Dry matter production and distribution characteristics of perennial rice under short cycle perennial root cultivation

To explore the dry matter production and accumulation characteristics of perennial rice and one-year hybrid ratoon rice and their derived rice cultivation models, and to gain a deeper understanding of the physiological and ecological formation mechanism of perennial rice rhizome cultivation, providing a basis for promoting sustainable perennial rice rhizome cultivation and achieving high and stable yields. Using ¹³C pulse labeling technology and crop physiological ecology methods to measure and analyze the yield variation differences of perennial rice in different rhizome cultivation seasons, which focus on studying the impact of shortened growth periods and differences in dry matter production and distribution on yield. The results showed that compared with the first season rice of 151 days, the growth periods of the first ratoon rice（FRR）of 81 days, the second ratoon rice（SRR）of 126 days, and the third ratoon rice（TRR）of 80 days were shortened by 70, 25, and 71 days, respectively. The dry matter distribution pattern in various organs of the plant was basically consistent with the control group, that is, the conventional hybrid ratoon rice（YY2640-FRR）, specifically manifested as the increase in the allocation amount and allocation rate of dry matter and non-structural compounds to the above-ground grain sink with the advancement of grain filling, while the allocation amount and allocation rate to organs such as stems, sheaths, and leaves decreased accordingly. Among them, the conversion and output rate of stem and sheath dry matter significantly increased, and this phenomenon was more obvious in perennial rice. Based on ¹³C isotope tracing technology, further research proved that compared with the first season rice of perennial rice, the allocation amount and allocation rate of dry matter to above-ground panicle organs in the later growth stage of perennial rice for ratoon rice were higher, but the allocation amount of ¹³C substances to other above-ground organs, especially stems, sheaths, and leaves, as well as underground soil, decreased season by season. In summary, it indicates that there is a significant synergy and trade-off relationship between the yield of perennial rice and the dry matter production and resource allocation of its vegetative organs, which reflects an important survival and evolution strategy and it may be the key reason why the yield of perennial rice is difficult to maintain high and stable in long-term rhizome cultivation.