title: Characterization and identification of cold tolerant near-isogenic lines in rice.
abstract: To exploit the genetic mechanism of cold tolerance in rice, cold tolerant near-isogenic lines (NILs) were developed by backcrossing Kunmingxiaobaigu (KMXBG), reported to be the most cold-tolerant variety at the booting stage, as donor, with the cold sensitive Japanese commercial japonica variety, Towada. Comparisons of cold tolerance-related traits between five BC(6)F(5) NILs and recurrent parent Towada under cold treatment and normal temperatures at the booting stage showed that the differences between the NILs and Towada were significant only for spikelet fertility-related traits. Analyses of cold tolerance in the NILs at the budding (germination), seedling and booting stages indicated both correlated effects and differences. Lines 1913-4 and 1916-1 showed strong and stable tolerance at all three stages. Whole genome marker screening showed that the proportion of genetic background recovery was more than 98%. Seventeen markers from KMXBG were introgressed in two or more NILs, and cold tolerance genes were possibly present in these marker regions. The NILs should be excellent materials for both rice improvement and map-based cloning of cold tolerance QTLs.
authors.affiliation: Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University , Beijing 100193, China ; Hubei Key Laboratory of Food Crop Germplasm and Genetic Improvement, Food Crops Institute, Hubei Academy of Agricultural Sciences , Wuhan 430064, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Yawen
authors.initials: Y
authors.lastname: Zeng
authors.forename: Guanglong
authors.initials: G
authors.lastname: Hu
authors.forename: Yinghua
authors.initials: Y
authors.lastname: Pan
authors.forename: Shuming
authors.initials: S
authors.lastname: Yang
authors.forename: Aiqing
authors.initials: A
authors.lastname: You
authors.forename: Hongliang
authors.initials: H
authors.lastname: Zhang
authors.forename: Jinjie
authors.initials: J
authors.lastname: Li
authors.forename: Zichao
authors.initials: Z
authors.lastname: Li
keywords: Oryza sativa; booting stage; cold tolerance; near-isogenic lines