Effects of different irrigation methods on the quality, yield, and water use efficiency of Kuerlexiangli pear

【Objective】The Modified Surge Root Irrigation (MSRI), an advanced micro-irrigation system specifically designed for the cultivation of deep-rooted fruit trees, represents a groundbreaking innovation that ensures precise water delivery to the tree's deep root zones. This study investigated its efficacy in enhancing fruit quality, yield, and water use efficiency (WUE) of Pyrus sinkiangensis‘Kuerlexiangli pear’under arid conditions.【Methods】A two- factor (irrigation method × rehydration) completely randomized block design was implemented in Korla, Xinjiang (In 2022—2023). Three MSRIvariants were tested: alternate bilateral (A-MSRI), simultaneous bilateral (B-MSRI), and unilateral (UMSRI) irrigation, combined with rehydration (R1) or non-rehydration (R2) treatments. The surface irrigation served as control (CK). The seven treatments were evaluated: R1A, R1B, R1U, R2A, R2B, R2U, and CK. The fruit quality parameters (external: volume, shape index, weight; internal: soluble solids content [SSC], firmness, soluble sugars, vitamin C, titratable acids, soluble proteins, stone cells, moisture content) were measured at maturity. The yield and WUE were quantified using standard agronomic protocols. The data underwent three-way ANOVA, Pearson correlation analysis, and multivariate evaluation via principal component analysis (PCA) and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).【Results】The improvement of gushing root irrigation increased the soluble solids content, soluble sugar content, yield and water use efficiency of Kuerlexiangli pear fruits, and at the same time effectively reduced the peeling hardness, titratable acid content and stone cell content of the fruits compared with the traditional diffuse irrigation method . Significant differences (p＜0.05) were observed among the treatments in the fruit quality, yield and water use efficiency from the point of view of irrigation method. The fruit quality, soluble solids content, soluble sugar content in the fruits under the B treatment were higher and titratable acid content and stone cell content were lower than those under the A and U treatments. The yield and water use efficiency, of B treatment was higher than those of A and U treatments. In addition, the presence or absence of rehydration equally significantly (p＜0.05) affected the fruit quality, yield and water use efficiency. The fruit quality, soluble solids content and soluble sugar content of the fruits under the non-rehydrated treatment were higher than those of the rehydrated treatment, while titratable acid content and stone cell content were lower than those of the rehydrated treatment. The yield and water use efficiency of the non- rehydrated treatment was higher than those of the rehydrated treatment. Among all the treatments, the fruit quality under the R2B treatment reached the highest in terms of soluble solids and soluble sugar content, which increased by 15.00% to 28.61% and 18.62% to 26.86%, respectively, compared with those of the CK; meanwhile, titratable acid content and stone cell content were the lowest, which decreased by 4.91% to 39.50% and 85.84% to 86.26%, respectively, compared with those of the CK, respectively. The yield and water use efficiency of the R2B treatments were the highest, increasing 64.29% to 90.73% and 230.61% to 271.96%, respectively, compared with those of the CK. The further analyses showed that the yield showed highly significant and positive correlation (p＜0.01) with the water use efficiency, in addition, both the yield and water use efficiency showed highly significant and positive correlation (p＜0.01) with the fruit soluble solids content and soluble sugar content, while highly significant and negative correlation (p＜0.01) with the titratable acid content and stone cell content. These results further confirmed the significant effect of the improved gushing root irrigation technique in enhancing the fruit quality and yield of balsam pear. The comprehensive evaluation of the different irrigation methods was carried out by principal component analysis and superiority solution distance method, which resulted in the comprehensive score ranking of each treatment. According to the results of the principal component analysis, the order of the integrated scores of the treatments was R2B＞R2A＞R1B＞R2U＞R1A＞R1U＞CK, and the order of the integrated scores of the treatments by the superiority and inferiority solution distance method was R2B＞R1B＞R2A＞R2U＞R1A＞CK＞R1U. The two integrated evaluation methods showed that the R2B treatment was the best, and the integrated scores of the CK treatment were the highest, and the CK treatment was the worst and the comprehensive score was the lowest.【Conclusion】The bilateral surge root irrigation without rehydration (R2B) seems to be the optimal irrigation method for Kuerlexiangli pear trees in arid areas. This study would provide a solid scientific basis for the application of MSRItechnology on fruit trees in arid areas, and be valuable for optimising irrigation management, improving fruit quality, yield and water use efficiency.