QTLs conferring root architecture in an interspecific Gossypium hirsutum x Gossypium barbadense population

Abstract

Genetic modification of the rooting system may lead to more drought tolerant upland cotton. A number of different root and physiological traits have been suggested as important mechanism of drought tolerance of cotton. This study was conducted to identify and map quantitative trait loci (QTLs) conferring root architecture in an interspecific cross Gossypium hirsutum x Gossypium barbadense population. An F 2 population was developed which differed greatly in root characteristics. A genetic map covering 3190.50 cM, with 219 marker loci and 26 linkage groups, was constructed by using this F 2 population. The Two F 2 populations were grown in tube and pots experiments. Tap root traits (length, weight, and lateral root numbers) were evaluated. QTL analysis via composite interval mapping detected 17 QTLs, for three root traits including 3 QTLs for fresh root weight, 6 QTLs for lateral root numbers, and 2 QTLs for tap root length in tube experiment, while in pot experiment, 3 QTLs for fresh root weight and 3 QTLs for lateral root numbers were identified. Individually the QTLs accounted for 11-28% of phenotypic variation. Common QTLs were indentified for fresh root weight and lateral root numbers on chr. 18 & chr. 25 respectively, in both pot and tube experiments. The QTLs for root traits, firstly detected in Gossypium, may provide a basis for marker-assisted selection to improve productivity in root-crop breeding.