Latent infection of Botrytis cinerea in rose flowers and combined chemical and physiological control of the disease

A high percentage of rose flowers collected during winter from greenhouses around Israel developed grey mould disease when incubated in the laboratory in favourable conditions. Symptomless flowers of various cultivars were incubated in a humidity chamber after surface disinfection. More than 50% of the symptomless flowers yielded the pathogen Botrytis cinerea Pers., thus showing the presence of latent infection which probably occurred 3–8 days earlier in the commercial greenhouses. Initially, the symptoms which occurred on affected petals were mainly restricted lesions. However, when flowers were incubated under favourable conditions, necrosis developed and spread. Chemical control of grey mould was tested on cut rose flowers. Partial control of the disease was correlated with reduction in necrosis and a relative increase in restricted lesions (<2 mm in diameter). Of the 18 fungicides which were tested, the following were the most efficient during incubation at 20°C: metomeclan, dichlofluanid, myclozolin, N-phenylcarbamate plus carbendazim (NPC + MBC), polyoxin D, prochloraz and iprodione. When incubated at 10°C, the most effective fungicides against grey mould of rose flowers were NPC + MBC, polyoxin D, chlorothalonil, the detergent Tween 20, and the inhibitor of ethylene activity, silver thiosulphate (STS). Diphenylamine was more effective at 4°C than at 10° or 20°C. STS in combination with each of the fungicides chlorothalonil, polyoxin B, myclozolin or merpan was additively more effective than STS or each of the respective fungicides alone.     

Inheritance of winterhardiness in roses

Summary Heritability in the broad sense and the distribution of levels of winterkill were analyzed in the offspring from hardy diploid and from hardy, semi-hardy and tender tetraploid roses. The heritabilities for different parental combinations ranged from 51 to 92%.The offspring from crosses of hardy parents were also hardy and showed little variation in hardiness levels. The offspring from crosses of hardy roses with the semi-hardy R. kordesii and the tender Queen Elizabeth survived the winters without coverage but showed a wider variation in hardiness levels.The desirable level of hardiness, an average winterkill of less than 10%, could be achieved through selection in the first or second generation of breeding, depending on the hardiness levels of the parents. The hypothesis is advanced that winterhardiness in roses is controlled by very few or closely linked genetic factors.Contribution No. 557     

Note: Evaluation of antibacterial activity of essential oil of<Emphasis Type="Italic">Rosa damascena</Emphasis> on<Emphasis Type="Italic">Erwinia amylovora</Emphasis>

Significant antibacterial activity was observed in the essential oil (E.O.) ofRosa damascena Mill. and the Minimum Bactericidal Concentration (MBC) of the E.O. was determined as 1386.5 μg ml⁻¹ forErwinia amylovora, the causal agent of fire blight disease. Ooze formation on immature pears and lesion formation in artificially inoculated shoots were completely (100%) prevented by the essential oil ofR. damascena (1500 μg ml⁻¹), essential oil ofThymbra spicata var.spicata (500 μg ml⁻¹) and streptomycin (100 μg ml⁻¹). Copper oxychloride plus maneb significantly reduced ooze formation and lesion formation, but the control was less than that obtained with the essential oils or streptomycin. The essential oil ofR. damascena may be a useful natural bactericide for the control of the fire blight pathogen,E. amylovora. http://www.phytoparasitica.org posting July 14, 2004.     

High density genetic map and quantitative trait loci(QTLs) associated with petal number and flower diameter identified in tetraploid rose

Rose is one of the most important ornamental and economic plants in the world. Modern rose cultivars are primarily tetraploid, and during meiosis, they may exhibit double reduction or preferential chromosome pairing. Therefore, the construction of a high density genetic map of tetraploid rose is both challenging and instructive. In this study, a tetraploid rose population was used to conduct a genetic analysis using genome sequencing. A total of 17 382 single nucleotide polymorphism(SNP) markers were selected from 2 308 042 detected SNPs. Combined with 440 previously developed simple sequence repeats(SSR) and amplified fragment length polymorphism(AFLP) markers, a marker dosage of 6 885 high quality markers was successfully assigned by GATK software in the tetraploid model. These markers were used in the construction of a high density genetic map, containing the expected seven linkage groups with 6 842 markers, a total map length of 1 158.9 c M, and an average inter-marker distance of 0.18 c M. Quantitative trait locus(QTL) analysis was subsequently performed to characterize the genetic architecture of petal number and flower diameter. One major QTL(qpnum-3-1) was detected for petal number in three consecutive years, which explained 20.18–22.11% of the variation in petal number. Four QTLs were detected for flower diameter; the main locus, qfdia-2-2, was identified in two consecutive years. Our results will benefit the molecular marker-assisted breeding of modern rose cultivars. In addition, this study provides a guide for the genetic and QTL analysis of autotetraploid plants using sequencing-based genotyping methods.     

