Effect of climate change on Spodoptera litura Fab. on peanut: A life table approach

Investigations were conducted to understand the direct effects of rising temperature and the host-mediated effects of elevated CO₂ (eCO₂) on Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera). This study involved i. the construction of life tables of S. litura at six constant temperatures viz., 20, 25, 27, 30, 33 and 35°C ± 0.5 °C reared on peanut (Arachis hypogaea L.) grown under eCO₂ (550 ppm) concentration in open top chambers ii. Estimation of threshold temperatures and thermal constants and iii. Prediction of the pest scenarios during near and distant future climate change periods. Significantly lower leaf nitrogen, higher carbon and a higher relative proportion of carbon to nitrogen (C:N) were observed in peanut foliage grown under eCO₂ over ambient CO₂ (aCO₂). The mean development time (days) of each stage, egg, larva, pupa, pre-oviposition and total life span decreased from 20 to 35 °C temperature on eCO₂ foliage. The thermal requirement of S. litura from egg to egg (within the range of 20 °C–35 °C) was 538.5 DD on eCO₂ as against 494.5 DD on aCO₂ foliage. Finite (λ) and intrinsic rates of increase (r_m), net reproductive rate (R_o), mean generation time (T) and doubling time (DT) of S. litura varied significantly with temperature and CO₂ and were found to have quadratic relationships with temperature. The present results on life table parameters estimated by the bootstrap technique showed that the ‘r_m’ values of S. litura on eCO₂ foliage were higher than those in the literature indicating a significant influence of eCO₂. The reduction of ‘T’ was noticed from a maximum of 50 days at 20 °C to minimum of 22 days at 35 °C and ‘λ’ which is the indicator of reproductive value of new eggs was highest at 35 °C and showed a negative relationship with temperature. The data on these life table parameters were plotted against temperature and two non-linear models developed for both CO₂ conditions and used for predicting the pest scenarios. Prediction of pest scenarios based on PRECIS A1B emission scenario data at eleven peanut growing locations of the country during near future (NF) and distant future (DF) climate change periods showed an increase of ‘r_m’ and ‘λ’ with varied ‘R_o’ and reduced ‘T’. The present results indicate that temperature and CO₂ are vital in influencing the growth and life table parameters of S. litura and that pest incidence is likely to be higher in the future.     

农业大数据的发展现状与发展趋势

介绍了农业大数据的概念和发展现状,阐述了农业大数据理论在农业中的主要应用,分析了农业大数据发展过程中存在的问题,并预测了农业大数据的发展趋势。     

中国作物分子育种现状与展望

分子育种是现代农业发展应用推广最迅速的育种新技术,对作物遗传改良产生了深远的影响。国际农作物育种已经进入分子育种时代,以DNA重组技术和基因组编辑技术等为代表的现代生物技术已成为世界上作物遗传改良的重要手段。本综述简要介绍了国际分子育种发展趋势,并对中国作物分子育种现状和国家相关政策导向、集成创新、科研管理体制、生物种业发展和人才现状等方面进行了分析,以期为中国农业和科技管理部门、生物技术工作者、育种家和种子企业提供参考。     

棉铃发育过程中不同组织IAA含量变化特点

为了解IAA与棉纤维品质形成间的关系及棉铃各部位IAA积累转运特点,本研究分析了棉铃各部分在发育过程中IAA含量的变化特点。通过选择陆地棉标准系TM-1、长纤维种质‘母35’和短纤维种质‘208’3个纤维长度差异较大的陆地棉材料,利用酶联免疫法对浙江杭州、海南三亚两地田间试验的各材料不同发育阶段的棉仁、棉籽壳、棉纤维、棉铃壳进行了IAA含量的测定。结果表明,不同参试材料的棉仁IAA含量存在明显差异,棉籽壳、棉纤维与棉铃壳的IAA含量峰值出现时间晚于棉仁,棉铃各个组织IAA含量具有随棉铃组织从内向外逐渐降低的趋势。研究表明,IAA可能是棉纤维发育的正效应因子,且棉铃发育过程中IAA可能呈初期在棉仁富集、随发育进程沿棉铃组织由内向外运输的规律。     

