Varying Nitrogen Concentrations to Optimize Basic Seed Potato Minitubers Production in a Three-Phase Hydroponic System

In hydroponics, nutrient management is the limiting factor to obtaining optimal production, and nitrogen (N) is the key component to consider when optimizing nutrient management in these types of systems. The objective of this study is to evaluate different combinations of N fertilizer concentrations in order to optimize the yield of basic seed potato minitubers in a three-phase hydroponic system. Treatments consisted of five combinations of N concentrations, applied before and after 21 days after plant transplant as follows, respectively: 1) 13 and 13, 2) 13 and 0, 3) 13 and 7.8, 4) 13 and 16, and 5) 13 and 26 mmol L^?1. Propagation was performed by transplanting 3–4 cm potato plantlets cv. Agata from sprouts. There were significant effects of N treatments on all measured variables (root, leaf, stem, and plant dry weight and minituber number and weight). To obtain the maximum minituber number yield, 9.51 minitubers/plant, corresponding to 67 minitubers/m², post 21-day adjusted N concentration was 18.4 mmol/L. Treatment 4 promoted higher basic seed potato minituber yield in a three-phase hydroponic system.     

Different Nitrogen Sources Affect Biomass Partitioning and Quality of Potato Production in a Hydroponic System

Crop production systems should reduce nitrogen application costs and assure that the appropriate form of nitrogen is used. Thus, three potato cultivars in a hydroponic system were supplied with two different nitrogen sources to determine the effect on biomass accumulation and partitioning, and total plant nitrogen content. Cultivars Agata, Atlantic and Bintje received, on alternate days, nutritive solutions differing only in either calcium nitrate or urea. Urea stimulated biomass accumulation and total nitrogen in shoots. Moreover, urea reduced the ratios tuber:shoot and tuber:root, and increased the ratio shoot:root, indicating competition for biomass partitioning between shoots and tubers. Urea stimulated greater tuber volume in the Atlantic cultivar, and increased tuber protein content, which is undesirable for industry. These results suggested that salts containing nitrate could be more appropriate for hydroponic potato cultivation, since urea compromised tuber quality and biomass partitioning in all cultivars studied.     

Yield and Quality Response of Two Potato Cultivars to Nitrogen Fertilization

Potatoes require high nitrogen (N) fertilizer rates because of their poor N efficiency. Better understanding of N dynamic in potato crops could improve N efficiency and thus enhance crop profitability and reduce N losses. A similar field experiment was conducted in Switzerland in 3 years, from 2009 to 2011, to investigate the yield and quality response to N fertilization of two commercial potato cultivars with different tuber qualities, Bintje and Laura. Five doses of ammonium nitrate were tested: 0, 80, 120, 160 and 200 kg N ha^?1. Aboveground and belowground biomass evolution, total yield, starch concentration and tuber sizes were measured annually. In 2011, the total N uptake and the soil mineral N content were also measured during the growing season and at harvest.The study showed that N fertilization had a positive effect on yield and the percentage of large tubers (>?70 mm) and a negative effect on starch concentration. Both cultivars presented the same potential yield, although cv. Laura’s yield was more affected by N fertilization deficiency and more responsive to the late N fertilizer application. At harvest, both cultivars had a similar N uptake efficiency and N utilization efficiency. However, they differed with respect to N uptake dynamics. Nitrogen uptake was slower for cv. Laura than for cv. Bintje due to a longer period required for the development of the belowground biomass. The results provide useful recommendations for improvement of N fertilization practices (e.g. rate and time of application) of these two cultivars in Swiss conditions.     

氮高效水稻品种苗期耐低磷种质的筛选与鉴定

以先前通过田间试验筛选出来的36个氮高效水稻品种为供试材料,在苗期进行了耐低磷筛选,并对获得的3个耐低磷和2个低磷敏感品种响应磷素胁迫的生理机制进行了初步研究。结果表明:1)正常供磷和低磷条件下,所有调查性状的相对值(低磷/正常供磷)中,相对根系干质量、相对地上部干质量、相对根冠比和相对分蘖数均具有较大的品种间变异(变异系数分别为16.9%、10.9%、11.4%、16.3%)。相关分析表明,它们呈显著或极显著正相关。因此,这4个性状可以作为水稻苗期耐低磷筛选的评价指标。2)在低磷条件下,筛选出的3个耐低磷品种比2个低磷敏感品种的根系生长旺盛且活力强,P吸收动力学参数中Km、Cmin小,而Vmax大,酸性磷酸酶(APase)活性升幅大,磷效率在两者之间也存在显著差异。同时,不同耐低磷品种适应低磷胁迫的调节机制也有所不同。表明筛选氮磷双高效的水稻品种是可行的,同时也为后续基因定位和遗传机制的研究提供了材料和生理学依据。     

