水稻氮素生理利用率选择参数

Selection Index for Screening Physiological Nitrogen Use Efficiency in Rice

将植株从衰老营养体转运氮到产量部分的效率定义为水稻氮素生理利用率，其选择参数根据单位吸收氮的产量及从衰老营养体转运氮到产量部分的能力具有较高预期响应确定。在盆栽试验条件下测定１００个Ｆ２植株的单位吸收氮产量（Ｇ／Ｎｔ）、产量（Ｇ）、收获指数（ＨＩ）、收获期秸秆氮浓度（ＳＮ％）及稿秆氮含量（ＳＮ）。结果表明，Ｇ／Ｎｔ，Ｇ及ＨＩ与ＳＮ％及ＳＮ呈显著的负遗传相关。由ＨＩ，Ｇ，ＳＮ％及ＳＮ构成的三个选择参数的通径分析表明，ＨＩ，Ｇ，ＳＮ％及ＳＮ在选择参数中直接效应大干间接效应。由ＨＩ和ＳＮ％及Ｇ，ＳＮ％和ＳＮ构成的选择参数对Ｇ／Ｎｔ的预期响应高于以Ｇ／Ｎｔ本身为参数的选择并与Ｇ／Ｎｔ高度相关。

Physiological nitrogen use efficiency defined as efficiency in transferring nitrogen from terminal parts for grain production was used in this study. Selection index, in terms of higher expected response to selection for grain yield per unit total nitrogen absorbed (G/Nt) and the genotypic ability to transfer N from terminal parts for grain production, was investigated using an F2 population in a pot experiment. G/Nt, G and HI were significantly and negatively correlated with straw N concentration (SN% ) and straw N content (SN) genetically.Three selection indices were established with the components of HI,G,SN% and SN.Path coefficient analysis indicates that the direct effects of the components of HI,G,SN % or SN were higher than the indirect effects in the selection indices. The expected responses on G/Nt to selection based on the developed selection indices were higher than or similar with that based on G/Nt alone. The selection indices composed of HI and SN% or based on G, SN% and SN could be used for screening G/Nt according to the higher expected response to selection and close correlationship with G/Nt. These selection indices are more clear in term of efficiency in N transportation from terminal parts for grain production.