Ideotype-based Selection of Superior Rice Genotypes using the MGIDI Framework for Germination, Agronomic Performance, Blast Resistance, Drought Tolerance, and Nutritional Quality
摘要
Developing rice cultivars with stable yield and high quality under environmental stresses requires efficient multi-trait selection tools. Conventional indices are limited by multicollinearity and subjective economic weights. This study aimed to assess the effectiveness of the multi-trait genotype–ideotype distance index (MGIDI) for identifying superior rice genotypes under water-limited environments. Fifty-two rice genotypes, including international aerobic rice lines, Iranian improved cultivars, and native landraces, were evaluated from 2014 to 2018. Five trait groups were considered: germination vigor and kinetics under osmotic stress, agronomic performance under field drought, physicochemical and cooking quality, micronutrient content (Iron [Fe], Zinc [Zn], Manganese [Mn], and protein), and blast disease resistance measured by the area under the disease progress curve (AUDPC). Factor analysis was used to manage multicollinearity, and MGIDI ranking was applied with a 15% selection intensity. Ten independent factors explained 81.97% of the total phenotypic variation. MGIDI identified eight superior genotypes, including the native cultivar ‘Alikazemi’ and elite IRRI-derived lines, showing balanced performance in yield stability, drought tolerance, grain quality, and disease resistance. Predicted selection differentials showed substantial gains in grain yield under drought stress (up to 26.1%), protein content (40.3%), zinc (15.7%), and iron (7.6%), while the AUDPC decreased by 27.5%. The strongest response to selection occurred at early growth stages under severe osmotic stress, with gains exceeding 100%. MGIDI effectively integrates complex trait relationships by eliminating subjective weighting and controlling multicollinearity. The index provides a robust ideotype-based framework for simultaneous improvement of yield, nutritional quality, and stress resilience, supporting sustainable rice breeding under water-limited conditions.