Reference "QTLs and epistasis for aluminum tolerance in rice (Oryza sativa L.) at different seedling stages."

Reference ID

7846

Title

QTLs and epistasis for aluminum tolerance in rice (Oryza sativa L.) at different seedling stages.

Source

Theoretical and applied genetics, 2000, vol. 100(8), pp. 1295-1303

Authors (7)

Wu-P	Liao-C-Y
Hu-B	Yi-K-K
Jin-W-Z	Ni-J-J
He-C

Abstract

To investigate the genetic background for aluminum (Al) tolerance in rice, a
recombinant inbred (RI) population, derived from a cross between an Al-sensitive
lowland indica rice variety IR1552 and an Al-tolerant upland japonica rice
variety Azucena, was used in culture solution. A molecular linkage map, together
with 104 amplified fragment length polymorphism (AFLP) markers and 103
restriction fragment length polymorphism (RFLP) markers, was constructed to map
quantitative trait loci (QTLs) and epistatic loci for Al tolerance based on the
segregation for relative root length (RRL) in the population. RRL was measured
after stress for 2 and 4 weeks at a concentration of 1mM of Al3+ and a control
with a pH 4.0, respectively. Two QTLs were detected at both the 2nd and the 4th
weeks on chromosomes 1 and 12 from unconditional mapping, while the QTL on
chromosome 1 was only detected at the 2nd stress week from conditional mapping.
The effect of the QTL on chromosome 12 was increased with an increase of the
stress period from 2 to 4 weeks. The QTL on chromosome 1 was expressed only at
the earlier stress, but its contribution to tolerance was prolonged during
growth. At least one different QTL was detected at the different stress periods.
Mean comparisons between marker genotypic classes indicated that the positive
alleles at the QTLs were from the Al-tolerant upland rice Azucena. An important
heterozygous non-allelic interaction on Al tolerance was found. The results
indicated that tolerance in the younger seedlings was predominantly controlled
by an additive effect, while an epistatic effect was more important to the
tolerance in older seedlings; additionally the detected QTLs may be multiple
allelic loci for Al tolerance and phosphorus-uptake efficiency, or for Al and
Fe2+ tolerance.