Fungal inoculation induces agarwood in young Aquilaria malaccensis trees in the nursery

Fungi are often used to induce agarwood inAquilariatrees. This study was conducted to evaluate the effect of several fungi on agarwood formation over time in youngAquilaria malaccensis （Lam.） trees. Typical changes in the length and light intensity of the resulting discoloration were observed after three and six month periods following inoculation. Wood samples were observed microscopically and classified into several light intensity groups. The discoloration length was meas-ured longitudinally. The duration after inoculation affected the mean of discoloration length： the 6-month old sample （1.70 cm） had a wider discoloration zone when compared to the 3-month old sample （1.17 cm）. When measuring the discoloration intensity, a positive relationship with time was perceived. Digital images, captured using a camera-equipped microscope, revealed that wood samples collected after six months appeared to be 1.8-times darker than after three months. We concluded that time, not the species of any of the tested fungi, had significant effect on discoloration length and intensity. Gas chromatography/mass spec-trometry （GCMS） analysis of the 6-month old sample yielded some important agarwood compounds such as benzylacetone, anisylacetone, guaiene and palustrol. This demonstrates that the tested fungi have the ability to induce agarwood formation in nurseryA. malaccensis trees.

Quantitative Trait Loci for Resistance to Stripe Disease in Rice(Oryza sativa)

In order to map the quantitative trait loci for rice stripe resistance, a molecular linkage map was constructed based on the F2 population derived from a cross between Zhaiyeqing 8 and Wuyujing 3. Reactions of the two parents, F1 individual and 129 F2：3 lines to, rice stripe were JnvestJgated by both artificial Jnoculation at laboratory and natural infection in the field, and the ratios of disease rating index were scored. The distribution of the ratios of disease rating index in Zhaiyeqing 8/Wuyujing 3 F2：3 population ranged from 0 to 134,08 and from 6.25 to 133.6 under artificial inoculation at laboratory and natural infection in the field, respectively, and showed a marked bias towards resistant parent （Zhaiyeqing 8）, indicating that the resistance to rice stripe was controlled by quantitative trait loci （QTL）. QTL analysis showed that the QTLs detected by the two inoculation methods were completely different. Only one QTL, qSTVT, was detected under artificial inoculation, at which the Zhaiyeqing 8 allele increased the resistance to rice stripe, while two QTLs, qSTV5 and qSTV1, were detected under natural infection, in which resistant alleles came from Zhaiyeqing 8 and Wuyujing 3, respectively. These results showed that resistant parent Zhaiyeqing 8 carried the alleles associated with the resistance to rice stripe virus and the small brown planthopper, and susceptible parent Wuyujing 3 also carried the resistant allele to rice stripe virus. In comparison with the results previously reported, QTLs detected in the study were new resistant genes to rice stripe disease. This will provide a new resistant resource for avoiding genetic vulnerability for single utilization of the resistant gene Stvb-i.

Resistance Identification of Different Flue-cured Tobacco Varieties against Black Shank

The resistance of 15 flue-cured tobacco varieties were identified by artificial inoculation of black shank. The results showed that K326, Yunyan 202 and NC102 belonged to resistance variety against black shank, and the resistance successively were K326 〉 Yunyan 202 〉 NC102 ; Yunyan 87, Cuibi 5, Yunyan 85, Yunyan 97 and Cuibi 7 belonged to moderate resistance variety against black shank, and the resistance successively were Yunyan 87 ~ Cuibi 5 ~ Yunyan 85 〉 Yunyan 97 〉 Cuibi 7 ; Cuibi 12, NC82, PYH06 and Cuibi 14 belonged to moderate susceptible variety against black shank, and the resistance successively were Cuibi 12 ~ NC82 ~ PVH06 ~ Cuibi 14; Cuibi 1 and Hongda belonged to high susceptible variety against black shank, and the resistance successively were Cuibi 1 〉 09011 〉 Hongda. The disease dynamics of flue-cured tobacco varieties were positively correlated with variety susceptibility, namely the earlier infection in susceptible variety, the faster the disease progression.

Resistance Analysis of Wheat Cultivars against Powdery Mildew in Anhui Province of China

[ Objective ] The paper was to determine the resistance level of the tried and pre-examination wheat cultivars against powdery mildew in Anhui Province of China. [ Method ] By using artificial inoculation and identification method in fields, the resistance of wheat cultivars was identified in consecutive three years from 2010 to 2012. [ Result] The highly susceptible （HS） cultivar accounted for 30%, 42% and 11% of total tested cultivars in the years of 2010, 2011 and 2012, respectively; moderately susceptible （MS） cultivar accounted for 53% of total tested cuhivars in 2010, which accounted for 47% and 57% in 2011 and 2012, respectively; moderately resistant （MR） cuhivar accounted for 17% of total tested cultivars in 2010, which accounted for 11% and 32% in 2011 and 2012, respectively. [ Conclusion] The paper can guide breeding direction, and also provide scientific basis for variety approval.