Diallel Analysis of Resistance to Cuticle Cracking in Tomato

Abstract

<jats:p>Genetic control of cuticle cracking (CC) in tomatoes (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) was studied using half-diallel analyses and reciprocal hybrid comparisons of five parents and reciprocal F<jats:sub>1</jats:sub> hybrids over 3 years in Bradenton, Fla. Maternal effects were usually not significant, but in general, CC incidence in hybrids with a resistant cultigen as the female parent was lower than if the resistant cultigen was the male parent. General combining ability (GCA) was significant at all harvests, with specific combining ability (SCA) becoming significant under high environmental stress. Narrow-sense and broad-sense heritabilities for CC incidence ranged from 0.45 to 0.69 and 0.62 to 0.89, respectively, increasing directly with environmental stress.</jats:p>

Description of biomechanical forces and physiological parameters of fruit cracking in pomegranate

“…Logistic regression analysis indicated that fruit volume had a positive effect on cracking rate in pomegranate. Previous studies on tomato and sweet cherry showed that larger fruits were more sensitive to cracking than small fruits (Emmons and Scott, 1998;Koske et al, 1980;Sekse, 1987;Tucker, 1934). According to Considine and Brown (1981), the force on the containing membrane increases as the radius of the spheroid increases.…”

“…Logistic regression analysis showed that the relationship between skin thickness and the resistance to fruit cracking in pomegranate was not significant. In a study, Emmons and Scott (1998) and Matas et al (2004) found that the cracking-resistant genotype of tomato had a thicker epidermal and cuticle layer than the sensitive genotype. In contrast, Lane et al (2000) suggested the skin's role in cracked resistance is related to the calcium content of the epidermis cells which increase the cell's integrity.…”

“…Many morphological characteristics, such as thickness and physical properties of the cuticle, number of hypodermal layers (Bargel and Neinhuis, 2005), fruit shape and fruit size (Emmons and Scott, 1998;Koske et al, 1980;Sekse, 1987;Tucker, 1934) affect sensitivity to cracking. In previous researches, have been reported the effect of fruits' morphological properties on cracking rate and intensity in agricultural crops; such as greenhouse tomato (Hetzroni et al, 2011;Lichter et al, 2002;Matas et al, 2004), sweet cherry (Lane et al, 2000), apple (Kasai et al, 2008), nectarine (Gibert et al, 2007).…”