小尾寒羊和新疆多浪羊群体BMPR-IB基因多态性研究

以影响Booroola Merino高产性能的BMPR-IB基因为候选基因，对小尾寒羊和新疆多浪羊群体进行BMPR-IB基因多胎性分析.结果表明：小尾寒羊和新疆多浪羊群体内均存在BMPR-IB基因（A746G）的突变个体.小尾寒羊群体内存在3种基因型（BB、B＋、＋＋），BB和B＋基因型在群体内为优势基因型，其基因型频率分别为0.548和0.397，表明BMPR-IB基因突变位点的B等位基因对小尾寒羊的高繁殖力具有显著的影响.新疆多浪羊群体内存在两种基因型（B＋、＋＋），＋＋基因型在群体内为优势基因，而B＋基因型频率为0.039.通过对群体产羔率的调查分析发现：新疆多浪羊并非是一个多胎绵羊品种，其高产性能主要体现在地方品种绵羊出现四季发情，因而群体内出现一年四季产羔.     

Role of mRNAs and long non-coding RNAs in regulating the litter size trait in Chuanzhong black goats

Fecundity improvement is one of the most important objectives for goat breeders as it can considerably greatly increase production efficiency. The molecular mechanisms underlying fecundity in goats remain largely unknown. To explore the molecular and genetic mechanisms related to the fecundities and prolificacies in Chuanzhong black goats, we performed high-throughput RNA sequencing to identify differentially expressed long non-coding RNAs (lncRNAs) and mRNAs (DElncRNAs and DEmRNAs, respectively) the ovaries of high-fecundity and low-fecundity goats; furthermore, we conducted functional annotation analyses to identify pathways of interest. Overall, 1,353 DEmRNAs and 168 DElncRNAs were identified. Quantitative real-time PCR (qRT-PCR) was performed to validate some randomly selected DElncRNAs and DEmRNAs. We found that two DElncRNAs ENSCHIT00000005909 and ENSCHIT00000005910 might positively influence the expression of the corresponding gene IL1R2 (upregulated in high-fecundity group), exerting co-regulative effects on the ovarian function, through which litter size might show variations. KEGG pathway analysis indicated that the DEmRNAs SRD5A2, LOC102191297 and LOC102171967 were significantly enriched in steroid hormone biosynthesis—this pathway was related to animal reproduction. To summarize, our findings expand the understanding pertaining to the biological functions of lncRNAs and contribute to the annotation of the goat genome; moreover, they should be helpful for further studying the role of lncRNAs in ovulation and lambing.     

基于ANSYS的大耕深旋耕刀结构优化设计

通过对现有R245旋耕刀的建模及静力学分析,以旋耕刀主导用材之一65Mn的屈服强度为依据,确定了R245旋耕刀所承受的极限载荷与工作载荷。采用等比例放大的方法,以GB/T5669-2008规定的R245旋耕刀结构为基础,设计了刀尖回转半径为300mm旋耕刀(其耕深可达20~22cm),同时以同比例放大确定了R300旋耕刀的极限载荷与工作载荷,基于ANSYS软件对所设计的R300旋耕刀在工作载荷下的应力场进行了模拟,并基于模拟结果重点对其刀刀柄尺寸进行了优化。结果表明:当刀柄厚度增加到25mm、刀柄宽度增加到40mm后,R300旋耕刀不仅在工作载荷下不会失效而且在极限载荷下也不会失效。     

Stand-scale transpiration estimates in a Moso bamboo forest: (I) Applicability of sap flux measurements

The applicability of sap flux (F_d) measurements to bamboo forests has not been studied. This study was undertaken to establish an optimal and effective design for stand-scale transpiration (E) estimates in a Moso bamboo forest. To this aim, we validated F_d measurements in Moso bamboos in a cut bamboo experiment. In addition, we analyzed how sample sizes affect the reliability of E estimates calculated from F_d and conducting culm area (A_{S_b}). In the cut bamboo experiments, we found that F_d measurement using a 10 mm probe was a valid means of determining the water-use behavior of a Moso bamboo, although a specific correction was needed. Furthermore, we calculated E from stand A_{S_b} (A_{S_stand}) and mean stand F_d (J_S). Employing Monte Carlo analysis, we examined potential errors associated with sample size in E, A_{S_stand}, and J_S using an original dataset with A_{S_b} and F_d measured for 40 and 16 individuals, respectively. Consequently, we determined the optimal sample size for both A_{S_stand} and J_S estimates as 11. The optimal sample sizes for J_S were almost the same under different vapor pressure deficit and soil moisture conditions. The optimal sample size for J_S at the study site was less than that of a coniferous plantation in the same region probably owing to small individual-to-individual variations in sap flux in the Moso bamboo forest. Our study concludes that sap flux measurements are an applicable technique for assessing water use in Moso bamboo forests.     

小麦籽粒发育过程中淀粉和激素含量的变化及其关系

为给小麦籽粒生长发育的化学调控提供依据,以蛋白质含量相近、粒重和淀粉含量差异大的小麦品种川麦32和川麦107为材料,研究了籽粒发育过程中淀粉、激素含量的变化及其相互关系.结果表明,大粒品种川麦32授粉后ZR含量高,灌浆中期IAA峰值高,而小粒品种川麦107籽粒发育期间淀粉含量高,GA含量也一直高于大粒品种川麦32,因而说明ZR和IAA含量与籽粒的大小及粒重关系密切,而GA含量与淀粉含量关系更密切.     

