Effects of maturity on seed quality of five conventional japonica rice cultivars

Abstract

Objective The aim is to explore the effect of maturity on seed quality of conventional japonica rice. Method Five conventional japonica rice cultivars of 'Chunjiangnuo 6', 'Shaonuo 9714', 'Xiushui 121', 'Xiushui 14' and 'Zhejing 70' were used as materials, and the effects of maturity on moisture content of fresh rice seeds, 1 000-grain weight and germination rate were compared and analyzed. Result The moisture content of fresh seeds decreased with the increase of maturity. Compared with the seeds in the normal harvest period(68 DAF for 'Shaonuo 9714', 73 DAF for other four cultivars), the 1000-grain weight of dry seeds of the five rice cultivars reached the maximum value at 50-55 days after flowering, which increased by 0.9%-2.6%, especially for 'Chunjiangnuo 6' and 'Shaonuo 9714'. The germination rate of five rice cultivars increased first and then decreased with the extension of the harvest period, and reached the maximum at 50 days after flowering, increasing by 1.0%-7.1% compared with the seeds in the normal harvest period, especially for 'Xiushui 121'. The results of correlation analysis also showed that the moisture content of fresh seeds and 1000-grain weight had significant or extremely significant correlations with germination rate. The germination rate of seeds could be well predicted by establishing a quadratic equation model between moisture content of fresh seeds and germination rate of different rice cultivars, and the regression equation was:y=-0.099 6x2+5.739 5x+15.883 0. Conclusion The seed quality of the five rice cultivars was improving as the seed maturity increasing, and reached the maximum then did not improve. So harvesting on time is necessary.