Response of tubers of five potato cultivars to co-inoculation with US-1 and US-8 genotypes ofPhytophthora infestans

Summary The severity of late blight tuber rot in five potato cultivars (Green Mountain, Sebago, Dorita, AC Brador and Island Sunshine) resulting from inoculation with US-1/US-8 combinations of Canadian isolates ofPhytophthora infestans was evaluated. In addition, the potential for mixed (A1∶A2) inoculations to result in oospore formation was examined. In studies conducted in 1996 and 1997, cv. Dorita (and Island Sunshine in 1997) developed the least amount of surface or internal necrosis relative to the other cultivars following co-inoculation with US-1 and US-8 isolates ofP. infestans. Differences also were revealed among isolate combinations used for inoculation. The combination of a US-1 isolate from Prince Edward Island with a US-8 isolate from New Brunswick consistently produced the least amount of necrosis in tubers of the various cultivars. There was no evidence of oospore production in any of the tubers examined. AAFC Contribution No. 919     

Drought pretreatment increases the salinity resistance of tomato plants

Agricultural productivity is worldwide subjected to increasing salinity problems. Various strategies are applied to overcome the deleterious effects of salinity on plants. This study was conducted in order to determine whether drought pretreatment of seedlings or seed pretreatment with NaCl increases the long‐term salinity resistance of tomato (Solanum lycopersicum L.) and whether the adaptive response to salinity is accompanied by physiological changes throughout the plant‐growth cycle. When plants were pretreated at the five‐leaf growth stage, the plant dry weight was significantly higher in drought‐pretreated than in non‐pretreated plants after 50 d of salt treatment. The positive effect of drought pretreatment applied at the five‐leaf stage was maintained throughout the entire growth cycle, as fruit yield of drought‐pretreated plants was 40% higher than that of non‐pretreated plants at the end of the harvest period (150 d of 70 mM NaCl treatment). Moreover, the most productive plants maintained lower Na⁺ and Cl^– accumulation in their leaves until the end of the growth cycle, which shows that adaptation is a long‐term response during which the plants adjust their physiology to the environmental conditions. Salt resistance was also improved through seed pretreatment with NaCl. In conclusion, drought pretreatment applied at the five‐leaf stage or seed pretreatment with NaCl provide an alternative way to enhance salt resistance in tomato, and the increase in yield is associated with physiological changes throughout the plant‐growth cycle.     

连作对马铃薯酚酸类自毒物质及根际真菌群落的影响

为研究连作对马铃薯根际土壤中酚酸类自毒物质及真菌群落的影响,通过收集不同连作季(1季、3季、5季)马铃薯根际土壤,利用高效液相色谱法测定酚酸类物质及Illumina高通量测序技术测定真菌ITS序列,结果表明:(1)连作土壤中检测出丁香酸、香豆酸、对羟基苯甲酸、阿魏酸,连作增强后,pH不断下降,对羟基苯甲酸、阿魏酸含量不...     

粤北马铃薯品种比较试验

为筛选出适合粤北山区冬种的优质马铃薯品种,对经前期初步筛选的4个优质马铃薯品种进行了对比试验.结果表明,荷兰薯16号(F)为早熟品种,薯形好,品质、商品薯率、产量等综合性状最佳,鄂马铃薯1号(E1)次之,两品种具有较好的推广前景.桂红皮1号(G)和韶引I号(S)为中晚熟品种,中小薯偏多,增产潜力大,但需进一步试验.     

Leak syndrome of potato in Tunisia caused byPythium aphanidermatum andPythium ultimum

Summary TwoPythium spp. were isolated from diseased tubers exhibiting rots at harvest, in summer stores and also in refrigerated storage. Symptoms shared features described for both pink rot caused byPhytophthora erythroseptica and leak caused byPythium spp. The causal agents were identified asPythium aphanidermatum andP. ultimum by morphological and physiological observations and by fingerprinting using oomycete specific primers to amplify the internal transcribed spacer (ITS1) within ribosomal DNAs. The optimum temperatures for infection were 30°C forP. aphanidermatum and 25°C forP. ultimum, corresponding to the optimum temperatures for growth in vitro. The optimum concentration for infection of tubers inoculated by dipping in a suspension of oospores or hyphal swellings after wounding was found to be 10³ reproductive organs/ml, whereas the infection threshold was 10 reproductive organs/ml.     

陇薯系列高淀粉马铃薯品种的淀粉产量及品质性状综合评价

为了评价高淀粉马铃薯品种的综合品质性状,本研究以甘肃省农业科学院育成的15个马铃薯品种(系)为参试材料,2011-2018年连续8年定点田间试验,测定了块茎产量、营养品质(干物质、淀粉、维生素C、粗蛋白)含量和矿物质元素(钾、钙、铁、锌)含量。结果表明,参试材料的块茎产量和营养品质含量均存在显著的基因型、环境及基因型与环境的互作效应,其中块茎产量、淀粉产量、干物质含量、淀粉含量性状的基因型效应大于环境效应,而营养品质中的维生素C、粗蛋白和还原糖含量的环境效应大于基因型效应。参试材料的块茎产量24 549~50 140 kg·hm^-2,淀粉产量4 271~9 298 kg·hm^-2,干物质含量21.07%~30.18%,淀粉含量14.63%~21.83%,维生素C含量12.20~18.95 mg·100g^-1,粗蛋白含量2.17%~2.71%,还原糖含量0.18%~0.43%,钾含量4 316~5 368 mg·kg^-1,钙含量85.10~138.40 mg·kg^-1,铁含量10.17~24.50 mg·kg^-1,锌含量2.45~3.80 mg·kg^-1。大西洋的衍生品种陇薯8号、陇薯9号、陇薯12号、陇薯14号、L0527-2、L08104-12、LZ111和L1149-2淀粉含量均超过18%,其中,L1149-2总体表现优异,其平均块茎产量50 140 kg·hm^-2、淀粉产量9 298 kg·hm^-2、干物质含量26.75%、淀粉含量19.30%、维生素C含量14.62 mg·100g^-1、粗蛋白含量2.52%、还原糖含量0.28%、钾含量5 297 mg·kg^-1、钙含量138.40 mg·kg^-1、铁含量20.40 mg·kg^-1、锌含量3.20 mg·kg^-1;而陇薯5号淀粉产量及营养品质较差。本研究为合理利用陇薯系列高淀粉马铃薯品种提供了科学依据,对改良高淀粉马铃薯品种产量和品质具有指导意义。     

