烟草花叶病毒番茄株、弱株系N_(14)对番茄的保护作用

多年调查鉴定表明,西宁地区蕃病毒病主要以烟草花叶病毒(TMV)侵染为主,表现为三个株系(条斑株系、轻花叶株系和重花叶株系),蕃茄生长后期,黄瓜花叶病毒零星发生,是否存在TMV的其他株系和马铃署的X病毒(PVX),Y病毒(PVY),需要今后进行大量的调查和鉴定工作。

茄子黄萎病发生与土壤接菌量的关系

结果表明，土壤接菌量与茄子黄萎病的发生及流行关系密切，接菌量大于３００ ｇ·株－１ 时，发病重；接菌量小，发病轻．土壤中微菌核的数量与地上部发病的程度呈正相关．一般重病茄田土壤中微菌核的数量，较轻病田及零星病田为高．茄子生长期茄株维管束变色株率，随接种量的增加而增加。

茄园棉铃虫防治技术

棉铃虫是杂食性害虫,除为害棉花外,还为害玉米、高粱、番茄等作物。近年来,棉铃虫为害蔬菜呈上升趋势。据调查,茄子因棉铃虫猖獗为害,年减产达五成以上。 茄园的棉铃虫主要以幼虫蛀食茄子的花蕾、花及果实,造成落花、落果,并使被虫蛀的果实腐烂;也为害嫩叶、嫩茎,食成孔洞,致使茄果产量和成品率下降,根据棉铃虫发生特点和为害特性,采取如下综合防治技术,可控制其发生为害。

Establishment of Rapid Propagation Technique for Cotyledon of Solanum torvum

[Objective] To research the mass propagation system for cotyledon of Solanum torvum. [Methods] With cotyledon of S. torvum as the research object, ef- fects of hormone combination on callus induction and adventitious buds differentia- tion of S. torvum were researched. [Results] With cotyledon of S. torvum as the ex- plants, the optimal culture medium for callus induction and adventitious buds differ- entiation was MS＋2.0 mg/L 6-BA＋0.3 mg/L NAA. The induction rates of callus and adventitious bud reached 100% and 85%, respectively. The number of average buds was 6. The optimal culture medium for the induction of adventitious roots was MS＋ 0.3 mg/L IAA. The rooting rate reached 100% and the number of average roots was 9. [Conclusions] One-step induction of callus and adventitious buds simplified the mass propagation system, and enhanced the test test efficiency.s

Management of Insect Vectors of Viruses in Tomato Plants Using Different Densities of Yellow Traps

The initial phase of tomato is critical to the infestation of insect vectors of viruses. Therefore, this study aimed to test the use of yellow card traps around the crop to manage insect vectors of viruses and test the best density of traps/tomato plants. Yellow card traps were placed on the border of the crop plot to capture adult insect vectors. Density of trap/tomato plant was assessed in 10 blocks at the following levels： 1/25; 1/50; 1/75; 1/100; 1/125; 1/150. The monitoring was carded out in 1% of the crop during 60 days in 2011 and 2012 crop. The evaluated systems were Conventional and Phytosanitary Pest Management （PPM）. During 2011 season the Conventional system received 14 insecticide applications whereas only 6 insecticide applications were made on the PPM, representing a reduction of 133%. In 2012, the crop under Conventional system was subjected to 15 applications of insecticides, over 8 on PPM, with a reduction of 87.5%. The PPM allowed a 90% reduction in application cost for this insects, obtaining a reduction of R$1,345.00/ha. The highest density was 60 plants/trap. We can conclude that the yellow card traps in tomato crop decreased infestations of insect vectors of viruses.

Effects of Humic Acid and Bread Yeast on Growth and Yield of Eggplant （Solanum melongena L.）

This study was carried out at the vegetable research field, College of Agriculture, University of Duhok, during the growing season of 2009 using the eggplant local cultivar. And a factorial Randomized complete block design （F-RCBD）. The experiment consisted of two factors, the first was inoculations with and without humic acid, and the second factor was three levels of dry bread yeast （0.5, 10 gm/L）. The results revealed that the growth was significantly increased in term of plant height, branches number%, total chlorophyll and mineral content in leaves （N.P.K） and the yield in term of fruit number/plant, fruit weight （gm）, plant yield （gm/plant）, total yield （ton/hectare）, fruit length and fruit diameter. The interaction between humic acid and bread yeast was highly improved the growth and yield traits.

