title: A practical protocol to accelerate the breeding process of rice in semitropical and tropical regions.
abstract: Breeding of excellent rice varieties is essential for modern rice production. Typical breeding procedures to introduce and maintain valuable agricultural traits require at least 8 generations from crossing to stabilization, always taking more than 4-5 years of work. This long and tedious process is the rate-limiting step in the development of new varieties, and therefore fast culturing methods are in urgent need. Taking advantage of early flowering characteristics of light-sensitive rice under short-day conditions, we have developed a practical protocol to accelerate the breeding cycle of rice, which we have termed the "1 + 2", "2 + 2", "1 + 3", and "0 + 5" methods according to the different rice varieties and different breeding purposes. We have also incorporated several techniques, including glume cutting, seed desiccation at 50°C in a drier seed dormancy breakage with low concentration of HNO3, and direct seeding. Using the above strategy, we have shortened the life cycle of light-sensitive rice varieties to about 70 days, making it possible for several rice cultivars to proliferate 4-5 generations in a single calendar year. This protocol greatly accelerates the process of new variety breeding, and can be used in rice research for shortening the process of genetic analysis and the construction of mapping populations.
authors.affiliation: Jiaxing Academy of Agricultural Sciences , Jiaxing, Zhejiang 314016 , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing NMR Center, College of Chemistry and Molecular Engineering, Peking University , Beijing 100871 , China.
authors.forename: Xianhui
authors.initials: X
authors.lastname: Hou
authors.affiliation: Xiuzhou District Seed Managemental Station , Jiaxing, Zhejiang 314000 , China.
authors.forename: Jindi
authors.initials: J
authors.lastname: Liu
authors.affiliation: Jiaxing Vocational Technical College , Jiaxing, Zhejiang 314000 , China.
authors.forename: Changgen
authors.initials: C
authors.lastname: Qian
authors.affiliation: Jiaxing Academy of Agricultural Sciences , Jiaxing, Zhejiang 314016 , China.
authors.forename: Rongcun
authors.initials: R
authors.lastname: Gao
authors.affiliation: Beijing Sunbiotech Co. Ltd. , Beijing 100193 , China.
authors.forename: Linchuan
authors.initials: L
authors.lastname: Li
authors.affiliation: Jiaxing Academy of Agricultural Sciences , Jiaxing, Zhejiang 314016 , China.
authors.forename: Jinjun
authors.initials: J
authors.lastname: Li
keywords: Oryza sativa; fast proliferation; life cycle; short-day; variety breeding