M.Sc. Defence: Shanthanu Krishna Kumar

Overview:

Woman viewing bad nectarine

Thesis Title: Enhancement of post-harvest shelf life of nectarines (Prunus persica (L.) Batsch var. nectarina) using hexanal

Advisory Committee       
Dr. Jayasankar Subramanian, Advisor
Dr. Alan J. Sullivan, Co-advisor                           
Dr. Gopinadhan Paliyath                                         

Examination Committee
Dr. Istvan Rajcan, Chair
Dr. Gale Bozzo (External)
Dr. Gopinadhan Paliyath
Dr. Jayasankar Subramanian                                                                                                                                  

ABSTRACT

Post-harvest technologies play a key role in enhancing shelf life and maintaining quality characteristics of tender fruits such as nectarines (Prunus persica [L.] Batsch var. nectarina). This research investigated the effects of an ‘Enhanced Freshness Formulation’ (EFF) with hexanal as the key ingredient to improve shelf life of nectarines. Pre-harvest sprays of EFF on ‘Fantasia’ nectarines, conducted at two commercial orchards in the Niagara region, ON, showed a general improvement in shelf life. Application of EFF delayed the incidence of chilling injury symptoms (internal browning and mealiness/woolliness) by one week. Treated fruits maintained significantly higher firmness until 38d post-harvest. There were no differences in total soluble solids, titratable acidity and colour values between treated and control fruits, suggesting an otherwise normal ripening behaviour. GC-MS analyses indicated reduced levels of volatile compounds associated with fruit ripening such as lactones, in EFF treated fruit and an increased level of C6 alcohols, aldehydes and acetates associated with unripe fruit. qRT-PCR was conducted to evaluate the expression levels of 22 genes potentially involved in ripening, to understand the regulatory effects of the hexanal formulation. EFF application induced a highly significant reduction in transcript levels of three Phospholipase D genes, five N-glycoprotein group genes, and other genes involved in ripening and softening processes. These findings indicate that, a delay in the ripening process caused by EFF, may be associated with the modulation of the expression of key ripening related genes, enhancing shelf life and quality of nectarines.

Kumar, S. K., El Kayal, W., Sullivan, J. A., Paliyath, G. and Jayasankar, S., 2018. Pre-harvest application of hexanal formulation enhances shelf life and quality of ‘Fantasia’ nectarines by regulating membrane and cell wall catabolism-associated genes. Sci. Hort., 229: 117-124.