Genetic control of fruit shelf life and yield in crossbreeding of Sletr1-2 mutant with Indonesian tropical tomatoes

Postharvest losses are a significant concern for tomato breeding associated with their short fruit shelf life. Sletr1-2 is a new ethylene receptor mutant that has a prominent character in a prolonged fruit shelf life. This research aimed to estimate the combining ability of Sletr1-2 mutant and determine the selection method for future breeding associated with the fruit shelf-life and yield. Four lines of tropical tomato, i.e., 'Intan,' 'Mirah,' 'Ratna' and 'Mutiara,' were crossed with the wild type Micro-Tom (WT-MT) and Sletr1-2 mutant tomato using a line x tester mating design. A randomized complete block design with four replications was used to evaluate twelve F1 and their parents. The study revealed significant differences in the GCA of the line and tester but not for SCA. The lines and testers contributed more to total variance than their interaction. 'Intan' and Sletr1-2 mutants had the greatest fruit shelf-life combiners, with additive gene action being the most prevalent. Simple phenotypic selection or pure line selection from selected crosses in advanced generations would be preferable. 'Mutiara' was the best combiner for yield and plant growth, with non-additive gene action was the most common. The breeding strategy that considered dominance, overdominance, and epistasis was preferred.

Performance Study of Nano/SiO2 Films and the Antimicrobial Application on Cantaloupe Fruit Shelf-Life

In the current study, novel films with chitosan/nano/SiO2/nisin films and their antimicrobial application on cantaloupe fruit shelf-life have been studied. Novel films were prepared by the addition of 1% chitosan, 1% nano silicon dioxide, and 1% nisin and freeze-dried for the performance study. Physicochemical properties such as tensile strength, optical, and thermal properties with the performance characteristics of the novel films were measured. Coated and uncoated cantaloupes with various coating solutions were stored and chilled at 4 °C in a relative humidity of 70% for up to nine days. The microbial population measurements have been detected every three days. Results show that the fourier transform infrared intensity (FTIR) of nano/SiO2 and with the addition of nisin (nano/SiO2/n) were higher than chitosan (CH) film except in the wavenumber (3150–3750 cm−1) films peaks. Novel nanofilms enhanced tensile strength as well as optical and thermal properties. XRD analysis reported two distinct peak values of 32.08 and 45.99 to correspond to nano/SiO2/n film orientation (7095) and (3316), respectively. Zeta potential values and turbidity were increased, while nano/SiO2 films decreased the hydrophobicity of the film surface by 80.07°. The coating treatments with nano/SiO2 and nano/SiO2/n both reduced the yeast and mold counts 2.49 and 1.92 log CFU/g, respectively, on day nine. In summary, chitosan/nano/SiO2/n novel film improved the functional properties of coating films, and those bio-nanocomposites are effective in food packaging.

Assessment of Tomato Maturity in Different Layers by Spatially Resolved Spectroscopy

Tomato maturity is important to determine the fruit shelf life and eating quality. The objective of this research was to evaluate tomato maturity in different layers by using a newly developed spatially resolved spectroscopic system over the spectral region of 550–1650 nm. Thirty spatially resolved spectra were obtained for 600 tomatoes, 100 for each of the six maturity stages (i.e., green, breaker, turning, pink, light red, and red). Support vector machine discriminant analysis (SVMDA) models were first developed for each of individual spatially resolved (SR) spectra to compare the classification results of two sides. The mean spectra of two sides with the same source-detector distances were employed to determine the model performance of different layers. SR combination by averaging all the SR spectra was also subject to comparison with the classification model performance. The results showed large source-detector distances would be helpful for evaluating tomato maturity, and the mean_SR 15 obtained excellent classification results with the total classification accuracy of 98.3%. Moreover, the classification results were distinct for two sides of the probe, which demonstrated even if in the same source-detector distances, the classification results were influenced by the measurement location due to the heterogeneity for tomato. The mean of all SR spectra could only improve the classification results based on the first three mean_SR spectra, but could not obtain the accuracy as good as the following mean_SR spectra. This study demonstrated that spatially resolved spectroscopy has potential for assessing tomato maturity in different layers.

