Effect of Forchlorfenuron (CPPU) and Ethychlozate on Fruit Development and Quality of Mango Cultivar 'Tainong 1'

The fruit swelling effect of forchlorfenurun （CPPU） and fruit thinning effect of ethychlozate on Tainong 1 mango （Mangifera indica L. cv. ） were studied. Spraying 32 mg/L CPPU at 7 and 21 d post flowering for just once significantly improved the fruit size of mango, but had no significant impact on fruit quality and flavor. Spraying 200 mg/L ethychlozate at 7 d post flowering for just once significantly increased fruit drop rate and single fruit weight of mango; fruit grade was improved and total soluble solid increased to the maximum value, so ethychlozate had good fruit thinning effect.

Biological Characteristics of Fusarium oxysporum f. sp.niveum Isolated from Watermelon Cultivated in Plastic Greenhouse and Indoor Toxicity Determination of Different Fungicides in Hainan Province of China

[ Objective] The paper was to study biological characteristics of Fusarium oxysporum f. sp. niveum in watermelon cultivated in plastic greenhouse in Hainan Province of China and to determine indoor toxicity of fungicides. [ Method] Effects of various factors on mycelial growth and spore germination were stud- ied, and the lethal temperature of spores and indoor toxicity of fungicides were also determined. [Result] The fungal mycelium had a better growth rate on water- melon juice medium than the others. The optimum temperature for mycelial growth and spore germination were 28 ℃ and 30 ℃, and the optimum pH values were 7 - 8 and 7 - 9, respectively. Light-dark alternation was conducive for mycelial growth. The lethal temperature of spore was 60 ℃ for 5 min. The fungal mycelium grew better while taking fructose and glucose as carbon sources and yeast extract and peptone as nitrogen sources. Toxicity determination showed that 50% pro- chloraz-manganese chloride complex WP had the greatest inhibition effect on mycelial growth, with the ECso value of 0.730 9 μg/mL; followed by 32.5% benzoic azoxystrobin SC, 30% benzoylate· propieanazol EC, 10% difenoconazole WG, 25% bromothalonil · carbendazim WP and 25% bromothalonil WP, with the ECso values from 1.884 7μg/mL to 8. 161 0μg/mL. [Conclusion] The study provided basic data for field control against F. oxysporum f. sp. niveum on watermelon cultivated in plastic greenhouse in Hainan Province.

Establishment of a Real-time Fluorescent Quantita- tive RT-PCR Method for Pineapple mealybug wilt as. sociated virus-2

Pineapple mealybug wilt associated virus-2 （PMWaV-2） is an important pathogen causing Mealybug wilt of pineapple （MWP）. We established a realtime quantitative RT-PCR （RT-qPCR） method with TaqMan probe based on specific primers of conserved nucleotide sequence of PMWaV-2 coat protein gene. The results showed that the method was higldy sensitive to positive sample, but had no fluorescence signal to health sample and blank control. The sensitivity of RTqPCR was about 100 times higher than general PCR. Reproducibihty test revealed that the coefficients of variation between intra-and inter-assay were beth within 1.85%, indicating it was a quantitative detection method for PMWaV-2 with simple operation, strong specificity, high sensitivity, and reliable reproducibility.

Establishment of Real-time Fluorescent Quantitative PCR for Pineapple mealybug wilt associated virus-3

[ Objective ] The paper aimed to establish a real-time fluorescent quantitative PCR （qPCR） detection method for Pineapple mealybug wilt associated vi- rus-3 （ PMWaV3 ）. [ Method] Specific TaqMan probe and primers were designed and synthesized according to the conserved sequence of coat protein（CP） gene of PMWaV-3, and the standard curve was established after optimizing the amplification condition of qPCR. [ Result] The results showed that the method was specific for the detection of PMWaV-3, and the sensitivity of the present method was about 10 times higher compared to general RT-PCR ; the variation coefficients of intra- assay and inter-assay were less than 1.73, respectively. [ Conclusion] The qPCR is an easy, fast and reliable method for quantitative detection of PMWaV-3.