Identification of Indica rice chromosome segments for the improvement of Japonica inbreds and hybrids.
Exploitation of heterosis has brought significant advance in plant breeding and agricultural production, although its genetic basis is still poorly understood. In this study, a total of 66 chromosome segment substitution (CSS) lines, derived from a cross between japonica rice inbred line Asominori (as the recurrent parent) and indica rice inbred line IR24 (as the donor parent), were used to investigate the genetic basis of heterosis in indica × japonica inter-subspecific rice hybrids. Each CSS line was crossed with the background parent Asominori, and the heterosis of F(1) hybrids was estimated by comparing the F(1) performance with its two parental lines. Field experiments were carried out across six different environments to evaluate yield and yield-related traits in the 66 CSS lines and their 66 corresponding F(1) hybrids. Quantitative trait loci (QTL) analyses were conducted using a likelihood ratio test based on the stepwise regression. Thirty-six QTL were identified with significant effects in CSSL, 21 with significant effects in hybrids and 13 with significant effects in both. On the basis of average dominance degree, of all the 70 QTL affecting yield-related agronomic traits, 28.6% (20) showed an overdominance, 35.7% (25) a partial dominance and 30% (21) an additive effect, indicating that all effects contribute to trait variation in japonica-indica rice hybrids. Effects of these QTL were examined to identify Indica rice chromosome segments of interest for the improvement of japonica inbred lines and hybrids.
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Provincial Center of Plant Gene Engineering, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
Zhiquan
Z
Wang
Chuanyuan
C
Yu
Xi
X
Liu
Shijia
S
Liu
Changbin
C
Yin
Linglong
L
Liu
Jianguo
J
Lei
Ling
L
Jiang
Chao
C
Yang
Liangming
L
Chen
Huqu
H
Zhai
Jianmin
J
Wan
D001947:Breeding; D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant / Q000235:genetics*; D003433:Crosses, Genetic; D017343:Genes, Plant; D005819:Genetic Markers; D005838:Genotype; D006823:Hybrid Vigor / Q000235:genetics*; D006824:Hybridization, Genetic; D012275:Oryza / Q000145:classification* / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci
D005819:Genetic Markers