Abstract:

Seven representative dual-purpose genic male sterile lines of rice were selected as experimental materials, and a sowing date experiment was conducted at the breeding base of rice dual-purpose genic male sterile lines in Shidian County to study the fertility transformation characteristics of different types of dual-purpose genic male sterile lines and the optimal sowing date for high-yielding reproduction of male sterile lines. The results showed that the sowing date had a significant impact on the fertility conversion and self-pollination rate of sterile lines. The peak values of fertility conversion and self-pollination rate of different male sterile lines varied greatly with the change of sowing date, and the tested sterile lines all had the optimal sowing date. The fertility conversion of photosensitive japonica sterile lines was mainly influenced by light length. Under the condition of ensuring safe full heading, delaying sowing was beneficial to fertility transformation and improving self-pollination rate, thus increasing reproductive yield. Due to the short growth period and rapid growth and development, the temperature sensitive early indica male sterile lines could achieve basic yield by early sowing to utilize the short-term low temperature in early June under the premise of ensuring the seedling age. The growth and development and fertility transformation of different temperature sensitive mid indica male sterile lines varied significantly. Identifying the optimal sowing date was the key to their high yield and high efficiency reproduction. By analyzing the temperature changes of the rice dual-purpose nuclear male sterile line breeding base in Shidian County over the years, it was found that the probability of high temperatures occurring from late June to mid July was high. The sensitive period of male sterile line reproduction should avoid this period as much as possible.

Key words: rice, dual-purpose genic male sterile line, parental reproduction, sowing date, sensitive period of fertility transformation, self-pollination rate

摘要：

选取7个具有代表性的水稻两用核不育系作为试验材料，在施甸县水稻两用核不育系繁育基地开展播种期试验，旨在研究不同类型两用核不育系的育性转换特点，并确定不育系高产繁殖的适宜播期。结果表明，播种期对不育系育性转换和自交结实率的影响较大，不同不育系育性转换和自交结实率峰值随着播期的变化呈现出较大差异，参试不育系均存在适宜播期。光敏型粳稻不育系育性转换主要受光长影响，在确保安全齐穗的前提下，推迟播种有利于其育性转换，提高自交结实率，进而提高繁殖产量；温敏型早籼不育系由于生育期短，生长发育迅速，因此在保证秧龄的条件下，通过早播利用6月初的短时低温可获得基本产量；不同温敏型中籼不育系的生长发育和育性转换差异大，找准最佳播期是实现其高产高效繁殖的关键。通过分析施甸县水稻两用核不育系繁育基地多年气温变化情况，我们发现该地在6月下旬至7月中旬出现高温的概率较高，不育系繁殖育性敏感期应尽量错开该时段。

关键词: 水稻, 两用核不育系, 亲本繁殖, 播期, 育性转化敏感期, 自交结实率