华盛优21丝苗是湖北华占种业科技有限公司和江西先农种业有限公司以华盛A为母本、 21丝苗为父本杂交育成的长粒优质三系杂交晚籼稻新品种。该品种生育期适宜、株型好、株高适中、米质优良（1级优质米）、丰产稳产和制种产量高。2021年和2022年分别通过湖北省和国家农作物品种审定委员会审定。文章介绍了其选育经过、特征特性、栽培技术要点和制种关键技术。

Huashengyou 21 Simiao is a new three-line hybrid late indica rice variety developed by Hubei Huazhan Seed Technology Co., Ltd. and Jiangxi Xiannong Seed Industry Co., Ltd., using Huasheng A as the female parent and 21 Simiao as the male parent. This variety has suitable growth period, good plant type, moderate plant height, excellent quality (level 1 standard), high and stable yield, and high seed production yield. It was approved by the Hubei Provincial Crop Variety Approval Committee and the National Crop Variety Approval Committee in 2021 and 2022, respectively. The paper introduced the breeding process, characteristics, bey cultivation techniques and seed production techniques of the variety.