Genetic Analysis of Tea Gray Blight Resistance in Tea Plants

抄録

Tea gray blight caused by Pestalotiopsis longiseta SPEGAZZINI is a severe disease in tea fields in Japan. The resistance of tea plants to the disease was found to be controlled by 2 independent dominant resistance genes Pl₁ and Pl₂, based on parent-offspring genetic analysis. There were 9 genotypes for resistance to P. longiseta in tea plants. Six genotypes Pl₁Pl₁Pl₂Pl₂, Pl₁Pl₁Pl₂pl₂, Pl₁Pl₁pl₂pl₂, Pl₁pl₁Pl₂Pl₂,Pl₁pl₁Pl₂pl₂, Pl₁pl₁pl₂pl₂ were resistant, 2 genotypes pl₁pl₁Pl₂Pl₂, pl₁pl₁Pl₂pl₂ were moderately resistant and one genotype pl₁pl₁pl₂pl₂ was susceptible. Since the cultivars harboring the Pl₁ gene with homozygosity always produced resistant plants to the disease in any cross combinations, they could become very important materials for the breeding of cultivars resistant to the disease.