A global sensitivity analysis of cultivar trait parameters in a sugarcane growth model for contrasting production environments in Queensland,Australia

New sugarcane cultivars are continuously developed to improve sugar industry productivity. Despite this sugarcane crop models such as the ‘Sugar’ module in the Agricultural Productions System sIMulator (APSIM-Sugar) have not been updated to reflect the most recent cultivars. The implications of misrepresenting cultivar parameters in APSIM-Sugar is difficult to judge as little research has been published on the likely values of these parameters and how uncertainty in parameter values may affect model outputs. A global sensitivity analysis can be used to better understand how cultivar parameters influence simulated yields. A Gaussian emulator was used to perform a global sensitivity analysis on simulated biomass and sucrose yield at harvest for two contrasting sugarcane-growing regions in Queensland, Australia. Biomass and sucrose yields were simulated for 42 years to identify inter-annual variability in output sensitivities to 10 parameters that represent physiological traits and can be used to simulated differences between sugarcane cultivars. Parameter main effect (S_i) and total effect (ST_i) sensitivity indices and emulator accuracy were calculated for all year-region-output combinations. When both regions were considered together parameters representing radiation use efficiency (rue), number of green leaves (green_leaf_no) and a conductance surrogate parameter (k_L) were the most influential parameters for simulated biomass in APSIM-Sugar. Simulated sucrose yield was most sensitive to rue, sucrose_fraction (representing the fraction of biomass partitioned as sucrose in the stem) and green_leaf_no. However, climate and soil differences between regions changed the level of influence cultivar parameters had on simulation outputs. Specifically, model outputs were more sensitive to changes in the transp_eff_cf and k_L parameters in the Burdekin region due to lower rainfall and poor simulated soil conditions. Collecting data on influential traits that are relatively simple to measure (e.g. number of green leaves) during cultivar development would greatly contribute to the simulation of new cultivars in crop models. Influential parameters that are difficult to measure directly such as transp_eff_cf and sucrose_fraction are ideal candidates for statistical calibration. Calibrating crop models either through direct observation or statistical calibration would allow crop modellers to better test how new cultivars will perform in a range of production environments.     

不同方法处理甘蔗叶梢饲喂山羊的试验研究

为了探讨不同处理方法对甘蔗叶稍营养价值的影响及饲喂山羊的效果,为科学利用甘蔗叶梢养羊技术提供科学依据。分别采用青贮、氨化、微贮的方法处理甘蔗叶梢,并进行山羊的饲养试验。结果表明,青贮、氨化、微贮甘蔗叶梢均达到优级标准;与新鲜甘蔗叶梢相比,氨化和微贮均提高了甘蔗叶梢的粗蛋白(CP)、粗脂肪(EE)、灰分(Ash)、钙(Ca)、磷(P)的含量;在精料相同的条件下,氨化、微贮均可极显著(P0.01)提高山羊对甘蔗叶梢的采食量、平均日增重和养羊的经济效益。     

甘蔗茎秆切割力的计算

利用弹性理论,采用双梁模型对甘蔗茎秆材料的切割进行了理论建模,并得出了蔗材切割力的理论计算公式。以单向复合材料为甘蔗茎秆的材料模型,分析了影响切割力的因素,建立了甘蔗材料单位切割力的经验公式。通过对甘蔗切割力试验数据的分析,得出本文试验条件下的甘蔗茎秆切割力经验公式,并通过试验对该经验公式进行了验证。     

甘蔗抗虫机制的研究进展

甘蔗是重要的糖料作物也是潜在的能源作物,而甘蔗的生长过程中长期受到各种虫害威胁。目前用于防治甘蔗害虫主要是通过化学防治和生物防治,带来的害虫耐药性和环境安全问题不容忽视。选育和利用抗虫品种,挖掘甘蔗自身抗虫特性是目前公认的最根本、经济有效和对环境影响最少的办法。笔者首先介绍了不同甘蔗品种对甘蔗螟虫的抗性等级,再从甘蔗的物理抗性和生理生化抗性2个方面阐述甘蔗的抗虫原理,并重点介绍了甘蔗的诱导型生理生化防御体系。全文还就目前甘蔗抗虫研究现状提出建议和展望,以期为培育甘蔗抗性品种以及蔗田害虫综合治理提供参考。     

广西甘蔗螟虫发生概况和动态变化

广西甘蔗对我国食糖安全起重要作用,而螟虫是影响甘蔗产业最重要害虫。因此,螟虫防治一直是科研工作者重点关注的科学问题,20世纪60年代以来研究者一直对螟虫预测预报、防治方法等进行了深入研究,但是几十年以来还是依赖化学防治为主,长期使用化学药剂,易导致害虫产生抗药性,污染环境破坏生态平衡。对螟虫种类、分布、为害特点等进行简述,重点分析广西甘蔗虫害预测预报、危害情况和防治方法等方面的历史和现状差异,并对现阶段螟虫防治存在的问题和未来发展提出了一些建议,望为广西甘蔗螟虫防治提供参考依据。     

