Genetics of yield, quality and shelf life characteristics in tomato under normal and late planting conditions

Abstract

Seventy nine genotypes of tomato (15 lines, four testers and their 60 F 1 hybrids produced in line · tester fashion) were evaluated under normal (E 1 ) and late planting (E 2 ) conditions in the Department of Vegetable Crops, Punjab Agricultural University, Ludhiana, India, to determine the nature of gene action controlling yield, quality and shelf life characteristics and to identify a few good combiner genotypes which may be used in further breeding programmes to extend the fruit availability period of tomato in North Indian plains. The lines were significantly different from testers for most of the characters thereby justifying the choice of testers. Additive gene action was predominant for days to ripening, total yield per plant, marketable yield per plant, number of fruits per plant, average fruit weight, fruit shape index and lycopene in both the environments, whereas non-additive genetic variance predominated in controlling firmness index, number of locules, pericarp thickness, alcohol insoluble solids (AIS), dry matter, total soluble solids (TSS), titratable acidity, TSS:Acid ratio, pH, ascorbic acid and shelf life, under both normal and late planting conditions. The best general combining ability (gca) effects, among females, in respect of yield per plant were shown by Spectrum in E 1 and by LT-42 in E 2 . Among the testers, the best gca values in both the environments were possessed by nor-RM-1 for total yield per plant, marketable yield per plant, number of fruits per plant, dry matter and TSS; by rin-RM-2 for firmness index, pericarp thickness and alcohol insoluble solids; by alc-IIHR-2050 for average fruit weight, number of locules and shelf life and by alc-IIHR-2052 for lycopene. The gca of ripening mutants had a nice consonance with their per se performance for most of the characters indicating that additive gene action was operative in these mutants for majority of the traits.

NATURE OF GENE ACTION FOR SOME ECONOMIC CHARACTERS OF TOMATO (Lycopersicon esculentum L.) VARIETIES

“…This indicated that these genetic parameters are unstable with different environmental conditions. Similar results were obtained by Garg et al, (2008), Adalid et al, (2012 and El-Nagashy (2012). CONCLUSION In conclusion, due to the pervious results, which confirmed the role of both additive and non-additive genetic variances in the inheritance of studied traits with different levels, the suggested suitable breeding program for improving these traits is recurrent selection program for vegetative traits and production of hybrids for fruit characters and chemical traits.…”

Combining ability and heterosis of relevant fruit traits of tomato genotypes for industrial processing

“…The estimates of the quadratic component of sˆi j of all traits were relatively higher than those of gˆi (Table 2) and the interpopulational breeding strategies are the most recommended for the improvement of these variables (Amaral Júnior et al 1999, Garg et al 2008, Shende et al 2012, Souza et al 2012, Saleem et al 2013). …”

Tomato second cycle hybrids as a source of genetic variability for fruit quality traits

“…The following fruit traits were evaluated: weight (W; g), diameter (D; cm), height (H; cm), shape (Sh; height/diameter), and shelf life (SL; in days from harvest to fruit softening or excessive wrinkling), following the methodology proposed by Garg et al (2008). In addition, the soluble solids content (SS, °Brix), measured with a hand refractometer, pH, titratable acidity of the homogenized juice (TA, g), pericarp thickness (PT, mm), locule number (LN), and fruit firmness (F), on the equatorial plane in two opposite areas of the fruit measured with a durometer type Shore A (Durofel DFT100, 0.10 cm 2 ) were assessed.…”