桂东南地区杂交水稻理想株型初探

Primary study on ideotype of hybrid rice in Southeast Guangxi

【目的】研究以玉林为代表桂东南地区杂交水稻理想株型的形态特征并量化其形态指标,为当地水稻育种和水稻株型改良提供理论依据。【方法】以桂东南地区15个杂交水稻品种为材料,观察记载其生育期、农艺性状及产量表现,综合分析各形态指标与产量之间的关系,初步确定桂东南地区水稻理想株型主要性状的量化指标。【结果】15个杂交水稻品种生育期介于113-124 d,株高为96-122 cm,剑叶长和宽分别为28.4-42.3 cm和1.3-1.9 cm,穗长为22.2-27.4 cm,有效穗数为229.5万-304.5万穗/ha,每穗粒数130-198粒,结实率均超过80.0%,千粒重均在20.0 g以上,产量为7762.5-8887.5 kg/ha。相关性分析结果表明,生育期、株高、穗长、每穗粒数、结实率和千粒重均与产量呈正相关,其中生育期和千粒重与产量的正相关达极显著水平（P〈0.01,下同）;剑叶长、剑叶宽和有效穗数与产量呈负相关,其中有效穗数与产量的负相关达极显著水平。通径分析结果表明,生育期、剑叶长、穗长、结实率和千粒重5个指标对产量的直接作用系数均为正值,其中生育期的正直接作用最大（0.60）;株高、剑叶宽、有效穗数和每穗粒数4个指标对产量的直接作用系数为负值,以株高的负直接作用最大（-0.40）。【结论】桂东南地区杂交水稻理想株型形态的量化指标为：生育期124 d左右,株高114-122 cm,剑叶长29.0-37.0 cm,叶宽1.3-1.5 cm,穗长26.0-27.0 cm,有效穗数225.0万穗/ha左右,每穗粒数140-160粒,结实率85.0%-89.0%,千粒重约29.0 g。

【Objective】In order to provide theoretical basis for breeding hybrid rice and improving local hybrid rice＇s plant type, the present experiment was conducted to study morphological characters and quantifiable indexes of hybrid rice ideotype in Southeast Guangxi represented by Yulin. 【Method】Using 15 hybrid rice varieties as material, the field experiment was conducted to observe and record growth period, agronomic characters and yield. Then relations between morphological indexes and yield were analysed comprehensively based on field data obtained, so as to primarily confirm quantitative indexes of main characters for hybrid rice ideotype in southeast region of Guangxi. 【Result】The results showed that, as for15 hybrid rice varieties, the growth period was 113-124 d, the plant height was 96-122 cm, the flag leaf length was between 28.4-42.3 cm, the flag leaf width was 1.3-1.9 cm, the ear length was 22.2-27.4 cm, the effective ear number per ha was 2.295×106-3.045×106, total grain number per panicle was 130-198, the grain filing rate was above 80.0%, the 1000-grain weight was more than 20.0 g, the yield was 7762.5-8887.5 kg/ha. In addition, the correlation analysis indicated that the yield had positive correlation with growth period, plant height, ear length, grain number per ear, 1000-grain weight and seed setting rate, but had extremely significantly positive correlation with 1000-grain weight and growth period（P〈0.01, the same below）. Moreover, the yield had negative correlation with length and width of flag leaf, and effective ear number, but had extremely significantly negative correlation with effective ear number. Furthermore, the path analysis further showed that growth period, flag leaf length, ear length, fruiting rate, 1000-grain weight had direct positive effects on yield, so the corresponding coefficients were positive. Especially, the plant period had the greatest direct positive effect on yield, the corresponding coefficient was 0.60. And the plant height, flag leaf width, effective ear number, and grain number per ear had direct negative effects on yield, so the corresponding coefficients were negative. Especially, the plant height had the greatest direct negative effect on yield, the corresponding coefficient was-0.40. 【Conclusion】The quantitative indexes of main characters for hybrid rice ideotype in Southeast Guangxi are as follows： growth period of about 124 d, plant height of 114-122 cm, flag leaf length of 29.0-37.0 cm, flag leaf width of 1.3-1.5 cm, ear length of 26.0-27.0 cm, effective ear number per ha of 2.250×106, grain number per panicle of 140-160, seed setting rate of 85.0%-89.0%, 1000-grain weight of about 29.0 g.