Study On Fertilizer Tolerance Properties And Heterosis Of Northern Japonica Hybrid Rice

To analyz the reason why japonica hybrid rice has the superiority of biomass and heterosis but weak yield,140 restorer lines and BT type cytoplasmic male sterility(BT-CMS)line Liao99A were used for investigating with low fertilizer and medium fertilizer to test heterosis and characteristic resistance.Main indicators of dry matter accumulation,partition,plant types,panicles characters,their relationships with yield in japonica hybrid rice were measured to confirm yield and characteristic resistance.The main conclusions as follows:1.Under normal fertility conditions,the yield,panicle numbers and biomass of F₁ group had a significant positive correlation with dry matter accumulation at heading stage and maturity stage,the grains per spike,seed setting rate and biomass had a significant positive correlation with the dry accumulation at maturity stage;the yield,panicle numbers,grains per spike and biomass had a significant positive correlation with flag leaf area;except for the1000-grain weight,the yield and yield composition were significantly positively correlated with the second stem length;the yield,panicle numbers,biomass and harvest index had a significant positive correlation with second internodes thick;the yield,panicle numbers,grains per spike,seed setting rate,biomass and harvest index were significantly positively correlation with grain density,grains number at primary branch,grains number at secondary branch,seed setting rate at primary branch and setting setting rate at secondary branch.Under the lower fertility condition,the yield,panicle numbers and biomass of F₁ group had a significant positive correlation with dry matter accumulation at heading stage and maturity stage;the grains per spike,seed setting rate and harvest index had a very significant positive correlation with dry matter accumulation at maturity stage.there was a significant positive correlation between the biomass and the dry matter accumulation traits at heading stage and maturity stage.There was a significant positive correlation between yield,panicle numbers and second leaf area,third leaf area,which were negatively correlation with other plant type traits;The correlation between other yield compositions and plant types characters was not significant.the correlation between biomass and flag leaf area,second leaf area,third leaf area was significantly positive;while the correlation between harvest index and flag leaf area,second leaf area,third leaf area was negative.The yield composition traits had a significant positive correlation with grains number at primary branch,grains number at secondary branch.Compared to those under normal fertility condition,yield of the F₁ group relied more upon dry matter accumulation after heading stage.2.The average yield of F₁ group was8.39 and8.72 t/hm² under normal and lower fertility condition,respectively,the latter was 3.93%higher than the former.The variation trend of yield and yield components was inconformity under different fertility conditions.The yield was positively correlated,while the panicle numbers was negatively correlated.The correlation of other yield component was not significant.Compared to those under normal fertility condition,low fertility condition is more conducive to the accumulation of dry matter in internode and sheath,espectally the accumulation of dry matter in the sheath.The correlation between dry matter accumulation,plant types traits,panicle characters was mostly insignificant.3.The yield,biomass and harvest index of restorer had a positive correlation under different fertility conditions,while had negative correlation with third leaf area,and correlation with second leaf area and third leaf area was significant.The yield is more dependent on biomass under normal fertility condition,while that relied more upon harvest index under low fertility condition.The yield of restorer had a significantly positive correlation with grain density,grains number at secondary branch,seed setting rate at primary branch,seed setting rate at secondary branch,1000-grain weight at primary branch,1000-grain weight at secondary branch,under normal fertility condition,while the yield of restorer had a significantly positive correlation with grain density,grains number at primary branch,grains number at secondary branch,1000-grain weight at primary branch,1000-grain weight at secondary branch under low fertility condition.4.The average yield of restorer group was 6.82 and 7.17 t/hm² under normal and low fertility condition,respectively,the latter was 5.13%higher than the former.The variation trend of yield and yield components was inconformity under different fertility conditions,and was not significantly correlated with the yield.There was a significantly negative correlation between panicle numbers and 1000-grain weight while the grains per panicle and seed setting rate was not significantly correlated.The biomass and harvest index was significantly positive correlated under different fertility conditions.Similar to F₁ group,the correlation between dry matter partition characters,plant type characters,panicle characters of restorer population were not significant.