Analysis on Grain Quality of Indica Hybrid Rice Combinations Bred During Recent Twenty-Five Years in China
MIN Jie; ZHU Zhi-wei; JIN Lian-deng; XU Li; ZHANG Lin-ping; TANG Sheng-xiang
(Rice Product Quality Inspection and Supervision Center, Ministry of Agriculture, P.R. China; China National Rice Research Institute, Hangzhou 310006, China)
To understand the grain quality of indica hybrid rice combinations in China and to clarify its key points for genetic improvement for the future, ten grain quality traits and their superior quality rates (SQRs) of 4495 indica hybrid rice combinations bred since 1984 were analyzed. The SQRs of the ten grain quality traits were from 34.2% to 97.9%, with an average of 78.5%. The excellent indica hybrid rice combinations with all the five key grain quality traits (head rice rate, chalkiness degree, transparency degree, amylose content and quality index) in or above the standards of the third class superior quality of rice occupied 29.9% of the total. The average SQRs for the ten grain quality traits of the tested combinations bred in the three periods, 1980s, 1990s and 2001-2008, were 64.2%, 71.1% and 81.4%, and the SQRs for quality indices were 84.5%, 86.4% and 88.5%, respectively. The excellent indica hybrid rice combinations bred in 2001-2008 with all of the five key quality traits in or above the standards of the third class superior quality occupied 32.9%, 18.0 and 11.9 percent points higher than that in 1980s and 1990s. The above results indicated that in general, the grain quality of the indica hybrid rice combinations bred in 2001-2008 was better than that in 1980s and 1990s. The tested combinations of Boyou-, Zhongyou- and Peiyou-series showed better grain quality. On the other hand, it was noticed that the SQRs of chalky grain rate and chalkiness degree were rather lower (only 34.2% and 55.1%, respectively) than that of other eight quality traits,which would be the emphasis of grain quality improvement of indica hybrid rice in recent future.