Postharvest Quality Traits Research Articles

Chipping ability, specific gravity and resistance to Pectobacterium carotovorum in advanced potato selections

ABSTRACTThe availability of potato varieties combining good tuber quality and resistance traits is very important for both processors and supermarkets. In the present study, post-harvest quality traits as well as resistance to tuber bacterial soft rot were evaluated in 42 advanced potato clones belonging to seven hybrid families. Differences in specific gravity were found among families and among clones, with about 30% of clones showing a high specific gravity (>1.080). Clones and varieties were assayed also for a comprehensive chipping profile. Overall, 43% of clones presented an acceptable chipping score (≤4.5) at harvest. In addition, following cold storage with and without reconditioning, various clones performed acceptably. Five clones from three families (Bolestra X MC 329, Spunta X Victoria and Majestic X Alcmaria) were classified as resistant to bacterial soft rot. An evaluation index is proposed to help identify clones with interesting combinations of traits.

Enhancement of post harvest fruit quality and leaf curl disease tolerance in tomato through hybrid breeding

Development of hybrids tolerant to leaf curl virus disease along with good post harvest/processing traits is the major thrust areas in tomato breeding now-a-days. A study was undertaken following 7 × 7 half diallel mating design utilizing four exotic and three indigenous lines to identify potential donors and crosses, to study the extent of heterobeltiosis and dominance behaviour, and to assess the genetic control of post harvest quality traits along with disease tolerance in tomato. Breeding strategies to improve characters governed by different types of gene action are discussed. Two parental lines, CLN 2777F and CLN 2777E could be utilized further in tomato breeding programme as they were identified as the most promising general combiners for fruit yield, processing quality and ToLCV tolerance. The maximum extent of heterobeltiosis (104.17%) was found in pericarp thickness followed by fruit yield plant-1 (63.57 %) and PDI of ToLCV disease (-60.00 %). The hybrids also exhibited various degrees of dominance effects. The study could also able to identify a promising cross ‘CLN 2777E × CLN 2777F’ which could be recommended for commercial exploitation after critical study in leaf curl disease prone areas of the tropics and sub-tropics.

Ethylene biosynthesis and signaling elements involved in chilling injury and other postharvest quality traits in the non-climacteric fruit of zucchini (Cucurbita pepo)

The immature non-climacteric fruit of zucchini is very sensitive to postharvest chilling injury (PCI). Although the fruit produces very low ethylene at harvest, cold storage induces an increase in ethylene production in the refrigerated fruit, and upon rewarming up to room temperature. The production of ethylene after rewarming was proportional to cold damage and found to be higher in the fruit of the cultivars most susceptible to chilling. The effects of the ethylene inhibitor 1-methycyclopropene (1-MCP) has been analyzed using the postharvest quality parameters of nine zucchini cultivars stored at 20°C and 4°C for 14 days. We have also determined the evolution of ethylene production in the fruit of these cultivars, and assessed the expression profiles of twelve ethylene biosynthesis and signaling genes in both control fruit and in 1-MCP treated fruit, of two cultivars that responded to 1-MCP. The 1-MCP treatment reduced the rate and delayed the onset of PCI symptoms and reduced fruit weight loss, although only in the fruit of the most chilling-susceptible cultivars, and concomitantly we found a reduction in the respiration rate and in the level of cold-induced ethylene. This data suggests that ethylene is not only a response of the fruit to cold damage, as occurs upon rewarming, but could also play a regulation role in the onset of PCI in this non-climacteric fruit. The genes CpACO1 and CpACS1 were found to be involved in the biosynthesis of the cold-induced ethylene, but the role played by CpACO1 was found to be the key function, since it was induced higher than CpACS1 in response to cold storage. More over CpACO1 was the only ethylene biosynthesis gene that was downregulated by the 1-MCP treatment. Some of the ethylene perception and signaling genes, including CpETR1, CpCTR1 and CpEIN3.1 were also induced in response to cold storage, and were downregulated in response to 1-MCP, indicating that the positive effect of 1-MCP in the fruit of certain zucchini cultivars is also associated with a downregulation of genes involved in ethylene perception and signal transduction pathways.

