Managing faba bean residues to enhance the fruit quality of the melon (Cucumis melo L.) crop

Mulching and/or topsoil incorporation of plant residues from green manure legumes can increase cropping system sustainability, and can supply and retain nutrients. Two field experiments were conducted in Italy over the period of 2006–2007, to investigate the effect of faba bean grown in a temperate environment to fruit morphology, quality and chemical composition of the subsequent melon (Cucumis melo L.) crop. Flowering faba bean plants were managed as mulch on the melon plant rows and cut and incorporated into the soil, in comparison with cultivated soil (control) and black plastic mulch.     

Wounding of melon fruits as a model system to study rind netting

The rind of muskmelon (Cucumis melo L. var. reticulatus) fruits contains a network of suberized periderm tissue, referred as the ‘net’, which originates in response to cracking of the fruit surface during its enlargement. Shallow cuts were made on the surface of melons to mimic naturally occurring cracking and induce net-like periderm development. Histological analysis of wounded fruits of the climacteric netted variety Krimka, and of two smooth melon varieties: the climacteric Momordica and the non-climacteric Tamdew, indicated that smooth melon varieties can undergo netting when their rind is fissured. Furthermore, the results implied that the climacteric character is not essential for net-tissue development, even though most netted varieties are climacteric. The involvement of ethylene in net-like periderm development was studied by analyzing the expression pattern of the ethylene-biosynthesis genes 1-aminocyclopropane-1-carboxylate synthase 1 and 1-aminocyclopropane-1-carboxylate oxidase 1 following wounding and during periderm development, and by applying the ethylene-generating chemical, Ethrel, as a lanolin paste, on the fresh cuts. Results suggested ethylene involvement in periderm initiation, but continuous exposure may interfere with further tissue development and organization. General implications of the current study on periderm development are further discussed.     

甜瓜细菌性软腐病病原鉴定

近年来,浙江义乌等地的甜瓜(CucumismeloL.)果实上普遍发生一种外观褐色小斑,果肉水渍状腐烂现象,局部田块发病率高,损失严重。为确定病原,从病果上分离到4个细菌菌株,分别定名为M1、M2、M3和M4。烟草过敏性反应和致病性测定表明M2和M4不具致病性,而M1和M3在烟草上能引起典型的过敏性坏死反应,接种甜瓜24h内即导致果实的明显腐烂,所引起的腐烂症状与田间发病果实一致。对M1和M3进行培养性状、革兰氏染色、形态学和鞭毛观察、马铃薯薯块腐烂试验,以及16SrRNA基因测序和比较,结果证明该病害是由软腐欧氏杆菌软腐亚种Erwiniacarotovorasubsp.carotovora引起。     

Identification of QTLs related to sugar and organic acid composition in melon using near-isogenic lines

The soluble sugar and organic acid composition of melon (Cucumis melo L.) fruit flesh has become a major focus of plant breeding worldwide in an attempt to improve taste. Thus, sugar and organic acid profiles were characterized using near-isogenic lines (NILs) derived from the Spanish cultivar Piel de Sapo (PS) and the exotic Korean accession Shongwan Charmi (PI 161375). Fruits were cultivated in only one environment. These data were used to map 60 quantitative trait loci (QTLs): 18 for individual sugars, eight for sucrose equivalents, five for the glucose-to-fructose ratio, seven for the total sugar content and 21 for organic acids. Within the QTLs that were associated with the sugar profile, 27 defined the sugar content: eight for fructose, six for glucose, four for sucrose, and nine for sucrose equivalents. Although increased sweetness of selected NILs compared with the parental PS was achieved by an increased glucose or fructose content, only glucose heritability was above 0.5. A total of 21 QTLs (two with positive effects and nineteen with detrimental effects compared with the PS levels) controlled the organic acid profile: l-glutamic, ascorbic and succinic acids (the principal ones) and fumaric, citric, oxalacetic, and isocitric acids. The levels of sugars imparted by the PI 161375 introgression frequently decreased the score grades given to NILs by consumers. Within the 32 QTLs mapped for sensory traits, 27 were associated with lower scores in taste (nine QTLs), sweetness (eight QTLs) or global quality appreciation (nine QTLs); two with increased fruit sourness or sweetness and three with increased fruit bitterness. The QTLs defined herein may assist breeders to understand the overall organoleptic balance (sweetness, sourness, and umami taste) in melon fruit, particularly those located within linkage groups III, V, VI, and VIII to XI.     

