Reference "Mapping QTLs associated with drought avoidance in upland rice grown in the Philippines and West Africa"

Reference ID

6836

Title

Mapping QTLs associated with drought avoidance in upland rice grown in the Philippines and West Africa

Source

Plant molecular biology, 2002, vol. 48, pp. 683-695

Authors (5)

Price-A-H	Townend-J
Jones-M-P	Audebert-A
Courtois-B

Abstract

Localizing genes that contribute to drought avoidance in a quantitative way
should enable the exploitation of these genes in breeding through marker-
assisted selection, and may lead to the discovery of gene identity and function.
Between 110 and 176 F6 recombinant inbred lines from a mapping population
derived from a cross of upland rice varieties Bala and Azucena have been
evaluated for indicators of drought avoidance in sites in the Philippines and
West Africa over two dry seasons. A molecular map with 102 RFLP, 34 AFLP and six
microsatellite markers has been used to map (by composite interval mapping)
quantitative trait loci (QTLs) for the visual scores of leaf rolling and leaf
drying and leaf relative water content. QTLs were mapped for each site and
across sites. A total of 17 regions were identified which contained QTLs with a
LOD score greater than 3.2. For leaf rolling, Bala was the parent contributing
the majority of positive alleles whilst for the other traits, Bala and Azucena
contributed more evenly. Six of the 17 regions influenced more than one trait,
explaining the phenotypic correlations between traits that were observed. Three
QTLs appeared to be specific to the Philippines experiments. One QTL had
opposing effects in the Philippines and West Africa. QTLs for relative water
content were detected on chromosome 8, congruent with an osmotic adjustment QTL
identified in another population. Only three of the QTLs identified here have
not been reliably identified in the two other populations that have been
screened for drought avoidance. By using several populations assessed for
drought avoidance in different sites, the distribution and utility of QTLs for
drought avoidance in rice is being elucidated.