Research Article

Austin J Biotechnol Bioeng. 2014;1(3): 4.

Shelf Life Evaluation in Selected Tomato (Solanum Lycopersicum L) F7 Recombinant Inbred Lines (RILs)

Sukanta Sinha*, Ramanjini Gowda PH, Sujeet kumar and Mallikarjuna NM

Department of plant biotechnology, University of Agricultural Sciences (GKVK), India

*Corresponding author: Ramanjini Gowda PH, Department of plant biotechnology, University of Agricultural Sciences (GKVK), Bengaluru-560 065, Karnataka, India.

Received: August 25, 2014; Accepted: September 19, 2014; Published: September 22, 2014

Abstract

Tomato (Solanum lycopersicum L), one of the most important vegetable crop in the world is susceptible to rapid post harvest softening and poor shelf life leading to great post harvest losses. Among all strategies available for minimizing the postharvest losses, genetics approaches, very precisely conventional breeding coupled with modern marker technology is the promising one because of more acceptability by the consumer. We have evaluated twenty four F7 RIL'S developed from the cross L121 X Vaibhav for high shelf life. L121 is a parent having (alc gene) a ripening mutant is able to prolong shelf-life but has poor agronomic character; Vaibhav is the good agronomic cultivar released by the University of Agricultural Sciences, Bangalore and Karnataka. The evaluation of F7 RILs resulted in the identification of tomato RILs with high shelf life. Among F7 RILs, parents and checks, the maximum shelf life was observed in RIL 7-3, RIL 110-2 (110days), followed by RIL 102-1 and RIL 182-4 (100 days) with an average shelf life of the F7 RILs were 63 days. Some genetic SSR polymorphic markers were identified to be associated with the fruit shelf-life which was determined by Single Marker Analysis (SMA). SMA revealed that the markers Tom184 and Tom144 are linked to high shelf life in tomato.

Keywords: Fruit Shelf life; SSR; Single marker analysis

Introduction

Tomato (Solanum lycopersicum L), being a climacteric fruit, has a relatively short postharvest life since many processes affecting quality loss take place after harvest [1]. The main factor associated with tomato postharvest shelf-life, particularly in tropical regions where the temperature is high, is increased respiration which results in faster fruit ripening and deterioration of fruit quality [2]. In India, the aggregate post-harvest losses from farm gate to consumers in tomato ranges from 13 to 26% [3].

Several efforts have been made to increase the shelf life of tomato fruits. An early effort was done with calcium treatment to the fresh fruits. Calcium helps maintaining cell wall integrity and hence reduces the action of cell wall degrading enzymes and consequently fruit softening [4]. One of the successful efforts was by Californian Company Calgene, which had developed a tomato variety called Flavr Savr tomato using the antisense RNA technology. The introduction of this gene in the reverse form, also called antisense, resulted in low production of the poly galactonurase enzyme. Consequently, ripe tomato fruits do not lose their firmness because the cell wall of these fruits, which is made of cellulose, does not degrade as rapidly as it does in normal tomatoes. Since the Flavr Savr tomato had been taken off from the market, there is no commercial tomato variety sold in the market with high shelf life.

In the fleshy fruit model, tomato, the plant hormone, ethylene, plays a central role in ripening [5,6]. Several fruit ripening mutants have been characterized in tomato. The rin (ripening-inhibitor), nor (non-ripening) and cnr (colorless non-ripening) upstream genes were shown to act on the ethylene signaling in ripening gene. Mutations in the ethylene receptor, the Nr (Never-ripe) gene, is also shown to affect fruit ripening [7,8]. Ethylene biosynthesis requires the conversion of Aminocyclopropane- 1-Carboxylic Acid (ACC) to ethylene by the ACC oxidase (ACO). ACC oxidases are encoded by multigene families in plants and have been described to be involved in ripening, growth, and development [9,10] have used several ripening gene mutants, such as alcobaca (alc), non-ripening (nor), never ripe, and ripening inhibitor (rin) to develop lines and cultivars with delayed ripening through disruption of the ethylene signaling pathway.

All genetic markers occupy specific genomic positions within chromosomes (like genes) called 'loci' (singular 'locus') [11]. Single Marker Analysis (SMA) is the method used in earliest studies on QTL mapping [12,13]. In this method, one marker is involved at a time to find the QTL - Marker association. This single marker analysis can be implemented as a simple t test, ANOVA, linear regression and likelihood ratio test and maximum likelihood estimation [14-16].

In this study, twenty four Recombinant Inbred Lines (RILs) with high shelf life along with parental lines and the commercial checks like Arka Alok, Pusa Ruby and Sankranti were used. The objective of the study was to find out the best tomato lines which can stay for long time after harvesting and also the molecular evaluation of the RILs using SSR markers which are linked to the trait.

Material and Methods

The study was conducted in the field during Rabi 2013 at the Department of Plant Biotechnology, University of Agricultural Sciences, Bangalore, which is located at an altitude of 899 m above Mean Sea Level (MSL) and at 13° 00' N latitude and 77° 35' E longitude. The field experiment was conducted using Randomized block design.

Experimental material

The experimental material includes F7 lines, which is derived from crossing between L121 and Vaibhav for evaluation of shelf life. In this experiment, L121 used as female parent is a tomato line with high shelf life. Another parent Vaibhav was used as male parent with good agronomical characters.

Evaluation of F7 RILs

The best 24 F6 RILs having high shelf life were sown in the field at Department of plant Biotechnology, Bangalore during Rabi 2013 (Table 1).