Tetraploid muskmelon alters morphological characteristics and improves fruit quality

Tetraploid muskmelon plants were induced successfully from diploid Cucumis melo inbred M01-3 (2n = 24) by colchicine. The morphological characteristics and fruit qualities of diploid and tetraploid muskmelons were investigated. The results showed that the leaves and flowers of the tetraploid plants were markedly larger, the plants were obviously higher, and the stems were thicker than those of the diploid plants. Transmission electron microscope observation revealed that the numbers of chloroplast, granule and grana, and the length of chloroplast and granule of the tetraploid plant leaves were significantly more or longer than those of the diploid plants. The soluble solid, soluble sugar and vitamin C contents in the tetraploid fruit were distinctly higher than those in the diploid fruit. The weight of the tetraploid fruit was 30% heavier than that of the diploid fruit. And the seeds from the tetraploid plants were broader and thicker than those from the diploid plants. Together, our results suggest that the tetraploid muskmelon exhibited better agronomical characteristics than the diploid muskmelon and the tetraploid muskmelon could be used as the improved variety and a potential germplasm for the development of triploid fruit.     

Grafting effects on postharvest ripening and quality of 1-methylcyclopropene-treated muskmelon fruit

In addition to managing soil-borne diseases in muskmelon (Cucumis melo L.) production, grafting with resistant rootstocks may impact fruit quality. The ethylene antagonist 1-methylcyclopropene (1-MCP) has been shown to extend shelf life of fresh muskmelon fruit. Postharvest characteristics of 1-MCP-treated melon fruit as affected by grafting, however, have not been well examined. This study was conducted to explore the influence of grafting with different rootstocks on ripening and quality attributes of 1-MCP-treated muskmelon fruit during postharvest storage. Grafted ‘Athena’ muskmelon with two commercial squash interspecific hybrid rootstocks including ‘Strong Tosa’ and ‘Tetsukabuto’ as well as non-grafted and self-grafted ‘Athena’ were grown in replicated field plots at the University of Florida Plant Science Research and Education Unit (Citra, FL, USA) during April–June 2010. Half-slip fruit from two harvests were treated with 1.0 μL L⁻¹ 1-MCP (18 h, 20 °C) and analyzed during storage at 13 °C. For fruit from the 27 May harvest, whole fruit and mesocarp firmness, titratable acidity, soluble solids, and ascorbic acid content were measured, while production of ethylene and CO₂ was determined on fruit from the 29 June harvest. Grafting did not show a significant impact on fruit yield but affected the fruit shelf life significantly. Fruit from non-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Strong Tosa’ demonstrated a shelf life of 31 d for the first harvest and 22 d for the second harvest. Shelf life of fruit from self-grafted ‘Athena’ and ‘Athena’ grafted onto ‘Tetsukabuto’ declined by 6 d and 3 d for the first and second harvest, respectively. Whole fruit firmness decreased by approximately 15.5% on average from 13 to 31 d except day 19 as a result of grafting, but to a lesser extent with ‘Strong Tosa’ rootstock. Mesocarp firmness of grafted melon was reduced by about 30.2% at days 13 and 19 compared to non-grafted ‘Athena’ fruit. In contrast, titratable acidity, soluble solid content, and ascorbic acid concentration were less affected by grafting. All the measurements except for ethylene and CO₂ production declined during storage regardless of the grafting treatment. Compared with ‘Strong Tosa’ rootstock, ‘Tetsukabuto’ resulted in a more rapid ripening under 1-MCP application, as reflected by earlier increase in ethylene production and higher respiratory rate. The study demonstrates that grafting effects on postharvest ripening and quality of ‘Athena’ muskmelon can vary markedly with rootstocks used.     