小尾寒羊血液蛋白(酶)位点上多胎性的比较研究

[目的]为了研究小尾寒羊血红蛋白和酯酶多态性与多胎性之间的相关性。[方法]采用垂直板聚丙烯酰胺凝胶电泳对118只小尾寒羊的血红蛋白和酯酶多态性进行了分析,并对有产羔记录的2.5岁经产母羊在血红蛋白和酯酶位点上的多胎性进行了比较。[结果]小尾寒羊在血红蛋白位点上的优势基因为HbB,基因频率为0.795;在酯酶位点上的优势基因为Es-,基因频率为0.598。在小尾寒羊产羔性状上,血红蛋白HbBB型和酯酶Es++型占优势,其中酯酶Es++型的产羔数显著高于其他基因型。[结论]血红蛋白和酯酶多态性与多胎性之间的相关性,可作为小尾寒羊育种中的早期选择依据。     

Interactive effects of deficit irrigation and vermicompost on yield,quality, and irrigation water use efficiency of greenhouse cucumber

Water scarcity is the most significant barrier to agricultural development in arid and semi-arid regions. Deficit irrigation is an effective solution for managing agricultural water in these regions. The use of additives such as vermicompost(VC) to improve soil characteristics and increase yield is a popular practice. Despite this, there is still a lack of understanding of the interaction between irrigation water and VC on various crops. This study aimed to investigate the interaction effect of ...     

Diet particle size preference and optimal ration for mud crab, Scylla serrata, larvae fed microbound diets

This paper reports on experiments to determine particle size preference and optimal ration for the various larval stages of the mud crab, Scylla serrata, fed microbound diets (MBD). All experiments used ¹⁴C-labelled rotifers as components of MBD, and ingestion was determined by assessing the ¹⁴C content of S. serrata larvae after feeding on the MBD. Five size ranges of MBD (<150, 150–250, 250–400, 400–600 and 600–800 μm) were used to assess ingestion by Zoea I, Zoea III, Zoea V and Megalopa. All were fed a ration equivalent to twice the equivalent dry weight of live foods provided to each larval stage under standard rearing conditions (standard ration). MBD particle size preference increased with increasing larval development. Highest ingestion rates by Zoea I, Zoea III, Zoea V and Megalopa were found for particle size ranges of <150, 150–250, 250–400 and 400–600 μm, respectively. MBD within these particle size ranges were used in subsequent experiments to assessed optimum rations for each of the four larval stages. Larvae were fed rations based on multiples or fractions of the standard ration (100%): 12.5%, 25%, 50%, 100%, 200% and 300%. There were no significant increases in ingestion, for any of the four larval stages, when ration was increased above 100%. For Zoea I, Zoea III and Zoea V larvae, there was no significant difference in the rate of MBD ingestion when ration was reduced to 50%; however, a 25% ration brought about a significant decrease in ingestion. There was no significant decrease in the rate of ingestion by Megalopa when ration was reduced from 100% to either 50%, 25% or 12.5%. The results suggest that rations currently used for larval rearing of S. serrata may be excessive. Little is currently known of the feeding behaviour and nutritional requirements of S. serrata larvae, and the results of this study are a significant development in this field.     

贵妃鸡血液生化指标与体尺性状及屠宰性能的相关性

为了解贵妃鸡血液生化指标及其与体尺性状、屠宰性能间的相关关系,随机选取12只（公母各半）14周龄贵妃鸡测定血液生化指标、体尺性状及屠宰性能并进行相关性分析。结果表明：14周龄贵妃鸡的平均体重为983．00 g,谷氨酰基转移酶与谷丙转氨酶、乳酸脱氢酶与总胆固醇、α-羟丁酸脱氢酶与乳酸脱氢酶、碱性磷酸酶与胫围、葡萄糖与体斜长、葡萄糖与胸肌重间均呈极显著正相关（P ＜0．01）,肌酸激酶与碱性磷酸酶、乳酸脱氢酶与胆碱酯酶、α-羟丁酸脱氢酶与总胆固醇、胆碱酯酶与胫围间均呈显著正相关（P ＜0．05）,甘油三酯与龙骨长呈极显著负相关（P ＜0．01）,葡萄糖与谷草转氨酶、谷丙转氨酶与体斜长、谷草转氨酶与胸肌重、谷氨酰基转移酶与体斜长间均呈显著负相关（P ＜0．05）,可将这些生化指标作为遗传标记以预测贵妃鸡的生产性能,进行贵妃鸡的早期选育。     

Number of crosses and population size for participatory and classical plant breeding

In the breeding of self-pollinating crops, crossing creates variation upon which selection is exerted. If the value of crosses cannot be predicted then this uncertainty means that many crosses need to be made. However, since there is a limit to the capacity of a breeding programme, more numerous crosses result in each cross having a small population size, fewer progenies in later generations and a lower probability of recovering good genotypes from each cross. Published theory on the optimum number of crosses in a plant breeding programme, for a predominantly self-pollinating crop, usually assumes that all crosses are equal value. This overestimates the number of crosses required. When the optimum size of a population in a favourable cross is considered, theory predicts that very large populations are desirable. The required population size is even larger if linkage of loci controlling different traits is also considered. Hence, in an inbreeding crop, one possible strategy is to select a small number of crosses that are considered favourable and produce large populations from them to increase the probability of recovering superior genotypes. In an out breeding crop, the analogy is a few composites with large population sizes. This low-cross-number strategy is ideally suited to the particular constraints and advantages of participatory plant breeding. Such an approach, although not essential, may still be advantageous in classical breeding. When a breeding programme is based on few crosses, which parents are chosen is crucial and farmer participatory methods are highly effective in narrowing the choice. Modified bulk population breeding methods, and recurrent selection are desirable strategies in the participatory plant breeding of self-pollinating crops when combined with a low-cross-number approach. This revised version was published online in August 2006 with corrections to the Cover Date.