不同甘薯品种抗旱性评价及耐旱指标筛选

在人工控水条件下,以15个甘薯品种为试验材料,设置干旱胁迫和正常灌水2个处理,研究了干旱胁迫条件下不同甘薯品种产量和农艺性状差异。根据产量抗旱系数法分级,抗旱品种(抗旱系数≥0.6)为济薯21、济薯25、济徐23、济薯15、烟薯25;中等抗旱品种(0.4≤抗旱系数0.6)为徐薯18、济薯26、北京553、济紫薯2号、济薯18;不抗旱品种(抗旱系数0.4)为郑薯20、济紫薯3号、济薯22、济紫薯1号、凌紫。干旱胁迫导致甘薯的叶片数、蔓长、叶面积系数和生物量下降,品种间降幅不同,抗旱性强的品种降幅小,抗旱性弱的品种降幅大。这些农艺性状指标与甘薯品种的抗旱性呈显著正相关,可作为甘薯品种抗旱性鉴定的指标。徐薯18可作为甘薯品种抗旱性鉴定的标准品种。     

福建甘薯良种选育成就与展望

概述了 6 0年代以来福建甘薯良种选育的成就 ,介绍了选育目标的变化以及选育方法、亲本组合配制和性状鉴定等的应用 ,并展望了甘薯品质改良的前景及潜力     

桑树红薯间作模式群体光合特性初步研究

为了提高桑树与红薯间作模式群体的光能利用率,优化桑树与红薯间作群体的空间配置,试验探讨了在桑树、红薯生长关键期及共生期内桑树和红薯的光合特性日变化及动态变化特点.结果表明,单作桑树、间作桑树和单作红薯在白天12:00有明显的光合“午休”现象,间作红薯的光抑制现象不明显;桑园间作群体的总生理指标值明显高于单作桑树,其中表观光能利用效率提高了48.13个百分点,表现水分利用效率提高了49.87个百分点,表观CO2利用效率提高了44.18个百分点.光合有效辐射是桑树光合能力的主要影响因子;间作桑树和单作桑树的净光合速率动态变化曲线呈“W”型;桑树与红薯间作群体中存在种间互作效应,桑树的遮阴影响了红薯的光合能力.     

Impact of common sweetpotato viruses on total carotenoids and root yields of an orange-fleshed sweetpotato in Tanzania

The growing and consumption of orange-fleshed sweetpotato (OFSP) is considered as a mean to alleviate vitamin A deficiency in sub-Saharan Africa (SSA) region. However, majority of the field-tested OFSP varieties are susceptible to major diseases especially sweetpotato virus disease (SPVD), which is caused by co-infection of sweetpotato chlorotic stunt virus (SPCSV) with sweetpotato feathery mottle virus (SPFMV). A high beta-carotene content but susceptible variety Resisto was used in this study to evaluate the effects of SPVD on total carotenoids content and root yield. Compared with apparently healthy plants, reduction of 43, 16, and 37% of the total carotenoids content in the OFSP variety Resisto were observed in plants infected with SPCSV, SPFMV, and co-infection of both viruses. Storage root fresh weight was significantly (P < 0.001) reduced due to virus infection with high reduction recorded for SPFMV infection followed by co-infection of SPFMV with SPCSV. The same case was for sweetpotato vine length. However, no major reductions were observed in the vine weights. Co-infection of SPFMV with SPCSV caused more severe symptoms than single infections of the two viruses and each isolate caused distinct disease symptoms on the infected sweetpotato plants. In general, there was no direct correlation between sweetpotato virus disease symptom severity and reduction in total carotenoids. To our knowledge, this is the first report of the negative impact of SPCSV and SPFMV on the total carotenoid accumulation in OFSP varieties. Therefore follow up studies in the area of biochemical analysis should be initiated to gain knowledge on the impacts of SPVD on the biochemical pathways of carotenoid accumulation.     