Reflective materials under hailnet improve orchard light utilisation,fruit quality and particularly fruit colouration

The increase in hailstorms, possibly due to climate change, has led to installation of hailnets in fruit orchards worldwide. This is associated with poorer fruit quality, particularly fruit colouration, which is determined by the light conditions viz diminishing light intensities and shorter day length in the autumn. To overcome these adverse effects of hailnets, five materials were examined as possible ground covers as to their light reflection and the subsequent effect on fruit quality including fruit colouration, using a 9-year-old apple orchard cv. ‘Gala Mondial’ on M9 under black hailnet near Bonn. The ground covers included the woven white plastic Extenday^R/Daybright™, the kaolin-coated, bio-degradable paper UniSet O™ and the aluminium-coated plastic Mylar™ and Svensson ILS Alu™; the latter is a white plastic interwoven with aluminium strips used as energy saving screen in greenhouses. The ground covers were spread in the alleyways 4–5 weeks before anticipated harvest; adjacent uncovered grass strips under the hailnet served as control. Light reflection, measured perpendicular at 1 m height in the alleyways at the time of fruit colouration, was 79–80% by Extenday^R/Daybright™, 75% by UniSet O™, 68% by Mylar™ and 58% by Svensson Alu ILS™. Apple fruit with any of the reflective ground covers ripened 2–3 days earlier without affecting internal fruit quality and sugar as indicative of taste. The reflective ground covers under black hailnet improved the proportion of well-coloured class I fruit relative to the control (uncovered grass) by an averaged 9%. Economic analysis showed that Extenday^R, with an expected lifetime of ten years (based on 4–6 weeks spread time per year) under hail nets in North-Western Europe, scored best based on 45 t ha⁻¹ yield in cv. ‘Gala Mondial’ and 0.40 € kg⁻¹ farm-gate price, resulting in 200 € ha⁻¹ net return. Manual labour for spreading and retrieving the ground covers had the major share of the overall gross cost and offers scope for improvement by mechanisation.     

诱抗剂处理对甜瓜叶部病害和果实品质的影响

以抗病品种银帝和感病品种卡拉克赛为材料,在露地条件下研究了几种植物提取液和苯并噻二唑(BTH)处理对甜瓜主要叶部病害及果实大小和品质的影响。结果表明,BTH、中草药提取液和侧柏提取液对甜瓜叶部各种主要病害的发生都有明显的抑制效果,尤其对白粉病的抑制效果最好,平均防效达75%。4种诱导剂中,BTH对各种病害的防效都较稳定,平均达51.44%,且在幼果期和伸蔓期+幼果期的预防效果均较植物提取液好。采前诱抗处理能明显提高两品种甜瓜果实品质及抗病品种(银帝)的产量,但对感病品种卡拉克赛产量影响不显著;初花期BTH处理可增加果肉厚度、提高可溶性固形物含量,并能改善果实经济性状。     

甜瓜杂交种SSR指纹图谱的构建

以2个甜瓜杂交品种(系)的种子东方蜜1号和01-31为试材,从63对SSR引物中筛选出10对扩增产物具有稳定多态性的引物,这些引物分布在甜瓜整个基因组,每对引物可以检测到2～4个数目不等的多态性片段(allele),共27个多态性片段,平均为2.7个,片段大小介于85￣270bp之间,并从入选的10对SSR引物中选出7对构建了这2个甜瓜杂交种的指纹图谱。在比较分析各试材图谱的基础上,探讨了品种指纹图谱的统计学方法,并对构建的2个甜瓜杂交种的指纹图谱进行了可信度分析,建立了适于种子检验中使用的标准SSR标记指纹图谱。实验表明,利用SSR技术进行甜瓜杂交种的纯度鉴定是可行的、有效的。     

Plant spacing and cultivar affect melon growth and yield components

The objective of this study was to evaluate the effect of cultivars and in-row spacing on vegetative growth and yield components in melon (Cucumis melo L.). The cultivars ‘Early Dawn’ (ED), ‘Superstar’ (SS) and ‘Medoro’ (ME) were grown in rows 1.5 m apart at plant spacing 0.6, 0.9, 1.2 or 1.5 m. Cultivars ED and SS were grown in 1998 and 1999, while ED and ME were tested in 2000. The main vine length, diameter, number of leaves and lateral branches were highest at 1.5 m in-row spacing in 1999 and 2000, while there was no influence of plant spacing on observed growth parameters in 1998. ED performed better compared with other two varieties, mostly due to more fruit per ha and per plant. Yield was significantly decreased with increased plant spacing in all 3 years of research. At in-row spacing of 1.5 m yield was in average 25% lower than at 0.6 m spacing. Average fruit weight slightly increased with plant spacing up to 1.2 m, even though the differences were significant only in 1999. Small differences among cultivars were also found. Number of fruit per ha decreased linearly while number of fruit per plant increased linearly as plant spacing increased in all cultivars except SS in 1999.     