基于神经网络的食用玫瑰花图像识别算法

针对单依靠颜色或形状将采摘期玫瑰花从图像中分割出来难度较大的问题,研究一种基于神经网络的食用玫瑰花图像识别算法。将处于采摘期的玫瑰花正面图像作为识别对象,先提取HSI色彩空间下的S分量,用最大类间方差法(Otsu)进行分割;再提取目标图像灰度共生矩阵下的纹理特征,选取区分度高的纹理特征,结合BP神经网络,建立识别模型。试验结果表明:该方法正确识别率85%,识别率主要受试验样本开放标准选取的影响,而受光照影响不敏感,是一种较好的识别方法。     

分子标记技术在月季育种中的应用

对分子标记技术在月季的种质资源鉴定、遗传多样性、分子标记辅助选择以及分子遗传图谱的构建等方面的应用进行了综述,并对其应用前景进行了展望。     

失水胁迫对月季花瓣内肽酶活性的诱导及对花朵衷老进程的影响

[目的] 研究失水胁迫对月季切花花瓣内肽酶活性和种类的诱导与花朵衰老进程加速之间的关系.[方法] 切花月季 samantha 为试材,分别进行了如下处理(1)反复失水胁迫处理,即依次失水胁迫24 h、复水12 h、然后再次失水胁迫24 h,(2) ABA 预处理后的失水胁迫处理,即50μmol-L-1的ABA处理12 h后,失水胁迫24 h;并以直接蒸馏水瓶插作为对照.[结果] (1)失水胁迫和再次失水胁迫,即两次胁迫处理期间花颈的弯曲状况相近,但失水胁迫后花朵的瓶插状况差异非常明显,其中,再次失水胁迫后的花朵出现了严重的僵蕾现象.ABA预处理明显减轻了失水胁迫期间花颈的弯曲程度.(2)第1次失水胁迫后复水6 h,花朵水势能够恢复到胁迫前的水平,而花枝鲜重和花瓣内肽酶活性在复水12 h后才能恢复到胁迫前的水平;再次失水胁迫后,花朵水势下降和花枝鲜重损失率都呈现与第1次胁迫相近的变化,但是花瓣内肽酶活性的变化更为剧烈,上升幅度更大.ABA预处理有效抑制了失水胁迫带来的水势降低、鲜重损失以及内肽酶活性的升高.(3)对照花材在自然开放和衰老进程中,没有检测到金属蛋白酶和巯基蛋白酶活性;丝氨酸蛋白酶活性一直占据主导地位,在衰老时进一步显著升高.失水胁迫对花瓣内肽酶活性和种类的诱导与花朵自然衰老诱导一致.失水胁迫明显诱导提高了丝氨酸蛋白酶活性,复水使其活性恢复到胁迫前的水平,再次失水胁迫进一步加剧其活性的升高.ABA预处理显著降低了失水胁迫诱导的丝氨酸蛋白酶活性的增加.[结论] 失水胁迫对花瓣中丝氨酸蛋白酶活性的强烈诱导与复水后瓶插期间衰老进程加速之间存在一定的联系.     

刺玫果的生物学特性

以人工栽培刺玫果为研究对象,通过调查研究掌握了刺玫果生物学特性及生长发育规律.结果表明,刺蔷薇、刺玫蔷薇物候期基本一致;采取第2年平茬的办法,可提高枝条分蘖数量2.3倍,匍匐繁殖枝条1.7倍;在栽培上,对4 a或5 a生枝条（枝条密度较大）进行剪除,生长良好,枝条活力旺盛;萌生枝条生长速度仅有一个高峰,从5月20日开始,至7月12日结束,从这一结果可以确定施肥重点,促进枝条生长发育,应在5月20日到7月初补施速效氮肥,为促进枝条成熟,应于7月中旬补施磷钾肥;果实从开花始期至果实膨大,6月1日花期结束平均果实直径达到0.46 cm,迅速膨大期在7月15日之前,此期生长量占果实总量85%.     

保加利亚玫瑰嫩枝扦插感病率的分析

通过三因素三水平27种组合的正交试验和分析,认为插穗腐烂病的发生是由于难生根的离体保加利亚玫瑰嫩枝插穗的抗性弱、空气和土壤的高温高湿条件所造成的;分析还表明土壤因素对保加利亚玫瑰嫩枝扦插腐烂病影响最大,其次是插穗因素和浸穗试剂,并据此提出感病率较低的4种组合类型.     

妙峰山玫瑰嫁接苗与自根苗生理生化指标比较

以日本无刺蔷薇（A）、美国多花无刺蔷薇（B）、美国M1号（C）为砧木嫁接妙峰山玫瑰（D），通过大棚盆栽对比试验研究妙峰山玫瑰嫁接苗与自根苗的光合特性和生理生化指标。结果表明：嫁接苗与自根苗的净光合速率（Pn）日变化规律相似，均呈单峰曲线，峰值出现在11：00—14：00，其中B＋D的P。最高，D最低；由综合最大净光合速率、光补偿点（LCP）、光饱和点（LSP）、表观量子效率（AQY）、水分利用效率（WUE）等指标可以看出，4种苗木的光合性能，以B＋D最优，A＋D最弱；C＋D叶片光合色素各项指标的测定值最低，D最高；嫁接苗的保护酶活性略高于自根苗，而膜脂过氧化产物丙二醛含量是自根苗较高。