400克/升氯氟醚菌唑悬浮剂对香蕉叶斑病的防治效果

通过大田试验研究了400克/升氯氟醚菌唑悬浮剂防治香蕉叶斑病效果及其对香蕉产量的影响。研究结果表明,分别以20毫升、13.3毫升、10毫升400克/升氯氟醚菌唑悬浮剂兑水60公斤分3次喷雾施药,第二次施药后14d后对香蕉叶斑病防治效果在60.43-66.52%,第三次施药后14d后对香蕉叶斑病防治效果在75.72-80.72%,并对香蕉的单株产量有明显增产效果。其中尤以20毫升400克/升氯氟醚菌唑悬浮剂兑水60公斤剂量喷雾处理的效果最好。     

耐盐抗旱优质高产棉花新品种‘衡棉1670’的选育研究

抗逆优质丰产棉花新品种的培育及应用是当前棉花生产节水提质增效的关键。‘衡棉1670’是河北省农林科学院旱作农业研究所以中早熟陆地棉品种资源材料‘衡棉210’为母本,以‘衡棉4号’为父本杂交,后代多年南繁北育,经旱棚盐池鉴定选择,在枯黄萎病混生重病地、不防治棉铃虫的高压胁迫下,经过多年连续定向选择育成。其突出表现为抗枯黄萎病、丰产优质、耐盐抗旱节水,适宜在河北省及黄河流域同类生态春播棉区推广种植,2019年8月通过河北省农作物品种审定委员会审定（审定编号为冀审棉20190013）。     

油菜高亚麻酸育种探析

为促进通过提高油菜种子亚麻酸含量途径增加中国人群亚麻酸的摄入量,提高健康水平的工作进程。结合文献资料,在剖析开展油菜高亚麻酸育种的意义、可行性、难点及可利用的有利条件的基础上,提出油菜高亚麻酸育种策略与技术途径。在工作实践中,陕西省杂交油菜研究中心研究团队创建并完善"油菜高亚麻酸种质的筛选方法",利用该方法开展油菜高亚麻酸种质资源筛选和高亚麻酸育种取得良好成效:油菜种质资源的整体亚麻酸含量、具有较高亚麻酸含量种质的百分比率、亚麻酸含量最高值、亚麻酸含量15%的种质数量均明显增加;获得一批亚麻酸含量大于15%(最高含量达21%)的甘蓝型油菜非转基因种质,育成高亚麻酸的不育系和恢复系;甘蓝型油菜高亚麻酸杂交种‘秦杂油7号’通过国家品种登记;2个亚麻酸含量15%左右的杂交种正在申请品种登记。发现在A02、C02及A06染色体上存在多个与亚麻酸显著关联SNP位点。提出开展基础机理研究和分子设计育种创新体系建设,开展高亚麻酸种质资源创新、综合评价和利用研究,构建高亚麻酸育种体系,规化高效保优栽培技术路线,开展油菜籽加工技术、抗氧化研究,构建标准体系等6方面建议。     

新型腐植酸有机肥对马铃薯茎基腐病的防效

马铃薯茎基腐病是影响马铃薯生产的重要病害,目前尚未有效的综合防控措施。试验的目的是通过新型腐植酸肥料与同等养分配方化肥的田间比较试验,探讨新型腐植酸有机肥对马铃薯茎基腐病预防效果。结果表明,5~15 g壤动FT/100 kg种薯配合腐植酸肥料对马铃薯生长发育安全,在出苗率、苗高、单株根数、最大根长、芽长分别优于配方化肥1.0~2.9个百分点、1.2~4.1 cm、1.1~5.2条、1.2~2.6 cm、0.3~1.1 cm;在单株薯重、平均单薯重、商品薯率、小区产量分别高于配方化肥66.7~394.4 g、4.6~12.1 g、4.3~11.4个百分点、12.23~83.46 kg/30.8m²;对主茎、匍匐茎、块茎基腐防效分别达78.29%~87.24%、75.62%~88.51%、72.05%~86.98%,增产效果达11.60%~79.12%。研究为开展农业技术防治马铃薯茎基腐病提供了新方法,对制定综合防治技术体系具有重要指导意义。     

