Relating amylose and protein contents to eating quality in 105 varieties of <i>Japonica</i> rice

Abstract

Abstract Background and objectives In rice, amylose and protein are the main factors that influence eating quality. The aim of this study was to determine the influence of the ranges in amylose and protein variation on rice eating quality and to explore the characteristics of amylose and protein in high eating‐quality rice varieties. A total of 105 japonica rice varieties (lines) from the middle and lower reaches of Yangtze River were studied. Findings When amylose content (AC) ranged from 7.35% to 19.98% and protein content (PC) ranged from 6.04% to 9.32%, amylose and protein were significantly ( p &lt; .01) negatively correlated with rice appearance, adhesiveness, balance degree, and taste value, and significantly ( p &lt; .01) positively correlated with hardness. However, when AC varied between 7.35% and 12.50% or between 14.11% and 19.98%, the eating characteristics had no significant correlation with AC; instead, they were significantly correlated with protein content (PC). PC had no significant influence on eating characteristics when it ranged from 7.86% to 9.32%. To improve eating quality (i.e., taste value &gt; 60), PC in varieties with high AC (14.11%–19.98%) should be &lt; 6.98%, and AC in varieties with high PC (7.86%–9.32%) should be &lt; 12.67%. Conclusions The results showed that the relationships among AC, PC, and eating quality were affected by the ranges of AC and PC variation. Rice varieties of the low amylose and low protein (LALP) combination should be the best choice for the high eating‐quality variety in the middle and lower reaches of Yangtze River. Significance and novelty Amylose and protein should be considered as the primary and secondary screening indices, respectively, in the selection and breeding of good eating‐quality rice varieties.