Combination of heat treatment and chitosan coating to improve postharvest quality of wolfberry (Lycium barbarum)

SummaryThe synergistic application of hot water dip at 42 °C for 30 min and 1% chitosan coating on differentiation in postharvest quality traits, microstructure as well as microbiological evolution of wolfberry fruits was investigated. Fresh wolfberry fruits were stored at 2 ± 0.5 °C and 90% relative humidity (RH) for 28 days. Results indicated the combination of prestorage heat treatment and chitosan coating maintained higher levels of ascorbic acid, total phenolic contents and antioxidant capacity as well as lower decay, compared with untreated wolfberry fruits. The possible mechanism was that the heat treatment almost sealed open stomata to limit the sites of pathogen penetration into fruits independently, followed by the biofilm formed by chitosan which controlled secondary infections as well as slowed changes in fruit respiration and metabolic activity in wolfberries. The synergistically treated fruit also exhibited a higher acceptability obtained by sensory analysis after cold storage. In this sense, the integrated application of heat treatment and chitosan coating could be regarded as an effective strategy to extend storage life and maintain the postharvest quality of wolfberry fruits.

Heterosis, dominance estimate and genetic control of yield and post harvest quality traits of tomato

Paucity of research on the development of tomato hybrid having desirable post harvest/or processing quality in the tropics compel to undertake this study. Therefore, the present investigation was undertaken to identify potential donors and crosses, to study the extent of heterosis and dominance behaviour, and to ascertain the genetic control of fifteen yield components and post harvest quality traits through line x tester mating design in tomato. Non-additive gene action controlled all characters studied, suggesting heterosis breeding for their improvement. Among parental lines, CLN2777-G’ and ‘FEB-2’ were the best general combiners for yield and processing traits and could be utilized further in tomato breeding programme. Crosses (‘CLN2768-A x A.C.AFT’ and ‘CLN2777-G x FEB-2’) showing high specific combining ability and yield involved parents showing high general combining ability for fruit yield per plant and other horticultural traits. All 9 F1 hybrids had significantly higher number of fruits per cluster and number of fruits per cluster over both mid-and better-parental values, while for the other traits, hybrids expressed average heterosis in both directions. The maximum extent of heterobeltiosis (53.56%) was found in lycopene content of fruit followed by number of fruits per cluster (32.59%) and fruit yield per plant (31.77%). The performances of the hybrids illustrated the presence of various degrees of dominance effects i.e., partial to overdominance /or no dominance. We could able to improve processing quality in spite of yield in the cross (‘CLN2777-G x FEB-2’) which can substantially make a dent for processing industry in the tropics.

'SANTACLARA', A NEW STRAWBERRY CULTIVAR DEVELOPED BY THE SPANISH PUBLIC BREEDING PROGRAM

Application for a new Spanish cultivar of strawberry have been presented to the Spanish Plant Variety Commercial Register in 2009. Its denomination is 'Santaclara'. An agronomic and sensorial characterization of this new short day cultivar, in comparison with other standard cultivars, was carried out in an experimental field at the production area of Moguer, Huelva (southwest coast of Spain). Results indicate a high level of adaptation to different mild agro-environments. 'Santaclara' is noted for its high content in ascorbic acid, its medium-high balanced agronomic, postharvest and fruit quality traits, and also shows excellent comparative qualities for the fresh fruit market.

PHENOTYPIC ANALYSIS OF NEW SWEET CHERRY AND APPLE CULTIVARS BASED ON POSTHARVEST QUALITY CHARACTERISTICS

The development of new cultivars of tree fruits can be greatly enhanced with better understanding of the basis and inheritance of postharvest quality traits. Quality is defined by many factors including firmness, soluble solids content and titratable acidity. An approach which does not presuppose interrelationships may be more productive to understanding phenotypic quality differences and physiological characters. Use of principal components analysis (PCA) provides a presentation of multiple measures of a large number of cultivars or selections without any presupposition of interrelationships. Several examples of PCA evaluations of postharvest character for different cultivars of apples and sweet cherries are presented. These examples demonstrate that postharvest changes in a complex of quality and physiological characters can be simplified to show how different cultivars are either similar or divergent from each other. The information can be used to provide guidance on cultivar selection in the short term and better focus genomic studies in the longer term.

QUALITY MAINTENANCE OF FRESH PRODUCE

High quality is essential for the successful marketing of fresh fruits and vegetables. The maintenance of quality after harvest is critical. Postharvest quality is modulated by both internal and external factors. Four areas in which significant advances in quality maintenance have been made over the past decade are critiqued. These include: 1) inhibition of ethylene action with 1-methylcyclopropene; 2) postharvest treatments to maintain the quality of fresh cut produce; 3) modified atmosphere, active, and intelligent packaging technologies; and 4) increasing selection for postharvest quality traits and quality stability in fruit and vegetable breeding programs. New innovations in quality maintenance will increasingly improve consumer satisfaction, convenience and safety.

