Abstract:
Cashew (Anacardium occidentale. L) crop, is the major cash crop in Tanzania. Cashew breeding
strategies rely on conventional breeding, which is time consuming and labor intensive. This
study aimed at developing single nucleotide polymorphic (SNPs) markers and genetic linkage
map for identifying quantitative traits loci (QTL) associated with yield, nut quality and plant
size. In this study, Genotyping by Sequencing (GBS) technique, tagged as DArTSeq, was used to
identify SNPs from reduced complexity cashew genome of F1 and F2 as well as ATA19/250
(Male parent) and Cook05 (female parent). The reduced libraries were sequenced using Hiseq
2500 illumina sequencer, besides, SNPs call was done by using DArTsoft v.7.4.7 (DArT P/L,
Australia).The study identified 6,364 high quality SNPs, of which 57.6% were transition and
42.4% were trans version. The average call rate, reproducibility and polymorphic information
content (PIC) of the SNPs was 99%, 98% and 0.31 respectively. Among the 6,364 markers,1009
were codominant markers of which 761 (75%) were assigned to 21 linkage groups of total length
2,330.6 cM with an average distance of 3.3cM between markers. This study revealed the first
SNPs linkage map which can be used in identifying QTL for efficient breeding program through
marker assisted selection |
