| With the improvement of living standards,people’s demand for rice has changed from "satiety" to "good".In order to produce more and better rice,more attention must be paid to the application of high quality rice varieties with high yield and high efficiency cultivation techniques.In recent years,many different types of japonica rice varieties were newly developed in Liaoning province.To study the characters of panicle neck vascular bundle,yield and rice quality of these different types of japonica rice varieties in response to different nitrogen density treatment can provide scientific basis for improving cultivation techniques of high quality,high yield and high efficiency.In this study,six japonica rice varieties of different types(Beigeng 1705,Beigeng 1604,Shennong 808,Fengjin,Liaoyou 9906 and Liaoyou 5206)were used as test materials,and four nitrogen fertilizer application levels(CK:N1(low nitrogen,8.4kg/667m2),N2(medium nitrogen,12.6kg/667m2),N3(high nitrogen,16.8kg/667m2)and 3 planting densities(D1(high density,30cm×13.2cm),D2(medium density,30cm×16.5cm),D3(low density,30cm×19.8cm)),and investigated the changes of vascular bundle traits,yield traits and rice quality traits under different nitrogen density treatments,and explored the relationship among them.The results show that:1.Nitrogen application rate had significant effects on vascular bundle character,yield and rice quality.With the increase of nitrogen application rate,the number of vascular bundles per unit area increased significantly,while the area of most of the vascular bundles increased first and then decreased.Panicle length,number of primary branches and secondary branches increased significantly.The effective panicle number per unit area increased first and then decreased,the total seed-setting rate and 1000-grain weight decreased significantly with the increase of nitrogen application rate,and the yield increased significantly,reaching800kg/667m2.With the increase of nitrogen application rate,chalkiness grain rate and chalkiness degree were significantly increased,protein content was significantly increased,amylose content was significantly decreased,taste value,appearance,viscosity and balance of white rice were significantly decreased,while hardness was significantly increased,taste value of white rice was significantly decreased.The peak viscosity,hot slurry viscosity and cold glue viscosity had the same response,and all of them decreased significantly with the increase of nitrogen application rate.The disintegration value and gelatinization temperature had no significant difference among nitrogen treatments.The peak time was shortened,and the reduction value decreased first and then increased.2.Planting density also had significant effects on vascular bundle character,yield and rice quality.With the decrease of planting density,the number and area of vascular bundle per unit area of panicle neck decreased.The planting density had little effect on most panicle traits,except the number of primary branches and seed density decreased significantly,other panicle traits did not reach significant level.With the decrease of planting density,the number of effective panicles decreased significantly,the number of grains per panicle decreased first and then increased,and the seed setting rate increased significantly.The highest yield was 755kg/667m2 under high density treatment.The effects of planting density on rice quality traits were not significant except for the decrease of my-rice percentage.3.Different types of japonica rice varieties had different responses to nitrogen application rate and planting density,and there was significant interaction between nitrogen density treatments.The number and area of vascular bundle of panicle neck per unit area of conventional japonica rice Beigeng 1705 and Beigeng 1604 reached the maximum at the level of N2D1(high density of medium nitrogen),at which time the effective panicle number and yield reached the maximum.The number and area of vascular bundle in panicle neck of shennong 808 and Fengjin were the highest at N3D1(high nitrogen and high density)level,and the number of effective panicle was the highest and the yield was the highest.The number and area of vascular bundle in panicle neck of hybrid rice Liaoyou 9906 were mostly at N3D1(high nitrogen and high density)level,and the effective panicle number and yield were the highest.The number and area of vascular bundle in panicle neck of hybrid japonica rice Liaoyou 5206 were the highest at N2D2(medium nitrogen and density)level,the number of effective panicle was the highest at N3D1(high nitrogen and density)level and the yield was the highest at N2D1(medium nitrogen and density)level.4.Nitrogen density interaction also had significant effects on rice quality traits of different types of japonica rice varieties.The chalkiness grain rate and chalkiness of conventional japonica rice with upright panicle type Beigeng 1705 and Beigeng 1604 are the lowest at the level of N0D2(medium density without nitrogen application),and the protein content is the lowest,the rice hardness is the lowest,and the rice taste value is the highest.The chalkiness grain percentage of shennong 808 and Fengjin were the lowest in N3D3(high nitrogen and low density)and N0D2(medium density without nitrogen application),the chalkiness was the lowest in N2D3(medium nitrogen and low density)and N0D2(medium density without nitrogen application),and the protein content was the lowest in N0D1(high density without nitrogen application)and N0D3(low density without nitrogen application),respectively.The hardness of rice was the lowest at N0D3(low density without nitrogen application)and N1D1(low density with nitrogen application)levels,and the taste value of rice was the highest at N0D3(low density without nitrogen application)and N1D1(low density with nitrogen application)levels,respectively.The chalkiness grain percentage and chalkiness degree of hybrid japonica rice Liaoyou 9906 and Liaoyou 5206 were the lowest at N1D2(low nitrogen medium density)level,and the protein content of hybrid japonica rice Liaoyou 9906 was the lowest at N0D2(no nitrogen medium density)level,and the rice hardness was the lowest and the rice taste value was the highest,while the protein content of hybrid japonica rice Liaoyou 5206 was the lowest at N0D3(no nitrogen medium density)level.At this time,the hardness of rice is the minimum,and the taste value of rice is the maximum.5.The vascular bundle characters of panicle neck were closely related to panicle characters,yield composition and rice quality characters.Neck vascular bundle number and area of per unit area and the effective number of ears,the grain density,shape index,yield were significantly or extremely significantly positive correlation,and the secondary branch number,spike grain Numbers per spike,the more significant or extremely significant negative correlation,and the appearance quality,cooking and eating quality,starch RVA spectrum characteristic values were significant or extremely significant negative correlation,were very significant positive correlation with protein content.6.Protein composition was significantly correlated with eating quality.Albumin content was positively correlated with appearance,viscosity,balance and taste value of rice,and negatively correlated with amylose content.Globulin was positively correlated with protein content and hardness.There was a significant negative correlation between gliadin and amylose content.There was a significant positive correlation between gluten and protein content,and a significant negative correlation between gluten and appearance,viscosity,balance and taste value of rice.That is,the increase of gluten content is not conducive to the improvement of cooking taste value of rice,while the increase of albumin content is conducive to the improvement of cooking taste value of rice.7.Considering the comprehensive yield,rice quality,lodging resistance,etc.,high yield japonica Beigeng 1705 and Beigeng 1604 with compact plant type and upright panicle type should adopt medium nitrogen(12.6kg/667m2)and high density(30cm×13.2cm)cultivation mode.The high quality rice varieties Fengjin and Shennong 808 were suitable for low nitrogen(8.4kg/667m2)and low density(30cm×19.8cm)cultivation mode.Two japonica hybrid rice varieties,Liaoyou 5206 and Liaoyou 9906,were suitable for medium nitrogen(12.6kg/667m2)and high density(30cm×13.2cm)cultivation mode. |
