小麦苗期性状与耐低氮性的遗传相关分析

Genetic correlation analysis between characters and low nitrogen tolerance of wheat at seedling stage

为研究小麦苗期性状与耐低氮性的遗传相关性,利用24份小麦品种,采用水培的方法,在低氮(0.4mol/L)和正常氮(4mmol/L)条件下,测定四叶期株高(PH)、根长(RL)和根条数(RN)等23个氮效率相关指标,利用各指标耐低氮指数进行主成分分析,采用隶属函数法计算综合评价值(D),通过系统聚类筛选耐低氮品种;同时联合分析氮效率相关性状遗传相关系数与遗传力确定育种中间接选择性状指标。结果表明:1)24个小麦品种被分为耐低氮型、中间型和低氮敏感型三类;其中耐低氮型品种包括长武89(1)3-4、安85中124-1、单R8093、平阳348和昌乐5号;低氮敏感型包括旱选12、白齐麦、烟农19号、陕225-9、晋麦33和中大91-品9;其余13个品种属于中间型。2)低氮胁迫条件下(分蘖数)TN、(叶宽)LW、(根鲜重)RFW、(茎叶鲜重)SFW、(植株总鲜重)PFW、(茎叶氮素积累量)SNA、(植株氮素积累量)PNA与耐低氮性综合评价值(D)之间的遗传相关、环境相关及表型相关均达到显著或极显著水平,正常氮处理下(叶面积)LA和(茎叶干重)SDW与D值之间的遗传相关、环境相关及表型相关均达到显著或极显著水平。3)在育种过程中,低氮条件下选择LW、RFW和PFW等性状;而正常供氮条件下选择LA、(植株总干重)PDW和(根氮素积累量)RNA等性状可以对小麦耐低氮性的选择取得较好的效果,选择效率较高。

In order to study the genetic correlation between the characteristics of wheat and its resistance to low nitrogen at seedling stage,24 wheat varieties were cultured in water under the conditions of low nitrogen(0.4 mmol/L)and normal nitrogen(4 mmol/L),respectively.At four-leaf stage,twenty-three nitrogen efficiency indexes,such as plant height(PH),root length(RL)and root number(RN)were measured.The low nitrogen tolerance indexes were used for principal component analysis,and the comprehensive evaluation value(D)was calculated by membership function method.Low nitrogen tolerance varieties were screened by systematic clustering.At the same time,the genetic correlation coefficient and heritability of nitrogen efficiency related traits were combined to determine the index of intermediate selection traits in breeding.The results showed that:1)The 24 wheat varieties were divided into three types,e.g.low-nitrogen,middle and low-nitrogen-sensitive.The varieties with low nitrogen tolerance included Changwu89(1)3-4,an 85 zhong 124-1,ShanR8093,Pingyang348 and Changle5.Low nitrogen sensitive types included Hanxuan12,Baiqimai,Yannong19,Shan225,Jinmai33 and Zhongda91-pin9.And 13 other varieties belong to intermediate type.2)Under low nitrogen stress(Tiller number)TN,(Leaf width,)LW,(Root fresh weight)RFW,(Straw fresh weight)SFW,(Plant fresh weight)PFW,(Shoot nitrogen accumulation)SNA,(Plant nitrogen accumulation)PNA and low nitrogen tolerance comprehensive evaluation value(D)genetic correlation,environmental correlation and phenotypic correlation reached significant or extremely significant level.The genetic correlation,environmental correlation and phenotypic correlation between(Leaf area)LA and(Straw dry weight)SDW and Dvalue under normal nitrogen treatment were significant or extremely significant.3)In the breeding process,LW,RFW and PFW traits were selected under low nitrogen condition;Under the condition of normal nitrogen supply,the selection of LA,(Plant dry weight)PDW and(Root nitrogen accumulation)RNA showed better effect on the selection of low nitrogen tolerance of wheat,and the selection efficiency was higher.