甘蓝型油菜重组自交系苗期磷效率的评价

设置低磷P1 (5 μmol L^-1)和高磷P2 (1 000 μmol L^-1)处理水培甘蓝型油菜重组自交系群体的135个株系及亲本的幼苗, 以地上部干重(SDW)、根干重(RDW)、根冠比(R/S)、主根长(AMRL)、地上部磷积累量(SPU)、总磷吸收量(TPU)、磷利用效率(PUE)作为耐性指标, 调查群体各株系和亲本间对缺磷反应的差异, 并对各性状参数与磷吸收、利用效率进行相关性分析。结果表明: (1) 低磷胁迫严重抑制甘蓝型油菜苗期生长, 所调查的各性状均表现出显著差异，其中地上部干重和根干重的变异系数较大；(2) 2种处理条件下, 各株系的地上部干重、根干重、根冠比和主根长4个性状均表现出显著分离, 并呈现正态分布，低磷处理的分离更为明显；(3) 相关性分析表明, 相对地上部干重和根干重可以作为磷效率的主要评价指标，为了避免遗传因素影响, 还应考虑低磷处理下基因型各性状的绝对差异；(4) 通过上述筛选指标，确定065﹑102﹑070为候选的极端磷高效基因型, 105﹑076﹑011等为候选的极端磷低效基因型。

Evaluation of Phosphorus Efficiency in Rapeseed (Brassica napus L.) Re-combinant Inbred Lines at Seedling Stage

Phosphorus (P) is one of the necessary mineral nutrients for plants. Despite high concentrations of total P in soil, its bio-available concentration is very low compared to the requirement of plants and soil organisms. P deficiency is a major factor limiting plant growth and productivity worldwide. The plant species or cultivars show significant difference in accumulation and utilizing soil P, thus, developing P-efficient crops has been proposed as an available strategy to improve the fertilizer use efficiency or to obtain high yields in low input agricultural systems. The aim of the study was to evaluate P efficiency of 135 recombinant inbred lines (RIL) derived from a cross between P-efficient cultivar and P-inefficient cultivar of rapeseed (Brassica napus L.) through investigating shoot dry weight (SDW), root dry weight (RDW), root/shoot-ratio (R/S), average maximal root length (AMRL), shoot phosphorus uptake (SPU), total phosphorus uptake (TPU) and P use efficiency (PUE) at the seedling stage in a solution culture experiment with low P (P1, 5 μmol L^-1) and normal P treatments (P2, 1 000 μmol L^-1). The correlation between the tested traits and P efficiency among the RIL was analyzed. The results showed that 1) low-P stress limited seriously plant growth at seedling stage, and there existed significant differences among the genotypes of the RIL compared with normal P treatment; 2) all of the four traits, SDW, RDW, R/S, and AMRL, showed normal distribution in the RIL under both P treatments and presented significant transgressive segregation; and 3) the correlation among the seven traits investigated in the study indicated that relative SDW and RDW could be used as available evaluation indices for P efficiency but the effect of genetic factor should be considered at the same time; 4) on the basis of the screening indexes, genotypes with extremely high P efficiency were screened from the population, but they should be identified on low-P soil further.