Comprehensive Evaluation of New Self-cultivated Sugarcane Lines by Grey Relational Analysis

The grey relational analysis( GRA) was used to evaluate the 10 sugarcane lines by 13 main agronomic characters. The result showed that the grey correlation degree of self-cultivated lines GNY08- 320(0. 7502),GNY08- 336(0. 7409),GNY08- 186(0. 7369),and GNY08- 225(0. 7277) were higher than ROC22(CK),so the 4 lines can be further tested,and the others were worse than CK that should be further observed or eliminated.

Disease Grading Criterion and Assessment of Yield Loss Caused by Maize Rough Dwarf Disease

[Objective] The paper was to study the disease grading criterion and assess the yield loss caused by maize rough dwarf disease. [Method] The ear lengths and yields of each healthy and infected plant of 5 cultivars were measured during 2009 and 2010. The severity grading criterion was deduced according to the ear length ratios. [Result]When the ratios were 0.92-1.00, 0.67-0.91, 0.41-0.66, 0.10-0.40 and 0, its corresponding disease grading criterions were 0, 1, 3, 5 and 7, respectively. The severity grading criterion was closely correlated to the yield loss. By analyzing the data of disease indexes and yield loss rates of 27 cultivars with DPS （Data Processing System）, the regression equations were established respectively. According to the comparison with each other, the Weibull Model was proved to have the highest fitting degree. Validating with the disease indexes of 27 cultivars in 2010, the equation supported the feasibility of the equation to predict the yield loss caused by maize rough dwarf disease. [Conclusion] The paper provided theoretical basis for further study on maize rough dwarf disease.

Field Control Effects and Crop Safety Assessment of Triazole Fungicides on Apple Rust

In order to provide a reference basis for efficient prevention and control of apple rust,apple rust(Gymnosporangium yamadai)was used as the test material,the field control effects of six triazole fungicides with different concentrations and different application times on apple rust,and the safety of application in different periods on the crop were investigated in field trials.The results showed that the control effect and safety of myclobutanil were excellent.In the prevention test,the effects of myclobutanil 40%EC 2000 times and 4000 times dilutions in protecting apple leaves from G.yamadai infection reached more than 98%at 10 d after the second spraying in the fruitlet stage,and in the treatment test,the control effects of inhibiting the spread of leaf lesions were 90.89%and 87.17%at 16 d after the fourth spraying in the fruit expansion stage,respectively.The results of the crop safety test showed that when applying the triazole fungicides with different concentrations from the red bud stage to the fruit expansion stage of apple trees,there were no adverse effects on the leaves,branches,flowers and fruit,as well as no rust or deformity on the fruit surface.When spraying the fungicides from the red bud stage to the fruit expansion stage,except that the single fruit weights in the treatment of the 10%difenoconazole DC 2000 times and myclobutanil 40%EC 4000 times dilutions were reduced without a significant difference from the control,and the values of other treatments were all reduced by more than 9%compared with the control.When applying the fungicides during the fruit expansion period,none of the tested fungicide treatments had a significant effect on the fruit growth.

Occurrence of Major Diseases and Insect Pests in Medium-term Growth Period of Sugarcane and The Diseases Resistance Evaluation in Guangxi

To figure out major diseases and insect pests of sugarcane and sugarcane resistance to diseases,the occurrence of major diseases and insect pests on 11 main sugarcane varieties in eight sugarcane producing areas of Guangxi was investigated during the medium-term growth period of sugarcane in 2015,and field resistance to smut and mosaic diseases was evaluated. The results showed that the dead heart rate（ DHR） ranged from 0. 00% to 38. 55%; new-planting sugarcane of Guiliu 2 and ratoon sugarcane of Liucheng 05-136 suffered the most severe damage in Beihai city,and the DHR were 38. 55% and 37. 66%,respectively. The incidence rate of smut disease ranged from 0. 00% to 24. 89%. Ratoon sugarcane was more susceptible to smut than new-planting sugarcane among all investigated varieties. Variety ROC22 was most susceptible to smut,and performed moderate susceptibility. Guiliu 2 was the second susceptible and performed resistance,with the incidence rate of 7. 45%. The rest nine varieties had high resistance. Sugarcane mosaic disease occurred mildly in Guangxi,and the incidence rate ranged from 0. 39% to 7. 73%. ROC22,Guitang 42 and Guiliu 2 expressed moderate resistance and the rests exhibited resistance. Sugarcane in Nanning and Beihai suffered more severe damage than those in other producing areas. The field evaluation system of sugarcane resistance to borers was expected to be constructed. ROC22 was most susceptible to smut,compared with other main varieties. Mosaic diseases occurred lightly in Guangxi. Multi-location and multi-year observation are necessary for accurate evaluation of sugarcane resistance to smut and mosaic diseases.