[Objective]The study was to establish the virus-free seedling breeding system of grape.[Method] The shoot stem-segments with single bud of 3 grape rootstock varieties 3309,101-14 mgt and rup were taken as the materials.They were pre-cultured for some time to explore the effects of key factors such as explant source,sampling seasons,medium types and hormone ratio on tissue culture and rapid propagation of grape.[Results]The contamination rate and frequency of callus brown of the pre-cultured explants were 20.00%~28.33% and10.00%-13.33% resp,and those of explants sampled outside were 56.67%-81.67% and 20.00%-25.00% resp.1/2MS basic medium was the most beneficial to germination of grape explants,and the germination rate of axillary buds of all varieties were 60%-72%.The germination rate of explants sampled in spring was higher and the required time of germination was shorter.The optimum initial medium for 3 varieties was 1/2MS +0.05 mg/L 6-BA+0.2 mg/L IBA,the optimum subculture and rooting medium were 1/2MS +0.05 mg/L IBA and 1/2MS +0.2 mg/L IBA.[Conclusion]The study had positive significance in accelerating industrial development of grape.
Plant type and irrigation scheme are key influencing factors of real-time yield estimation and monitoring of winter wheat in precision farming. In this paper, MODIS remote sensing data were used in combination with GPS and ground-truth non-remote sensing data to determine the dynamics of normalized difference vegetation index (NDVI) of winter wheat cultivars with different plant types under irrigation and non-irrigation conditions. The relationship between NDVI and yield of different winter wheat culti-vars in different growth stages was then analyzed. Results showed the trends in NDVI with developmental stages of different wheat cultivars were same, following a low-high-low curve. There were obvious differences in NDVI from jointing to booting stages for different cultivars, and NDVI for cultivars with horizontal plant types was higher than that for cultivars with erect plant types. It im-plied that the jointing-to-booting stage was the best period for identifying plant types of winter wheat cultivars. Even for the same cultivar, mean NDVI was obviously different at each growth stage for irrigated and non-irrigated lands. NDVI for irrigated winter wheat was higher than that for non-irrigated winter wheat, with a notable difference especially at the early heading stage. At early heading stage, NDVI was strongly correlated with yield in irrigated and non-irrigated lands. However, regression equation based on NDVI both in the early heading and filling stages gave better prediction for wheat yield than that based on NDVI only in the early heading stage. This was especially the case for non-irrigated wheat fields.
The research showed that the contents of each form of nitrogen descended in Ablic soil with no fertilization and only application nitrogen and phosphorus chemical fertilizer in soybean successive planting. The reduction of amino-acid nitrogen was maximum, and the contents of amino-acid nitrogen with no fertilization and only application nitrogen and phosphorus chemical fertilizer were reduced 148.00% and 66.00% respectively for last ten years. The each form of nitrogen not only was increased with long term application organic fertilizer and soybean straw ploughing under, but also nitrogen fraction was changed.
The research on the reservation of the seed bank in soil and the biological diversity of weeds in teaching practice base for silkworms of Shengyang Agriculture University was done in their germination and elutriation,with Simpon index and Shannon-winner.The result showed annual plants was the dominant species among the weed group,types and quantity of which were the major part in weed bank in soil.There were 23 species of weeds,belonging to 13 families,of which,Humulus [Humulas scandens(Laur.)Marr.]and Purslane(Portulaca oberacea L.)accounted for the largest population of seed bank,18.7% and 12.1% respectively of the total.
Starch is a major photosynthate and quality index for winter wheat.Planting density influences the growth and development of winter wheat through factors,such as,thermal,light,temperature,etc.This in turn influences the generation,development and transportation of photosynthate to wheat grains which eventually determine wheat yield and quality.Chlorophyll density is strongly related with spectral parameters and accumulated starch.Thus,chlorophyll density was used to serve as a link between canopy spectra and starch accumulation in this study.The aim of the study was to explore suitable density for forecasting accumulated starch content for the purpose of building a model for the accurate forecasting of starch accumulation via spectral remote sensing.In this study,Jing 9549 winter wheat cultivar was cultivated in 2009 and the Jing 9549,Le 639 and Chang 4738 cultivars cultivated in 2010 at planting densities of 3.0×106 planthm2,4.5×106 planthm2,6.0×106 planthm2,7.5×106 planthm2,9.0×106 planthm2.In the field experiments,canopy spectral,chlorophyll density and starch accumulation of winter wheat were measured in the five different planting densities.The accuracy of the monitoring model with NDVI(1 200 nm,670 nm) was highest(0.920 6) at 7.50×106 planthm2 wheat planting density.The model was verified with data for the cultivation period of 2009 to 2010.The result showed a strong agreement with a correlation coefficient of 0.954 2.The 7.5×106 planthm2 density was the most reasonable planting density for monitoring starch accumulation in winter wheat.Also the data for the five densities were integrated to construct a multi-density simulation model.The multi-density model accuracy was 0.883 1 and its relative error(RE) was also the lowest(0.905 4).Thus to some extent,the multi-density simulation model was widely applicable and practically significant.The spectral remote sensing monitoring model for observed optimum density and accumulated starch at different wheat planting densities gave the theoretical basis and guidance for large-scale monitoring of wheat quality from space.
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