W. A. Harindra Champa

Potential of putrescine (PUT) and salicylic acid (SA) as postharvest dip treatments on maintaining quality and extending the shelf life of lime (Citrus aurantifolia Swingle) fruit cv. Local was investigated. Fruit harvested at commercially mature stage were dipped in different concentrations of PUT (0.5, 1.0, and 1.5 mmolL⁻¹), SA (1.0, 2.0, and 3.0 mmolL⁻¹), and control (0.0 mmolL-1) for 15 minutes and stored in cold room (13 ± 1°C, 90 ± 5% RH). Evaluation of peel color (L*, a*, b*), total chlorophyll content (TCC), TSS, TA, physiological weight loss (PWL), visual quality, and decay incidence were carried out at 0 day (before treatment) and at 14, 28, 42–56 days of storage. Out of two reagents examined, PUT showed promising effect compared to SA on maintaining quality and extending the postharvest life of lime cv. Local during cold storage (13 ± 1°C, 90 ± 5% RH). The lowest dose of PUT (0.5 mmolL⁻¹) and the middle dose of SA (2 mmolL⁻¹) effectively suppressed the degradation of peel color, retarded the rate of deterioration of TSS and TCC while reducing the rate of increase in PWL. The lowest concentrations of both PUT (0.5 mmolL⁻¹) and SA (1.0 mmolL⁻¹) exhibited higher efficacy in preventing the deterioration of TA. In conclusion, exogenous treatment of PUT at the dose of 0.5 mmolL⁻¹or SA at the concentration of 2 mmolL⁻¹for 15 min could be recommended as an effective tool for maintaining quality and extending the shelf life of lime cv. Local.

Lime (Citrus aurantifolia Swingle) has a year round demand because of its utilization in food industry, indigenous medicine and domestic culinary. However, the production is highly seasonal. Hence, a study was conducted to evaluate the effect of cinnamon bark oil and hexanal incorporated bio-wax for extending its postharvest life. Lime cv. Local at optimum maturity was harvested and brought to the laboratory immediately. The bulk sample was divided into four replicated lots each containing 120 fruits. Two lots were dipped in the wax formulation for 45 s while the other two were kept as controls (no wax). Treated and control samples were stored in cold room (13°C ± 2°C; RH 90%) and ambient conditions (32°C ± 2°C; RH 70%) in plastic crates respectively. Evaluation of physicochemical attributes were conducted before treatment (day 0) and at 7-day intervals, until fruit exhibits limit of marketability. Bio-wax treatment decreased the rate of peel color deterioration and retarded the rate of increase in fruit firmness (P < 0.05). The bio-wax treatment also significantly contributed to reduction in the rates of variation in total soluble solids, titratable acidity, and juice pH. The treatment also reduced the physiological weight loss and peel browning by 50% thus treated fruit stored under ambient condition showed a marketable life of 15 days while those stored under cold room demonstrated a marketable life of 60 days. In conclusion, cinnamon bark oil and hexanal incorporated bio-wax could be used as a promising tool to extend postharvest life of limes.

Significance of preharvest foliar sprays of brassinosteroid (BRs) on physicochemical properties and postharvest life of table grape cv. Flame Seedless were studied. The experiment was performed on 12-year old own rooted, grapevines planted at 3m x 3m spacing trained on overhead system. Vines were treated with aqueous solutions of BRs (0.0, 0.1, 0.5 and 1.0 mg l-1) at pea stage and at veraison. After harvesting, clusters were divided into two lots in which one was subjected to initial quality evaluation, while the other was stored in cold room (3-4 o C, 90-95% RH) for evaluation of postharvest quality. Clusters treated with 0.5 and 1.0 mg l-1 BRs showed significant increase in cluster weight and breadth as well as berry weight, length and breadth. BRs, at the dose of 0.5 mg l-1 effectively reduced the rate of berry softening, maintained external colour, stabilized anthocyanins, increased total phenols along with reduced rate of degradation in TSS and TA during low temperature storage on the contrary to other two doses and the control. It also exhibited protective role against decay development. Preharvest foliar spray of 0.5 mg l-1 BRs could be an effective means of maintaining quality and extending postharvest life of grape cv. Flame Seedless during cold storage.

Table grapes (Vitis vinifera L.) rank fourth in the world fresh fruit production after citrus, bananas and apples. In Sri Lanka, grapes are grown in an area of about 100 ha. It is one of the main fruits imported to the country and according to Sri Lanka Customs, 5.1 million kg of grapes worth Rs. 1.1 billion were imported in the year 2012. These imports can be significantly reduced as there is ample scope to produce grapes locally in the land available in the North and East of Sri Lanka. The crop thrives well in these Dry Zone areas having well drained deep soils with assured irrigation. Dry weather during flowering, fruit development and maturity is essential for the production of quality grapes. Unlike other fruit crops, proper pruning of vines at the correct time is mandatory to stimulate fruiting. In order to produce a quality bunch of grapes, there are many practices that viticulturists must be aware of. This article is based on the author's three-year experience at a vineyard situated in the Punjab Agricultural University, Ludhiana, Punjab, India. The paper discusses preharvest and postharvest practices that should be adopted for producing high quality table grapes, along with recent research advances on the role of plant growth regulators in quality improvement.

Significance of preharvest salicylic acid (SA) treatments on maturity, quality and postharvest life of grape cv. Flame Seedless were studied during two years. The experiment was performed on 12-year old own rooted, grapevines planted at 3 m × 3 m spacing trained on overhead system. Vines were treated with aqueous solutions of SA (0.0, 1.0, 1.5 and 2.0 mM) at pea stage and at veraison. After harvesting, clusters were divided into two lots in which one was subjected to initial quality evaluation, while the other was stored in cold room (3–4 °C, 90-95 % RH) for evaluation of postharvest quality. SA at the dose of 1.5 and 2.0 mM hastened berry maturity by 3 to 5 days, produced less compact bunches alongside larger berries in contrast to control and the lowest dose. The same doses effectively maintained peel colour, higher firmness, lower pectin methyl esterase activity and electrolyte leakage alongside suppressing degradation of TSS and TA during cold storage. These two doses also exhibited higher efficacy on maintaining anthocyanins, phenols and organoleptic properties while reducing weight loss, rachis browning and decay incidence. Correlation analysis demonstrated that many quality parameters are interdependent. In conclusion, preharvest spray of 1.5 mM SA proved to be an effective means of improving quality and extending postharvest life of grape cv. Flame Seedless.