从甜瓜子叶中提取总DNA

用分子标记方法检测甜瓜杂交种子纯度,如果从真叶中提取DNA,检测周期至少需要15d。为了缩短检测周期,我们分别以甜瓜的成熟干种子、吸胀水后“露白”种子、3d龄刚转绿子叶、6d龄子叶、9d龄子叶和12d龄子叶为材料,进行了提取总DNA的研究。结果表明:除了干种子和吸胀水后“露白”种子外,其他的材料都可以提取到DNA,但是DNA的质量因子叶日龄不同而存在很大的差异。不同日龄的子叶中,以3d龄子叶提取的DNA质量好。子叶6d龄时,提取的DNA质量次于3d龄,少量DNA开始出现降解,以后随着子叶日龄的增加,DNA降解加重。另外,与以真叶为材料提取的DNA样品相比较,子叶DNA样品中的蛋白质等杂质含量高,应增加氯仿抽提纯化次数。     

A new peptide of melon seeds which shows sequence homology with vicilin: Partial characterization and antifungal activity

Plant resistance against pathogens involves a broad variety of proteins, which can be either constitutive or induced. Different types of antimicrobial proteins have been purified from plant seeds, including chitinases, β-1,3-glucanases, defensins, thionins, lipid transfer proteins, lectins and vicilins. The aims of this study were to isolate and characterize defense-related proteins, particularly antimicrobial peptides, present in melon (Cucumis melo L.) seeds. Seed proteins were extracted with phosphate buffer, pH 5.4 and subjected to precipitation with 90% relative ammonium sulfate saturation. The precipitate was re-dissolved in distilled water and heated at 80 °C for 15 min. A DEAE–Sepharose column equilibrated with 0.1 M Tris–HCl pH 8.0 was employed for further purification of the peptides with antifungal properties. Fractions with inhibitory activity were detected in the non-retained basic peak (P1). To test whether P1 peptides were able to permeabilize the yeast plasma membrane, we monitored their effects on glucose-stimulated acidification of the incubation medium by yeast Saccharomyces cerevisiae cells. This fraction strongly inhibited glucose-stimulated acidification of the medium by yeast cells in a dose-dependent manner, and inhibition was up to 60% for all concentrations tested. Effects of the P1 fraction upon the growth of the phytopathogenic fungus Fusarium oxysporum were also observed. Proteins in P1 fraction were also subjected to automated N-terminal amino acid sequencing. Partial N-terminal sequence of a major 8 kDa protein revealed homology with previous reported storage vicilins from different seeds.     

利用RAPD快速鉴定甜瓜杂交种的遗传纯度

通过PCR程序优化 ,建立了快速进行甜瓜RAPD分析的技术体系。从 80个随机引物中选出 5个可进行 3个甜瓜杂交种纯度鉴定的引物 ,其中OPM17可同时用于 3个甜瓜杂交种的纯度鉴定。通过多个品种间的RAPD分析 ,建立了 3个杂交种的特有指纹图谱 ,可用于 3个杂交种的遗传纯度鉴定     

Use of ISSR,SRAP, and RAPD markers to assess genetic diversity in Turkish melons

The genetic relationships among 63 melon (Cucumis melo L.) genotypes collected from various regions of Turkey were determined by comparing their molecular ISSR, SRAP, and RAPD markers with those of 19 foreign melon genotypes to investigate the taxonomic relationships and genetic variation of Turkish melon germplasm. Total 162 polymorphic markers (69, 18, and 75 obtained from ISSR, SRAP, and RAPD primers, respectively) were used to define the genetic similarity among the melon genotypes by dendrogram or two and three dimensional scalings. The average similarity (SM coefficient) between any two pairs of accessions examined as estimated by molecular variation was 0.73 ± 0.48. Within-group genetic similarities ranged between 0.46 and 0.96. Related genotypes or genotypes collected from similar regions were partitioned to similar clusters. Southeastern Anatolian genotypes were distinctly apart from group inodorus and group cantalupensis (sweet) genotypes. This reinforced the position of Turkey in the secondary genetic diversity center of melon. The genetic diversity among Turkish genotypes (H = 0.28 and I = 0.42) was only a little less than that of the world accessions (H = 0.30 and I = 0.45). On the other hand, the percentage of polymorphic loci among Turkish melon genotypes (90.7%) was even higher than that of the world accessions (87.6%).     

