微生物侵染木薯块根导致病变而腐败,通过对木薯少根根霉菌株(Ca-201613)的鉴定、优化培养,对衍生产物及其淀粉消化功能研究.结果表明:(1)菌株最适培养温度为35.0℃,属于嗜热型真菌,而≥40.00℃会抑制生长;(2)添加20.0 g/L葡萄糖的培养条件下,获得菌株最高生长量和代谢衍生物产量,而≥30.0 g/L会抑制生长;(3)添加10.0 g/L木薯淀粉,有利于促进菌株生长和代谢;(4)菌株代谢物的鉴定得到853个化合物,包括腺苷类、酸类、脂类和激素类;(5)菌株GR891和SC9块根的衍生物中检测出8种可溶性单糖,总糖含量为381.36μg/mg和399.55μg/mg,其中葡萄糖含量占87.42％～92.30％.木薯少根根霉是对淀粉具有糖化功能的益生菌株,为菌株"变弊为利"应用提供理论依据.

气候条件是农业发展的一个重要因素,不良天气引起的气象灾害具有不确定性,严重阻碍和损害农业的发展.通过对不良天气影响下受害葡萄园区的调查,发现受灾种植区种植生产管理受阻、病虫害发生情况严重.本文分析了导致葡萄产量减少、品质下降,成本高、效益低的原因,并提出了灾后管理和补救措施,为保障农产品质量安全和促进农业科可持续发展提供参考.

Cassava is an ideal food security crop in marginal and drought environment. However, the post-harvest storage of cassava is urgent problem to be resolved. In this study, the storage tolerant and non-tolerant cassava were screened by measuring the change of Peroxidase (POD), Superoxide dismutase (SOD), Catalase (CAT) and Malondialdehyde (MDA) in seven cultivars of cassava. Compared with other cultivars, the cultivar of SC14 showed the highest level of SOD, MDA and POD respectively at 0 day, 12 day and 9 day postharvest while exhibited lowest level of CAT at 0 day postharvest, indicating the strongest antioxidant capability and storage tolerance. In contrast, GR15231, termed as storage non-tolerance cultivars, showed lowest SOD and POD at 12 day and kept a relative high level of CAT at 12 day post-harvest. In addition, SC14 has higher level of starch and dry substance than GR15231. Mass spectrum was performed for SC14 and GR15231 to explore the key metabolites regulating the storage tolerance of cassava. The results showed that the expression of glutathione (reduced) and raffinose was significantly decreased at 12 day post-harvest both in tolerant SC14 and non-tolerant GR15231. Compared with GR15231, SC14 showed higher level of raffinose both at 0 and 12 day post-harvest, indicating that raffinose may be the potential metabolites protecting SC14 cultivar from deterioration post-harvest. Additionally, raffinose ratio of SC14a/SC14b was five times less than that of GR15231a/GR15231b, reflecting the slower degradation of raffinose in SC14 cultivar compared with GR15231 cultivar. In conclusion, the antioxidant microenvironment induced by reduced glutathione and higher level of raffinose in SC14 cultivar might be the promising metabolites to improve its antioxidant capacity and antibiosis and thus maintained the quality of Cassava root tubers.

探讨了稀植栽培对3个木薯品种生长发育的影响.结果表明:木薯稀植栽培的种植密度比对照降低了13.34％～55.56％,产量增加了350.00～6927.84 kg/hm2,块茎淀粉含量提高了28.45％;与对照相比,木薯稀植栽培的植株高度和一级分枝高度分别增加了9.43％～93.93％和19.29％～101.68％,主茎直径和最大薯块直径分别极显著增大了7.02％～65.57％和21.17％～67.52％;稀植栽培处理因子对木薯的生长发育具有极显著的影响;稀植栽培减少肥料使用量9.54％～37.54％,管理和收获效率分别提高了15.00％～25.00％和15.00％～20.00％,减少劳动力投入20.00％～25.00％.

