| Three tests were conducted in this study. In variety performance test, PeiAi64S/E32, PeiLiangYou500 , PeiAi64S/B52 , Liang YouPeiJiu , KangLiangYou2054 , Lu18S/53159, T98A/259 and 316A/180 were used, the yield and yield components , sprouting properties of axillary buds and source-sink properties were studied. In stubble height test, PeiAi64S/E32 was used, the effects of stubble height on the ratooning ability of axillary bud from different nodes, source-sink relation of ratooning rice, the recovery of root vigor of main crop and the growth of ratooning roots were studied. In node-cuttage test, PeiAi64S/E32, PeiLiangYou500 were used, the growth and developmental properties and ratooning ability of axiliary buds of different nodes in vitro and in vivo were studied . The main results are as follows:1. Significant difference at the 0.01 level existed respectively in yields of main crop, ratooning rice and the whole yield between 8 combinations. As for yield of ratooning rice, Lul8S/53159 was highest, KangLiangYou2054 was second and PeiAi64S/B52 was third . As for the whole yield of two crops, PeiAi64S/E32 was highest, PeiAi64S/B52 and Lul8S/53159 were 2nd and 3rd respectively.2. Positive correlation existed between the yield components with yield in ratooning rice. And coefficient of partial correlation between the effective tiller number, whole grams per panicle and seed-setting percentage with yield were significant at the 0.01 level. The path analysis showed that the effect of the effective tiller on yield was biggest. It was bigger than that of whole grains per panicle and seed-setting percent. So it can distinctly improve yield of ratooning rice by improving grains per panicle.3. About the choice of ratooning rice variety, we should choose the varieties (combinations) with longer growth duration, more number of leaves, middle gram number per panicle, high 1000-grain weight, higher LAI and moderate ratio of grain number to leaf area. Increase of tiller-bearing percent is advantageous to enhancing the yield of main crop and ratooning rice. In addition, in order to gain high yield of ratooning rice, we should pay attention to following points: fertilizing to urge the growth of axillary buds in appropriate stage, shifting reaping stage to an appropriate earlier time, leaving high stubble.4. Comparing to main crop, the leaf number of ratooning crop was less, leaf area per culm was smaller, the ratio of grain number to leaf area was bigger. The type of source-sink relation of ratooning rice belonged to the source-limited. To ratooning rice from high stubble, the 2nd and 3rd node from top were overwhelming tillers, their yield contribution percent was about orover 70%. The changing of yield contribution percent of different nodes under different stubble heights showed different trends. Compared with lower nodes', upper nodes' ratooning rice had its distinguishing feature: less leaf number per culm, smaller leaf area per culm, bigger ratio of grain number to leaf area.5. Nutrition condition in early productive phase of main crop had decisive effect on ratooning rate, and N content was the dominant factor. Accumulation of nitrogen and carbohydrates in stem and sheath in late productive phase had no significant correlation to ratooning rate, but had close correlation to growth and development of axillary buds.6. Roots in ratooning crop consist of roots of main crop and ratooning roots, and roots of main crop is the main part. Ratooning roots mainly come from ratooning tillers of lower nodes. Higher stubble was advantageous to recovery and maintenance of activities of roots of main crop; Lower stubble was advantageous to production of ratooning roots. When stubble was 10 cm, the percentage of ratooning roots to the whole roots was 34.38%.7. In vivo, the ratooning rate of axillary buds from different nodes showed (from the top): the 2nd > the 3rd > the 5th > the 4th. But in vitro, the trends above was uncertain, and the difference between different nodes became smaller. In vitro,... |
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