Fig. 1: The phenotypic change across improvement breeding for rice hybrids.

a, Three periods were divided on the basis of key developments of hybrid rice breeding. b, The proportion of hybrids from the three breeding periods. c–k, Box plots demonstrating phenotype distribution for hybrids from the three breeding periods: heading date (c); full grain number per panicle (d); valid panicle number (e); full grain number per plant (f); flag leaf length (g); flag leaf width (h); amylose content (i); gel consistency (j); chalkiness (k). Sample size is shown in parentheses. Significance test was conducted by one-way ANOVA for data with homoscedasticity distribution or Kruskal–Wallis test for data with heteroscedasticity distribution. Multiple comparison was further conducted by the least significant difference (LSD) method with ‘Bonferroni’ correction for homoscedasticity distribution or Nemenyi test for heteroscedasticity distribution. Different lowercase letters above the box plots represent significant phenotype differences (P ≤ 0.05).