QTL mapping of adventitious root formation under flooding conditions in tropical maize (Zea mays L.) seedlings

Quantitative trait loci (QTLs) controlling adventitious root formation (ARF) on the soil surface were evaluated under flooding conditions in I 10 individuals of an F-2 population derived from a cross between a dent inbred line 'B64' and a tropical Caribbean flint inbred line 'Na4'. The ARF capacity of seedlings suggested the existence of continuous variation in the F2 population. The QTLs for ARF were located on chromosomes 3 (bin 3.07-8), 7 (bin 7.04-5) and 8 (bin 8.05). Alleles of line Na4, with a high capacity for ARF, increased ARF in the case of all the QTLs. By comparing chromosome positions of ARF loci in the B64 x Na4 population with those in a B64 x teosinte (Zea mays ssp. huehuetenangensis) population, the region conditioning ARF on chromosome 8 was consistent across the two populations. In the present study, overlap between the QTLs for ARF in the B64 x Na4 cross and QTLs for root traits measured in aerated hydroponic culture was also observed as reported in other mapping populations.