Resistance Identification Of Maize To Tetranychus Cinnaburinus

Tetranychus cinnabarinus (Boisduval) is the worldwide harmful mites, occurred more and more seriously year by year, and it had become one of the primary pest attacking maize.In order to meet the needs of researches on maize resistance and to seek a quick and easy method for identifying resistance and evaluation criteria, the resistance of36maize inbred lines to mites occurring naturally in field were primarily identified, then that of8selected maize inbred lines differing in the susceptibility were further identified in the laboratory and in field, and the resistance reaction type of8maize varieties were measured. the results are as follows:1.Priliminary identification of the resistance of36maize inbred lines to mites occurring naturally in fieldWith mites occurring naturally in field, and leaf hazard index as evaluation index, the resistance of36maize inbred lines were analyzed through the dynamic clustering analysis. The results showed that36varieties were divided into6types. Among36varieties, one belonged to type Ⅰ, four to type II, five to type Ⅲ, thirteen to type Ⅳ, seven to type Ⅴ, and six to type Ⅵ. The resistance of typeⅠwas the highest, while type Ⅵ was the weakest.2. Further identification of the resistance of8maize inbred lines to T. cinnabarinusWith8varieties covered with network at seedling stage and adult stage, then T. cinnabarinus were inoculated, as well as the leave hazard index, mite sentiment index and mite population density as evaluation index, the resistance of8varieties were further identified. The results showed that the resistance level of8maize varieties were almost the consistent at the seedling stage and adult stage.H1014168were characterized highly resistance at both seedling stage and adult stage by3kinds of index, while H1019005highly susceptible by leaf hazard index and mite sentiment index at both seedling stage and adult stage, however, H1019005were characterized highly susceptible by population density at seedling stage, while moderate susceptible in adult stage. In the same stage, the resistance level of8varieties were almost the consistent by3index. The match rate of mite sentiment index method and the leave hazard index was as high as75%, while that of population density and mite sentiment index (or leaf hazard index)37.5%-50%. Therefore, leave hazard index and mite sentiment index were suitable for evaluating the resistance of maize to mites.By inoculating mites on pot culture indoor and mites population quantity as evaluation index to identify the resistance of8different resistance varieties. Result showed that, after inoculated mites20d, the mite population quantity was the lowest (11.Omites/plant) on H1014168,while the largest on H1014599and H1014591(both18mites/plant). On H1014603and H1019005, population growth multiples of mites was the highest,23.36and24.13times respectively, beneficial to the population development, while on H1014168was the lowest, only2.44times, bad for the population development.3. The resistance reaction type of8maize inbred lines to T. cinnabarinusThe antixenosis of8maize detached leaves to T. cinnabarinus was measured at seedling and adult stage after put mites2h,12h,24h,36h,48h,60h. The results of Curve regression analysis showed that in seedling stage leaves, the b value of H1014299,H1019005,H1014599,H1014603were greater than1, in H1019005was maximum, as high as1.7143, the antixenosis was the weakest; the b value of H1014168was minimum(0.1886), and the antixenosis was the strongest. In adult stage, the b value of H1019005,H1014599,H1014603,H1014591were greater than1and in H1014599was the maximum (1.6743), antixenosis was the weakest, while the b value of H1014168was minimum (0.1771),the antixenosis was the strongest.By fed mites with the detached leaves and formed a life table, the effect of8maize varieties to development, reproduction and population life parameters of T. cinnabarinus was studied. The results showed that among8maize varieties, the average development period from egg to adult was the longest(10.48d) on H1014168, and on H1019005was the shortest(8.35d). Spawning quantity was minimum(39.84eggs/female) on H1014168, and maximum (70.23eggs/female) on H1019005. Longevity of adult female was the longest on H1014591and H1019005,16.71d and16.71d respectively, significantly longer than H1014168(10.0d). On H1014603, the intrinsic growth rate was the largest(0.3025) and the shortest population doubling time(2.1627d), just the opposite on H1014168, the intrinsic growth rate was the minimum(0.1799) and the longest population doubling time(3.3753d). The survival curve of8maize inbred lines were type Ⅰ. H1014591had the highest survival rate, and lowest survival rate on H1014168. Result showed that H1014168had antibiosis to T. cinnabarinus, was unfit for its development, reproduction and population increase, while H1019005, H1014591and H1014603were suitable for it.The change of plant height of the8maize varieties were measured after mites hurt12d and got rid of mites to restore growth30d at seedling stage in field to determine the tolerance to T. cinnabarinus. H1014591performance for compensation growth as the growth ratio were significant difference between different population density and Ck after damaged12d, while there were no significance difference after recovery growth30d. The growth ratio of H1014553,H9117086and H1014168were no significant difference between different mite density and ck both after damaged12d and recovery growth30d, performance tolerance to mites’harm. Compared to the other7varieties, the growth ratio of H1014168was the highest whether at the damage stage or recovery growth stage, indicate d that it had strongest tolerance to T. cinnabarinus.