分期播种对耐高温东北粳稻农艺性状的影响及耐热性评价

Effect of interval sowing on agronomic traits and thermo-tolerance of japonica rice from Northeast China

用5份耐高温东北粳稻("东稻2号"、"东农03-33"、"东农415-1"、"合江195"和"吉粳3")为材料在中国科学院亚热带农业生态研究所长沙水稻试验站进行分期播种试验(播种日期分别为2011年3月20日、3月30日、4月9日、4月19日、4月29日、5月9日、5月19日和5月29日),研究了分期播种对供试材料株高、主穗穗长、结实率、千粒重、单株穗数、每穗总粒数、单株产量等农艺性状的影响,并分析了自然温度与结实率的关系,评价了供试材料在抽穗扬花期的耐热性。研究结果表明,随着播种期推迟各品种播始历期逐渐变短,不同播种期间的单株穗数、每穗总粒数、单株产量变异幅度较大,而株高、主穗穗长、结实率、千粒重在不同播种期间的变异幅度较小。结实率与日最高温度和日平均温度均呈负相关,"合江195"结实率受温度影响最小,"东稻2号"、"东农03-33"、"东农415-1"的结实率与温度显著相关(P<0.05),"吉粳3"为极显著相关(P<0.01)。回归分析发现,在一定温度范围内,结实率与温度呈二次曲线关系,且日最高温度和日平均温度对结实率的影响具有一致性。抽穗扬花期遇到高温的各播种期处理材料,除"东农03-33"5月29日播种结实率为58.7%、"吉粳3"5月19日播种结实率为52.5%外,其他材料结实率均在64.9%～75.1%之间,表现出较强的耐热性。综合分期播种的田间农艺性状表现和各材料结实率与自然温度之间的关系,认为"东稻2号"和"合江195"适合作为早稻在湖南种植。

The agronomic traits including plant height, panicle length, seed set, 1000-grain weight, panicles per plant, grains per panicle and theoretic yield per plant of 5 thermo-tolerant japonica rice cultivars （＂Dongdao 2＂, ＂Dongnong 03-33＂, ＂Dongnong 415-1＂, ＂Hejiang 195＂ and ＂Jijing 3＂） from Northeast China were evaluated and the relationships between nature air temperature and seed set were analyzed by use of interval sowing populations （Mar. 20, Mar. 30, Apr. 9, Apr. 19, Apr. 29, May 9, May 19 and May 29 in 2011） at Changsha, and then the thermo-tolerance at the heading stage of them was summarized. Results showed that when sowing date was postponed, the days to flower became short gradually. There were wide variations in panicles per plant, grains per panicle and theoretic yield per plant. Meanwhile the variations in plant height, panicle length, seed set and 1000-grain weight were small among different sowing dates. A negative correlation was noted between daily mean and maximum temperature and seed set. Even though the seed set of ＂Hejiang 195＂ was affected least by air temperature, the seed set of ＂Dongdao 2＂, ＂Dongnong 03-33＂ and ＂Dongnong 415-1＂ correlated with air temperature significant at the 5% level, while that of ＂Jijing 3＂ significant at the 1% level.Within a certain range of temperature, the regression curve for seed set and air temperature was cone-shaped. Furthermore, the effects of daily maximum and mean temperatures on seed set of rice were consistent. Among the interval sowings that coincided with high temperatures at the heading stage, the seed set varied in the range of 64.9%-75.1%, beside that of＂Dongnong 03-33＂ sowed on May 29, and ＂Jijing 3＂ sowed on May 19, whose seed sets were 58.7% and 52.5%, respectively. These cultivars exhibited more reliable thermo-tolerance among the tested rice cultivars. Based on the analysis of agronomic characters of interval sowing and the relationship between nature air temperature and seed set, it was recommended to plant ＂Dongdao 2＂ and ＂Hejiang 195＂ as early season rice in Hunan Province.