New plant-type (NPT) rice can increase grain yield globally. Although many studies have shown the association between harvest and yield-related traits in rice, it remains obscure in the case of NPT rice. This study aimed to elucidate the relationship between agronomic and yield features in new plant-type rice based on a 12-years multi-experiment. A large dataset of 704 NPT rice lines of various generations (F₄ to F₁₀), derived from 24 different populations, underwent study. The analysis of variance showed a highly significant population effect (P < 0.01) on all traits studied. The NPT rice populations had groupings into four clusters, with a highly substantial cluster effect (P < 0.01) on the number of total tillers (NTT), number of total grains (NTG), number of filled grains (NFG), and thousand-grain weight (TGW). Standard best NPT lines from each experiment achieved an average of 1.67 t ha^-1 or 26% higher yield than the Ciherang variety. Determining the yield advantage of NPT lines was by higher plant height (PH) (r = 0.37), panicle length (PL) (r = 0.15), NTG (r = 0.28), NFG (r = 0.28), TGW (r = 0.10), and lower days to harvest (DTH) (r = -0.10). The principal component analysis biplot revealed that NFG could better serve as a selection characteristic for enhancing grain yield in developing NPT rice adapted to irrigated tropical ecosystems.

Keywords: Cluster analysis, combined analysis, genotype × trait, grain yield, Pearson correlation, rice breeding

Key findings: The new plant-type rice architecture allows a higher yield (26%) than the green revolution rice type represented by the Ciherang variety. Genetic diversity among the NPT lines is prevalent; therefore, breeding-improved NPT rice varieties are promising.