生姜主栽品种枯萎病抗性评价及抗病性鉴定指标筛选

【目的】筛选抗枯萎病的生姜品种,建立抗病评价体系,为生姜枯萎病抗病品种选育及抗病机理研究提供理论参考。【方法】选取5个生姜主产区的主栽品种,采用室内人工接种法测定枯萎病菌(腐皮镰刀菌)侵染对不同生姜品种超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、几丁质酶(CHI)、β-1,3-葡聚糖苷酶(GLU)活性及次生抗菌物质含量、超氧阴离子(O₂-·)、过氧化氢(H₂O₂)、丙二醛(MDA)含量等的影响,结合抗病系数、主成分分析、聚类分析、相关分析和隶属函数对5个生姜品种幼苗的抗病性进行综合评价。【结果】山东大姜病情指数最低(4.0)、发病率最低(4%)、发病周期最长(24 d),表现出较强的抗病性;罗平小黄姜病情指数最高(45.2)、发病周期最短(7 d),表现抗病性较弱。不同生姜品种幼苗接菌后的生理生化指标均出现不同程度的变化,其中,山东大姜的抗氧化酶(SOD、POD、CAT)活性、防御酶(PAL、CHI、GLU)活性和次生抗菌物质(总酚、类黄酮、木质素)含量均高于其他品种,O₂-·、H₂O₂和MDA含量低于其他品种,而罗平小黄姜呈现相反趋势。主成分分析将12个单项生理生化指标转换为3个独立综合指标,聚类分析将5个生姜品种划分为3类,结合隶属函数综合评价结果,5个生姜品种抗病性强弱表现为:山东大姜>凤头姜>竹根姜>贵州黄姜>罗平小黄姜,与人工接种试验中5个品种的发病程度一致。相关分析结果显示,SOD和类黄酮与抗病性综合评价值(D值)呈极显著正相关(P<0.01)。【结论】5个生姜品种中山东大姜抗病性最强,罗平小黄姜抗病性最弱;SOD和类黄酮可作为生姜枯萎病抗性鉴定的主要参考指标。     

Improvement in winter wheat productivity through regulating PSII photochemistry,photosynthesis and chlorophyll fluorescence under deficit irrigation conditions

Deficit irrigation is critical to global food production, particularly in arid and semi-arid regions with low precipitation. Given water shortage has threatened agricultural sustainability under the dry-land farming system in China, there is an urgent need to develop effective water-saving technologies. We carried out a field study under two cultivation techniques: (1) the ridge and furrow cultivation model (R); and (2) the conventional flat farming model (F), and three simulated precipitation levels (1, 275 mm; 2, 200 mm; 3, 125 mm) with two deficit irrigation levels (150 and 75 mm). We demonstrated that under the ridge furrow (R) model, rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate (P_n), quantum yield of PSII (ΦPSII), electron transport rate (ETR), performance index of photosynthetic PSII (F_v/F_m′), and transformation energy potential of PSII (F_v/F_o). In addition, during the jointing, anthesis and grain-filling stages, the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model, respectively, primarily due to improved soil water contents. The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis, biomass and wheat production. The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing P_n, biomass, wheat production, and chlorophyll fluorescence parameters in dry-land farming areas.     

Tomato mottle mosaic virus: Characterization,resistance gene effectiveness,and quintuplex RT-PCR detection system

Tomato mottle mosaic virus (ToMMV), an economically important species of the genus Tobamovirus, causes significant loss in yield and quality of tomato fruits. Here, we identified the Shandong isolate of ToMMV (ToMMV-SD) collected from symptomatic tomato fruits in Weifang, Shandong Province of China. ToMMV-SD caused symptoms such as severe mosaic, mottling, and necrosis of tomato leaves, yellow spot and necrotic lesions on tomato fruits. The obtained full genome of ToMMV-SD was 6 399 nucleotides (accession number MW373515) and had the highest identity of 99.5% with that of isolate SC13-051 from the United States of America at the genomic level. The infectious clone of ToMMV-SD was constructed and induced clear mosaic and necrotic symptoms onto Nicotiana benthamiana leaves. Several commercial tomato cultivars, harboring Tm-2² resistance gene, and pepper cultivars, containing L resistance gene, were susceptible to ToMMV-SD. Plants of Solanum melongena (eggplant) and Brassica pekinensis (napa cabbage) showed mottling symptoms, while N. tabacum cv. Zhongyan 100 displayed latent infection. ToMMV-SD did not infect plants of N. tabacum cv. Xanthi NN, Brassica rapa ssp. chinensis (bok choy), Raphanus sativus (radish), Vigna unguiculata cv. Yuanzhong 28-2 (cowpea), or Tm-2² transgenic N. benthamiana. A quintuplex RT-PCR system differentiated ToMMV from tomato mosaic virus, tomato brown rugose fruit virus, tobacco mosaic virus, and tomato spotted wilt virus, with the threshold amount of 0.02 pg. These results highlight the threat posed by ToMMV to tomato and pepper cultivation and offer an efficient detection system for the simultaneous detection of four tobamoviruses and tomato spotted wilt virus infecting tomato plants in the field.     