连城县马铃薯新品种筛选试验初报

通过对我县引进的 7个马铃薯新品种进行试验 ,筛选出适宜我县进一步试验示范的马铃薯新品种坝薯 10号、荷 14、中薯 3号、中薯 4号、无花 ,尤其是坝薯 10号、荷 14抗美洲斑潜蝇危害效果好、产量高 ,其中坝薯 10号产量达 184 0 3kg 6 6 7m2 。     

Economic Optimum Nitrogen Fertilization Rates and Nitrogen Fertilization Rate Effects on Tuber Characteristics of Potato Cultivars

The objective of the research was to determine the economic optimum nitrogen (N) fertilization rates and to determine the effects of N fertilization rates on tuber characteristics and fresh mass loss after storage under cold and ambient conditions of four potato cultivars, Ágata, Asterix, Atlantic, and Monalisa. The experiments were, simultaneously, conducted in the same area and similar experimental conditions during the fall/winter period in Viçosa, Minas Gerais State, Brazil. In each experiment, five N fertilization rates (0, 50, 100, 200, 300 kg ha^?1) were evaluated in a randomized complete block design. For all cultivars, increasing N fertilization rate increased total and marketable yields and tuber dry matter yield up to a maximum following a quadratic model. Increasing N fertilization rate linearly increased the tuber protein concentration of Atlantic and Monalisa and had no effect on tuber pH. N fertilization rate effects on tuber mass, tuber titratable acidity, and fresh mass loss during storage were cultivar-dependent. N use efficiency (tuber yield divided by N fertilization rate) decreased with increase in N fertilization rate. The economic optimum N fertilization rates ranged from 147 to 201 kg ha^?1 depending upon cultivar and relative prices of N and potato tubers. Depending on the cultivar, under favorable price conditions (low N price and high tuber price), the economic optimum N fertilization rates to be applied by potato growers were 92–95% of the estimated N fertilization rate for obtaining the maximum potato yield, whereas under unfavorable conditions (high N price and low potato tuber price) the economic optimum N fertilization rates to be applied should be decreased to 86–92% of the rates for maximum yield.     

小麦耐低磷基因型的筛选

为发掘新的耐低磷小麦种质,利用磷源液相控制释放系统,通过相对生物量、根冠比和根部结构特征等形态指标,对41份小麦材料进行耐低磷种质筛选.结果表明,供试材料中,231104、231106和231122的相对生物量均在80%以上,根系发达,根毛长且密.其中,231122的相对生物量接近100%,在低磷胁迫下根部干重和根冠比明显高于正常供磷对照.用231个SSR标记进行多态性分析发现,它们与洛夫林10号和小偃54的多态率分别超过60%和58%.由此说明,231104、231106和231122是不同于洛夫林10号和小偃54的耐低磷种质,且能在低磷胁迫下优先保证根部生长,并调整根的形态结构,以利于吸收磷素,满足植株正常生长的需要.     

马铃薯脱毒试管苗快繁中污染抑菌剂的筛选

在马铃薯脱毒试管苗工厂化快繁过程中,常因各种原因出现细菌污染,严重影响试管苗的生长,给生产带来损失。为了解决这一问题,本试验分别加入卡那霉素、青霉素、链霉素及青霉素和链霉素配合使用的抗生素,研究抑菌剂及抑菌剂浓度在马铃薯快繁过程中的抑制细菌的效果。结果表明:在培养基中加入卡那霉素、青霉素G钠、青霉素和链霉素的混合物都能抑制细菌的污染,但青霉素各处理不仅能抑制细菌污染,而且对试管苗的生长有明显的促进作用,其中青霉素60 mg.L-1的效果最好,同时抑菌剂的抑菌作用具有时效性。     

Quantification of Field Resistance to Verticillium dahliae in Eight Russet-Skinned Potato Cultivars Using Real-Time PCR

