University of Arkansas, Fayetteville Division of Agriculture


Fruit firmness, blackberry breeding, Arkansas


Since 1964, the University of Arkansas blackberry breeding program has worked to improve fruit quality and shipping capabilities. A major limitation in blackberry fruit is postharvest handling potential for the shipping market. Maintaining fruit firmness in storage is crucial. Red drupelet reversion (or simply reversion) is also an important postharvest disorder in which drupelets change from black to red during storage. It is hypothesized that reversion is increased when fruit is picked at hot temperatures and exposed to a rapid change of temperature. These studies evaluated harvest time/temperature, as well as storage temperature, on berry firmness and the incidence of reversion. In Study One, eight genotypes were evaluated. Fruit was harvested at four harvest times (7:00 AM, 10:00 AM, 1:00 PM and 4:00 PM) and then stored for 7 d at 5 °C before evaluation. Results indicated significant sources of variation were genotype and time of harvest for the variables compression (a measure of firmness) and incidence of reversion. Breeding selection A-2453T maintained high firmness and low incidence of reversion after storage compared to other genotypes. Reversion was also significantly lower at the 7:00 AM harvest time compared to later harvests. Study Two included two genotypes harvested at 7:00 AM and 1:00 PM which were evaluated at different storage temperatures (5 and 1 °C). No significant effects were found; however, trends suggested that A-2453T maintained higher firmness despite storage temperature. These studies confirm differences in firmness and reversion among genotypes as well as reveal harvest time impact on reversion.