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以云南 16个地州和 5个稻作区为单位 ,对 4 77份云南稻种核心种质进行了耐冷性鉴定及其地理分布研究。结果表明 :(1)低温条件下花药长与结实率呈极显著正相关 (0 .5 88 ) ,温室条件下两者关系不大 (0 .0 80 )。(2 )低温条件下不同稻作区云南稻种核心种质孕穗期耐冷性差异较大 ,滇西北高寒粳稻区的稻种核心种质孕穗期耐冷性最强 ,南部边缘水陆稻区最弱。而温室条件下基本未受到冷害 ,结实率接近或超过 70 %。因此 ,耐冷育种目标和品种因稻区而异。 (3)低温条件下不同地州云南稻种核心种质孕穗期耐冷性差异十分明显 ,而温室条件下基本未受到冷害 ,结实率均大于 6 5 %。根据稻种核心种质的结实率降低率及其地州间的自然气候差异 ,可将 16个地州划分为重冷害区、冷害区和轻冷害区。 (4)不同稻作区或不同地州间云南稻种核心种质孕穗期耐冷性的差异 ,进一步揭示了由海拔和纬度差异引起的温度变化不仅是籼粳分化的主导因子 ,也是造成籼粳两个亚种六大生态群之间差异和云南稻种遗传多样性大的根本原因 ,同时也是耐冷基因形成的关键因素 ,孕穗期耐冷性是云南地方稻种与地州或稻作区低温长期协同进化的结果。
Based on the 16 prefectures and 5 paddy fields in Yunnan, the cold tolerance identification and geographical distribution of 4 77 Yunnan rice germplasms were studied. The results showed that: (1) There was a significant positive correlation between anther length and seed setting rate under low temperature (0.5888), while the correlation between anther length and seed setting rate in greenhouse was not significant (0.080). (2) Cold tolerance of core collection of Yunnan rice germplasm differed greatly in different rice cultivars at low temperature, and cold tolerance of core collection of rice germplasm was the highest at the booting stage in northwest Yunnan and weakest at the southern edge. Under the condition of greenhouse, the chilling injury rate was almost not exceeded and the seed setting rate was close to or exceeded 70%. Therefore, cold tolerance breeding objectives and varieties vary with the rice area. (3) The cold tolerance of core collection of Yunnan rice germplasm in different states at low temperature was very obvious at the booting stage, but was not affected by chilling injury and the seed setting rate was more than 65% in greenhouse. According to the rate of decrease of the seed setting rate of core collection of rice seed and the difference of natural climate among the states, 16 prefectures and territories can be divided into heavy cold damage area, cold damage area and light cold damage area. (4) The difference of cold tolerance at the booting stage of Yunnan rice germplasm in different paddy fields or between different prefectures further revealed that the temperature change caused by the difference of altitude and latitude is not only the dominant factor of indica-japonica differentiation but also the cause of indica-japonica differentiation The differences between the six ecotypes of two subspecies and the basic causes of large genetic diversity in Yunnan rice are also the key factors for the formation of cold tolerance genes. Cold tolerance at booting stage is the result of long-term The result of co-evolution.