Global climate change, its impact on stable food production in the future and
possibilities to overcome the problem are the major priorities for research.
Breeding varieties with increase adaptability to changing environments,
together with better tolerance/resistance to abiotic stress, pest and
diseases are possible solution. Maize is one of the most important crops,
with high grain yield reduction induced by drought stress. In the present
study twenty-six maize landraces from drought tolerant mini-core collection
were tested under optimal, drought, and a combination of drought and high
density stresses in the field. Morphological traits, plant height, total
number of leaves, leaf length, leaf width, anthesis-silking interval and
grain yield were recorded for each entry in two replications in three
experiments. Besides, drought tolerant indices were evaluated to test the
ability to separate more drought tolerant accessions from those with less
stress tolerance. Five stress tolerance indices, including stress tolerance
index (STI), mean productivity (MP), geometric mean productivity (GMP),
stress susceptibility (SSI), and stress tolerance (TOL) were calculated. Data
analyses revealed that STI, MP and GMP had positive and significant
correlations with grain yield under all conditions. Three-dimensional
diagrams displayed assignment of landraces L25, L1, L14, L3, L26, L15 and L16
to group A, based on the stress tolerance index and achieved grain yield
under optimal, drought stress, and a combination of drought and high density
stress. A biplot analysis efficiently separated groups of landraces with
different level of drought tolerance and grain yield. Based on all obtained
results, maize landraces L25, L14, L1 and L3, as the most valuable source of
drought tolerance, could be recommended for further use in breeding programs.
Molecular and genetic dissection of the USDA rice mini-core collection using high-density SNP markers
