播种密度和方式对机插籼稻分蘖成穗的影响

Effect of Seeding Density and Method on Tillering Characteristics of Mechanical Transplanting in indica Rice

为探讨育秧播种密度及方式对机插籼稻分蘖成穗的影响,本研究以常规籼稻黄华占,杂交籼稻F优498为供试材料,在不同播种方式及密度处理下,研究不同育秧处理机械移栽后水稻的分蘖成穗特性。结果表明,机插移栽后主茎4/0~9/0是一次分蘖发生的优势叶位,4/0~8/0是其分蘖成穗的优势叶位,产量贡献率总和达到50%左右;主茎3/0~7/0是二次分蘖发生的优势叶位,4/0~7/0是二次分蘖成穗主体,产量总贡献率为30.20%,其中主茎第5叶位是一、二次分蘖成穗的绝对优势叶位。不同播种方式间,机械条播分蘖发生率和成穗率均高于机械散播和人工撒播,一次分蘖优势叶位产量贡献表现为机械撒播最大(51.90%),机械条播最小(46.50%),二次分蘖优势叶位产量贡献率以机械条播最大(33.30%);在不同密度间,密播主茎及一次分蘖贡献率均大于稀播,但二次分蘖贡献率稀播较大。机械条播和稀播下主茎、一次分蘖、二次分蘖间每穗实粒数、千粒重均高于其余处理,其分蘖成穗的优势主要体现在二次分蘖上。生产上可通过机械条播及稀播的协同调控,充分发挥优势蘖位的作用,提高分蘖发生率及成穗率,进而提高产量。本研究结果可为机插育秧筛选较优的播种方法,同时为机插秧合理利用优势叶位提供理论和实践依据。

Two indica rice varieties(conventional indica rice Huanghuazhan and hybrid indica rice F you 498) were used to investigate the effect of seeding densities(50 g/plate and 100 g/plate) and seeding methods(mechanized drilling seeding, mechanized broadcasting, artificial broadcasting) on tillering characteristics of machine--transplanted rice. The results showed that 4/0 to 9/0 and 4/0 to 8/0 of the main stem were the dominant leaf positions for formatting primary tillers and effective tillers, respectively, which contributed to approximately 50% of grain yield. The superior leaf position for secondary tillers group emergence was 3/0 to 7/0, and 4/0 to 7/0 for ear-bearing, which contributed 30.20% to yield. The 5/0 leaf position was superior in formatting the primary and secondary effective tillers. Among different sowing methods, the tiller emergence rate and effective tillers percentage of mechanized drilling were higher than those of mechanized broadcasting and artificial broadcasting. The largest and smallest contribution to the yield of superior leave positions for primary tillers was the mechanized broadcasting(51.90%) and mechanized drilling seeding(46.50%), respectively. Mechanized drilling seeding made the largest yield contributions rate of secondary tillers in dominant leaf position(33.30%). Compared to 50 g/plate, 100 g/plate treatment led a higher contribution percentage of main stem and primary tillers, but a lower contribution percentage of secondary tillers. Mechanized drilling with lower seeding density increased the number of grains per panicle and 1000-grain weight between the main stem, the primary and the secondary tillers, which possessed higher effective tillers percentage of secondary tillers. Overall, the coordinated regulation of mechanized drilling with sparse sowing density could improve rice yield by increasing the emerging and effective percentage of tillers at the superior leaf positions. The results of this study can be used to select better seeding methods for machine-transplanted seedlings, and provide a theoretical and practical basis for the rational use of dominant leaf position of machine transplanting.