Highly polymorphic AFLP markers as a complementary tool to ITS sequences in assessing genetic diversity and phylogenetic relationships of sweetpotato (Ipomoea batatas (L.) Lam.) and its wild relatives

Comparative analyses of genetic diversity and phylogenetic relationshipsof sweetpotato (Ipomoea batatas (L.) Lam.) and its wildrelatives in Ipomoea series Batataswere conducted using amplified fragment length polymorphism (AFLP) and sequencedata from the internal transcribed spacer (ITS) region of the ribosomal DNA. LowITS divergence among thirteen species of ser. Batatasresulted in poorly resolved relationships. More variable AFLP characters werefound to be more efficient in characterizing genetic diversity and phylogeneticrelationships at both intra- and interspecific levels within ser.Batatas. Highly informative AFLP fingerprints of 36accessions representing 10 species of ser. Batatas weregenerated using only six primer combinations. Of the species examined,I. trifida was found to be the mostclosely related to I. batatas, whileI. ramosissima andI. umbraticola were the most distantlyrelated to I. batatas. The highlypolymorphic AFLP markers are a valuable tool in assessing genetic diversity andphylogenetic relationships of sweetpotato and its wild relatives.     

不同生态环境对甘薯主要品质性状的影响

为研究甘薯鲜薯总胡萝卜素、淀粉、蛋白质、还原性糖和可溶性糖等主要块根品质特性在不同地区的生态变异,选用"徐薯25"与"徐22-5"杂交所获得的不同甘薯基因型,在4个生态点进行栽插试验,系统分析不同生态环境下甘薯块根主要品质性状的变异规律。结果表明:生态点、年份、基因型、地点×基因型互作、年份×基因型互作对甘薯鲜薯总胡萝卜素、淀粉、蛋白质、还原性糖和可溶性糖的影响均达到显著水平。胡萝卜素表现为基因型×环境互作效应大于基因型效应和环境效应,而其他品质性状均表现为环境效应远大于基因型效应和基因型×环境互作效应;可溶性糖和蛋白质含量的年际效应明显大于基因型主效应或基因型×年份互作效应,而其余3个品质性状的基因型×年份互作效应大于基因型主效应或年份主效应。在4个生态点中,徐州点的胡萝卜素、还原性糖和可溶性糖含量最高,但淀粉含量最低;烟台点的蛋白质含量最高,胡萝卜素含量最低;南昌点的蛋白质含量最低,胡萝卜素含量最高;万州点的还原性糖和可溶性糖含量最低,上述品质性状随纬度变化的规律不明显。值得关注的是,不同环境下,蛋白质含量为烟台点>徐州点>万州点>南昌点,表现出随纬度升高而增大的趋势。不同年份处理间,2008年的胡萝卜素、还原性糖及可溶性糖含量高于2009年,而2008年的淀粉和蛋白质含量低于2009年。淀粉、可溶性糖含量变幅范围在2年间差别不大,而其他3个性状变幅范围在2年间差别较大。各甘薯基因型在不同地点、不同年份间品质性状的变异中,以胡萝卜素变异系数为最大,淀粉变异为最小。     

南方甘薯新品种比较试验

以广薯87为对照,通过品比试验,分析了新近引进（选育）的福薯21、泉薯10号等9个南方甘薯新品种的产量、薯块品质、抗病性等性状,并评述了其在生产和育种上的利用价值：泉薯10号、福薯21、金薯2号可作为高产鲜食品种推广,桂粉3号和龙薯14宜作为优质高产品种推广。     

微量法快速提取甘薯叶DNA条件的优化

[目的]筛选出一种简便快捷的DNA微量提取方法。[方法]从不同处理甘薯植株的叶片中提取DNA样品并用紫外分光光度法和琼脂糖凝胶电泳法检测其纯度和质量。[结果]正常光照下甘薯植株的DNA产量最高,48h黑暗处理的次之,24h黑暗处理的最低。在正常光照下和48h黑暗处理中项芽的DNA产量都明显高于叶片;在24h黑暗处理中,顶芽与叶片的DNA产量比较接近。叶片DNA的纯度高于顶芽,正常光照下和24h黑暗处理中DNA的纯度高于48h黑暗处理中的。DNA电泳图谱表明,正常光照下叶片DNA的电泳条带一般比顶芽的好。48h黑暗处理中顶芽和叶片DNA的电泳条带没有很大差异。[结论]该试验为大批量实生苗DNA的快速提取和多种分子生物学研究奠定了实践基础。     

不同施磷量对鲜食型甘薯产量及磷素吸收的影响

采用田间试验的方法,设置了6个磷水平(0,37.5,75.0,112.5,150.0,187.5kg/hm²),研究不同施磷量对鲜食型甘薯产量、干物质积累和磷素积累的影响。结果表明,施磷能够显著增加甘薯产量并提高商品薯率,当施磷量为P205112.5kg/hm²时增产幅度最大。施磷水平对甘薯干物质积累与分配有显著影响,在甘薯各生长时期施磷条件下块根干物质积累量和积累速率整体上均显著高于不施磷处理(P<0.05),同时施磷还提高了地下部干物质分配比率,促进了块根产量的形成。施用磷肥可以显著提高甘薯对磷素的积累,随着施磷量的增加,甘薯植株的磷积累量呈现增加趋势。     

