云南稻核心种质苗期耐冷性及其地理生态差异

Eco-geographic difference and cold tolerance at seeding stage of core collection for rice in Yunnan

采用Nagamine等（1991）法研究了598份云南稻核心种质在稻作区划间、地州间苗期耐冷性强弱、变异程度及其地理生态差异。结果表明，稻作区划间苗期耐冷强弱差异较大，平均耐冷级别为：Ⅰ（4．70）〉Ⅱ（4．78）〉Ⅴ（4．79）〉Ⅲ（534）〉Ⅳ（5．36），40份强耐冷种质频率为Ⅱ（45％）〉Ⅰ（25％）〉Ⅲ（22．5％）〉Ⅴ（5．0％）〉Ⅳ（2．5％），其变异系数为Ⅱ（32．22％）〉Ⅰ（31．28％）〉Ⅴ（29．65％）〉Ⅲ（19．66％）〉Ⅳ（19．59％）；揭示了苗期耐冷性与低温胁迫下水稻冬存育秧、冷泉水密切相关，其耐冷基因源是云南南部地区冬季育秧和滇中一带苗期倒春寒长期协同进化的结果；苗期而冷种质广泛存在于热带、亚热带和温带地区，品种间苗期耐冷差异也明显。云南稻核心种质16个地州平均苗期耐冷强弱差异较大。根据气候、生态、云南稻种多样性及其苗期耐冷性等将云南稻作区划分为重冷害多样性贫乏区、冷害多样性中区和轻冷害区三部分。其中，曲靖、大理、楚雄、昆明和丽江5个地州平均耐冷级别3．65-4，32，0-2级苗期强耐冷种质占27．5％（2．5％～10％）和高海拔冷泉水苗期灌溉，属于重冷害多样性贫乏区；文山、红河、思茅、保山、德宏和临沧6个地州平均而冷级别4．45～5．40，0-2级苗期耐冷种质占70％（5％～30％）和冬春育秧，属于冷害多样性中区；怒江、玉溪、昭通、迪庆和西双版纳5个地州平均耐冷级别5．05～5.87，0-2级苗期耐冷种质占2．5％（0～2．5％），属于轻冷害多样性扩散区。水稻冬春育秧种高海拔冷泉水灌溉在云南稻核心种质苗期耐冷基因源演化中起了重要作用。

Eco-geegraphic difference, grade and variation of cold tolerance at seeding stage 598 accessions core collection from prefectures and rice regions zone in Yunnan rice were identified using Nagamine et al （1991） under 5℃ low temperature condition. Results showed that it was bigger difference for cold tolerance at seedling stage among prefectures, average grade for Ⅰ （4.70）〉Ⅱ（4.78）〉Ⅴ（4.79）〉Ⅲ（5.34）〉Ⅳ（5.36）, frequency of cold tolerance landraces for Ⅱ （45%）〉Ⅰ（25%）〉Ⅲ（22.5%）〉Ⅴ（5.0%） 〉Ⅳ（2.5%）, and coefficient of variation of Ⅱ（32.22%）〉Ⅰ（31.28%）〉Ⅴ （29.65%） 〉Ⅲ （19.66%）〉Ⅳ（19.59%）. Their cold tolerance at seedling stage were closely related to seedling grown on winter or spring and cold fountain under cold stress, the cold tolerance at seedling stage resulted from the synergetic evolution of Yunnan rice and low temperature for seedling grown between winter on southern Yunnan and spring on middle Yunnan. The germplasms of cold tolerance were not only widely existed on tropic, subtropic and temperature zone, but also difference with cold tolerance among plants of one landrace. There was relatively bigger difference for cold tolerance at seedling stage of core collection among 16 prefectures in Yunnan rice landraces. It was divided into three regions according to cold tolerance at seedling stage, climatic and ecology： Serious Cold Damage and Diversity Smallness Region including 5 prefectures i.e. Qujing, Dali, Chuxiong, Kunming and Lijiang, 3.65-4.32 of average grades for cold tolerance, cultivars of 0-2 grade account for 27.5% （2.5%-10%） and cold fountain with high elevation; Cold Damage Diversity Center Region including 6 prefectures, i.e. Wenshan, Honghe, Simao, Baoshan, Dehong and Licang, 4.45-5.40 of average grades for cold tolerance, cultivars of 02 grade account for 70%（5%-30%） and seedling grown on Winter or Spring. Light Cold Damage and Diversity Diffuse Region including 5 prefectures, i.e. Nujiang, Yux, Zhaotong, Diqing and Xishuangbanna, 5.05-5.87 of average grades for cold tolerance, cultivars of 0-2 grade account for 2.5%（0-2.5%）. It is an important role on evolution of cold tolerant landrace at seedling stage for core collection in Yunnan rice about seedling grown on winter or spring and irrigation for cold fountain on high elevation.