【摘要】 观察两系高产组合培两优特青25丘不同程度早穗的稻田，并辅以育秧方式、播种期、播种量、寄插密度和大田密度试验，分析早穗形成的特点及与产量性状的关系。结果表明，长秧龄及高氮是影响早穗的主要因素，两段秧和烯效唑具有一定范围的缓解作用。严重早穗可造成12％～14％的减产，表现优势穗减少，穗均总粒数和千粒重下降；轻度早穗仍属高产栽培的正常范围，高位分蘖补偿成穗及早穗结实率提高是大田补偿栽培可利用的主要特性。并以营养体的发育程度建立了早穗的评价系统。更多还原

【Abstract】 Investigations on premature heading were made on 25 plots of Peiliangyou Teqing, a high-yieldingtwo-line hybrid rice combination. Supplementary experiments were made with the same combination under different treatments of seedling-raising methods, sowing date, sowing rate, temporary planting densities, and transplanting densities. Characteristics in occurrence of premature heading and its influences on yield components wereanalyzed. It was found that longer seedling age and higher nitrogen application were the major factors causing premature heading. Heavy premature heading could cause reduced spikelet number per panicle and 1000-grain weight,and decrease the yield by a margin of 12-14%. Light premature heading would not cause yield loss under highyielding cultivation,since later occurring tillers could compensate the total panicle number, and premature headingpanicles had a higher seed setting rate. An evaluation system for premature heading was established based on thevegetative growth of rice plants.更多还原