| Rice is the most important food crops in our country,how to continue to increase rice yield and improving rice quality has been the primary goal of breeders.In recent years,germinated rice panicle have occurred in China’s middle and lower reaches of the Yangtze River,harvest sprouting not only directly affect the yield of rice,paddy rice quality and storage,but also reduces the breeding value.Therefore,screening identified rice varieties with moderate sleep characteristics important for rice production and development of the seed industry.Food is the first necessity of the people,paddy storage has been a top priority of national food security.Optimization of conventional japonica storability evaluated,selected resistant storage of elite germplasm,identification of seed vigor storability different varieties of rice seedling and associated physiological and biochemical quality,optimizing the evaluation system,and contribute to the aging mechanism to explore different seeds difference between varieties,provide a reference for breeding new varieties.Main results are as follows:1.The single plant was harvested after 35 days of storage,and stored at 26 °C and 65% RH,The germination percentage of seeds stored for 15 days could be used to effectively distinguish the dormancy difference of varieties.Four 7-level dormant strains were screened out,namely ZH15-78,HZ13-24,Ning 15-2 and Chunjiang 154;the germination tendency and germination percentage showed a very significant positive correlation(0.68～0.93)within 60 days after the seeds were harvested,and the germination percentage had a very significant negative correlation with the dormancy level and dormancy period They are(﹣ 0.37～ ﹣ 0.92)and(﹣ 0.56～ ﹣ 0.79),respectively,and the dormancy level and dormant period have a very significant positive correlation(0.67).Based on K-means cluster analysis,it was found that there are 4 types of japonica rice varieties that break dormant forms: Type I germination tendency is lower in the early stage,but the germination percentage rises faster;Type II germination tendency and germination percentage are higher in the first three periods,but The germination percentage decreased at the fourth time point;the dormancy of class III was weak,and the dormancy period was short;the germination tendency of the four varieties of class IV was low,the germination percentage increased slowly,and the dormancy period was longer.2.Through the identification of the storage tolerance of 71 japonica rice varieties,3 indica rice and 2 indica-japonica hybrid rice after 3 months of storage,it is considered that under the combination of 41 ℃,RH 90% and aging for 12 days,the The evaluation of storage tolerance characteristics was more suitable;the results showed that the storage tolerance of tested japonica rice was quite large.The storage tolerance of indica rice was better than that of japonica rice.Nine varieties with first-class storage tolerance including Zhejiang 99 and Xiushui 14 were selected.According to the germination percentage and aging index of the varieties after 12 days of artificial aging,K-Mean cluster analysis found that the test varieties can be divided into 4 types,Class I,24 varieties represented by Zhejing 99 and Xiushui 14 with an average germination percentage higher,the aging index is lower;and the nine varieties represented by Class IV Jiahe 239 and Chunjiang 157 have low average germination percentage and high aging index.The correlation between the dormancy characteristics and the storage characteristics of conventional japonica rice varieties is not significant.3.At 41 ℃ and 90% RH,set a time gradient to aging treatment of 4 japonica rice varieties(all dormancy periods are 46 d to 60 d,different storage resistance).It was found that after 12 days of aging,the seed vigor and seedling quality of each variety showed significant differences.Among them,the germination percentage of Xiushui 14 at 15 days of aging is higher than other varieties,reflecting its excellent storage resistance,this is also confirmed by the results of the seedling rate in the field.With the aging time prolonged,the activities of antioxidant enzymes(SOD,POD,CAT,APX)in the seeds all declined to varying degrees,and the balance of the redox reaction in the cells was destroyed and exacerbated cell aging.In the correlation analysis of seed vigor index,seedling quality and physical and chemical index,it was found that germination tendency,germination percentage,germination index,vigor index,seedling height were significantly correlated with CAT,POD,SOD,soluble sugar content.Therefore,in actual production,the germination tendency,germination percentage,germination index,vigor index,seedling height of seeds aged 12 d under the conditions of 41 °C and RH 90% can be considered as the main indicators for testing the vigor of conventional japonica rice.CAT,POD,SOD,soluble sugar content as supplementary indicators. |
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