Participatory crop improvement and formal release of Jethobudho rice landrace in Nepal

Jethobudho is an aromatic rice landrace of the Pokhara valley in middle hills of Nepal. Although local consumers are willing to pay a high price for its purchase, the landrace has a problem with quality variation. Decentralized participatory population improvement for specific market-identified traits was conducted on “Jethobudho” populations collected from farmers’ fields in seven geographic regions of the valley in Nepal. The preferred post harvest quality traits, field tolerance to blast and lodging, and superior post harvest quality traits of Jethobudho were established by a consumer market survey. These traits were used for screening the materials. 338 sub-populations of Jethobudho were evaluated for yield, disease, lodging resistance, and post harvest quality traits. Significant variation was found for culm strength, neck blast tolerance, awn characteristics, panicle length, number of grains per panicle, test grain weight and post harvest quality traits, whereas no significant variation was found in grain yield, plant height, tiller number, maturity period and leaf blast. Based on these identified traits and micro-milling evaluations, 183 populations were screened in on-farm and on-station nurseries, and in succeeding years populations were further screened by plant breeders and expert farmers in research trials, resulting in the selection of 46 populations for post harvest quality traits. Six accessions with similar agronomic traits, field tolerance to blast and lodging, and superior post harvest quality traits, were bulked and evaluated on-farm using participatory variety selection (PVS). The enhanced Jethobudho accessions were also evaluated for aroma using simple sequence repeat (SSR) and found to have unique aromatic genetic constitution. Community based seed production groups were formed, linked to the Nepal District Self Seed Sufficiency Programme (DISSPRO), and trained to produce basic seeds (truthfully labeled) of Jethobudho. The National Seed Board of Nepal released the enhanced landrace in the name of “Pokhareli Jethobudho” in 2006, as the first bulk variety of traditional high quality aromatic rice improved through participatory plant breeding to be formally released in Nepal for general cultivation under the national seed certification scheme. Landrace improvement is shown as an important option for supporting programmes for in situ conservation of landraces on-farm.

Genetics of Postharvest Longevity and Quality Traits in Late Generation Crosses of Antirrhinum majus L.

Progeny of 158 F5 × F5 crosses of Antirrhinum majus (snapdragon) selected within and among cut flower postharvest longevity (PHL) categories (long = 12.6-16.8 days, middle = 9.3-12.1 days, and short = 4.8-8.9 days) were evaluated for PHL and quality traits. Results were compared with previous studies involving F2 × F2 progeny, and F3, F4, and F5 inbred lines. Heritability of PHL in F5 × F5 progeny (0.77 ± 0.11) agrees with that of inbred lines (0.79 to 0.81) but is higher than in F2 × F2 progeny (0.41). Therefore, selection for increased PHL should progress more rapidly and predictably through application of inbred lines rather than F2 individuals. Significant differences between F5 × F5 progeny PHL categories confirm PHL is heritable with a significant additive component. Heritabilities of quality traits in A. majus are high, suggesting selection for quality traits should progress without difficulty. Phenotypic and genotypic correlations of PHL with quality traits are not consistently significant across PHL studies in A. majus. Discrepancies between studies suggest most traits may not be correlated to PHL or are subject to strong environmental influence.

CHARACTERIZATION OF DFD (DELAYED FRUIT DETERIORATION): A NEW TOMATO MUTANT

Fruit softening is a complex physiological event and a major determinant of postharvest fruit quality. Attempts to understand the molecular basis of softening have focused on cell wall metabolism and it is now generally believed that fleshy fruits soften as a consequence of polysaccharide degradation in the primary cell wall and middle lamella. Tomato has provided the principal model system for these studies and yet efforts over the last ten years to substantially reduce softening in transgenic tomato lines by suppressing the expression of genes encoding cell wall degrading proteins, such as polygalacturonase (PG), pectin methylesterase (PME) and expansin, have been largely unsuccessful. We have recently identified a tomato line that we named the DFD (delayed fruit deterioration) mutant, which promises to provide a new perspective of the key molecular determinants of softening and other postharvest quality traits. The two major characteristics of DFD are substantially reduced fruit softening and complete resistance to postharvest disease, which collectively result in a remarkable shelf life. Unlike other well known ripening-related tomato mutants such as rin (ripening inhibitor) and nor (non-ripening), DFD fruits undergo essentially normal climacteric ripening while attached to the plant, with all the organoleptic characteristics and quality properties that are essential for commercialization, such as color, aroma and accumulation of sugars. However, the DFD fruits also maintain a firm texture for a dramatically extended period of time after harvesting and can be stored with no further treatment at room temperature for more than seven months with any signs off deterioration. Moreover, after more than one year, intact and untreated DFD tomatoes show no signs of microbial infection. These data suggest the need for a new model to understand the key features that underlay tomato fruit softening and tissue disintegration.