Abstract:

Panicle is one of the important objective for improving the plant type of rice. Studying on the panicle traits were lagged behind compared with studying on the culm and leaf. Recent years, studying on the effect of panicle traits on seed setting ability and yield increased, but little of reports could be found in integrative comparing with the classification in different panicle type and studying on the relationship of panicle type with yield and quality. In this paper, 40 rice cultivars bred during recent years in Liaoning were used to study panicle character differences, panicle type classification and their relationships with grain yield and quality for providing the theoritic basis to improve panicle type. The results showed that 13 panicle traits varied significantly among cultivars. The tested cultivars were classified into heavy panicle type (HPT), middle panicle type (MPT), and thin panicle type (TPT) according to panicle weight; dense panicle type (DPT), semi-dense panicle type (SDPT) and loose panicle type (LPT) according to grains density; erect panicle type (EPT), semi-erect panicle type (SEPT), and curved panicle type (CPT) according to panicle-neck curvature (PNC); superior-on-the-up-part type (SUT), superior-on-the-middle-part type (SMT), and superior-on-the-low-part type (SLT) according to panicle trait index (PTI), respectively. The panicle characters of HPT were similar to those of DPT, with fewer panicles per plant, more grains per panicle, higher grain density, higher ratio of secondary branch grains/total grains, lower seed-setting rate, which resulted in the higher yield and inferior grain quality. Relation of EPT with HPT or DPT was not as significant as that of HPT with DPT. The panicle number, primary branches, grains per panicle, grain density of EPT were similar to those of HPT or DPT. EPT had lower ratio of secondary branch grains to total grains per panicle, but higher seed setting rate, which resulted in that the processing qualities, appearance qualities and eating qualities of erect panicle rice cultivars were superior to those of heavy panicle type and compact panicle type rice cultivars. SUT cultivars had higher seed setting rate and better quality characters, but lower grain yield. Therefore, it may be advantageous for harmonizing yield and quality by combining EPT with SUT.

Key words: Rice, Character of panicle, Panicle type, Yield, Quality