‘鸭梨’、‘新高’果实发育过程中果肉及种子有机酸含量的变化

为了研究梨种子对果实生长发育的影响,采用高效液相色谱(HPLC)技术对‘鸭梨’和‘新高’果实发育过程中果肉和种子中的有机酸含量进行了分析。结果表明：两个品种果肉中主要的有机酸组分均为苹果酸和奎尼酸,发育初期‘鸭梨’与‘新高’果肉中各组分的比率相近,但果实成熟时‘新高’果肉中苹果酸的比率59.98%显著高于‘鸭梨’的37.51%；两个品种种子中的有机酸组分比率的动态变化相近,与果肉相反,主要表现在奎尼酸比率的增加和苹果酸比率的减少。两个品种果肉和种子中的总酸、草酸、奎尼酸,苹果酸,莽草酸,柠檬酸含量均随着果实的成熟呈下降趋势,‘鸭梨’果肉中的奎尼酸、莽草酸、柠檬酸含量高于‘新高’；‘新高’在果实成熟时种子中的总酸含量4.59mg/g显著低于‘鸭梨’13.00mg/g,‘鸭梨’成熟果实种子中的草酸、奎尼酸、莽草酸含量显著高于‘新高’；在果实发育初期,种子中的苹果酸含量极显著高于果肉,在果实成熟时则显著低于果肉。     

粪肠球菌生长曲线的测定及其对小鼠脑组织的影响

为测定致羔羊脑炎粪肠球菌（Enterococcus faecalis）的生长曲线，寻求一种快速而准确的方法测定不同生长时期粪肠球菌数量，并客观评价其毒性强弱及其对小鼠脑组织的影响，试验采用平板菌落计数法和OD-Monitor振荡比浊法（D_λ值法）测定粪肠球菌的生长曲线，探究该菌在合适时间段内的吸光值（D_{600 nm}）与平板菌落计数法测定的活菌数（CFU）的关系。用粪肠球菌感染小鼠，观察记录小鼠的死亡情况，最后采用Karber法计算粪肠球菌感染小鼠的半数致死量（LD₅₀）。用LD₅₀的剂量感染小鼠，及时采集死亡小鼠脑组织，未死亡的小鼠72 h后全部剖杀取脑组织，一部分做涂片染色，制作病理切片，观察病理变化；一部分进行培养，用于PCR方法进行细菌的回收鉴定。结果显示，用两种方法测定此株粪肠球菌的生长曲线基本一致，在2~8 h生长迅速，为对数生长期，8~14 h生长缓慢，为稳定期，14 h之后死亡数增加，进入衰亡期；对12 h粪肠球菌D_{600 nm}与CFU的关系进行探讨，成功建立回归方程：y=20.769x-1.3422，R²=0.997；其感染小鼠的LD₅₀为7.77×10¹¹个活菌。以此剂量感染小鼠，脑组织涂片染色和培养染色，均能看到革兰氏阳性球菌；PCR结果显示，均出现了大小为112 bp的条带。对脑组织进行病理学观察发现该菌可导致脑组织充血、出血、形成微血栓，脑膜充血。通过生长曲线和其D_{600 nm}与CFU关系的建立，可实时监测粪肠球菌数量，为后期更深入研究粪肠球菌穿越血脑屏障的机制奠定重要的理论基础。     

Nutritional Qualities of the Low-Value Bivalve Mollusks Paphia malabarica and Villorita cyprinoides at the Estuarine Waters of the Southwestern Coast of India

The bivalve mollusks Paphia malabarica and Villorita cyprinoides collected from the estuarine system located in the southwest coastal waters of India were evaluated for their nutritional composition. A balanced essential to nonessential amino acid ratio (> 1.0) with a greater quantity of sulfur-containing amino acids in these species demonstrated that they could provide well-balanced protein depositions. The n-3/n-6 polyunsaturated fatty acid ratio in P. malabarica was found to be greater than 2, and, therefore, can be considered as a healthy diet. The C₂₀–C₂₂ long-chain polyunsaturated n-3 fatty acids (for example, docosahexaenoic acid and eicosapentaenoic acid) accounted for more than 23% of the total fatty acid content in P. malabarica as compared to about 7% in V. cyprinoides. P. malabarica showed greater hypocholesterolemic/hypercholesterolemic ratio (1.7) and lesser atherogenicity (0.7), thrombogenicity (0.3) indices when contrasted with those in V. cyprinoides, thereby indicating the nutritional superiority of the former. A greater content of vitamin D₃ (> 150 IU), along with significant quantities of calcium and phosphorus (> 500 mg/100 g) in the clams, signified their importance in preventing osteoporosis. This study demonstrated the importance of bivalves, in particular, P. malabarica as a valued species for human consumption.     

