Screening Method Studies On N、P、K Highly Effectiveuse Rubber Tree Rootstock Material

There are obvious effect of the rootstock on the growth, latex yield and resistant ability of rubber budding tree. Therefore, it is significance that selection and propagation of the rootstock material which makes for the rubber budding tree grow fast, give a high yield and high resistance in the improvement of rubber tree planting material, directing rubber budding breeding, or discussing the theory of rubber rootstock selection. In this paper, a N, P, K highly effective use plants screening system was studied by that to treat the rubber seedling of 3 varieties, GT1, RRIM600 and PR107 with the N, P, K nutrient regulation, that developed from the N, P, K stress screening method, to select the N、P、K highly effective use rootstock material for rubber budding tree, a megaphanerophyte. The main results shown as follows:A N, P, K nutrient regulation screening system was established for the highly effective use rubber seedling plants base on the low N, P, K stress screening system for some of crops. It was that the uniform seedlings were grown in the raised sand bed and up-took in normal way until the plants grown 2-flush leaves, and then low N, P, K stress on the seedling until the plants appeared obvious nutrient deficiency symptom, which were marked, then refertilizing to the plants growth recovered and re-marked, and followed by low N, P, K stress and marked again. The plants with outstanding character in biological traits, physiological and biochemical characteristics were selected through the system. It possible to screen out the highly effective use rubber seeding plants under the N, P, K nutrient short or sufficient environmental conditions.70 N, P, K highly effective use rubber seedling plants were screened out in total, of which there were 21 GT1 and RRIM600 seedling plants respectively, selection rate were 11.67%; 28 PR107 seedling plants, selection rate 15.56%, under the condition of N, P, K nutrient deprivation or sufficiency, through almost 3 years by the N、P、K nutrient regulation screening system.The N、P、K highly effective uses rubber seedling plants selected out by the system shown superiority in growth and physiological biochemistry characteristic. The plants screened out were significantly or very significantly superior than the other plants in the same treatment and ck (fertilized conventionally) in biology character target (height, stem diameter, leaf-umbrella distance, leaf area, the value of leaf SPAD), the leaf nutrient target (the leaf content of N, P and K), photosynthesizes speed Pn, moisture content use efficiency WUE, the resistance target (relative conductivity, the MDA content, the Pro content) and the enzyme activity target (the NR and SOD activeness) and so on.The relativity among 20 screening parameters was analyzed and result shown that there were closed relation among some parameters. According to the degree of relation among the main biological characters, the order in the related rate of the N highly effective use was: leaf-umbrella distance, the value of leaf SPAD, stem diameter, leaf area and height. Among the leaf nutrient character it was:K content, P content and N content. Of the P highly effective issue was:height, stem diameter, leaf-umbrella distance, the value of leaf SPAD and leaf area; among the leaf nutrient character was:P content, N content and K content. Of the K highly effective use was:stem diameter, height, the value of leaf SPAD, leaf area and leaf-umbrella distance; among the leaf nutrient character was the P content, the K content and the N content. So that it was suggested that when to screen out the N, P, K highly effective use rubber seedling plants, the closed relation screening parameters would be observed to instead of the all screening parameters that in order to reduce the workload and improve the screening efficiency in the screening system.In summary, the nutrient highly effective use plant screening system was improved by the mean of nutrition regulating not only nutrient stressing. It was probed that the method to screen out the N, P, K highly effective use rubber seedling plants under the environmental conditions of N, P, K nutrient deprivation or sufficiency. And some N、P、K highly effective use plants, which could highly effective use the nutrient under the environmental conditions of N, P, K nutrient deprivation or sufficiency, were elected. However, it only would be used in rubber production or as the rubber rootstock germplasm for scientific research after the further discriminated by molecular analyzed and the compatibility tested of rubber tree stock and scion.