Evaluation of low phosphorus tolerance and germplasm screening of spring wheat

Phosphorus deficiency is one of the important abiotic stresses affecting agricultural production. Screening phosphorus-efficient crops is an important method for optimizing soil phosphorus and reducing phosphate fertilizer applications. In this study, the low phosphorus tolerance of 162 spring wheat germplasms was evaluated, and the tolerant materials were screened at seedling and adult stages. A correlation analysis and a principal component analysis of low phosphorus tolerance coefficients of eight indicators were conducted at the seedling stage to find the comprehensive indicators; a cluster analysis was performed to determine the low phosphorus tolerance of 162 materials according to their comprehensive evaluation value calculated with the subordinative function values. Then, low phosphorus tolerant materials and phosphorus sensitive materials were selected by determining the comprehensive evaluation value at the adult stage of the screened materials. The changes in acid phosphatase activity of the selected materials were analyzed. The results showed that there were different effects on the growth indicators at seedling stage and adult stage under low phosphorus stress, and that spring wheat growth inhibition increased as the stress time extension. Eight indicators at the seedling stage and 10 indicators at the adult stage were transformed into four comprehensive indicators (the cumulative contribution rate was 82.60%) and three comprehensive indicators (the cumulative contribution rate was 83.23%) by the principal component analysis, respectively. The cluster analysis showed that the 162 spring wheat germplasms at the seedling stage were divided into four types: low phosphorus tolerant (10 germplasms), slightly low phosphorus tolerant (26 germplasms), slightly low phosphorus sensitive (91 germplasms) and low phosphorus sensitive (35 germplasms). Five low phosphorus tolerant materials and four phosphorus sensitive materials were selected for phosphorus-efficient identification at the adult stage. Finally, one low phosphorus tolerant material, wp-35, and one phosphorus sensitive material, wp-119, were selected. The analysis of the two materials showed that the acid phosphatase activities in roots and leaves increased under low phosphorus stress, and that the acid phosphatase activity in wp-35 was higher than in wp-119. This study can provide germplasm resources, and a theoretical basis for the analysis of low phosphorus tolerance and the cultivation of low phosphorus tolerant spring wheat varieties.