镇巴县药用大黄林药间作技术研究

为研究药用大黄林药间作的关键技术,于陕西省镇巴县盐场镇响洞村退耕香椿林地下移栽一年生药用大黄种苗,并测定其生长发育情况。结果表明,药用大黄生物量的积累随种植年度的增加而增加,第1年增长较为缓慢,第2年、第3年增速较快;不同郁闭度对药用大黄生物量的积累有显著性影响,当郁闭度为40%时,生物量积累最为显著,药用大黄平均单根鲜重高达5.3 kg。镇巴县药用大黄与香椿树林药间作,可以有效地缓解土地资源匮乏,保护野生资源不被破坏,同时也是生态种植的一种应用,为镇巴县林药间作模式提供有效的技术支撑。     

张家界农业旅游发展的SWOT分析及对策研究

张家界依托其得天独厚的自然条件,已迅速发展成为旅游产业大市。然而张家界的旅游资源与农业资源密不可分,自然景观与田园风貌紧密相连。为寻找适应于张家界农业旅游的发展道路,采用SWOT分析法重点对张家界农业旅游发展的机会、优势、劣势及挑战几个方面进行分析,并提出发展对策。     

春季低温对小麦颖果发育的影响

为了探明春季低温（倒春寒）导致小麦减产的细胞学机理，以扬麦15为材料，在小麦幼穗处于雌雄蕊分化期至药隔期之间时，设置-3 ℃低温处理，通过树脂半薄切片对颖果不同发育时期的形态结构进行观察。结果表明：（1）在颖果发育早期，低温促进了颖果的长度生长，抑制了宽度生长；与对照相比，低温处理组小麦颖果发育进程缩短；（2）低温处理组颖果果皮发育早，中果皮降解速度快；（3）低温处理增加了胚乳淀粉体的积累量，降低了蛋白体的积累量，发育后期胚乳充实度显著低于对照组；（4）与对照相比，低温处理后颖果韧皮部面积和珠心突起传递细胞面积增大。以上结果表明，春季低温处理更有利于养分运输组织的发育，使得灌浆时间缩短，最终导致淀粉积累量增加及颖果早熟。     

我国猕猴桃产业发展现状及对策建议

近年来我国猕猴桃产业发展迅速,产业发展潜力很大,但由于起步较晚、主导品种不明确、管理技术体系落后、质量标准体系不完善等原因,仍然存在诸多问题。主要问题包括(:1)尽管采收面积和产量均位居世界第一位,但单位面积产量低,而且生产总量占水果总量的比例仍然很小(;2)果实品质较差,进口单价始终高于出口单价,进出口贸易逆差明显。笔者通过对国内外猕猴桃生产、贸易数据的统计分析和产业调研,总结产业发展现状,梳理出我国猕猴桃产业存在的主要问题,并分析产生的原因,为促进我国猕猴桃产业健康发展提出对策及建议。     

Accelerated ageingof wheat grains: Part I- Influence on rheological properties of wheat flour

Natural ageing is defined as handling and storage of freshly harvested grain for several years under storage condition to achieve suitable flour quality after milling. Accelerated ageing of wheat which is obtained using higher temperature during a specific storage time under controlled relative humidity may improve the quality of wheat flour. The present study addresses the effect of accelerated ageing on the rheological properties of wheat flour produced by freshly harvested wheat. The process of accelerated aging was performed by three different factors including rise in wheat moisture content (16, 18 and 20% w/w), control of storage temperature (30, 40 and 50°C) and control of the storage time (2, 5 and 8 days) using a central composite design. After the grain milling, rheological properties of wheat flour of different treatments were studied. Results indicated that promoting the storage time to 8 days and temperature up to 40°C could improve rheological properties such as dough stability, dough development time and farinograph quality number. This phenomenon may be due to oxidation and rearrangement of disulfide bonds resulting in increasing strength and improving flour quality. Increasing moisture content and storing in higher temperatures resulted in weakening rheological properties.     

寻甸县森林资源特点及发展建议

根据2015年寻甸县森林资源规划设计调查结果,对森林资源数量、质量和结构等因子进行了对比分析。结果表明,全县森林资源具有以下特点:林地面积大、公益林比例高、天然林为主、龄组结构渐趋合理、混交林比例偏低、经济林以核桃、板栗为主。据此,提出了增绿、增质和增效的林业发展建议。