Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2012
Publication Date: 3/4/2012
Citation: Turketti, S.S., Curry, E.A., Lotze, E. 2012. Role of lenticel morphology, frequency and density on incidence of lenticel breakdown in 'GALA' apples. Scientia Horticulturae. 138:90-95. Interpretive Summary: Lenticel breakdown (LB) is a skin disorder prevalent on ‘Gala’ apples that appears as a brown pit centered on a lenticel mainly after the fruit have been packed. Although many postharvest factors associated with LB have been discovered, there is also a strong year-to-year variation. This work reports on trials conducted in South Africa and Washington State examining new etiological approaches: 1) a histological study of lenticel size on fruit at 40, 70 and 100 days after full bloom and its relationship with early season temperatures and 2) correlation of lenticel density with LB development, with the presupposition that LB incidence could be related to microclimate and fruit development.
Technical Abstract: A two-year study was conducted in the arid fruit growing regions of South Africa and eastern Washington State to examine the etiology of lenticel breakdown (LB). The evaluation of lenticel size, including peel imprints and tissue cross-sections, presented no clear relationship between lenticels size and LB incidence. We identified “air pockets” underneath lenticel regions and we suggest that these contribute to incidence of LB in apples. Evaluation of lenticel density and its relationship to LB indicated a highly correlated inverse relationship. Moreover, no significant correlation between LD and fruit weight was found. This may indicate susceptible fruit are less able to repair cracking of the lenticular annulus. Further research is needed to substantiate this possibility. The study of lenticel morphology indicated that humidity and temperature play an important role in LB due to their influence on the rate of fruit growth and cuticle development. Environmental conditions during early fruitlet development as well as during final stage of fruit enlargement should be considered in future work.