甘薯体细胞胚状体及其在脱毒、扩繁中的应用

通过甘薯徐薯18茎尖体细胞培养诱导胚性愈伤组织和胚状体,建立了体细胞无性系.胚性愈伤和胚状体诱导培养基为MS附加0.5～2.0mg/L 2,4-D、0.5mg/L NAA、0.1mg/L BA及100mg/L HL.研究结果表明:采用茎尖体细胞胚胎发生途径能够同时实现试管苗的深度脱毒及大幅度提高扩繁量,脱病毒率达95%,扩繁量达382.9倍.田间种植该脱病毒种苗能     

不同产量水平甘薯品种光合产物分配差异及其原因

选取我国北方薯区主栽的食用型甘薯品种龙薯9号、红香蕉、泰中6号、苏薯8号、遗字138和北京553,于2011—2012年2个生长季在山东农业大学农学试验站进行大田试验,研究不同产量水平甘薯品种光合产物的分配差异及其原因。在甘薯主要生长时期测定茎蔓各部位蔗糖含量和基部茎粗、在块根膨大过程中对功能叶进行13C标记,探索不同品种13C同化物分配特点,同时研究上述项目与收获指数和块根产量的关系。结果表明,高产品种龙薯9号、红香蕉、泰中6号和苏薯8号产块根均在60 t hm–2左右,而中、低产品种遗字138和北京553产块根在50 t hm–2以下。高产品种的收获指数显著高于中、低产品种。在块根膨大前期高产品种的块根成为光合产物的分配中心,而中、低产品种的块根则在块根膨大后期成为分配中心;在块根膨大前、中期,高产品种13C同化物在块根中的分配比例显著高于中、低产品种,即高产品种光合产物由功能叶向块根的转运能力强于中、低产品种。供试品种茎蔓基部的蔗糖含量均高于顶部,且中、低产品种的蔗糖浓度差大于高产品种;随着甘薯生长发育,中、低产品种茎蔓基部增粗速率高于高产品种。相关分析表明,块根产量与收获指数呈极显著正相关(r=0.98**,2011;r=0.93**,2012);块根13C分配率与块根产量和收获指数均呈显著正相关(0.87*和0.91**,2011;0.92**和0.99**,2012);生长中后期,基部茎粗与块根产量和收获指数均呈显著负相关(–0.78*和–0.83*;–0.88**和–0.95**)。块根成为光合产物分配中心的时间早、光合产物由功能叶向块根的转运能力强是高产品种收获指数显著提高的主要原因,而中、低产品种光合产物由叶片向块根转运能力差的主要原因是块根中光合产物卸载不畅。     

Variation in Gelatinization Characteristics of Storage Root Starch During Sweetpotato Growth and Development

The differential scanning calorimetry (DSC) and rapid visco-analyzer (RVA) were used to determine the starch gelatinization characteristics during the growth of three sweetpotato cultivars. The results showed that the starch contents of three sweetpotato cultivars all decreased as growth progressed. Changes of the amylose contents differing in harvesting dates should be discriminated according to the cultivars. At the early harvests amylose contents of Xushul8 and Zheda9201were relatively high, but those of Zhe3449 were low. As the growth duration of sweetpotatoes prolonged, the peaks of DSC thermograms tended to occur at a low temperature and not to be so obstrusive with the increased width of the peak.Obvious decreases were observed, values of onset, peak and conclusion temperatures, as well as enthalpy of phase transitions, as growth time lengthened. The peak viscosities, as determined through RVA, showed a rising tendency as growth progressed. In addition, statistical analysis revealed that there were correlations between the amylose content and gelatinization characteristics to some extent, which were affected by genotypes evidently.     

甘薯花青素的提取及其抑菌效果分析

 建立了甘薯块根花青素（sweetpotato anthocyanin,SPAC）的大孔树脂吸附制备技术，分析了其抑菌作用和机理。结果表明，在0.8%柠檬酸、物料比1∶200，60℃温水浴提取2 h的条件下可获得最大的提取率3.81 mg·g-1。 粗提物经AB-8大孔树脂过柱纯化后可获得色价为225.1E的纯品，色价提高6倍。研究发现SPAC对3种常见致病菌均有抑菌作用，并与其浓度呈正相关。通过电镜观察、SDS-PAGE分析及生长曲线比较表明，SPAC抑菌机理是通过SPAC与细胞中的蛋白或酶结合，使其变性失活，抑制对数生长期的细胞分裂，而后使细胞质固缩、解体，导致细胞死亡。SPAC具有色素和抑菌双重功能，是理想的功能性天然色素。     

Enlargement of the variances in amount and composition of anthocyanin pigments in sweetpotato storage roots and their effect on the differences in DPPH radical-scavenging activity

To investigate the effect of differences in anthocyanin composition on radical-scavenging activity in the purple-fleshed sweetpotato storage root, 124 sweetpotato clones with various compositions of anthocyanin were produced by crosses among superior sweetpotato genetic resources, and were analyzed for anthocyanin composition and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity (RSA). The highest content of anthocyanin among the clones was twofold higher than the content of cv. Ayamurasaki, which has been released for use in industrial pigment production in Japan. The range of variance in anthocyanin composition was very wide, as the ratio of peak areas of cyanidin-based anthocyanins to total anthocyanin peak areas ranged from 85.7% to 6.0%. The relationship between anthocyanin content and RSA was positively correlated. Correlation coefficients between RSA and the HPLC peak areas of cyanidin-based anthocyanins ranged from 0.606 to 0.687, whereas those of peonidin-based anthocyanins were 0.124–0.271. These results clearly demonstrated that cyanidin-based anthocyanins are closely related to DPPH RSA in sweetpotato storage roots.