Effect of Individual Plants of Inbred Line Used as Parents on F-1 Phenotype Characteristics and Germination by Storage Period of Seed-propagated Strawberry

Abstract

This work assessed the percent germination according to seed storage duration and influence on F-1 hybrid progeny by individual plants of inbred lines, used as parents in crosses, in the F-1 hybrid strawberry cultivar 'Seeberry' . Seed germination was the highest, at approximately 90%, when seeds were sown in the year of crossing. Percent germination dropped to 40 - 50% after 1 - 2 years of storage, with further substantial decreases in percent germination after 3, 4, and 5 years of storage. For stored seed, therefore, the optimal storage duration was about 2 years. However, germination of stored seed could be substantially improved, up to approximately 90% germination, with the application of a priming treatment such as MgCl2. The degree of uniformity of F-1 hybrid progeny with advancement of selfing generation of cross parents showed no significant differences both in crosses between the S9 or S10 generation. However, when individual F-1 crosses of the S9 generation were considered, one of nine crosses exhibited reduced plant vigor and yield. Overall, for optimal germination, F-1 hybrid seed strawberry should be sown in the same year as crossing. Where storage is required, seeds should be sown within 2 years, preferably with a priming treatment to improve germination. Furthermore, vegetative propagation of each individual of inbred lines using crossing parents appears preferable to seed propagation for maintaining the purity of the F-1 hybrid cultivar.