Effects of Salicylic Acid on the Growth and Some Physiological Characters in Salt Stressed Tomato Plants （ Solanum L ycopersicum）

Excessive soil salinity is an important constraint limiting the distribution of plants in natural habitats, and is an increasingly severe agricultural problem in arid and semi-arid regions. Higher salinity levels caused significant reduction in growth parameters like leaf area, leaf length and root and shoot dry weight. Salicylic acid （SA）, a plant phenolic is now considered as a hormone-like endogenous regulator, and its role in the defence mechanisms against biotic stressors has been well documented. In recent years its role has been widely investigated in abiotic stress （salinity, drought, water deficit and so on）. The aim of the present work was to study the effects of salicylic acid on growth and some physiological characters of salt stressed tomato plants. The presence of salicylic acid at low concentration （0.01 mM） in culture medium riched with NaCl 100 mM （6 g·L^-1） improves the tolerance of tomato cv. Golden Sunrise to salinity. This amelioration results in stimulation of growth and development of plants. The applied of SA in saline medium induce： （i） an increase in chlorophyll content; （ii） a better supply of essential elements in plant growth, such as K＋; （iii） a decrease in toxic ions such Na＋ and CI in aerial organs; and （iv） an additional synthesis of organic solutes and osmoprotectors like proline and proteins. All these results suggest that salicylic acid could be successfully used in alleviating depressive effects of salt on the productivity of the cultivated tomato.

A Review on Tomato Regeneration

The present status of studies on regeneration of tomato in vitro was introduced, and the key factors that influence the shoot regeneration system in tomato were summarized, such as genotypes, explants type, explant physiological status, plant hormones and additives. The paper also discussed issues existing in tomato tissue culture and prospected the future development of this system.

Effect of the Chemical Mutagens Sodium Azide on Plant Regeneration of Two Tomato Cultivars under Salinity Stress Condition in vitro

The study was carried out to induce variations and stimulate callus induction, plant regeneration from different explants of two tomato （Lycopersicon esculentum Mill.） cultivars Trescantos and super Regina by using tissue culture technique and Sodium azide as a chemical mutagens at concentrations （0.0, 2.0 and 4.0） mM under salinity stress condition at the levels（3.0, 6.0 and 9.0） dS/m. Different plant growth regulators were tested for their potentials in callus induction. The results revealed that treated seeds with SA （sodium azide） at concentration （2.0） mM increased seed germination percentage, seedling height and root length as compare to control treatment. While （4.0） mM concentration cause a reduction in all parameters mentioned above. Concerning to callus induction both cultivars showed a different response against different tested media with varying concentrations of plant growth regulators and despite their variable response to all tested media a combination of （2.0） mg from Kinetin （KIN） and lndol acetic acid （IAA） was found to be the most effective as compare to other treatments. Moreover, when callus transferred to a stressed media the variation was observed in explants fresh weight, and high reduction with the increment of salt level were recorded. Similarly the regeneration efficiency from stressed callus were observed at the level 3.0 and 6.0 dS/m while 9.0 dS/m the callus failed to regenerate plants for all three explants of both tomato cultivars.

MicroRNAs in tomato plants

MicroRNAs (miRNAs) are a specialized class of small silencing RNAs that regulate gene expression in eukaryotes.In plants,miRNAs negatively regulate target mRNAs containing a highly complementary sequence by either mRNA cleavage or translational repression.As a model plant to study fleshy fruit ripening,miRNA studies in tomato have made great progress recently.MiRNAs were predicted to be involved in nearly all biological processes in tomato,particularly development,differentiation,and biotic and abiotic stress responses.Surprisingly,several miRNAs were verified to be involved in tomato fruit ripening and senescence.Recent studies suggest that miRNAs are related to host-virus interactions,which raises the possibility that miRNAs can be used as diagnostic markers for response to virus infection in tomato plants.In this review,we summarize our current knowledge systematically and advance future directions for miRNA research in tomato.

Alteration of Sl YABBY2b gene expression impairs tomato ovary locule number and endogenous gibberellin content

Tomato is an ideal model species for fleshy fruit development research. Sl YABBY2 b regulates the ovary locule number, which is increased by gibberellins, in tomato. However, the relationship between Sl YABBY2 b and endogenous gibberellin is poorly understood. In this study, Sl YABBY2 b-overexpressing and RNA interference(RNAi) transgenic tomato plants were used to elucidate the mechanism by which Sl YABBY2 b regulates the ovary locule number and endogenous gibberellin content in tomato. Sl YABBY2 b-overexpressing plants showed fewer locules and lower gibberellin content than the control plants. Contrasting results were found in the RNAi lines. Therefore, the Sl YABBY2 b gene negatively regulates tomato ovary locule number and endogenous gibberellin content. Furthermore, the expression of Sl YABBY2 b gene was remarkably higher than that of the wild type in the apical shoots of gibberellindeficient mutants. This showed that the gibberellins can inhibit the expression of Sl YABBY2 b gene negative regulation. Further study revealed that Sl YABBY2 b suppressed the expression of Sl GA20 ox1 and Sl GA3 ox2, but increased that of Sl GA2 ox1 and Sl GA2 ox5 in the apical shoots of Sl YABBY2 b-overexpressing plants, thereby reducing gibberellin content. Contrasting results were found in the RNAi lines. Our results showed that the Sl YABBY2 b gene was located on gibberellin signal transduction pathways, fed back regulation of the synthesis of gibberellin, and felt exogenous gibberellin signal to further regulate the formation of tomato locule.