Postharvest Quality of ‘Carabao’ Mango as Affected by Spun-Bound Bagging Materials

A safe option to address some production problems such as insect damage, diseases, and blemishes in mango is fruit bagging. ‘Carabao’ mango fruit at 55 days after flower induction (DAFI) were bagged with three bagging materials: old newspaper (control), spun-bound high density polyethylene (SHDPE, DuPont™ Tyvek® Homewrap, 0.15 mm thick) and non-woven spunbound polypropylene (NSPP, 0.03mm thick). Bagged mango fruit were harvested at 118 DAFI. At harvest, NSPP bagging material resulted in better quality of fruit compared to newspaper and SHDPE. Advanced color change was observed both in newspaper and SHDPE at 4 and 8 days after harvest (DAH). Compared to newspaper and SHDPE, slower color change was observed in fruit bagged with NSPP up to 8 DAH. The degree of anthracnose infection did not differ among bagging materials. Higher degree of stem end rot (SER) infection was noted in newspaper at table ripe stage (TRS). Onset of SER was delayed by about a day in NSPP and SHDPE. At 8 DAH, lowest weight loss was observed in mango bagged with newspaper. Slightly longer shelf life of about a day (0.72 d) was noted in NSPP-bagged fruit. Shelf life was reduced in newspaper which may be attributed to fruit reaching TRS faster by a day and earlier onset of SER. Total soluble solids in fruit bagged with SHDPE was lower upon harvest and during storage at 8 days while firmness did not vary among bagging materials. NSPP showed potential as bagging material that can maintain better quality of ‘Carabao’ mango fruit.

Chitosan-based Edible Coating Prolongs Musa troglodytarum L. (‘Pisang Tongkat Langit’) Fruit Shelf-life and Changes the ACS1 and ACO1 Gene Expression Profile

Musa troglodytarum L. (‘Pisang Tongkat Langit’), a banana cultivar which originated from Eastern Indonesia, has an economic potential due to the high β-carotene content on its pulp. Being a climacteric fruit, M. troglodytarum has a short shelf-life that can reduce fruit quality. In this study, the effect of 1.25% (w/v) chitosan coating on M. troglodytarum fruit shelf-life and ACS1 and ACO1 gene expression analysis using quantitative PCR were evaluated. Results showed that the application of chitosan coating delayed the fruit ripening process for two days by delaying several fruit physical and chemical changes. ACS1 and ACO1 gene expression analysis showed a different expression pattern, the expression level was lower on chitosan-coated fruits on the first day compared to control. In conclusion, chitosan-based edible coating delayed M. troglodytarum fruit ripening and changed the ACS1 and ACO1 gene expression pattern, compared with the chitosan coating effect on Cavendish banana which also prolonged fruit ripening and suppressed ACS1 and ACO1 expression in a previous research.

Phenotypic diversity and chemical properties of pawpaw fruit quality in Ugandan germplasm

Pawpaw (Carica pawpaw L.) fruit production and utilisation have been on the increase in Uganda. However, challenges related to identification of phenotypes with inherent characteristics for improvement of fruit shelf life have limited identification of better varieties. The objective of this study was to evaluate the phenotypic diversity and shelf life determinants of Uganda’s pawpaw accessions and their variations based on selected quality parameters. Nineteen accessions were collected as seeds from different markets of Uganda, germinated and planted in Namulonge-Wakiso district, central Uganda. The accessions were significantly (P<0.05) variable in terms of fruit weight parameters, with dry matter ranging from 14 - 19% and fruit weight of up to 3.9 kg; while pulp weight was up to 3.2 kg per fruit. Pulp firmness parameters were also significantly variable (P<0.05) and highly correlated with shelf life of the fruit, which ranged from 7 - 13 days depending on the accession. Fruit pulp pH ranged from 4.4-5.6; while titratable acidity of the fruit ranged from 0.03-0.08%. The accessions were clustered in four main clusters depending on the fruit firmness properties, fruit shelf life, fruit weight, pH and titratable acidity as definitive parameters. These accessions were distinguished based on morphological parameters, and henceforth defined for nutritional and economic uses. Accessions with high fruit firmness (>5 kg F) such as 16/20’ 16/16, 16/17 and 18/1; and external pulp thickness (>2 cm) such as 16/16, 16/17 and 18/1 had improved fruit shelf life and are recommended for marketability and processing.