Abstract: Panicle number, grain number per panicle and 1 000-grain weight are the three elements for rice yield, tiller is important composition factor of panicle number, and high-nodal-position tillering is a special tillering way of rice. Wild-type R818 and its high-nodal-position tillering mutant W33 were taken as experimental materials, and pot planting and field experiments were conducted to study the morphological characteristics and genetic behavior of high-nodal-position tillering traits in rice. The results were as follows. ① During the seedling stage, the plant height, leaf size, root number and root length of W33 were not significantly different with R818. ② At the early tillering stage, there was obvious secondary tiller in W33; at the mid-late tillering stage, the tiller bud of R818 were gradually enterring a dormant state, while tiller buds of W33 were still in active state except for the panicle neck node, and there were significant or extremely significant difference in the plant height, leaf length of main stem, and the first, second, third and fourth tiller number between them  at the heading stage, the average number of tillers per plant in W33 reached 79.7, which was 7.5 times of  R818. ③ The average grain number and yield per panicle of R818 were significantly different with those of W33, however the average grain yield per plant was not significant different between them. ④ F1 of positive and negative cross of W33 and R818 did not show high-nodal-position tillering characteristics, and the backcrossing progeny of their F1 with W33 showed two phenotypes of non-high-nodal-position tillering and high-nodal-position tillering, in which the separation ratio of the two traits was suitable for 1∶1 by 2 test; F2 progeny of positive and negative cross exhibited two phenotypes of non-high-nodal-position and high-nodal-position tillering, and their separation ratio was consistent with 3∶1 by 2 test. The results showed the high-sectional divisional capacity of W33 was exuberant, and the number of divisions in the middle and late stages was  significantly higher than R818;  the high-nodal-position tillering capacity in W33 was strong, and the numbers of the first, second, third and fourth tillering were significantly or extremely significantly higher than those of R818 in the mid-late tillering. The characteristics of high-nodal-position tillering trait were shown as single-gene recessive inheritance. These results could provide reference theoretical for the further research and utilization of high-nodal-position tillering in rice.

Key words: rice, high-nodal-position tillering, morphological characteristics, hereditary behavior, mutant

摘要： 穗数、每穗粒数和千粒重是构成水稻产量的三要素，分蘖是穗数的重要构成因素，高节位分蘖是水稻的一种特殊分蘖方式。以野生型水稻R818及其高节位分蘖突变体W33为试验材料，采用盆栽和大田试验，研究水稻高节位分蘖的形态特征及其遗传行为。结果表明:①幼苗期，W33的株高、叶片大小、根条数、根长与R818无显著差异。②分蘖前期，W33已出现明显二次分蘖；分蘖中后期，R818的分蘖芽逐渐进入休眠状态，而W33除穗颈节外的其他节位，分蘖芽仍处于活跃状态，二者的株高、主茎叶长及一、二、三、四次分蘖数差异显著或极显著；至抽穗期，W33的单株平均分蘖数达到79.7个，是R818分蘖数的7.5倍。③R818和W33的平均单穗谷粒数和单穗产量差异显著，但单株产量无显著差异。④W33与R818的正反交F1均无高节位分蘖；正反交F1与W33的回交后代表现为无高节位分蘖和有高节位分蘖两种表型，经2检验，其分离比均符合1∶1；正反交F2均表现为无高节位分蘖和有高节位分蘖两种表型，经2检验，其分离比均符合3∶1。表明W33的高节位分蘖能力旺盛，分蘖中后期的一、二、三、四次分蘖数显著或极显著高于R818；高节位分蘖特性表现为单基因隐性遗传。研究结果可为水稻高节位分蘖研究与利用提供理论参考。

关键词: 水稻, 高节位分蘖, 形态特征, 遗传行为, 突变体