有机肥对土壤特性及农产品产量和品质影响研究进展

施用有机肥是农业生产的重要措施,对绿色农业发展起到积极作用,而且越来越广泛施用。本文介绍了目前有机肥基本概况,重点综述了有机肥对提高土壤肥力、提高作物产量和品质、促进养分利用以及对病虫害发生影响等方面研究的最新进展,分析了当前有机肥施用对耕地质量和农产品安全风险、施肥效率低、以及有机肥品种研发不足、相关质量标准滞后等问题,并对当前有机肥推广应用的形势和发展前景进行了分析和展望。     

工业级棉短绒清理回收工艺的改进

为降低棉短绒中的杂质含量，提高棉短绒的质量及收率，对棉短绒清理回收的生产工艺进行了改进，创新连续化多级除杂装备和短绒精细化分离工艺。棉籽清理除杂工艺中，增加了圆筛、棒条机，并且调整了风力清籽机组配置；短绒分离工艺中，增加了五联筛和新型棒条机。改进后的工艺能够提升对毛棉籽的除杂效果，彻底清理剥绒得到的棉短绒中的碎棉仁、棉壳及棉秆等杂质。此外，该工艺还能回收棉短绒下脚料，满足大型生产线的生产要求。     

EPS364, a Novel Deep-Sea Bacterial Exopolysaccharide,Inhibits Liver Cancer Cell Growth and Adhesion

The prognosis of liver cancer was inferior among tumors. New medicine treatments are urgently needed. In this study, a novel exopolysaccharide EPS364 was purified from Vibrio alginolyticus 364, which was isolated from a deep-sea cold seep of the South China Sea. Further research showed that EPS364 consisted of mannose, glucosamine, gluconic acid, galactosamine and arabinose with a molar ratio of 5:9:3.4:0.5:0.8. The relative molecular weight of EPS364 was 14.8 kDa. Our results further revealed that EPS364 was a β-linked and phosphorylated polysaccharide. Notably, EPS364 exhibited a significant antitumor activity, with inducing apoptosis, dissipation of the mitochondrial membrane potential (MMP) and generation of reactive oxygen species (ROS) in Huh7.5 liver cancer cells. Proteomic and quantitative real-time PCR analyses indicated that EPS364 inhibited cancer cell growth and adhesion via targeting the FGF19-FGFR4 signaling pathway. These findings suggest that EPS364 is a promising antitumor agent for pharmacotherapy.     

Development of a core set of KASP markers for assaying genetic diversity in Brassica rapa subsp. chinensis Makino

Single‐nucleotide polymorphisms (SNPs) are rapid, economical and reliable genotyping tools. Non‐heading Chinese cabbage (Brassica rapa L. subsp. chinensis Makino) is now an economically important vegetable crop worldwide. In this study, 1,167 SNPs were evaluated for 7polymorphism among 70 representative non‐heading Chinese cabbage inbred lines using a Kompetitive Allele Specific PCR (KASP) genotyping assay. On the basis of identified polymorphisms and the results of a principal component analysis, we selected 50 core SNPs that were balanced sufficiently to provide adequate information for genetic identification. The core SNPs were used for construction of a neighbour‐joining dendrogram that separated the 70 inbred lines into four main groups and several subgroups corresponding to Caixin, Heiyebaicai, Huangxinwu, Naibaicai, Taitsai, Pak‐choi, and Wutatsai. This categorization was superior to that achieved using a dataset of 479 polymorphic SNPs. To confirm the utility of the core SNP markers in genetic identification, we tested their stability and resolution using 162 commercial hybrid cultivars. The SNPs, which represent a cost‐effective, accurate marker set for germplasm analysis and cultivar identification, are suitable for molecular marker‐assisted breeding in non‐heading Chinese cabbage.     

Effect of nitrogen root zone fertilization on rice yield,uptake and utilization of macronutrient in lower reaches of Yangtze River,China

Improper application of nitrogen (N) has led to high N losses and low N use efficiency in the lower reaches of Yangtze River in China. An effective method to solve such problems is the deep fertilized N in root zone (RZF). Limited information is available on the effect of RZF on the uptake of macronutrients (N, P and K) and rice yield. Field experiments, conducted from 2014 to 2015, compared the farmer fertilizer practice (FFP, with 225 kg ha^?1 of N, split into three doses) and RZF using the same rate but placing N 5 cm away from rice roots in holes 10 cm deep (RZF10) or 5 cm deep (RZF5) as a single application. The highest mean yield (10.0 t ha^?1) was obtained in RZF10, which was 19.5% more than that in FFP. Root zone fertilization of urea (whether 10 cm deep or 5 cm deep) resulted in greater accumulation of N, P and K in stem, leaf sheaths, leaf blades and grains compared to that in FFP in sandy and in loam soils. The uptake of N, P and K was the highest in RZF10 (average at 176.7, 66.2 and 179.1 kg ha^?1, respectively), higher than that in FFP by 45.0, 17.0 and 22.6%, respectively. N apparent recovery efficiency was markedly higher in RZF10 (53.1%) than in FFP (27.5%). RZF10 significantly increased the N, P, K uptake compared with FFP under different N rates in both sandy and loam soils. These results suggest that the N, P and K input amount should be re-determined under RZF.     