The production of high-amylose cassava through CRISPR/Cas9-mediated mutagenesis of thestarch branching enzyme gene SBE2 was firstly achieved. High-amylose cassava (Manihot esculenta Crantz) is desirable for starch industrial applications and production of healthier processed food for human consumption. In this study, we report the production of high-amylose cassava through CRISPR/Cas9-mediated mutagenesis of the starch branching enzyme 2 (SBE2). Mutations in two targeted exons of SBE2 were identified in all regenerated plants; these mutations, which included nucleotide insertions, and short or long deletions in the SBE2 gene, were classified into eight mutant lines. Three mutants, M6, M7 and M8, with long fragment deletions in the second exon of SBE2 showed no accumulation of SBE2 protein. After harvest from the field, significantly higher amylose (up to 56% in apparent amylose content) and resistant starch (up to 35%) was observed in these mutants compared with the wild type, leading to darker blue coloration of starch granules after quick iodine staining and altered starch viscosity with a higher pasting temperature and peak time. Further 1H-NMR analysis revealed a significant reduction in the degree of starch branching, together with fewer short chains (degree of polymerization [DP] 15–25) and more long chains (DP>25 and especially DP>40) of amylopectin, which indicates that cassava SBE2 catalyzes short chain formation during amylopectin biosynthesis. Transition from A- to B-type crystallinity was also detected in the starches. Our study showed that CRISPR/Cas9-mediated mutagenesis of starch biosynthetic genes in cassava is an effective approach for generating novel varieties with valuable starch properties for food and industrial applications.

为探讨微量元素水溶肥的功效,开展了中兴微量元素水溶肥在木薯种植中最佳施用方法和浓度的研究,探讨其对木薯产量和品质的影响.结果 表明:施用微量元素水溶肥有利于提高木薯的淀粉含量,对木薯矮化、茎粗增加有一定效果,但对木薯产量影响不明显,表明该肥适合在有大风、台风等地区推广应用.

研究了7个食用木薯种质的农艺性状、产量、淀粉含量、氢氰酸含量、胡萝卜紊含量和蛋白质含量.结果 表明7个食用木薯种质各有所长,均有作为新品种选育或作为育种亲本创制新种质的应用前景,其中2014-68和14S-35产量和淀粉含量极高,产量分别达60.9±13.0 t/hm2、53.7±8.7 t/hm2,淀粉含量较高,而氢氰酸低,可以做工业与食用兼用品种;14S-36和2014-41胡萝卜素含量极高,分别达1330 μg/100 9和1600 μg/100 9,分别比对照高410％、513％,故薯肉自带诱人的鲜艳黄色,且产量较高,可作特异木薯食用品种;老挝6、14S-35和贵港食用的蛋白质含量较高,分别比对照高74％、44％和28％.

从国外引进的5个食用木薯品系在南宁进行品比试验,结果表明:各参试品系适应性好,农艺性状除了Bading都表现较好,综合评价表现最好的是老挝6,每亩产量达3031.3kg,比对照增产24.54％,淀粉含量比对照增加1.43％.

木薯是我国热带亚热带地区重要的经济作物,培育和推广高产优质的木薯新品种,可以有效提高木薯单产,改良木薯品质,对木薯产业的发展起着重要的作用.木薯"桂热7号"是广西亚热带作物研究所和广西木薯研究所于2001年从国际热带农业中心引进的杂交种子[CM9948-1(SM805-15×SM1438-2)]选育而成,2015年通过广西省品种审定(桂审薯2015003号),2016年获广西科技重大专项资助(桂科AA16380012).该品种集高产、优质于一体,适宜热带、亚热带地区种植.项目创建了木薯"桂热7号"的综合配套高产栽培技术体系,创造了显著的经济效益和社会效益.

对3种木薯杂交种子进行催芽、幼苗参数分析及不同因子主体效应分析.结果表明,(1)木薯杂交种子水选率排序为SC5>ELE-1>SC124,可以反映不同品种木薯种子的优劣程度;(2)4种处理方法对木薯种子催芽、生长影响的试验中,试剂浸种处理、水浸种处理的发芽率、株高、叶片数极显著或显著高于其他处理,试剂处理的发芽时间极显著或显著少于其他处理;(3)品种、处理因子对木薯杂交种子发芽率、发芽时间、幼苗株高和叶片数大都具有极显著效应;(4)品种和处理间交互因子对木薯杂交种子发芽率、发芽时间均具有极显著效应;(6)不同年份因子对木薯杂交种子的各指标参数均无显著效应.通过探讨不同主体因子对木薯种子萌发的效应,为杂交育种、种质创新利用提供了理论基础.

