Study On Spectral Characteristics Of Different Medium Indica Rice Varieties And Their Relationship With Yield

In order to understand the correlation between the difference in spectral characteristics of different varieties and the leaf SPAD value and yield,the spectral data,SPAD value and yield data of the main growth period were collected.To explore the SPAD value estimation models of 11 different medium indica rice varieties and rice yield models at different growth stages.The main findings are as follows:（1）The changes of the original spectral reflectance response curves of different medium indica rice varieties are consistent.The reflective peaks of chlorophyll were formed at 550nm,the absorption valley is at 680nm,and the high reflection platform is formed at the near infrared band（760～1000nm）.The spectral reflectance characteristic after the first-order derivation is more obvious,the largest peak appears at"660～750nm",and there are differences among varieties at the position of"red edge",which is roughly in the range of 710～720nm.（2）The leaf SPAD value of each medium indica rice variety had a similar change trend,and the maximum value was at the initial or full heading period.The SPAD value first increased and then decreased.Among the correlations between the leaf SPAD value and the original spectral reflectance of different rice varieties,the correlation coefficient of the leaf SPAD value and the original spectral reflectance changed in the same direction,and the correlation between the 695-715nm band was relatively stable and negatively correlated.The correlation trend of the first derivative of the canopy spectrum of 11 different rice varieties is roughly consistent with the chlorophyll correlation of the leaves,but the fluctuation is relatively large,and the correlation is stable only at the bands of 495-550nm and 685-715nm,showing a very significant negative correlation and correlation coefficient Larger.（3）Four sensitive wavelength with the highest reflectance spectral correlati on coefficient,three sensitive wavelength with the highest first-order derivative correlation coefficient and four spectral parameters with the highest correlation coefficient were selected as independent variables,and SPAD value was the de pendent variable,to construct an estimation model for SPAD value of 11 differ ent indica rice varieties.According to the RMSE and R² of the model,the best estimation model of each breed was obtained.Quanyoujietian No.1,y=8087.6x²-1488.7x+104.52;Cliangyou No.4,y=379036x²-5755.9x+55.889;Weiliangyou534,y=8.3355x^-0.279;Fengliangyou No.4,y=193002x²-4541x+62.485;Chengliangyoujiuhuazh an,y=-355.06x²+0.4103x+43.176;Zhongxiangyoumeixiangxinzhan,y=15163x²-3258.6x+211.15;551liangyou570,y=3.1285x^-0.392;Zhenliangyou2056,y=-680190x²+5903.1x+27.164;Jingliangyoumeixiangyouzhan No.1,y=146.66 x²-132.51x+65.498;Minshengyou 827,y=495565x²-9665.3x+82.899;Mangyang,y=564261x²-10730x+86.9.（4）The determination coefficient（R²）and root mean square error（RMSE）of 8 variety models were comprehensively analyzed to obtain the best estimati on model of yield of each variety.Quanyoujietian No.1,y=0.1347x²-2.1631x+583.5;Fengliangyou No.4,y=991.92x²-1451.5x+1133.5;Chengliangyoujiuhuazhan,y=-3807x²+2779.5 x+138.98;Zhongxiangyoumeixiangxinzhan,y=15163x²-3258.6x+211.15;551liangyou570,y=-991.26x²+969.29x+363.24;Zhenliangyou 2056,y=-0.0717x²+5.9692x+536.6;Minshengyou 827,y=-0.0984x²+6.8723x+584.51;Ma ngyang,y=2785.5x²-4420.5x+2404.1.