STUDY ON THE FERTILITY AND FRUIT QUALITY OF NATURAL PENTAPLOID STRAWBERRIES NATIVE TO CHINA

Five natural pentaploid strawberry accessions, which were similar in plant appearance but obviously different in fertility, were collected from Heilongjiang and Jilin provinces in China over the last twenty years. They were identified as pentaploids (2n=5x=35) by counting their chromosomes in root-tip cells. They were vigorous. Their fertility could be classified into three types: female completely sterile but male fertile (FCS); female poorly fertile but male fertile (FPF); female fertile but male sterile (FF). In this study, five natural pentaploid strawberry accessions were used as materials to determine their fertility, fruit quality and morphological characteristics. The FCS and FPF types had normal pollen viability of average 42.1%. There were small, medium and large pollens, but the length of the polar axis of most pollens was 40.1~60.0 µm. The pollens were absent in FF type. In natural pentaploid strawberries Heilongjiang 2 and Heilongjiang 6, the content of soluble solids was 13.8 and 14.3%, the content of vitamin C was 877.0 and 843.0 mg/kg, the content of soluble sugar was 5.87 and 6.01%, and the content of titratable acid was 0.38 and 0.31% respectively. These natural pentaploid strawberries collected from Northeast China were precious materials for the study of the origin, classification, genetic relationship and unreduced gametes of Fragaria species.