Genomic DNA extraction and library construction
The whole genomic DNA was extracted from frozen young leaves according
to the CTAB method (Yu et al. , 2019). The p-pool and g-pool
representing buds turning purple and buds keeping green samples,
respectively, were constructed by collecting 30
BC2F2 individuals in each pool. DNA
quality was detected, and their concentration was quantified by
electrophoresis on 0.8% agarose gel and a spectrophotometer (NanoDrop,
United States), respectively. Sequencing libraries were constructed
according to the instruction of the TruSeq DNA PCR-free prep kit
(Illumina). The quality of libraries was tested using Agilent High
Sensitive DNA kit by Agilent Bioanalyzer, and the qualified libraries
were sequenced by the Illumina NovaSeq platform. The raw sequencing data
were filtered using fastp (v0.20.0) to discard those reads with low
quality.