Analysis of walnut fruit quality based on source-sink relationships

In the paper, we investigate the relationship between the walnut fruit quality and the leaf-to-fruit ratio (LFR). The LFR had a significant effect on the physical quality of walnuts (P < 0.05), and the fruit volume, fruit fresh weight, fruit dry weight, nut dry weight and kernel dry weight increased with an increasing LFR. However, the LFR had no significant effect on the crude protein and crude fat kernel contents (P > 0.05). The number of cells per unit area and the cross-sectional area of the green husk cells with 5L:1F were significantly higher than those with 1L:3F and 2L:3F (P < 0.05). The number of cells per unit area of the kernel with 1L:3F and 2L:3F was significantly higher than that with the other LFRs (P < 0.05). There was no significant difference in the NDW between the natural and girdled fruit-bearing shoots with 2L:1F (P > 0.05). We concluded that the high carbohydrate availability with the high LFR augmented the fruit size by increasing the number of cells in the green husk and kernels. There was no change in the crude protein and crude fat contents in the kernels, possibly due to the proportion of the sugar to the fat distribution not affected by the LFR. Two leaves with good light were necessary to ensure the normal growth and development of one walnut fruit on girdled fruit-bearing shoots.