Revisiting rice breeding methods – evaluating the use of rapid generation advance (RGA) for routine rice breeding

Rice production needs to increase in the future in order to meet increasing demands. The development of new improved and higher yielding varieties more quickly will be needed to meet this demand. However, most rice breeding programmes in the world have not changed in several decades. In this article, we revisit the evidence in favour of using rapid generation advance (RGA) as a routine breeding method. We describe preliminary activities at the International Rice Research Institute (IRRI) to re-establish RGA on a large scale as the main breeding method for irrigated rice breeding. We also describe experiences from the early adoption at the Bangladesh Rice Research Institute. Evaluation of RGA breeding lines at IRRI for yield, flowering time and plant height indicated transgressive segregation for all traits. Some RGA lines were also higher yielding than the check varieties. The cost advantages of using RGA compared to the pedigree method were also empirically determined by performing an economic analysis. This indicated that RGA is several times more cost effective and advantages will be realized after 1 year even if facilities need to be built. Based on our experience, and previous independent research empirically testing the RGA method in rice, we recommend that this method should be implemented for routine rice breeding in order to improve breeding efficiency.     

红蓝LED光照强度对茶树生长及生物化学成分的影响

以‘黔湄601’一年生茶树苗为试材,光量比为1∶3的LED红蓝光作为光源,探讨不同光照强度对茶树幼苗生长特性的影响、光合色素及生物化学成分的变化趋势,探索茶树苗生长发育对光强的响应机制。采用LED精准调节光质和光强,设置50μmol·m-2·s-1、100μmol·m-2·s-1、150μmol·m-2·s-1、200μmol·m-2·s-14个处理。结果表明,不同光强处理15 d后,50μmol·m-2·s-1光照强度有利于茶树叶色素含量的增加及Ca/Cb值的降低;100μmol·m-2·s-1光照强度有利于茶树叶茶多酚含量的降低及氨基酸含量的增加,酚氨比值最低;150μmol·m-2·s-1光照强度对茶树叶重增加有促进作用;200μmol·m-2·s-1光照强度有利于茶树叶茶多酚含量的增加和氨基酸、光合色素含量的减少;酚氨比值最高,光合色素含量最低。红蓝LED光照强度过低、过高都不利于茶叶品质形成,综合考虑,100μmol·m-2·s-1光照强度最有利于茶叶功能成分的积累,是茶叶LED光源设施栽培的理想光照强度。本研究结果对于设施茶树种植具有重要的参考意义。     

苗后除草剂喷施时期对杂草防治及冬油菜产量和品质的影响

为了探究苗后除草剂不同施用时期对北方冬油菜田间杂草的防控效果及其对冬油菜生长、产量和品质的影响,以当地主栽甘蓝型冬油菜天油2266和白菜型冬油菜天油H614为试验材料,选用对冬油菜安全的苗后除草剂高效氟吡甲禾灵,设置4个喷施时期处理,于2018-2019年开展大田试验。结果表明,越冬后不同时期喷施苗后除草剂,甘蓝型冬油菜田间杂草总数较对照减少57.54%~92.56%,杂草总鲜重较对照降低75.40%~97.48%,第2时期（3月25日）处理产量较对照增加354.50kg/hm²;白菜型冬油菜田间杂草株防效和鲜重防效分别为55.91%~92.02%和37.17%~97.46%,产量较对照增加2.29%~16.77%。因此,在冬油菜大量返青但未封行前施用苗后除草剂,可显著防控田间杂草并增加冬油菜籽粒产量。     

棉花叶枝数与种植密度对单株结铃数的影响

为了探明棉花叶枝数和密度对单株结铃的影响规律，试验设置5种留叶枝方式：不留叶枝（CK）、留1叶枝、留2叶枝、留3叶枝、留全部叶枝；5个种植密度（万株·hm^－2）：2.25，3.00，3.75，4.50，5.25。研究结果表明：在同一密度条件下，随叶枝的增多，单株铃数增加；留1叶枝单株铃数较对照增加10%左右，留2、3叶枝单株铃数较对照增加15%左右，保留全部叶枝较对照增加25%左右。在同一叶枝处理下，随密度的增加，单株铃数减少；密度每增加7500株·hm^－2，5种留叶枝方式的单株结铃分别减少2.60个、3.04个、3.06个、3.44个和3.71个。总铃数随叶枝和密度的增加而增加，当总成铃为88.24万个·hm^－2时产量最高。     

基于深度学习的牛肉大理石花纹等级手机评价系统

大理石花纹是影响牛肉品质等级的重要指标,目前中国牛肉加工企业对大理石花纹的评价是由专业分级人员参照标准图谱完成,具有主观性强、耗费人工的缺点。针对上述问题,该研究提出了基于深度学习的智能分级方法,设计一种具有4层卷积的神经网络结构,实现了大理石花纹特征的自动提取,并基于智能手机开发了牛肉大理石花纹检测软件。该研究共采集样本图像1 800张,按3:1:1分为校正集、验证集和测试集。为进一步验证模型,将该方法与传统机器视觉方法进行了比较,提取了牛肉大理石花纹的大、中、小脂肪颗粒个数,脂肪总面积和脂肪分布均匀度5个参数,并建立了多元线性回归模型。试验结果表明,该研究所用方法大理石花纹检测准确率更高,验证集检测正确率为97.67%。最后编写了手机软件,将模型移植入Android手机,在手机平台上调用模型进行大理石花纹检测。试验表明,该软件对测试集样本的检测准确率为95.56%,单张检测时间低于0.5 s。该研究结合卷积神经网络分类能力强和智能手机运行速度快等优点,开发了牛肉大理石花纹的手机评价系统,具有较好的实用性和便携性,可提高牛肉大理石花纹检测效率,有助于提高农畜产品检测的智能化水平。