Researches On The Super Rice Parent C815S And Its Utilization On The Heterosis

C815S,which has been approved by the Examining and Approving Committee of Cultivar of Hunan Province,was bred by Hunan Agricultural University using AnxianglingS as a female parent and Peiai64S as a male parent.At present,more than ten hybrid rice combinations have been bred used C815S as female parent and approved by the Examining and Approving Committee of Cultivar of Province,such as C Liangyou 396,C Liangyou 87 and C liangyou 343 and so on.This showed that C815S had good agronomic and economic traits,stronger combining ability,security in seed production. Fertility tranfer,agronomic traits,outcrossing habits,seed propagation of C815S and hetorosis performance,combining ability,plant shape,root traits,physiological traits,high and stable yield of hybrid rice combinations derived from C815S were studied in the paper, the main results are as follows:1.Dual-purpose genic rice male sterile C815S had outstanding agronomic and economy characteristics,the plant height was 80.0cm,flag leaf length was 54.2cm,flag leaf width was 2.03cm,angle of flag leaf opening was less than 7.5°,total leaf number of each plant was 14-17 leaves,and C815S plant had faster leaf-appearance,developed root system,stronger tillering ability at the seedling stages,the sowing-mature duration was 74-89 days under low temperature and high temperature and showed fast growth rate and growth quantity.C815S had strong and thick culm,more strong lodging-resistance ability, bigger panickle.2.C815S had lower infertility threshold temperature,more stable fertility,safer seed production and easier seed propagation.The sterility of C815S was controlled by temperature and length of day,when length of day was 13.5h,fertility conversion critical threshold temperature was 22℃,sterility of C815S was started from sterility to fertility in the summer at Changsha Hainan Province.The sterility of C815S was stability when the length of sunshine was less than 12.0h and the sterility start temperature was 23.0℃. fertility conversion law was the same as Peiai64s,but the sterility start temperature was lower 1.5℃than that of Peiai64s,C815S could product seed in Guangdong,Guangxi and Huna,Irrigated with the water of 20.0～22.0℃for 15 days during theⅣtoⅥstage at panicle-developing stage,and the depth of irrigated water was 18-22cm,the seed of C815S could be propagated successfully.If the sowed time was arranged from 10 to 15 in November,and fertility-sensitive period were arranged before February 5,the success-probility would be over 90%for seed propagation of the C815S at Lingshui, Hainan Province.3.The outcross characteristics of C815S were excellent and the yield in seed production was high.C815S came into full flowering stage in 2-6 days after heading stages.The peak of anthesis time was from 9:30 to12:00.The anthesis rate was reached 76.7%before noon.Compared with the control,the duration of the flower-opening was longer.The stigma vitality duration was 6 days and the rate of protrusive stigma was 90.5%.And the rate of cervical tablets pack was 4.6%,and more sensitive to application of "920",the best dosage of "920" to relieve cervical tablets pack was 15.0-20.0 g/667m~2.The outcross seed set capacity of C815S and different male parent in seed production was higher than that of Peiai64S,and yield in seed production was higher.4.C815S had wider compatibility and stronger combining ability.The average seed set rate of F1 between the cross of C815S and IR26,Nanjin11,Balila and Qiuguang was 81%,and showed excellently wide compatibility.The general combining ability(GCA) of C815S was best compared with dual-purpose genic rice male sterile LongS,7guang S052,Peiai64S and CMS LineⅡ-32A.The GCA of the effective tillers number,total grain number,grain density,yield per plant and economic coefficient of C815S was 6.656,6.342, 7.236,16.669 and 6.705,respectively,and ranked at the first in the examinated dual-purpose male sterile lines.The GCA of the seed setting rate and 1000-grain weight was 0.329 and 2.353,respectively,and ranked the 2nd.Meanwhile,the GCA of plant height was-2.197,and ranked the fourthly.According to the GCA performance,C815S was fitted to breed hybrid rice combination with high yield and lower plant height.The variance of specific combining ability(SCA) of C815S in effective tillers number and yield per plant was larger,Super-high-yield hybrid rice combination was bred by crossing of C815S and 9113 and Minghui63.5.Compared with Shanyou63 and Liangyoupeijiu,the combinations derived from C815S had quicker leaves-appearance and tillering rate at seedling stages,more steady growth during late growth stage,so it benefitted to form big and more spikes.The length, width and area of the up third leaf of C815S were larger than those of Shanyou63 and smaller than those of Liangyoupeijiu.The basal angle of flag leaf and leaf droopy angle were smaller,leaf rolling index(LRI) of C815S was moderate.With the decrease of leaf location,the basal angle of flag leaf increased,while the LRI decreased.Compared with the control,C815S had shorter and thicker basal internodes,stronger lodging-resistance ability,and the dry matter weight per plant decreased slowly after milking stage,and yield components coordinated.So Cliangyou combinations were fitted to ideal plant shape of super hybrid rice compared with Shanyou63 and Liangyoupeijiu.6.Compared with Shanyou63,the number of adventitious roots,length of adventitious roots,total absorbing surface area,active absorbing surface area and root vigor of the hybrid combinations crossed by C815S at heading stage were higher.The capacity of absorb for water of root was higher than that of Shanyou63 after heading stages.The hybrid combinations crossed by C815S could keep higher root vigor during the late growth stage.For the hybrid combinations from C815S,the contents of chlorophyll,soluble sugar and soluble protein in functional leaves of Cliangyou combinations during the late growth stage were higher,MDA content was less.The activities of SOD and POD decreased more slowly and higher than that of the control.ΦPSII value and qP value of flag leaves in chlorophyll fluorescence parameters decreased during the late growth stage,butΦPSII value and qP value of flag leaves were higher than that of the control,while qP value increased and lower than that of the control.Net photosynthetic rate of flag leaves was higher compared with the control during the late growth stage.So lower senescence and more strongly photosynthetic capability in functional leaves during the late growth stage were the physiological basis of Cliangyou Combinations.7.The significant difference was founded in yield and yield-stability between Cliangyou combinations and the control Shanyou63.Yield of five hybrid rice combinations was higher than average yield of Cliangyou combinations,the effect of high yield was positive,C Liangyou396 had the highest yield coefficience,while yield of Cliangyou343 and Cliangyou1768 was significantly higher than that of the control,the high and stable yielding coefficient(HHYC) of five combinations was higher than that of the CK,C Liangyou396 was 84.621,C Liangyou343 and C Liangyou1768 were over 90. The yield of C Liangyou1102 and C Liangyou87 increased by 9.8%compared with the CK.8.The analysis of super-high-yield of Cliangyou396 showed that CLiangyou396 had some characters,such as growth period was moderate,plant morphology was ideal,leaf was thick and straight,ability of tillering was stronger,culms was stout,panicle was large, seed setting rate was higher,resist ability to high temperature and low temperature was higher,turn color was excellent at late growth stage,adaptability was wide,yield potential was higher,rice quality was excellent.Compared with the control Shanyou63,seed setting rate increased by 4.5%,1000-grain weight increased by 1g.Compared with the control Liangyoupeijiu,after transplanted in the field,the number of tiller was more,the percentage of effective tillers was higher,growth increment during growth period was larger,dry matter accumulation number was higher,panicles per unit area was more,total spikelet numbers was higher,the rate of grain filling was quicker and grain filling period was longer.