| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4510640 | Field Crops Research | 2011 | 11 Pages |
Genetically improved crops with higher water productivity help maintaining and increasing agricultural production in drought-prone areas. Their development involves, as in the case of maize, selection for high grain yield and improved secondary traits. With the objective of better understanding the role and regulation of the morphology of drought adaptation, a recombinant inbred line (RIL) population of tropical maize (Zea mays L.) was evaluated in six field experiments under intermediate (IS) and severe (SS) drought stress at flowering and under well-watered (WW) conditions in Mexico. The analyses per water regime revealed 32 quantitative trait loci (QTLs) for the five measurements of relative content of leaf chlorophyll (CL), 25 for the five visual ratings of plant senescence (SEN), and 11 for the three measurements of electric root capacitance (RCT). Impressive clusters of QTLs were observed on chromosomes 2 (bins 2.03-05), 4 (bin 4.09), and 10 (bins 10.04-05), suggesting that a small number of genes control chlorophyll metabolism and plant senescence. The high CL and low SEN of the drought resistant parent are aspects of its high water productivity resulting from improved constitutive traits. Co-locations of QTLs for CL, SEN and RCT with QTLs for plant height (PHT), the anthesis-silking interval (ASI), and grain yield (GY) were observed in bins 1.06-07, 8.06, and 4.09 but not for the large QTL clusters on chromosomes 2 and 10, suggesting independent genetic control of reproductive traits. Still, the phenotypic data showed that high CL and low SEN were favorable for grain yield production under drought, while delayed SEN was associated with higher grain yield under WW conditions. CL and SEN are suitable to complement selection for drought tolerance in order to sustain future breeding progress.
• We evaluated the response to drought stress of tropical maize. • The study is based on six field experiments. • There was an impressive clustering of QTLs along the genome. • The information contributes to sustain progress in breeding for drought tolerance. • More drought-tolerant crop varieties are urgently needed.
