DIFFERENTIATION AND CLASSIFICATION OF PARENTAL LINES AND FAVORABLE GENIC INTERACTIONS AFFECTING F1 FERTILITY IN DISTANT CROSSES OF RICE (ORYZA-SATIVA L.)
Rh. Li et al., DIFFERENTIATION AND CLASSIFICATION OF PARENTAL LINES AND FAVORABLE GENIC INTERACTIONS AFFECTING F1 FERTILITY IN DISTANT CROSSES OF RICE (ORYZA-SATIVA L.), Theoretical and Applied Genetics, 96(3-4), 1998, pp. 526-538
This study was intended to investigate the extent of genetic different
iation in parental lines of rice hybrids and to analyze the genetic ba
sis underlying the fertility phenomenon in distant crosses, Two subset
s of rice material (111 entries in total) were used, including XI. dou
bled-haploid (DM) lines and 30 Indica and Japonica I-ice varieties or
lines (as a control). The DH lines was derived from a heterotic Indica
/Japonica cross (Gui630/02428) by anther culture. The materials in the
control represent a broad spectrum of the Asian cultivated rice gene
pool including landraces, primitive cultivars, historically important
cultivars: modern elite cultivars, super rice and parents of superior
hybrids, In accordance with the NC II design, 57 out of the DH lines w
ere test-crossed to two important wide compatibility lines: photoperio
d-sensitive genetic male sterile (PGMS) line N422s and thermo-sensitiv
e genetic male sterile (TGMS) line Peiai64s. The F(perpendicular to)s
and their parents. 182 entries in total, were examined for the perform
ance of seven traits in a replicated field trial. All the rice materia
ls was surveyed for polymorphisms using 92 RFLP markers selected from
two published molecular marker linkage maps. Genotypes of the FI hybri
ds at the molecular-marker loci were deduced from the parental genotyp
es. The analysis showed that there were two types of genetic different
iation in the two subsets of rice material; that is, qualitative diffe
rentiation in the control and quantitative differentiation in the DH l
ines. In addition, favorable genic interactions (both intra-or inter-l
ocus) contributed to better increase the fertility in hybrids of dista
nt crosses through incorporation of a wide-compatibility line as the f
emale parent. Favorable genic interactions can be applied in hybrid ri
ce breeding programs by selecting parents with an appropriate extent o
f genetic differentiation.