[Objective] The aim was to obtain more high-quality research materials by constructed regeneration system of cassava cultivars. [ Method] According to the cell totipotency, with young leaves and axillary buds as materials, we optimized the medium composition, induced the somatic embryogenesis and differentiation, as well as organ development, and cultivated regeneration lines. [ Result] The regeneration a-bilities for four cultivars were in the order of GR3, SC205, GR9891, GR911;the axillary buds were better than young leaves to induce somatic embryonic callus;IBA had much better effect to induce the formation of cassava somatic embryo than 6-BA, and they showed synergistic effect;The combination of IBA and NAA had better effect to induce the rooting of adventitious buds than using only one. [ Conclusion] Efficient re-generation systems for four main cassava cultivars (SC205, GR891, GR911 and GR3) were established, which provided technical basis for protection and innovation of cassava germplasm.

[Objective]Somatic embryogensis induction of cassava hybrid seed and seedling regeneration system were constructed to provide technology reference for cassava breeding and germplasm innovation.[Method]Hybrid seeds of cassava variety Southern China 5(SC5)at various maturity degrees were used as explant materials,including cotyledons (a1)and germs(b1)of immature seed,cotyledon(a2)and germ(b2)of mature seed,cotyledon(a3),germ(b3)and hy-pocotyl(c3)of germinated seed.Different exogenous hormones were used to induce the somatic embryogenesis,forma-tion of cotyledon organ,development and rooting of adventitious bud(stem and leaf organ).And the induction effects of these exogenous hormones were compared.[Result]Pre-culture with basic culture medium(M1)could control the pollu-tion rate(<5.00%)of explants,maintain their biological activities(>90.00%).The browning rate of pretreated materials decreased 30.00%-40.00% than control(not pretreated,CK),and swelling rates of cotyledon(a),germ(b)and hypocotyl (c)increased 6.67%-13.33%,6.67%-50.00% and 20.00% respectively.Inducing somatic embryogenesis with 4.00 mg/L 2,4-D and 12.00 mg/L Picloram,somatic embryogenesis induction rate of germ was the highest,hypocotyl was the se-cond and cotyledons was the lowest.Somatic embryogenesis induction rate of mature seed material was higher than imma-ture seed material,and the effects of 4.00 mg/L 2,4-D was better than that of 12.00 mg/L Picloram.0.10 mg/L BAP and 1.00 mg/L NAA could induce differentiation and proliferation of somatic embryogenesis.But the induction rates of soma-tic embryogenesis in a,b and c induced by 0.05 mg/L BAP+0.50 mg/L NAA were significantly(P<0.05,the same below) increased compared with those adding single 0.10 mg/L BAP or 1.00 mg/L NAA.The adventitious buds induction rate were 30.00%(a2),40.00%(a3),40.00%(b1),53.33%(b2),70.00%(b3)and 13.33%(c3)respectively,which showed that for the same tissue,somatic embryogenesis induction rate of mature seed materials were better than immature seed materials.Among all the seed materials with various maturities,the effects of b were the best. The rooting rates were 23.33%(a2),23.33%(a3),16.67%(b1),30.00%(b2),56.67%(b3)and 0(c3)respectively;the rooting rate of b3 was significantly higher than other materials,and there was no significant difference between a2,a3,b1 and b2.It showed that for the same tissue,rooting induction of mature seed materials was easier than immature seed materials,and their de-velopment was also better.Out of seven hybrid seed materials with various maturities,regeneration plants of a2,a3,b1, b2 and b3 were obtained through somatic embryogenesis induction with success rate of 71.43%.[Conclusion]Pre-culture can inhibit browning of cassava hybrid seed tissues and increase the swelling induction effects. In cassava planting, adding 4.00 mg/L 2,4-D in medium can induce somatic embryogenesis,and adding 0.05 mg/L BAP and 0.50 mg/L NAA misture in medium can proliferate somatic embryogenesis.In addition,seed materials with high maturity level(e.g.em-bryo of germinated seed)should be selected as explant materials.

