ABSTRACT
Using image analysis technology, the morphological measurements of paddy, brown (BR), and milled (MR) grains of 408 rice (Oryza sativa L.) lines representing a wide range of grain morphology were obtained, and the measurements' relationships with grain weight, milling quality, and chalkiness were investigated. The principal component analysis identified two morphological traits with a total variance of 95.7% in MR. Weight of MR was modeled as a function of the principal components using linear regression (R2 = 0.95). For milling quality measurements, dominance analyses indicated that single grain weight of the paddy and BR grains were two primary parameters in determination of BR and MR recovery, whereas surface area, perimeter, and diameter were primary parameters that controlled head milled rice (HR) recovery. All measured morphological properties (surface area, perimeter, diameter, length, width, length-to-width ratio, roundness, and thickness) and grain weight significantly correlated with percentage of chalky (%C) grain and chalkiness (%C × % area with chalk) for all milled grains. The grain width, roundness, and thickness positively correlated with chalkiness, whereas the length and length-to-width ratio negatively correlated with chalkiness. The growing environment significantly affected grain HR recovery, %C grain, and chalkiness but had little effect on grain morphology and weight.
