Grain shape is a key breeding target that influences both grain yield and appearance quality in rice. Breeding for long-slender grains is an effective strategy to improve grain quality (Jain et al., 2004; Wang et al., 2012, 2015a). In the past two decades, several quantitative trait loci (QTLs) responsible for grain size and shape have been identified, including GS3 (Fan et al., 2006), GS5 (Li et al., 2011), GW8 (Wang et al., 2012), GW7/GL7 (Wang et al., 2015a, 2015b), GLW7 (Si et al., 2016), GW5 (Liu et al., 2017), LGY3 (Liu et al., 2018) and OsSPL18 (Yuan et al., 2019). The introduction of the different allelic combinations of gs3-gw8Amol, gs3-GW7TFA and GW5NIP-gs3-GW79311-GW8NIP-OsMADS19311 regulatory module into indica rice breeding programs simultaneously improve grain yield and quality (Wang et al., 2012, 2015a; Wu et al., 2018). However, the underlying mechanisms of the relationship between grain yield and quality are still elusive, simultaneously improving grain yield and quality remains a major challenge in the production of new rice varieties (Bai et al., 2018).