QTL ASSOCIATED WITH DROUGHT TOLERANCE IN A POPULATION OF TROPICAL MAIZE USING LINES AND TEST CROSSES

Abstract

In order to make progress in improving tolerance to water stress in maize (Zea mays L.) it is necessary to accumulate information on quantitative trait loci (QTL) associated with this character in elite inbred lines adapted to drought conditions that can be used for scenarios of climate change. In this study, a group of doubled haploid inbred lines derived from the LPSC7F64 × CML495 cross and a group of test crosses by the CML494 inbred line were evaluated under dry and irrigated environments. Results indicated that under both moisture conditions the normalized differential vegetation index (NDVI) was the parameter most associated with yield (r_g > 0.85), as well as the index that combines early vigor, final vigor and senescence (COMBO; r_g > 0.68). QTL were identified for early vigor under drought conditions (Bin 1.03), explaining 10.9 % of the phenotypic variation (% PV) (additivity + 26), as well as COMBO under drought (Bin 1.02/1.03) with 7.49 % PV (additivity + 28). Likewise, several QTL were also identified for drought and irrigation (Bin 4.05), where COMBO_LR (13 % PV) and area under the senescence curve (AUCSEN_DS) (13.8 % PV) were remarkable. Furthermore, other COMBO_LR QTL were located at Bin 5.05 (11.6 % PV) and COMBO_LR at Bin 7.03 (9.9 % PV). Additionally, QTL were found for yield (additivity 0.12 t ha^-1). These QTL can be useful for improving maize yield under both drought and irrigation conditions.