The higher standardized range followed by higher estimates PCV suggested the possibility of exploiting variability for fruit quality and yield traits. The germplasm lines which recorded extremities values for a specific character can be used as contrasting parents in hybridisation programme to study the inheritance and gene action governing the respective character (Dar and Sharma 2011; Joseph et al. 2014; Meena et al. 2015; Rakesh et al. 2018).
Higher PCV and GCV with close correspondence between them indicated that environmental had meagre influence and hence selection can be made based on their phenotypic performance. The high broad sense heritability coupled with high GAM indicated the role of additive gene effects for TSS, pH, lycopene, ascorbic acid, titratable acidity, fruit length, diameter, weight, pericarp thickness, pulp content, locule number, shelf life, plant height, number of branches, number of clusters, number of fruits/cluster and yield/plant. Hence selection would be rewarding for improvement of such traits. Moderate broad sense heritability and high GAM recorded for fruit firmness indicated good response to selection and in turn better chances of improving trait (Vinod et al. 2012; Narolia et al. 2012; Meena and Bahadur 2014; Ravindra et al. 2015; Rakesh et al. 2018).
The prevalence of wide variation for physiological loss in fruit weight is directly correlated with respiration rate of fruits which intern depends on keeping quality of fruits. The tomato fruit experiences physiological loss in fruit weight during breaker to turning followed by pink and red stages. It is an important physical quality parameter determining wholesomeness and shelf life of fruits. Most fruits contain 80–85% water by weight and major portion of it is lost by transpiration followed by evaporation (Wilkinson 1965). Therefore, there is need to maintain adequate water to prolong shelf life of fruits even when they lose some amount of water during storage.
When fruit is harvest at breakers stage, the respiration rate of fruit slowly goes on increasing i.e. climacteric rise with number of days elapsed from harvesting. The ethylene is rapidly produced in fruit at breaker stage, drives series of reactions that together define fruit ripening process (Moneruzzaman et al. 2008).
The higher rate of change in physiological loss in fruit weight signified the higher dehydration rate that happened in tender tissue of turning stage tomatoes (Moneruzzaman et al. 2008). The negative values for rate of change in physiological loss in fruit weight for turning to pink stage and pink to red stage indicated the slower rate of dehydration. The high shelf life tomato germplasm lines had slow respiration rate which resulted in slow rate of water loss as well as weight loss. The slow physiological losses in fruit weight and slow pace in rate of change in physiological loss in weight may contribute to higher shelf life in tomato germplasm lines.
The longer shelf life germplasm lines had slower phase of biochemical reactions. There is natural tendency for perishable fruits and vegetables to degrade to simpler inorganic compounds such as Co2, H2O, and NH3 through spontaneous biochemical reaction which leads to loss of free energy and reduction in shelf life and other (Moneruzzaman et al. 2008). Cultivation of these varieties can be transported to long-distance markets and farmers can get good price for their produce during price crash periods in local markets (Moneruzzaman et al. 2008; Dar and Sharma 2011).
The fruit firmness is one of the critical components of internal fruit quality and it is the final index on which the consumer's perception and decision to purchase a given batch of tomatoes depends. With advancement in fruit ripening, changes in fruit texture, structure, and composition of their cell walls by breakdown of insoluble protopectin into soluble pectin takes place leads to softening of fruits which considerably influences post-harvest performance, i.e. transportation, shelf life, and pathogen resistance. Pericarp thickness assumes prime importance among parameters which condition fruit firmness. Thick pericarp fruits would stand long-distance transport and keep well for longer days (Chakraborty et al. 2007).
The calcium and magnesium interact with pectic acid in the cell wall to form calcium and magnesium pectate, thereby having a direct influence on fruit firmness (Marschner 1995; Jones 1999). It has beneficial effects on marketing and storage of fruits through inhibition of abnormal senescence and reduction of respiration rate, ethylene synthesis, protein breakdown, weight loss, and reduces incidence of physiological disorders during storage (Parker and Maalekuu 2013; Abrol et al. 2017). The fruit containing low calcium and magnesium are sensitive to physiological and pathological disorders, consequently have short shelf life.
Fruit epicuticular waxes are complex mixtures of very long-chain lipid compounds and main components of the cuticle deposited on outer surface of fruits (Lara 2019). They retards rate of moisture loss, maintain turgidity, plumpness and extend shelf life (Wills and Golding 2016). Waxing influences respiration rate by decreasing oxygen and increasing carbon dioxide content in the internal atmosphere of the fruit (Parker and Maalekuu 2013). Under this restricted air exchange condition, benefits of modified atmosphere may be achieved. Kumar et al. (2018) reported that in tomato mutants, ripening inhibitor and non-ripening had significant increase in C18 cutin monomers which had increase in waxes characterized by reduced water loss rate during post-harvest.
The higher shelf life in P-4, L-00191, L-03686, AR-23, PKM-1 and Bony best contributed by higher fruit firmness and epicuticular wax content. Similarly, higher fruit firmness is responsible for high shelf life in TLB-133, Patriot, and L-00398. High shelf life in Red ball might be due to higher fruit firmness, pericarp thickness, calcium, magnesium and epicuticular wax content.