Study On The Grain Quality Characters At Different Positions On The Rice Panicle

It is of great significance to study the changes of physicochemical indexes and quality characteristics of rice grains at different positions on the panicle during the ripening process,so as to reveal the mechanism of rice quality formation and growth.In this paper,the degree of strong(weak)potential of grains in different positions of panicle was studied from six aspects of rice moisture,brown rice grain weight,mature grain rate,milling quality,appearance quality and amylose content.The most suitable harvest period of rice based on the whole panicle quality was determined according to the characteristics of varieties and panicles,and the correlation of relevant indexes in the process of grain maturity was analyzed.The main conclusions are as follows:1.The moisture content of rough rice in different positions on the panicle decreased exponentially with the increase of harvest time,and the stronger the rice was,the faster the water loss was;The 1000-grain weight,mature grain rate and roughness rate of grains in different positions increased with time,and no significant change occurred after reaching the maximum value.The earlier the stronger the grain filling,the faster the ripening.The grain weight of primary branch grain in any position after ripening was significantly greater than that of secondary branch grain,and the difference between mature grain rate and roughness rate decreased with time,and there was no significant difference at last;With the increase of harvest time,the whiteness of milled rice in different positions decreased first,then increased rapidly,and finally increased slowly;the length,width and thickness of grain were independent of the degree of strong(weak)potential of grain,which showed that the grain size of primary branch was significantly larger than that of secondary branch;The whole grain rate,green grain rate and milky white grain rate are related to the degree of strong(weak)potential.The higher the whole grain rate is,the lower the green grain rate and milky white grain rate is.There is no significant difference between the amylose content of primary and secondary branches at any position,and the amylose content of primary and secondary branches decreases from the base to the top.2.The degree of strong(weak)potential of grains in different positions on the panicle of Jinchuan No.1 was as follows:Ⅰ-1>Ⅱ-1>Ⅲ-1>Ⅳ-1>Ⅰ-2>Ⅱ-2>Ⅴ-1>Ⅲ-2>Ⅳ-2>Ⅴ-2;The degree of strong(weak)potential of grains in different positions on the panicle of Jinyuan 45 was as follows:Ⅰ-1>Ⅱ-1>Ⅲ-1>Ⅰ-2>Ⅳ-1>Ⅱ-2>Ⅴ-1>Ⅲ-2>Ⅳ-2>Ⅴ-2;The degree of strong(weak)potential of grains in different positions on the panicle of Jinyujing 18 was as follows:Ⅰ-1>Ⅱ-1>Ⅲ-1>Ⅳ-1>Ⅰ-2>Ⅴ-1>Ⅱ-2>Ⅲ-2>Ⅳ-2>Ⅴ-2.The degree of grain strength(weak)of different varieties is slightly different according to the characteristics of panicle,but the whole can be simply summarized as the middle and above primary stem grain > the upper secondary stem grain > the lower primary stem grain >the middle and below secondary stem grain.3.The most suitable harvest time based on the whole panicle quality should be determined according to the variety characteristics and ear characteristics:Jinchuan No.1belongs to the high-quality variety with primary branch and grain,which should be harvested in time when the primary branch and grain are mature on day 0;Jinyuan 45 belongs to the conventional high-yield variety with secondary branch and grain,which should be harvested when the secondary branch and grain are all mature on day 20;Jinyujing 18 belongs to the vertical spike type variety with primary and secondary branch and grain accounting for half respectively,which should be harvested when most grains are mature on day-5.4.The results showed that with the increase of 1000 grain weight,the water loss,the roughness and the mature grain rate increased.