Trait association studies in diverse genotypes of rice for their utilization in biofortification

Abstract

Rice is the staple food crop for more than half of the world population. Thus, rice varieties enriched with various micronutrients qualifies as a better alternative to combat micronutrient deficiency. The present investigation was undertaken to study the degree and direction of association for grain characters especially grain Zinc (Zn) content and grain Iron (Fe) content in 30 genotypes of rice. The correlation coefficient analysis findings at the phenotypic level were used to determine whether the various traits were correlated with yield and the significance of the relationship among them. This data shows significant positive correlation at the phenotypic and genotypic level for grain yield per plant with days to 50% flowering (0.356 & 0.373), number of panicles per plant (0.340 & 0.522), panicle length (0.293 & 0.356), test weight (0.307 & 0.346) and kernel breadth (0.283 & 0.339). The signs (positive or negative) reflect the consequence of increasing or decreasing one variable over the other. The traits plant height ((-0.399 & -0.410) and kernel L/B ratio (-0.237 & -0.291) showed negative correlation  with yield indicating that shorter plants as well as grains having shorter length with more breadth are more likely to produce more yield thus selection should be carried out against height . One possible reason for this could be that in plants with shorter stature have higher nutrient use efficiency and are resistant to lodging. The traits days to 50% flowering, number of panicles per plant, panicle length, and test weight and kernel breadth showed positive correlation indicating that selection towards higher values for these traits would consequently improve the yield. It was also found that the traits Zn and Fe content were positively correlated with each other implying that simultaneous selection of these traits could be done for the purpose of biofortification.