云南元阳哈尼梯田两个不同时期种植的水稻地方品种表型比较

Comparison of phenotypic traits of rice landraces,grown in two different periods in Hani's terraced fields in Yuanyang County,Yunnan

为揭示中国云南元阳哈尼梯田中所种植的水稻(Oryzasativa)地方品种的表型性状在30年间的变化,我们通过田间实验方法,对元阳哈尼梯田农户在20世纪70年代种植的66个(简称"过去的品种")和近10年间种植的69个(简称"当前的品种")代表性水稻地方品种的农艺性状进行了比较。结果表明,23个农艺性状的多样性指数(H′)平均值,过去的品种(1.784)大于当前的品种(1.766);过去品种的变异系数平均值和相似性系数平均值(分别为19.5%和0.2107)均小于当前的品种(分别为21.7%和0.2149)。因子特征值大于1的主成分,过去的品种有8个(PC1-8),当前的品种有6个(PC1-6),分别能够解释总变异的83.2%和81.4%。23个表型性状的聚类树形图和前3个主成分分布散点图均能将供试品种分为与籼、粳两个亚种相对应的两类。与过去种植的品种相比,当前种植的品种表现为籼型品种、糯性品种、红米品种,以及落粒性极强和强的品种比例降低;当前种植品种的株高、穗颈长、穗下节长、千粒重和剑叶角度等参数显著下降,相反,单株有效穗、剑叶宽、每穗实粒数和结实率等参数显著增加,其株型更紧凑。总体而言,元阳哈尼梯田农户当前种植的水稻地方品种有单一化和遗传多样性降低的趋势,这可能是由于杂交水稻的推广,以及当地农民对产量性状的选择和传统文化习俗的淡化所致。建议对云南元阳哈尼梯田及时采取水稻地方品种与稻作传统文化并重的保护举措。

We used field experiments in Hani＇s terraced fields in Yuanyang County,Yunnan Province,to compare 23 phenotypic traits of 135 paddy rice landraces,including 66 ones that used to be grown during the 1970s（past-grown landraces） and 69 ones that have been grown during the past decade（current-grown landraces）.Comparing 23 phenotypic traits,the average Shannon-Wiener diversity index of the past-grown landraces（H＇ = 1.784） was higher than that of the current-grown landraces（H＇ = 1.766）,while the average coefficients of variation and that of similarity of the past-grown（19.5% and 0.2107,respectively） were lower than those of the current-grown（21.7% and 0.2149,respectively）.There were eight and six principal components with eigenvalues 1 in the past-grown and current-grown landraces,respectively,accounting for 81.4% and 83.2% of their overall variation,respectively.Based on a cluster analysis of the 23 phenotypic traits and a scatter plot of the first three principal components,these landraces could be grouped into two subspecies,indica and japonica.There was a slightly lower proportion of the indica,waxy,and red pericarp color varieties,as well as strong seed-shattering types in the current-grown landraces than in the past-grown ones.Average plant height,panicle neck length,node length under spike,1,000-grain weight and flag-leaf angle were all lower in the current-grown.On the other hand,average panicles per plant,flag-leaf width,filled grains per panicle and seed-setting rate increased in the current-grown landraces.In addition,the current-grown landraces had more compact plant types.The simplification and decrease in the genetic diversity of current-grown landraces compared to past-grown landraces may have resulted from the increased use of hybrid rice,selection for high yield traits,and less consideration of the traditional cultural habitude by local ethnic groups.More attention should be paid to both conservation of rice landraces as well as to the traditional rice culture in Yuanyang Hani＇s terraced fields in Yunnan Province.