Jx. Li et al., Analyzing quantitative trait loci for yield using a vegetatively replicated F-2 population from a cross between the parents of an elite rice hybrid, THEOR A GEN, 101(1-2), 2000, pp. 248-254
Although F(2)s are the most informative populations for genetic analysis, i
t has been difficult to use F-2 populations directly for QTL analysis becau
se it is usually difficult to assess the reliability of the data, due to an
inability to estimate the experimental errors. In this study, we performed
a QTL analysis for yield and yield-component traits of an F-2 population b
ased on data from replicated field trials over 2 years using vegetative sho
ots of ratooned plants, making use of the ratooning habit of rice. The obje
ctive of this study was to explore the possibility of conducting QTL analys
es directly based on an F-2 population by means of ratooning plants. The ex
perimental population was from a cross between 'Zhenshan 97' and 'Minghui 6
3', the parents of 'Shanyou 63', an elite rice hybrid widely grown in China
. Agenetic linkage map containing 151 molecular markers was constructed for
QTL I napping. A total of 20 distinct QTLs were detected. eight of these w
ere detected in both years and remaining 12 in only 1 year. Compared with t
he results of our previous analysis of the F-2:3 families from the same cro
ss, it was shown that most of the QTLs detected in the ratooned F-2 populat
ion were also detected in the F-2:3 population. However, the estimates of b
oth additive and dominant types of genetic effects for many of the QTLs bas
ed on F-2 ratoons were substantially larger than those based on F-2:3 famil
ies. The results indicate that vegetatively ratooned F-2 populations may ha
ve considerable utility in the mapping of QTLs, especially if dominant type
s of gene actions are of concern, although there were certain technical lim
itations in making use of such populations in the experiments.