Neopestalotiopsis eucalypti,a causal agent of grapevine shoot rot in cutting nurseries in China

Grapevine (Vitis vinifera L.) is an economically important fruit crop in the world, and China ranks first in the production of grapes with approximately 15% of the world's total yield. However, diseases that cause the death of grapevine shoots pose a severe threat to the production of grapes. In this study, the fungus Neopestalotiopsis eucalypti was identified as a causal pathogen of grapevine shoot rot based on the morphology of conidia and a phylogenetic analysis. The phylogenetic analysis was performed with three isolates based on the combined sequence of internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (Tef) and the β-tubulin (Tub2) genes. The three isolates were all identified as N. eucalypti. Pathogenicity tests of the three fungal isolates were conducted on grapevines shoots in vitro and in vivo. The results showed that all three fungal isolates caused severe rot lesions on the inoculated grapevine shoots, and N. eucalypti was re-isolated from the inoculated grapevine shoots. Therefore, N. eucalypti was confirmed as a causal agent of the grapevine shoot rot. This is the first report of N. eucalypti causing grapevine shoot disease in China.     

Commercial cash crop production and households’ economic welfare: Evidence from the pulse farmers in rural China

Whether promoting cash crop production can increase household welfare has long been the focus of the food policy debate. This study first investigated the determinants of household behavior in commercial pulse farming. It then examined how households’ commercial pulse production improves their economic welfare. We used a dataset of 848 households collected from 2018 to 2019 to estimate the determinants of household behavior in commercial pulse farming by the Heckman two-step model. The endogenous treatment regression (ETR) method was employed to examine the impact of commercial pulse farming on household economic welfare. The results showed that factors such as market purchase prices, agricultural technology services, farmers’ access to loans, and government subsidies promoted smallholders’ commercial pulse farming; production costs and perceptions of climate change risks constrained smallholders’ commercial pulse production. Overall, commercial pulse production has increased household farm income but there was a limited impact on household off-farm income. Our findings suggest that policies aiming to increase households’ cash crop production and market access could significantly improve the economic welfare of pulse farmers.     

基于江苏省河蟹主产区气象因子的产量BP神经网络预测

为提高江苏河蟹主产区产量预测能力,以此为基础制定科学合理的河蟹养殖发展规划,本研究对河蟹主产区附近设立的7个观测台站2013—2017年的气象数据和该区产量数据进行了采集,利用插值法补足少量缺失值,通过主成分分析选取了最能代表江苏省河蟹主产区特点的5个主成分作为研究对象建立BP神经网络,探索其用于江苏省河蟹主产区产量随气象因子变化的规律。结果表明,通过PCA主成分分析降维处理后数据的大部分特点能被BP神经网络学习到,预测值与真实之间的相关系数为0.82267,具备一定的模拟气象因子数据与产量之间的关系的能力。     

3个草莓品种在广西南宁市露地种植表现及品质特性

为筛选出适宜广西南宁地区露地栽培的草莓良种,引进‘京藏香’、‘京桃香’、‘红颜’3个草莓品种并进行试种和调查分析。结果表明,‘京藏香’、‘京桃香’、‘红颜’在露地栽培条件下物候期与‘甜查理’较接近,果实可溶性固形物含量都在10.5%以上,果实大小适中,平均单株产量在0.211 kg以上,平均单位面积产量在18990 kg/hm²以上。这些草莓品种产量较高,果实品质优良,抗性中等或偏弱,在做好水肥管理和病虫害综合防治的情况下可作为优良品种进行推广。     

贺兰山东麓酿酒葡萄叶片、叶柄营养诊断及分析

以宁夏贺兰山东麓主栽的7年生'梅鹿辄'和'赤霞珠'的叶片为研究对象,通过对贺兰山东麓不同产区酿酒葡萄'梅鹿辄'和'赤霞珠'叶片进行营养诊断,分析研究高产园和低产园中酿酒葡萄叶片的大量、中量及微量元素营养状况.结果表明,在高低产园中,'梅鹿辄'和'赤霞珠'的叶片养分含量差异较大,微量元素含量>大量元素含量>中量元素含量.     

不同土壤改良剂对土壤养分及烤烟内在品质的影响

为探讨不同土壤改良剂对植烟土壤和烤烟品质的改良效果,设置不施用肥料（CK）和分别施用聚丙烯酰胺（T1）、生物炭（T2）和高碳基有机肥（T3）共4个处理,采用大田试验研究了不同处理对烤烟农艺性状、土壤理化性质、烟叶内在品质和经济性状的影响。结果表明,T3处理烤烟具有更高的生长指标,尤其在最大叶面积上显著高于T1和T2处理,增幅分别为17.06%和14.48%;T3处理土壤电导率显著增高,较T1和T2处理分别提高了83.38%和85.82%;T2处理土壤有机碳含量最高,相比于T1和T3处理,增幅分别为113.60%和53.45%;相比于CK,T3处理土壤细菌数量显著提高了10.44%,真菌数量显著降低17.51%;与CK相比,T2和T3处理显著提高了烟叶总糖、还原糖、钾含量和糖碱比、钾氯比,烟叶氯含量不同程度降低。T3处理下烟叶总糖、还原糖和钾含量较T1处理显著提高了8.22%、12.67%和5.26%;在产量、产值指标上,T3处理较T1和T2处理分别显著提高了14.29%和7.01%、20.81%和12.62%。说明施用土壤改良剂能不同程度提高土壤养分和烟叶内在品质,以高碳基有机肥处理效果最佳。