| With the enlargement of arid scope, the lack of world resources and seasonal arid, drought-farming and water-saving agriculture, which raising WUE become positive countermeasure .studying on the wheat especially wheat's WUE difference and it's positive mechanism will provide basis for taking better measures to breeding cultivating and engineer in order to improve WUE.Total 19 kinds of Triticinae crop evolution materials and 16 kinds of modern varieties (water land varieties and dry land varieties) were used in this research.. The root system characteristic (root-weight, root-length) and root-shoot were measured as well as comparing these analyzed data with WUE in the field. The major results were as follows:l.WUE's sequence of different evolution materials were: water land varieties>dry land varieties>6x>4x>2x.In the course of evolution and the domesticating (2x-->4x-->6x),the yield and harvest index of Triticinae and WUE correspond raised .The root -weight was favorable of WUE at some range, too heavy could bring to disadvantage for WUE.2. WUE sequence of diploid was as follows: RR>AA>BB>DD. R's chromosome group material has bigger shoot weight and root-weight, and these probably were the major cause that bring it's the highest WUE and yield. The shoot-weight and root-weight in the D group were between two parties but its WUE was the lowest, it could have function of controlling low WUE.3. Comparing wild species with cultivars: cultivars>wild species. The weight of shoot and root, the length of root and the ratio of root-shoot of wild species were less than cultivars.4.In different ploidies of rye which contains R chromosome group, the sequence of WUE was: AABBDDRR>AABBRR>RR. The sequence of root-weight was: RR> AABBDDRR) AABBRR and ET was: AABBDDRR>RR>AABBRR. However, root-length was opposite: AABBRR>RR>AABBDDRR The root-weight of diploidy rye was the heaviest and the hexaplod's was the lightest, which indicated R chromosome may increased of root-weight, but B or A decreased the function of R's promotion. The root weight of octoploidy rye was in the middle, which showed D chromosome complements have the function of decreasing A or B's inhibiting function to root-growth.5.WUE was controlled by many factors. The correlation, partial correlation and stepwiseregression analysis indicated: The relation ship of WUE and yield was the most closely (0.987, 0.9851). The main cause was that the difference of yield of all kinds of material was bigger than the difference of ET. The other notable indexes correlative to WUE were : ET(-0.428),economic coefficient (0.754),soil water content(0.428),root-weight (0.373)root-length (100-150cm) (0.384)6.The stepwise discrimination analyzed seven types in all of materials (2x 4x 6x water land varieties and dry land varieties, rye).The most discriminating indexes chooser were economic index and root-weight in 150-200cm soil. It wasn't significant various between 6x and modern varieties. The same trend at secales. 2x and all of materials were significant various.The research of WUE difference and control mechanism of Triticinae evolution materials is a hot spot problem, and research at the aspect of root system and WUE's relation at present is still not gone deep into and existed supplying materials. By the experiment with root system,the author studied the regulation and control of the WUE and providing theory base.
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