不同整枝留果方式对甜瓜产量与品质的影响

在海南采用简易竹木大棚进行哈密瓜类甜瓜金海蜜品种不同整枝留果方式试验,结果表明,采用双蔓单果(主蔓留果)方式,甜瓜单果重、网纹、可溶性固形物含量、产量等表现最好;建议生产上使用该种整枝留果方式栽培。     

甜瓜组织培养再生植株中的四倍体变异

甜瓜未成熟子叶,幼苗子叶和真叶离体培养的再生植株中存在着明显的四倍体变异,比率分别为３０％,１６．２％和４２．９％,四倍体植株在花冠,气孔,花粉,种子和果实的形态和大小方面均与二倍体植株表现明显的差异。再生植株叶片气孔大小和气孔保卫细胞内叶绿体数目可以作为从再生植株中早期鉴别四倍体植株的可靠指标。组织培养可以成为获得四倍体甜瓜的有效途径。     

甜瓜辐射花粉诱导单倍体的影响因素研究

以Co60γ射线为辐射源,研究了辐射剂量200,300,500,800,1200,1500和2000Gy对甜瓜单倍体诱导率的影响。同时在辐射花粉授粉6h后,用1,10,50,100和200mg/L的2,4-D,以浸蘸柱头和节间注射2种处理方法,研究2,4-D对甜瓜辐射花粉诱导单倍体的影响。研究结果表明,辐射剂量在200~1500Gy时,坐果率低于对照(96.7%),但不同剂量间坐果率没有明显的差异,都达到80%以上;而在2000Gy时坐果率明显降低,仅为63.3%。2,4-D的两种处理方法在低浓度(1mg/L)时,对坐果率没有影响;但随2,4-D处理浓度的升高,坐果率呈下降趋势。浸蘸柱头对出胚率和植株再生率没有明显影响,而在100mg/L浓度下采用节间注射处理时出胚率和植株再生率分别为2.8%和1.09%,明显高于其他处理。     

Phenolic content and free radical scavenging activities in rambutan during fruit maturation

The 1,1-diphenyl-2-picrylhydrazyl (DPPH^•) scavenging activity, changes and accumulation of phenolic content were studied in the peel, seed and pulp of rambutan, Nephelium lappaceum L. (Rongrien and Seeechompoo cultivars) during fruit maturation. The IC₅₀ values of the radical scavenging activity of the peels, in both cultivars remained low through fruit development (1.42–4.75 μg/mL) but the values of the seed and pulps were low at the beginning and increased markedly toward fruit development until harvest (4.87 to >1000 μg/mL). The accumulation of phenolic compounds in rambutan peels of Rongrien and Seechompoo cultivars increased continuously until reaching a maximum of 1653 and 733 mg per fruit at the time of being harvested, at 112 and 98 days after full bloom (DAFB), respectively. Ellagic acid, corilagin and geraniin in the peels of both cultivars were observed and quantified. The major component in the peels of the two cultivars was geraniin. The accumulation of ellagic acid, corilagin and geraniin in the peels increased and reached the maximum at the harvest stage, especially the major constituent of geraniin (1011 and 444 mg/fruit for Rongrien and Seechompoo, respectively). The free radical scavenging property was observed to have a relationship with the phenolic content quantified in different parts of the rambutan fruit. This research demonstrates potential data on phenolic constituents through fruit development, especially in the peels at the time of harvest.     

Quality fruit improvement in sweet pepper culture by bumblebee pollination

The percentage of ovules that set seeds per fruit has been used to evaluate the bumblebee activity of a two campaigns greenhouse trial. The experiment was carried out with two commercial cultivars of sweet pepper, ‘bell’ type, called Bardenas and Vergasa. The averages of the percentages of seed set per fruit of the two campaigns were 49.8% (Bardenas) and 40.7% (Vergasa) on the pollination treatment, whereas the averages of the control (self-pollination) treatment were 27.5% and 25.7%, respectively. Percentages of seed set per fruit was strongly related with the number of bee visits, but weakly with duration of visits.