Identifying Sand Pear Cultivar S-genotypes Using Gene Chips

Pear is a popular fruit and has been cultivated for its fruit production around the world. However, its yield depends on the combination of various cultivars because of its self-incompatibility of gametophyte controlled by a single locus and multiple S allele genes. Different S genotype varieties have to be properly mixed in cultivation for regular pollination and fertilization and successfully fruiting and breeding. Sand pear has 700 varieties and majorly cultivated in southern China for fresh fruit markets. Among them, S genotype had been completely identified for only 40 varieties and further studies on the identification of S multiple allele genes and its sequence analysis should be carried out about 85% of varieties. Conventional S genotype identification of pear varieties requires enormous investment, complicated technology, and time-consuming. Based on S multiple allele genes of pear varieties in China, by means of 3’RACE technology, identified cDNA, and gene group sequence of 47 S genes, oligonucleotide microarray and cDNA chips for detection of S gene were established. From the pedigrees and origin of sand pear varieties and the chips, genotypes of pear varieties, especially their S genes, should be identified. Analyses on cloning, sequencing, and homology of the newly discovered unknown S genes should be further investigated. The studies should present a thorough investigation of pear S gene resources from southern China, identify S genotypes of pear varieties, and provide an important scientific basis for the innovation and high-yield cultivation systems of sand and other pears in southern China.