Changes in potato production over the past 10 to 20 years, have resulted in increased emphasis being placed on breeding for resistance to Verticillium wilt, caused by Verticillium dahliae Kleb. While many russet-skinned cultivars recently have been released with reported resistance to Verticillium wilt, information is lacking on the level of pathogen colonization, and therefore, the level of true genetic resistance is not known. Eight russet-skinned cultivars were grown in field trials with low and high levels of V. dahliae in the soil, and evaluated for wilt, stem colonization, yield, and tuber vascular discoloration. A recently developed QPCR assay was validated, with strong relationships to culture plating assays over three stem sampling dates. Additionally, stem colonization levels, as determined by QPCR, were related to wilt and tuber vascular discoloration. However, total yield did not exhibit a strong relationship to any other parameter evaluated in this study. Results from these studies indicate that varying levels of true resistance are present in the russet-skinned cultivars evaluated, and that the QPCR assay can be reliable in rapidly evaluating resistance to V. dahliae under field conditions. Based on pathogen quantification using stem colonization derived from traditional plating assays and QPCR, the resistance level of several cultivars is more clearly defined and discussed.     

胡萝卜素漂白法快速筛选耐储藏水稻品种

根据水稻种胚脂氧合酶的主要同工酶LOX-3的活性缺失可以提高耐贮性的特性,研究了快速测定LOX-3酶活性以筛选耐储藏水稻品种的方法。报道了水稻种胚LOX-3具有共氧化的次生反应特性,并根据该特性建立了快速筛选其缺失体的胡萝卜素漂白法（检测时间为3 h）,优化了反应体系。推测在正常氧压下水稻种胚LOX-1和LOX-2不具备或仅具备相对较弱的共氧化次生反应能力。与LOX-3缺失体的单克隆抗体技术和I2-KI比色法相比,胡萝卜漂白法具有方法简单、成本低、快速的优点。还探讨了胡萝卜素漂白法在耐储藏水稻品种改良和相关分子克隆研究中的应用前景。     

耐酸铝大豆品种资源的筛选与鉴定

对引进的139份主要来自湖南省的大豆种质资源,苗期采用简单钙溶液法和全营养液法,以主根相对伸长率为评价指标,分析大豆对铝毒的耐性表现。结果表明,大豆对铝毒的耐性存在基因型差异。首先通过简单钙培养法筛选得到耐酸铝材料12份,之后通过全营养法进行验证获得耐酸铝大豆种质资源8份,即沅陵矮子早<甲>、长沙夏黄豆、常德中和青豆、凤凰青皮豆<乙>、十月青豆、人潮溪黄豆1、中作04563、中作05675。进一步以垦丰15、桂春8号为对照品种,采用土培法对获得的8份大豆耐性材料进行盆栽鉴定,以单株粒重、百粒重、叶绿素含量和株高作为耐铝毒性的评价指标,分析大豆对铝毒耐性的综合表现。遴选出1份耐性较强的材料,即人潮溪黄豆1,可供大豆耐铝毒性遗传育种研究利用。     

抗机械损伤褐变马铃薯品种(系)的筛选

采用分光光度法研究了21个马铃薯新品种(系)在机械损伤条件下的褐变。筛选试验表明,4℃褐变24 h后,品种(系)云薯301、S03-259、S04-801和JS05-53-275的褐变度变化值为0.004~0.081,而且初始褐变度都很小,因此这4个品种(系)可作为抗机械损伤褐变品种(系)加以研究和开发利用。     

Model-Based Evaluation of Maturity Type of Potato Using a Diverse Set of Standard Cultivars and a Segregating Diploid Population

The objective of this paper is to evaluate the performance of the conventional system of classifying maturity type in potato and to provide a concept of maturity type based on crop physiology. We present an approach in which physiological traits are used to quantify and assess maturity type unambiguously for a set of varieties covering a wide range of maturity classes and a diploid F1 population separating for maturity and well-adapted to Dutch growing conditions, both grown in six environments. We defined physiological maturity based on four traits: the duration of maximum green canopy, the area under the green canopy cover progress curve, and the rate and duration of tuber bulking. The results indicated that physiological maturity type criteria tended to define maturity classes less ambiguously than the conventional criterion. Moreover, the conventional criterion was subject to more random noise and lacked stability and/or repeatability compared with the physiological traits. The physiological maturity criteria also illustrated the physiological trade-offs that existed between the selected traits and underlined the subtle complexities in classifying maturity type. This study highlighted the capabilities of different maturity type criteria in discriminating between different maturity classes among the large set of genotypes. Our new approach involving key physiological traits could be beneficial in offering physiology-based criteria to re-define maturity type. An improved criterion based on important physiological traits would allow relating the maturity to crop phenology and physiology. These new criteria may be amenable to further genetic analysis and could help in designing strategies for potato ideotype breeding for genotypes with specific maturity types.     

