Performance of agronomic traits and polymorphism of major genes of rice with different plant architectures

【Objective】The purpose of the study was to analyze the performance of agronomic traits and major genes polymorphism of rice with different plant architectures,to reveal their yield traits and genetic basis,and to provide theoretical reference for ideal plant architecture breeding.【Method】The ideal plant architecture strain Shaoniejing was used as the control,and the natural recombinant new germplasm RIL60 and RIL61 came from Beibeinuo,Jingnuo 1 and a recombinant inbred line were used as materials to study the agronomic trait performances and genetic differences of rice with different plant architectures,and to compare the plant architecture characteristics at different days after flowering(10,17,24 and 31 DAF). At the same time,the ideal plant architecture genes IPA1,Gn1a and DEP1 and the waxy gene Wx genotypes were identified for the five germplasms.【Result】Shaoniejing was ipa1 and gn1a-m1 mutant,and its leaf traits were greatly different from other germplasms,with the characteristics of longer lanceolate leaves,shorter inverted trilobate leaves and narrower leaves. The stem,leaf and panicle dry matter of Shaoniejing were less than those of other germplasms throughout four developmental stages. However,the increase of panicle dry matter at different developmental stages was greater than that of other germplasms,indicating that this germplasm had stronger utilization rate of light energy and dry matter accumulation rate within the same period of time,and it had a significant advantage in 1000-grain weight compared to the other four germplasms. The functional leaf angle of RIL60 was greatly different from other germplasms,and its tower-type characteristic was more conducive to the accumulation of photosynthetic products,thus it was closer to the ideal plant architecture. Its panicle weight was lower than that of RIL61,but it showed a significant increase in the number of effective panicles per plant compared to RIL61(P<0.05,the same below),resulting in no significant difference in yield per plant between RIL60 and RIL61(P>0.05). The functional leaf area of RIL61 exhibited an advantage compared to the other four germplasms across four developmental stages. The dep1 mutant,Beibeinuo,had a more compact plant architecture and erect panicles. It had lower panicle dry matter accumulation in the early stages,but exceeded other germplasms at 31 DAF period,featuring more primary and secondary branches and dense panicle spacing and belonging to heavy panicle type germplasm,indicating its strong photosynthetic product conversion ability. Jingnuo 1 showed no advantage in the traits of panicle weight and grain density,but its yield per plant was the highest because of the highest number of effective panicles. The weight of panicle indexes affecting ideal rice plant architecture yield was number of effective panicle number per plant>panicle weight>1000-grain weight.【Conclusion】RIL60 and Shaoniejing are basically consistent with the ideal plant architecture characteristics such as few ineffective tillers,large number of grains per panicle,excellent light reception posture,and thick and sturdy stems,which can be used as the ideal plant architecture breeding germplasm. Jingnuo 1 has better plant architecture,more effective tillers per plant and higher yield per plant,which can also be used as the parent of ideal plant architecture breeding. In future ideal plant architecture breeding,priority should be given to panicle weight and effective panicle number per plant,selecting germplasms with larger panicles and more effective tillers,while moderately lowering the requirement on 1000-grain weight. Additionally,trying to choose germplasms containing beneficial alleles like IPA1 and DEP1 can be expected to breed high-yielding rice varieties with ideal plant architecture.