杂交水稻

了解不育系的开花习性对于提高制种产量、降低用种成本和促进杂交水稻高质量发展具有重要意义。以爽1S、Y58S、广占63-4S、龙S、晶4155S、汉2S等6个两系不育系为对象，研究了其开花习性。结果表明，参试的6个不育系的不育性均表现稳定，爽1S、Y58S、晶4155S和汉2S的花期集中、午前花率较高，有利于制种；龙S开花历期较为分散、盛花期开花率较低，不利于制种产量提高；而广占63-4S受高温天气影响，导致闭颖开花，柱头活力很低，不利于在高温环境下制种。综合来看，爽1S的开花习性最优，其在当日集中开花时段内的开花率峰值最高（33.0%），第1天开花率（10.3%）和前4天的累计开花率（75.3%）最高，柱头最长（2.52 mm），单边柱头外露率（32.1%）、双边柱头外露率（37.9%）、柱头总外露率（70.0%）以及柱头活力系数（1.77）最高，每穗粒数最多（370.7粒），午前开花率、张颖角度、张颖时间、柱头宽度、柱头表面积和柱头体积排名第2。

Understanding the flowering habits of sterile lines is of great significance for enriching the high-yield seed production theory of hybrid rice, improving seed production yield, reducing seed costs and promoting the high-quality development of hybrid rice. Taking six two-line male sterile lines, namely Shuang 1S, Y58S, Guangzhan 63-4S, Long S, Jing 4155S and Han 2S, as the research objects, their flowering habits were studied. The results showed that the male sterility of the tested six male sterile lines was stable. Shuang 1S, Y58S, Jing 4155S and Han 2S had concentrated flowering periods and a relatively high forenoon flowering rate, which was beneficial for hybrid seed production. The flowering duration of Long S was relatively scattered, and the flowering rate during the full-blooming stage was low,which was not conducive to increasing the yield of hybrid seed production. Guangzhan 63-4S showed closed glume flowering due to the influence of high-temperature weather, and the stigma vitality was very low, making it unsuitable for hybrid seed production in high-temperature environments. Overall, Shuang 1S had the best flowering habits. It had the highest daily flowering peak during the concentrated flowering time of a day(33.0%), the highest first-day flowering rate(10.3%), and the highest cumulative flowering rate in the first four days(75.3%). In addition, it had the longest stigma(2.52 mm) and the highest single-side stigma exsertion rate(32.1%), double-side stigma exsertion rate(37.9%),total stigma exsertion rate(70.0%) and stigma vigor coefficient(1.77), and the largest number of spikelets per panicle(370.7). It ranked second in terms of forenoon flowering rate, glume-opening angle, glume-opening time, stigma width,stigma surface area and stigma volume.