Analysis of Boron Efficiency and Different Tissues Boron Content of Main Brassica napus Cultivars in Yunnan

PurposeTo evaluate the boron efficiency of Brassica napus cultivars cultivated in Yunnan, analyzing the differences of boron content in the tissues of seedling stage and their correlation with boron efficiency, so as to provide a theoretical basis for high-efficiency boron breeding of B. napus and analysis of boron efficiency.

MethodWith 21 main B. napus cultivars cultivated in Yunnan and two cultivars from other provinces, normal boron (NB, 25.00 μmol/L) and low boron (LB, 0.25 μmol/L) were used in this experiments. We determined the boron contents in roots, stems, petioles and leaves of 23 cultivars at seedling stage, and the two-step screening method (biomass at seedling stage, yield during the whole growth period) was used to evaluate its boron efficiency.

ResultsThree high-efficiency boron varieties, six medium-efficiency boron varieties, and 14 low-efficiency boron varieties were screened out, the results showed that the yield were consistent with those of seedling screening, indicating the method was reliable. The boron content of each tissue under both NB and LB showed the order of leaf > petiole > stem > root, and the boron content of the same tissue of different boron efficiency varieties under NB conditions had little difference, however decreased in varying degrees, and the decreasing range was low-efficiency boron varieties > medium-efficiency boron varieties > high-efficiency boron varieties. The correlation analysis showed that the boron efficiency ratio had an extremely significant positive correlation with the tissue boron content under low boron content (P<0.01), an extremely significant negative correlation with the reduction rate of the tissue boron content (P<0.01), and the highest correlation with the reduction rate of the root boron content.

ConclusionThe root boron content reduction rate can be used as a reliable indicator for evaluation of boron efficiency in B. napus. There are few high-efficiency boron varieties in Yunnan. Therefore, attention should be paid to applying boron fertilizer and selecting high-efficiency boron B. napus germplasm resources as breeding parents in Yunnan.