Morpho-agronomic and molecular characterization of hybrid rice NSIC Rc318H (Mestiso 48)

Exploitation of male sterility genes in hybrid rice substantiates heterosis and increased vigor in F1 hybrids. Selection pressure on a limited number of traits during line development has resulted to similar morphological features among modern rice varieties with phenotypic and genotypic characterization being the best way to effectively factor out obscurity. This study aimed to evaluate grain yield and quality, characterize morpho-agronomic traits, assess reaction to biotic stresses, and to determine the molecular profile of Mestiso 48. Data indicated that it exhibited more than 15% yield advantage over the check Variety, PSB Rc82, in 50% of the valid trials across regions. Its long and slender grains are comparable with the check but have slightly higher amylase content. Sensory evaluation revealed that a panel of consumers preferred Mestiso 48 over PSB Rc82 and IR64 in its cooked state at 73.9%. Its plants are slightly taller than PSB Rc82 at 109 cm and mature at 110 d after sowing across seasons. Generally, Mestiso 48 is moderately resistant to green leaf hopper and shows intermediate reaction to brown plant hopper and yellow stem borer. Molecular characterization revealed that Mestiso 48 and its female parent are indica whereas its male parent is japonica. This evidence not only explains the superior performance of this particular hybrid, but also justifies the necessity to consider heterotic groupings in breeding programs. Both parent lines and the hybrid were observed in a subcluster composed of improved varieties in a phylogenetic tree which inferred high levels of genetic similarity. It was released by the registry number NSIC Rc318H. Since then, it has set the standard for hybrid rice varieties not only for the breeding program at the Philippine Rice Research Institute, but also on a national level through the National Cooperative Testing. Farmers have responded positively to Mestiso 48 in participatory varietal selections in multiple sites across the country since 2015 wet season.