysis method was used to analyze soil fertility indicators and environmental factors,and the environmental driving factors of soil fertility indicators for artificial forests of the main soil types in Guangxi were obtained.The results showed that over 90%of the soil fertility index of artificial forests in the entire region was between 0.20 and 0.50.The order of soil fertility index of different soil types of artificial forests from high to low was yellow brown soil>yellow red soil>yellow soil>red soil>limestone soil>latosolic red soil>laterite.In artificial forests of latosolic red soil,the correlation between soil alkaline nitrogen and organic matter,annual average temperature was high,while the correlation between soil available phosphorus and organic matter,pH was high,and the correlation between soil available potassium and environmental factors such as slope,altitude,rainfall,accumulated temperature,and slope aspect was high.In artificial forests of red soil,the correlation between soil alkaline nitrogen and slope,altitude was high,while the correlation between soil available phosphorus and accumulated temperature,rainfall was high,and the correlation between soil available potassium and pH was high.In artificial forests of limestone soil,there was a high correlation between soil alkaline nitrogen and slope,organic matter,a high correlation between soil available phosphorus and accumulated temperature,rainfall,and a high correlation between soil available potassium and pH.

Soil Fertility Properties of Tobacco Growing Area in Jiyuan

Soil fertility properties of the main tobacco growing area in Jiyuan （Shaoyuan,Wangwu,Xiaye and Daiyu） in west Henan Province were analyzed. Results showed that Jiyuan was one of the potential areas which could produce tobacco leaves with high quality. Its main properties of soli fertility were as follows：the content of total nitrogen,alkali-hydrolysable nitrogen,olsen-phosphorus and organic matters were suitable for high-quality tobacco production; especially,all the flue-cured tobacco growing areas in Henan Province were rich in available potassium; besides,the concentrate of water soluble chloride ion was at reasonable level. The problem was that the micro-elements such as Zn-DTPA and available boron content were at a low level in individual areas. Based on this survey,the recommendations for fertilization in Jiyuan such as stabilizing nitrogen rate,increasing phosphorus,stabilizing potassium,and applying boron commonly and supplementing zinc for the deficient soils were put forward.

Characterization of Fertility Alteration in 8 Environment-sensitive Genic Male-sterile Lines of indica Rice

Eight indica ( Oryza sativa L.) environment-sensitive genic male-sterile (EGMS) lines, 2-2S, K1405S, F131S, 2136S, Pei-Ai 64S, 1290S, GD-IS and N17S, were sequentially seeded with 10-15 d interval at three sites, Wuhan in 1997, Guiyang in 1997 and Sanya in 1997 and 1998, China. The results of investigations on self-sterilities showed that all of eight EGMS lines had stable sterile periods of longer than 30 d at Wuhan. They can be used for seed production of two-line hybrid rice, but can not reproduce themselves. Their stable sterile periods were shorter than 30 d at Guiyang, they can reproduce themselves and can not be used for hybrid seed production. In Sanya, their stable sterile periods were longer than 150 d, all of eight lines can be used for seed production in summer and autumn and reproduce themselves in winter. The fertility of all eight lines were sensitive to temperature. The sensitive stages, sensitive duration and critical point of temperatures (CPT) of fertility alteration in various lines were different. The sensitive stages of 2-2S and K1405S were from 18 d to 9 d before heading, the sensitive durations were 7-10 d and the CPTs were 23.7-24.5 degreesC. The sensitive stage, sensitive duration and CPT of F131S were from 17 to 5 d before heading, 13 d and 24.3-24.7 degreesC, respectively. The sensitive stage, sensitive duration and CPT of 2136S were from 18 to 12 d before heading, 7 d and 24.6-25.1 degreesC:, respectively. The sensitive stages, sensitive durations of Pei-Ai 64S, 1290S, N17S and GD-1S were from 24 to 13 d before heading and 10-13 d. And their CPTs were 24.6-25.1 degreesC, 25.5-26.2 degreesC, 25.4-26.1 degreesC,, and 24.1-24.7 degreesC, respectively.

Characteristics and Evaluation of Soil Fertility in Sugarcane-producing Areas in Guangxi

[Objective] Soil fertility in Guangxi sugarcane-growing areas was evaluated to provide theoretical reference for sugarcane scientific planting and fertilization and further optimize evaluation system for soil fertility in Guangxi sugarcane-growing ar- eas. [Method] Nutrients of soil samples in 3 006 plots were measured, and fertility characters were evaluated based on the improved Nemerow composite index method. [Result] Soil in Guangxi sugarcane-growing area was sticky and acidic with an average pH value of 4.94. Available B was insufficient with an average content of 0.24 mg/kg. Exchangeable Mg was low with an average content of 62.34 mg/kg. Organic matter content was moderate. The contents of alkali N, rapidly available P, rapidly available K, available Cu, available Zn, available Mn and available Ca were moderate. However, unlike the soil in high-yield areas, there was unbalanced nutri- tion distribution. According to Nemerow integrated index method, soil fertility in sug- arcane-growing areas was grade lU, namely low fertility. The integrated fertility index was 0.56. Individual fertility indexes including rapid available Cu, rapidly available Zn, exchangeable Mg, available Mn, rapidly available manganese Mn and alkali N were at poor level. Other indexes were at medium or high level. [Conclusion] It could be concluded that soil fertility in Guangxi sugarcane-growing area was gener- ally low, The above-mentioned evaluation method could help to build a quantified and scientific soil fertility evaluation system and reduce the impacts of subjective factors during evaluation process.

Genetic Analysis and Mapping of Genes Involved in Fertility of Pingxiang Dominant Genic Male Sterile Rice

Pingxiang-dominant genic male sterile rice （PDGMSR） was the first dominant genic male sterile mutant identified in rice （Oryza sativa L.）, and the corresponding dominant genic male sterile gene was designated as Ms-p. The fertility of PDGMSR can be restored by introduction of a dominant epistatic fertility restoring gene in some rice varieties. In the present study, E823, an indica inbred rice variety, restored the fertility of PDGMSR, and the genetic pattern was found to be consistent with a dominant epistatic model, therefore, the dominant epistatic fertility restorer gene was designated as Rfe. The F2 population from the cross of PDGMSR/E823 was developed to map gene Rfe. The F2 plants with the genotypes Ms-pMs-pRferfe or Ms-pms-pRferfe were used to construct a fertile pool, and the corresponding sterile plants with genotypes Ms-pMs-prferfe or Ms-pms-prferfe were used to con- struct a sterile pool. The fertility restoring gene Rfe was mapped to one side of the microsatellite markers RM311 and RM3152 on rice chromosome 10, with genetic distances of 7.9 cM and 3.6 cM, respectively. The microsatellite markers around the location of the Ms-p gene were used to finely map the Ms-p gene. The findings of this study indicated that the microsatellite markers RM171 and RM6745 flanked the Ms-p gene, and the distances were 0.3 cM and 3.0 cM, respectively. On the basis of the sequence of rice chromosome 10, the physical distance between the two markers is approximately 730 kb. These findings facilitates molecular marker-assisted selection （MAS） of genes Ms-p and Rfe in rice breeding programs, and cloning them in the future.