基于叶片质外体相关成分和酶活性响应的龙葵耐Cd机理研究

为探讨龙葵(Solanum nigrum L.)耐镉(Cd)机理,采用基质培养法,研究了50 μmol·L^-1 Cd(CdCl₂·2.5H₂O)处理120 d对其生长和叶片细胞壁果胶、木质素含量、多聚半乳糖醛酸酶(PG)、纤维素酶(Cx)、NADH-过氧化物酶(NADH-POD)、愈创木酚过氧化物酶(GPOD)和松柏醇过氧化物酶(CAPX)活性以及质外体汁液中过氧化氢(H₂O₂)含量和GPOD、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和超氧化物歧化酶(SOD)活性的影响。结果表明,与对照相比,Cd处理显著抑制了龙葵地上和地下部的伸长生长、降低了根的干物质积累(P<0.05),但茎的分枝增多,叶面积、叶绿素含量、净光合速率和胞间CO₂浓度无显著变化(P>0.05);细胞壁结合酶NADH-POD、GPOD和CAPX活性以及果胶含量显著增高(P<0.05),而PG活性显著下降(P<0.05),Cx活性和木质素含量无显著变化(P>0.05);质外体汁液中H₂O₂含量显著增加(P<0.05),GPOD和SOD同工酶谱及活性无显著变化(P>0.05);CAT同工酶谱带增宽,APX同工酶谱带数增加,二者活性均显著升高(P<0.05)。说明50 μmol·L^-1 Cd较长时间处理龙葵植株,其地上部分生长仍处于良好状态,表现出对Cd毒害的耐性,这与Cd处理后叶片细胞壁果胶含量和结合酶GPOD以及质外体汁液中APX、CAT活性升高有关,推测这是龙葵耐Cd的一种机理。     

冷凉灌区马铃薯施肥量与种植密度对马铃薯生长及产量的影响

为了明确不同施肥量(复合肥)和种植密度对冷凉灌区马铃薯生长的影响。试验以‘冀张薯12号’为供试品种,开展施肥量与种植密度二因素试验,设3个施肥量(600、1100、1600 kg/hm²)与4个种植密度(5.25万、6万、6.75万、7.5万株/hm²),研究不同施肥量与种植密度对马铃薯生长、产量与水分利用效率的影响。结果表明：增加施肥量能延缓马铃薯生育期,提高种植密度能缩短生育期;随施肥量增大,马铃薯株高、茎粗、叶面积指数及叶片SPAD值均显著增大;随种植密度增加,马铃薯株高、茎粗、叶面积指数及叶片SPAD值与产量均表现为先增后减趋势,施肥量与种植密度对马铃薯株高、SPAD值与产量的影响顺序为施肥量>密度;随施肥量和群体种植密度的增加,马铃薯大薯产量、大薯数、产量、水分利用效率均呈先增后减的变化趋势,产量要素之间呈极显著正相关关系,其中,以处理F₂D₃的马铃薯产量与水分利用效率最大。通过二元二次回归分析表明,当施肥量达到1065.366 kg/hm²,种植密度达到6.7...     

马铃薯植株7个主要性状的配合力分析

研究了mira等10个马铃薯品种的22个杂交组合无性一代的植株生长势等7个植株性状的群体遗传和配合力效应。结果表明,晚疫病的亲本加性效应达90.6%;开花性、茎色分离、株高分离、株形分离等4个植株性状的亲本非加性效应分别为72.3%,80.1%,81.5%,93.0%;植株生长势和花色分离的亲本加性和非加性效应均很重要,其加性效应分别为45.2%,47.9%,非加性效应分别为54.8%,52.1%。双亲(至少有1个)一般配合力高的杂交组合的群体表现,优于双亲具有一般配合力平均值的杂交组合;而双亲具有一般配合力平均值的杂交组合的群体表现,优于双亲一般配合力都很低的杂交组合。根据亲本配合力可以有效预测杂交组合后代群体的遗传表现。     

马铃薯衰老相关基因的电子克隆与生物信息学分析

利用电子克隆获得马铃薯衰老相关基因(StSAG)的cDNA序列,并对其进行生物信息学分析.结果表明,马铃薯衰老相关基因的cDNA序列全长1 062 bp,包含一个561 bp的开放阅读框,编码186个氨基酸;StSAG的等电点为7.20,为亲水叶绿体蛋白,无信号肽,有12个磷酸化位点,在N末端有一个较短的伸展肽段.StSAG与茄科植物烟草亲缘关系最近.