Mutants of a Diploid Strawberry, Fragaria vesca, for Understanding Developmental Processes and Physiological Responses

Genomic resources for the diploid strawberry, F. vesca, include inbred lines, a sequenced genome, and recently published comprehensive transcriptome data for flower and early fruit development.  To date, only a few morphological or physiological genetic traits, such as runnering, leaf color, and fruit color have been described and mapped.  Recent advances in DNA sequencing and the F. vesca genome reference sequence now make it possible to identify the gene likely to be responsible for a mutant phenotype, without genetic mapping.   EMS mutagenesis was used to generate M2 populations for two different inbred cultivars, the Hawaii 4 line for which there is genome sequence, and the YW5AF7 line.

One trait that we are currently focusing on is runnering.  A recessive mutation in the YW5AF7 line, which does not normally runner, resulted in runners being formed at every node, and elongation of the crown.  Several potential non-runnering Hawaii 4 mutants have been obtained.  Additional mutants include: palemale, which has pale yellow to white anthers, produces no pollen, and retains petals for weeks after the flower has opened; incomplete male, which is missing the inner whorl of anthers;  petiolulong, which has highly elongated petiolules (the stems at the base of each leaflet; floppy, which has thin, weak, petioles and narrow light green leaflets; and stickypollen, which forms a locule shaped mass of pollen,  possibly due to abnormal production of the pollen coating, the pollenkitt, which is produced by the tapetum.  We are currently screening mutated seedlings for increased thermotolerance or resistance to auxin.