Molecular detection of sugarcane striate virus and sugarcane white streak virus and their prevalence in the Miami World Collection of sugarcane and related grasses

Viruses in the genus Mastrevirus (family Geminiviridae), including those infecting sugarcane, have natural geographical ranges almost exclusively restricted to Africa and the Indian Ocean islands off the African coast. Only sugarcane white streak virus (SWSV) in Barbados and sugarcane striate virus (SStrV) in Florida and Guadeloupe are known to infect a few sugarcane varieties in the Western Hemisphere. In this study, PCR assays were developed to detect these two viruses in sugarcane. Five hundred and seventy-one DNA samples from Saccharum species and interspecific hybrids from the Miami World Collection of sugarcane and related grasses were tested for the presence of SStrV and SWSV by PCR. No variety was found infected by SWSV but SStrV was detected in 19 varieties. PCR data were confirmed by sequencing amplified fragments (248 bp). These fragments shared 93%–100% nucleotide identity with SStrV sequences from the GenBank database. SStrV isolates were distributed in six phylogenetic groups, including the four strains of the virus. Most varieties infected by SStrV originated from Asia, thus confirming a previous hypothesis stating that this virus originated from this continent. Absence of SStrV in commercial sugarcane in Florida also suggested that this virus has not been spread in this location, while infected plants have been present for several decades.     

纳米磁珠联合PCR检测甘蔗杆状病毒方法的建立和初步应用

本研究通过对DNA提取裂解液的成分和用量以及裂解时间等因素进行系统优化,建立了一种高通量的磁珠法提取甘蔗总DNA,再进行PCR检测甘蔗杆状病毒(SCBV)的方法。采用核酸自动提取仪,应用纳米磁珠提取甘蔗总DNA,经PCR检测甘蔗杆状病毒,并与以试剂盒提取DNA为模板的PCR检测结果进行比较。结果显示,经优化的裂解液成分为EDTA·Na20.08 mol/L、NaCl 0.8 mol/L、SDS 2%和Tris-HCl0.10 mol/L,裂解时间为20 min,可用于纳米磁珠提取甘蔗总DNA进行SCBV检测。所建立的方法通量高、成本低、耗时短,可用于SCBV的批量检测。     

甘蔗茎尖脱毒培养技术研究

针对热处理结合茎尖分生组织培养甘蔗脱毒苗在茎尖培养阶段由于污染率和褐变率高培养成功率较低问题,在甘蔗的热处理、茎尖解剖、接种等阶段设计不同试验进行研究探讨,以期提高茎尖培养的成活率和成功率。试验结果表明,不同的甘蔗品种在热处理时应需不同的水浴温度和时间;在茎尖解剖前,使用75％酒精处理可以减少茎尖培养的污染率;在接种前,将茎尖放到无菌水或者150mg／L的PVP（聚乙烯毗咯烷酮）溶液中浸泡15min可以减少酚污染,PVP还对其生长有促进作用;活性炭的作用有利有弊,需要进一步的研究确定其用量。     

国家甘蔗品种第五轮区域试验广西隆安点表现

2006-2008年间。在广西隆安县对12个参试材料和2个对照品种进行了2年新植和1年宿根的区域试验,结果表明：MEX105新宿平均含糖量和甘蔗蔗糖分最高,比对照增产增糖明显。Q170平均蔗茎产量最高,新宿平均合糖量高于两对照．比对照增产增糖较大。CP88—1762、粤糖94—128、HOCP92-648、HOCP91—555的平均蔗茎产量和平均含糖量均高于两对照,表现较好,其它品种表现不突出。MEX105、HOCP91-555、闽糖96—1409、闽糖93—730、FR93—435、CP88-1762平均甘蔗蔗糖分高于两对照,其它品种的甘蔗蔗糖分表现不突出。     

滴灌条件下不同施钾量对甘蔗产质量的影响

为了评估甘蔗生产上应用滴灌施肥技术的效应,比较了滴灌系统及传统方法施用钾肥对甘蔗产量和品质的影响以甘蔗品种粤糖00—236为试材．进行了1年（2006～2007）露天盆栽滴灌种植试验。设置了4个通过滴灌系统施用的钾肥（KCl）水平,K1：10g／盆,K2：15g／盆,K3：20g／盆和K4：30g／盆,滴灌各处理施尿素15g／盆,和1个常规施肥方式（肥料施用量为尿素30g／盆和KCl30g／盆）。试验结果表明．滴灌施肥显著促进了甘蔗的生长．比常规施肥的甘蔗产量获得显著提高,K1、K2、K3和K4处理的每盆蔗茎收获量分别比常规管理的增加了19．2％、38．6％、45．9％和56．4％、滴灌条件下,施钾量不同对甘蔗产质量有显著影响．甘蔗产量随施钾量的增加而增加．但过多施用钾肥对甘蔗品质有负面影响.在甘蔗生产上应用滴灌施肥技术,可以节省钾肥的施用量。而且钾肥用量为常规推荐施用量的一半即可获得较常规施犯高三成以上的产量,通过滴灌系统施用钾肥既有经济效益．又有环境效益．