For exploring cold tolerant gene resource in rice, especially in indica rice, to promote cold tolerant rice breeding, 18 germplasms, which were selected from 150 accessions collected from "rice germplasm repository of Guangdong Province"and the rice region in southern China, were used in the cold resistant rice germplasm screening test at the seedling stage.'Lijiangxintuanheigu'was employed as cold-tolerant control and'Gui 99'was employed as cold-sensitive control in the test. The test for screening cold tolerant germplasms was carried out in phytotron by low temperature stress (PGV-36, the mean daily temperature 8.5℃) method. The results showed that: (1) the growth and development of the tested materials slowed significantly under the low temperature stress, even stopped as the treatment went on; (2) under low temperature stress for 3 d or 6 d, the death rate of the tested materials was different significantly but the cold tolerance of japonica rice on the whole was better than that of the indica rice;(3) the death rate of the tested materials, which continued to grow 10 days under the natural environment after 3d or 6d low temperature stress, was employed as the evaluation index of cold tolerance, the cold tolerance of'Jing 44'was the strongest, as its death rate was less than 25% after 8.5℃ low temperature stress for 6 days, the second was'Miao 110','2-319'and'Huazhan', the cold tolerance of'Yuanbaozhan'and'Miao 108'was medium, but that of the other 12 germplasms such as'318','R2168'and'Chuangfeng 1', etc was weak. In the cold tolerant germplasms,'Huazhan'and'2-319'was indica rice,'Miao 110'was derived from the cross of indica and japonica, they all could be applied to cold tolerance breeding in indica rice.%为了发掘水稻尤其是籼稻耐冷基因资源,促进水稻耐冷育种,以'丽江新团黑谷'为耐冷对照,以'桂99'为冷敏感对照,从"广东省水稻种质资源库"以及南方稻区收集的150份材料中初步筛选出18份作为本试验的供试材料,采取人工气候箱低温胁迫法(PGV-36,日均温8.5℃),进行水稻苗期耐冷种质资源筛选研究.结果显示:①秧苗期日均8.5℃的人工气候箱低温胁迫会导致水稻秧苗生长发育明显减缓受阻,随着时间的推进,供试材料的生长发育停止.②经人工气候箱低温胁迫后,不论是处理3天还是6天,各供试材料幼苗死亡率差异达到极显著水平;总体上粳稻的耐冷性强于籼稻.③以低温胁迫3天和6天后各供试材料自然气候条件下恢复生长10天的幼苗死亡率为指标评价鉴定其耐冷能力,'粳44'耐冷性强,8.5℃人工低温胁迫6天后死亡率在25%以下;其次是'苗110'、'2-319'和'华占';'源宝占'、'苗108'耐冷能力中等,'318'、'R2168'和'创丰1号'等12份材料耐冷性弱;耐冷性强的种质中'华占'、'2-319'为籼稻,'苗110'为籼粳交后代,可应用于籼稻耐冷育种.
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