野生马铃薯抗PVY材料的鉴定与筛选

通过人工接种的方法对5类野生马铃薯材料进行了马铃薯Y病毒(PVY)的抗性鉴定和筛选。它们对PVY抗性存在明显的差异,其中Solanum stoloniferum(S.A2)×S.stenotomum(104)和S.stoloniferum(S.A5)×S.stenotomum(105)组合抗性最强,属于抗病群体,S.chacoense×S.stenotomum(103)组合属于中抗群体,S.chacoense(102)和S.demissum(101)组合属于感病群体。并从中筛选出一批抗PVY的育种材料:0级抗性材料108份,1级抗病材料56份,3级抗病材料94份。     

马铃薯抗Y病毒资源材料的鉴定与筛选

用洋酸浆(Physalis floridana)、A6(Solanum demissum×Aquila)的后代、黄苗榆烟(Nicotianatabacum)、鲁特格尔斯番茄(Lycopersicon esculentum cv.Rutgers)4种指示植物汁液摩擦接种法,对55份马铃薯普通栽培种进行Y病毒的带毒鉴定试验,选出33份不带马铃薯Y病毒的材料;用接种过的番茄为砧木,以不带马铃薯Y病毒的材料为接穗进行嫁接传毒试验;对嫁接后能正常生长30 d以上的材料又回接了该种病毒病的寄主进行抗性鉴定试验。通过试验筛选出10份抗马铃薯PVY病毒的材料,其中免疫的有1份,过敏的有9份,从而为马铃薯抗Y病毒育种提供资源材料。     

基于GGE-biplot的大豆耐低磷资源筛选

为了准确评价大豆耐低磷基因型在不同环境中的稳定性和适应性,采用GGE双标图,通过4种评价指标数据计算耐性因子GGE双标图数学模型对前期鉴定、评价获得的7个大豆耐低磷种质资源分别进行不同环境下耐低磷能力分析评价。结果表明:耐低磷性强且多环境下稳定性较好的品种为丰收24。以地下部干重计算耐性因子双标图显示垦鉴27表现出多环境下稳定的耐低磷性,而以地上部干重为评价指标则显示其耐低磷性较好但并不稳定;同样,以单株磷含量为评价指标显示克交05-1397同样表现出多环境下较稳定的耐低磷性,而以根系活跃吸收表面积评价指标显示其耐低磷性较好但不稳定。因此在利用GGE-biplot筛选耐低磷大豆资源时应结合具体的环境条件。研究结果对适于黑龙江地区不同环境条件下耐低磷大豆的应用具有重要的指导意义。     

马铃薯抗寒种质资源分类及其利用

马铃薯(Solanum tuberosum)作为最重要的粮食作物之一,在全世界范围内被广泛种植,但马铃薯栽培种均不耐低温霜冻且马铃薯栽培种种内几乎没有遗传变异,在生产过程中通常遭受霜冻而导致严重减产甚至绝收。马铃薯野生种中具有丰富的抗寒种质资源,部分野生种材料耐低温霜冻能力强并且能通过短暂的冷驯化使耐低温霜冻性得到进一步提高,是改良普通栽培品种耐冻性的重要种质资源。已有研究表明至少在35个马铃薯野生种中发现有耐低温霜冻的无性系存在。在所有具有强抗寒能力野生种当中,S. commersonii和S. acaule被认为是抗寒能力最强的2个野生种,是改良马铃薯耐冻性的重要基因资源。随着近年来气候变化加剧,极端天气愈来愈频繁,引进马铃薯野生种质资源并评价其耐冻能力,挖掘植物自身的耐冻基因,解析耐冻机制,进而培育耐低温霜冻的马铃薯品种尤显必要。