Genetic Analysis of Drought Resistance in Maize Using Physiological, Morphological and Molecular Markers
Asian Journal of Biotechnology and Genetic Engineering,
Drought is one of the limiting factors to annual maize production worldwide, as every year, about 15 to 20% of maize yield is lost to drought. Improvement in maize drought tolerance has always been one of the main objectives of a plant breeder. Measurement of physiological and morphological characters related to drought tolerance might prove very useful. The main objective of this study is to assess the markers, physiological and morphological traits, as well as molecular markers, which are considered as primary indices of drought tolerance mechanism. Maize, being a C4 crop, has a great mechanism of drought tolerance. Severe water stress may result in hampering photosynthesis, disturbing the overall metabolism, and finally leading to necrosis of the plant.
Similarly, other factors such as membrane stability, Chlorophyll contents, leaf area, delayed senescence, and rooting system are the most important markers to identify a crop plant in drought conditions. The final portion of this review discussed molecular markers and DNA marker-assisted selection which have become an amazing option for drought analysis in the maize crop. In this study at the Research Institute of Agrarian Business, about 113 maize lines were selected. With PCR using two Molecular Markers, dhnC397 and rspC1090, the polymorphic SNP sites of dhn1 and rsp41 were determined. As a result of this, using dhnC397, a 164-bp segment was found at the dhn1 site. For a genotype, carrying (CCA AGG) variants, PCR products were digested by using StyII restriction enzyme resulting in 02 bands, 131-bp and 33-bp. A similar approach was used for the identification of rsp41 gene polymorphism. Passing through the HpaII restriction enzyme, resulted in 02 bands, 225-bp and 61-bp. The alleles produced by using PCR and restriction enzymes are associated with drought resistance in maize. In this study, the alleles associated with drought resistance were identified in about 68 lines out of 113 by using these molecular markers. This concept can be used for breeding drought-resistant maize hybrids as well.