[目的]构建未薯核心种质.[方法]对161份木薯种质的6个性状参数值进行分析、评价.[结果]建立了Minkowski遗传距离进行质心聚类分析,优先取样法(D2C5S3)适合木薯核心种质构建;获得了木薯核心种质25份,占原种质的15％,能代表原有种质的遗传多样性和完整性;同时也反映了供试木薯种质的遗传背景较狭窄,遗传多样性范围相对较小,存在遗传冗余现象.[结论]木薯核心种质的构建为木薯种质资源保护和利用提供理论依据.

为实施中央“走出去”战略,扩大我国农业技术影响力,帮助缅甸提高木薯产量,提升木薯产业水平,将我国目前推广种植的5个木薯优良品种:桂热4号、桂热5号、华南5号、华南205和华南8号引种到缅甸,通过试验筛选出适合当地的高产高淀粉含量木薯品种,为进一步推广打下坚实基础.结果表明,引入的5个中国优良木薯品种适应性强,在缅甸生长良好,保持了高产优质的优良性状.整体表现优于当地对照品种黄心木薯,鲜薯淀粉含量为21.58 ％～27.47％,鲜薯产量为27.65～38.73 t/hm2,单位面积淀粉产量为6.02～10.31 t/hm2,鲜薯产量及淀粉产量分别比对照增加21.33 ％～69.94％和-0.7 ％～70.1％,品种优势明显,具有很好的推广前景.对扩大我国加工企业的原料来源,缓解我国木薯原料紧张的局面具有重要意义.

该文基于灰色关联理论和方法,对19个木薯种质材料的6个性状指标进行了综合评价研究.结果表明:(1)建立了灰色关联分析和Topsis综合评价方法,获得结果基本是一致的,并与种质资源田间综合表现相符,适用于木薯种质资源的综合评价;(2)灰色关联度对种质资源的评价中,因其灰色关联度(ri)差异系数为0.161 8,差异较小,不能很好地评价出种质资源的优劣,而Topsis法评价结果中Ci值差异的差异系数为0.907 5,差异很大,能更好地评价品种的优劣;(3)通过评价比较,筛选获得了8份具有育种潜力的木薯种质材料.研究结果为木薯种质资源评价、应用提供了科学依据.

The concept,significance and methods of the crop core collection were described,importance of comprehensive study on core collection of germplasm resources and necessity of wide application were analyzed and discussed.It is considered that constructing for crops core collection was an effective method,which was to resolve the current contradictions in germplasm resources research.

By the molecular techniques of identification and evaluation transgenic innovative materials in cassava(Manihot esculenta crantz),rapid detection by PCR,the positive rate of transformation materials was 42.9%,detection by Southern Blot,obtained rate of positive material was 31.8%,45 regeneration materials were got.Detection by Sem-quantitative RT-PCR,the target gene expression approximate in leaves with the wild type,while the expression in roots had significant difference.Observation,recording,evaluation of phenotypic variation positive materials were carried out.In short,a reliable system for genetic transformation regeneration was established,which provided technical and material foundation for cassava breeding.

为了解不同木薯品种对红蜘蛛抗性的差异,2012年6～9月调查了木薯红蜘蛛对12个木薯品种的为害情况,同时设置红蜘蛛防治处理作为对照,收获时测定产量性状以了解非防治状态下木薯受红蜘蛛为害的程度.结果表明:不同木薯品种对木薯红蜘蛛的抗性程度不同,同时在不同生长时段抗性也有差异,9月以前抗性都在中抗以上,到了9月份随着红蜘蛛持续为害木薯抗性减弱,达到高感程度.木薯各品种产量受红蜘蛛为害后均比对照有不同程度的减产,GR3、新选048减产最多,GR891、GR911减产较小.为木薯种植推广和品种布局提供理论依据.