Natural occurrence of and inoculation experiments withConidiobolus coronatus andConidiobolus sp. in glasshouse populations ofBemisia tabaci

Bemisia tabaci (Gennadius), the sweetpotato whitefly, has only one known entomophthoralean pathogen,Erynia radicans (Entomophthoraceae). Two new pathogens have been isolated recently from a glasshouse population of this pest:Conidiobolus coronatus and another, undescribed species ofConidiobolus (Entomophthorales: Ancylistaceae). Artificial inoculation experiments revealed that eggs ofB. tabaci are practically immune to infection by either species. Second-instar larvae are highly resistant, only high doses of conidia causing between <1% and 4.6% mortality. Adults were found to be much more susceptible. Doses of 60 conidia/mm² ofC. coronatus caused average mortalities ofca 95%. The maximum mortality of adults caused byConidiobolus sp. was much lower,ca 30%, at a dose of 210 conidia/mm². The incubation period (inoculation to death) for both species, under our experimental conditions, is very short: 18–24 h forC. coronatus and 30 h forConidiobolus sp. Both fungi produced loricoconidia (conidia metamorphosed into resting spores) on cotton leaves and other dry surfaces. This ability allowedConidiobolus sp. to remain viable for 17–21 days on cotton leaves, in glasshouse conditions and in the absence of hosts, whileC. coronatus persisted for 10–14 days.     

Hot-water baths,biologicals and re-curing effects on rhizopus soft rot during sweetpotato packing

Rhizopus soft rot (RSR) caused by Rhizopus stolonifer is one of the most devastating postharvest diseases of sweetpotato. It causes greatest losses when sweetpotatoes are removed from storage, washed and packed for marketing. The disease has been managed effectively by prophylactic application of synthetic fungicides on the packing line. However, there is increasing demand for alternative management strategies that do not rely on prophylactic use of synthetic fungicides. While curing immediately after harvest is a standard industry practice, re-curing after storage is not widely practised for postharvest disease management. In this study, the use of hot-water baths, biocontrol agents and re-curing after storage were investigated as potential replacements for synthetic fungicides that are widely used during sweetpotato packing. Hot-water baths at 52 °C for 10–15 min immediately after inoculation reduced RSR incidence by as much as 75%, but increased susceptibility to post-treatment Rhizopus infection. The biological control product Bio-Save® (a.i. Pseudomonas syringae strain ESC-10), used in conjunction with a 4 min water bath at 52 °C, gave similar protection (1.2% RSR, t = −1.7, P = 0.514) as the industry standard treatment with dicloran. Re-curing for as little as 4 h after washing roots significantly reduced RSR and deserves further evaluation to optimize conditions and determine its influence on other postharvest diseases.     

基于SLAF-seq技术的甘薯种质资源群体遗传进化分析

基于简化基因组测序技术对122份甘薯种质资源进行分析,开发SNP位点并将其应用于种质资源群体结构和遗传进化分析。结果表明, 从122份甘薯种质资源中共获得563.18 Mb读长,不同材料的读长数量在1 419 809~8 392 785范围之间。测序质量值Q30在90.61%~96.82%之间,平均Q30为92.78%。测序获得的GC含量在36.46%~40.33%之间,平均GC含量为38.17%,对照GC含量为40.72%。根据测序结果共开发出高质量的SLAF标签2 388 759个,平均测序深度为17.45×。其中,多态性的SLAF标签77 761个,占SLAF标签总数的3.26%。根据所获得多态性SLAF标签统计SNP位点信息,共计获得129 063个群体SNP位点。遗传进化分析表明122份种质资源可以分为3个大类,分类结果与它们的地理来源无直接关系,聚类结果可为甘薯育种亲本组配和杂种优势利用提供科学依据。     

甘薯茎基部腐烂病调查及病原鉴定

2012年以来浙江省台州市及其周边市县甘薯产区发生了大面积的甘薯茎基部腐烂病,导致当地甘薯种植面积大幅度下滑。为明确浙江省甘薯茎基部腐烂病的发生情况、病原组成及种类,本团队于2015年至2018年对浙江省11个县市区进行了田间调查并采集127份病样分离鉴定病原菌,结果表明浙江省甘薯茎基部腐烂病主要存在4种主要症状,根据病菌的致病性、形态特征、ITS和16S rDNA序列分析鉴定,主要鉴定到达旦提狄克氏菌(Dickeya dadantii)、齐整小核菌(Sclerotium rolfsii)、拟轮枝镰孢菌(Fusarium verticillioides )、腐皮镰刀菌(F. solani)、尖镰刀菌(F. oxysporum)、甘薯间座壳菌(Diaporthe batatas)、毁坏性拟茎点霉(Phomopsis destruens)和爪哇镰孢(F. javanicumS)等8种致病病菌,各地区病原菌组成分布均有所不同,采集的样品普遍为多种致病菌复合侵染危害。