Effect of dietary protein content on growth rate,survival and body composition of juvenile cauque river prawn,Macrobrachium americanum (Bate 1868)

We determined the effect of four concentrations of dietary crude protein, 30.7, 37.2, 41.8 and 46.8% on growth rate, survival and body composition of the juvenile cauque river prawn (Macrobrachium americanum). The prawns were hatched in the laboratory from the spawn of one wild ovigerous female. Prawns consuming 37.2% crude protein reached a final weight of 0.58 g (feed conversion ratio of 2.15), which was significantly better than the other treatments. Survival was 100% in all treatments. Protein content in the diets had no significant effect on whole body proximate composition and amino acid profile. Juveniles consuming the 37.2% crude protein diet grew faster than those fed the other diets. Specific growth rate was adjusted to the two‐slope broken‐line regression analysis model to estimate the optimal protein requirement. In conclusion, these results demonstrated that the 37.2% protein level diet is optimal for juvenile cauque river prawn M. americanum in the experimental conditions of this study.     

Molecular cloning and functional characterization of the fatty acid delta 6 desaturase (FAD6) gene in the sea cucumber Apostichopus japonicus

The sea cucumber (Apostichopus japonicus), an important echinodermata, had high value in nutrition and medicine for its rich collagen, sulphated polysaccharide, glycosides and polyunsaturated fatty acids (PUFA). The cDNA of the fatty acid desaturase gene in A. japonicus (AJFAD6) was cloned and was found to encode a desaturase with delta 6 FAD activity. Sequence analysis indicated that AJFAD6 included an open reading frame of 1392 bp, encoding 463 amino acids. AJFAD6 has all the conserved motifs found in other members of the FAD6 family, including an N‐terminal cytochrome b5 domain and three histidine‐rich regions. qRT‐PCR showed that AJFAD6 was expressed in all tissues tested during juvenile development and was mainly expressed in the respiratory tree at 150 days after adherence (150 days) and in the intestine at 100 days. Furthermore, AJFAD6 mRNA was also detected in the analysed adult tissues, with higher expression in the intestine and testis. Functional characterization of AJFAD6 in a recombinant yeast, Pichia pastoris, showed that AJFAD6 could catalyse exogenous linoleic acid (LA) and α‐linolenic acid (ALA) to produce γ‐linoleic acid (GLA) and stearidonic acid (STA), respectively, at conversion rates of 11.1% for LA to GLA and 3.4% for ALA to STA. Our results suggested that the biosynthetic pathway of PUFA existed in the sea cucumber, but endogenous production of eicosapentaenoic acid, arachidonic acid and docosahexaenoic acid from either LA or ALA precursor appeared to be limited.     

Apparent digestibility coefficients of animal and plant feed ingredients for juvenile Pseudobagrus ussuriensis

A study was conducted to determine apparent digestibility coefficients (ADCs) of dry matter (DM), crude protein (CP), lipid, gross energy, phosphorus and amino acids (AAs) from Peruvian fish meal (PFM), native fish meal (NFM), meat bone meal (MBM), dried daphnia meal (DDM), soybean meal (SBM), full‐fat soybean (FSBM), cottonseed meals (CSM), rapeseed meal (RSM) and corn gluten meal (CGM) for Pseudobagrus ussuriensis (7.8 ± 0.06 g). Test diets were formulated to contain a 70:30 mixture of reference diet to test ingredient with chromic oxide (5 g kg^–1) serving as the inert marker. ADCs of DM ranged from 49.94% (CGM) to 87.11% (PFM), the highest ADCs of DM were observed in PFM and the lowest was found in CGM. ADCs of CP in the test ingredients ranged from 74.92% (CGM) to 93.41% (SBM). ADCs of crude lipid ranged from 51.80% (CGM) to 94.07% (PFM) for fish. ADCs of energy ranged from 56.42% (CGM) to 90.09% (PFM). ADCs of phosphorus ranged from 21.81% (CSM) to 65.70% (PFM). AA availability for the test ingredients followed a similar pattern to ADCs of CP, in which values for PFM, NFM and MBM were generally higher (p < .05) than those of other protein ingredients. Among all plant meals, the AA availability values in SBM were higher (p < .05) than those in CGM, CSM and RSM. The availability of most AAs in CGM was the lowest (p < .05) among all tested ingredients. In conclusion, PFM and NFM are good sources of available protein and AAs. When fishmeal supply is limited, MBM and DDM are substitutes for fishmeal reduction in P. ussuriensis diets; at the same time, SBM and FSBM are also very acceptable protein feedstuffs. However, CSM, RSM and CGM could not be used at high levels in P. ussuriensis diets because of their inferior digestibilities.