Quantitative calculation of optimum panicle number per plant of super high-yield rice

Chinese. 【目的】建立水稻单株成穗数通式和有效分蘖叶位理论分蘖数函数,并确定超高产水稻的秧苗分蘖成活率（s）、本田期分蘖发生率（r）、分蘖缺位数（bn）、适宜等穗期及校正系数（a）等相关参数。【方法】选择云南水稻特殊高产生态区,2005年进行杂交籼稻Ⅱ优107密度试验,2005～2006年进行杂交籼稻Ⅱ优107、Ⅱ优318、Ⅱ优7954、Ⅱ优084、Ⅱ优航1号和协优107大区超高产试验。对试验的水稻分蘖消长进行调查分析,并最终测产。【结果】所有参试品种都遵循n-3的叶蘖同伸规律,有效分蘖叶位理论分蘖数（A）可以表示为有效分蘖叶位数（E）的函数,有效分蘖叶位数（E）与主茎总叶龄（N）、伸长节间数（n）、移栽叶龄（SN）、分蘖缺位数（bn）和校正系数（a）有关,E=（N-n-SN-bn-a）;超高产群体的矫正系数（a）宜取1.5;常规湿润秧移栽大田后有1.5叶的分蘖缺位（bn）,带2叶分蘖成活率（s2）和带1叶分蘖成活率（s1）分别为0.8和0.3;穴盘带土移栽,bn=0.5,s2=1.0,s1=0.5;本田期秧苗活棵至等穗期,分蘖发生率（r）80%左右。【结论】超高产水稻常规湿润秧本田期有效分蘖叶位E=（N-n-SN-3）,单株分蘖成穗数ES=（1＋t3＋0.8t2）（1＋0.8A）＋0.3t1,其中t1、t2、t3分别代表秧苗带1叶、2叶和3叶分蘖数;穴盘小苗移栽本田期有效分蘖叶位E=（N-n-SN-2）,单株分蘖成穗数ES=（1＋t3）（1＋0.8A3）＋t2（1＋0.8A2）＋0.5t1,其中A2、A3分别代表2叶分蘖、3叶分蘖及主茎本田期理论分蘖数。通过两年与实际茎蘖动态的比较,公式描述较好。

English. [ Objective ] This study was conducted to summarize the general formula of panicle number per plant （ES） of rice and establish the function of theoretic number of tillers for effective tillering leaf position, and determine the tiller surviving rate of seedling （s）, tiller emerging rate after transplanting （r）, missing tiller number after transplanting （bn）, and adjusting factor （a）. [Method] Field experiments were performed in the special high-yield area at Taoyuan, Yongsheng County, Yunnan province, and tiller number and grain yield were determined. Five transplanting density treatments were conducted with an Indica hybrid rice variety, Eryou 107, in 2005; and six Indica hybrid rice varieties, Eryou 107, Eryou 318, Eryou 7954, Eryou 084, Eryouhang No. 1 and Xieyou 107, were used in high-yield field experiment in 2005 and 2006, respectively. [Result] All varieties followed the ＂n-3＂ law of synchronously emerging of tiller with leaf. The theoretic number of tillers for effective tillering leaf position （A） was calculated and can be expressed as the function of the number of effective tillering leaf position （E）. E was related with the total leaf number （N）, leaf age at transplanting （SN）, elongated node number （n）, missing tiller number after transplanting （bn） and adjusting factor（a）, E-（N-n-SN-bn-a）. The adjusting factor （a） for super high-yield rice should be taken as 1.5. For traditional wet-bed seedling, bn was 1.5, surviving rate of tillers with 2 leaves （s2） was 0.8, surviving rate of tillers with 1 leaf（s0 was 0.3; while for seedling tray, bn was 0.5, s2 was 1.0, slwas 0,5. From seedling recovering to stage of tiller equal panicle, r was 80% or so. [Conclusion] For traditional wet-bed seedling, E （N-n-SN-3）, ES=（l＋t3＋O.8t2）（l＋O.SA）＋O.3tl; for seedling tray, E-（N-n-SN-2）, ES=（I＋t3）（I＋O.8A3）＋ t2（l＋O.8A2）＋O.5tb where tl, t2, t3 represents the tillers with 1, 2 and 3 leaves, respectively, A2 and A3 represent the emerged tiller number after transplanting for tillers with 2 and 3 leaves, respectively. The comparison of theoretical and actual tiller number showed that the formula well depicted the tiller emergence characteristics of super high-yield rice.