Losses in litchi at various stages of supply chain and changes in fruit quality parameters

During May and June of 2012 and 2013, a study was conducted to assess losses at the farm, wholesale and retail levels in the supply chain of litchi in India. Changes in fruit quality parameters after harvest and the effectiveness of an improved corrugated fibre board (CFB) box versus conventional wooden box packaging to minimize postharvest losses were also studied. Farm-level samples were collected immediately after harvest from farmers' orchards in the Muzaffarpur district of Bihar state. Wholesale market samples were procured from the Delhi market, and retail samples from the Muzaffarpur and Delhi market. Real-time data on losses and quality parameters of fruits were recorded by transporting litchi from Muzaffarpur to Delhi (distance 1000 km) by truck. Studies indicated that the average loss (fruits discarded at sorting) apparent at the farm level during 2012 and 2013 was 30.4% and 25.8%, respectively. The average loss at the wholesale market level in Delhi was 15.8% and 12.4% during 2012 and 2013, respectively. The highest mean loss (up to 20.5%) was observed at the retail level. The mean fruit weight loss during transport to Delhi was 9.42% and 7.07% during 2012 and 2013, respectively. The mean total loss in the supply chain of litchi ranged from 35.3% to 43.8%. The total soluble solids, respiration and ethylene evolution in litchi fruits were found to increase after transport, whereas acidity and colour parameters (L*, a* and b* values) significantly decreased over time. The predominant pathogen associated with fruit decay was Alternaria alternata (Fr.) Keissler. CFB packaging significantly reduced various losses, thus indicating its effectiveness in its current use in non-refrigerated trucks for transport.     

The efficacy of combined application of edible coatings and thyme oil in inducing resistance components in avocado (Persea americana Mill.) against anthracnose during post-harvest storage

Avocado fruit has high economic value; however, major post-harvest losses are encountered throughout the supply chain mostly due to anthracnose disease caused by the fungus Colletotrichum gloeosporioides. Increasing consumer concern regarding food safety and demand for organically produced fruits makes it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry; particularly in disease control. Antifungal effects of Gum Arabic (GA) (10%), Aloe vera (AL) (2%), chitosan (CH) (1%) alone or in combination with thyme oil (1%) were investigated in vitro. CH + thyme oil and AL + thyme oil [1:1 or 3:1 v/v] showed fungicidal effects while AL, CH, GA and GA + thyme oil [3:1 v/v] showed fungistatic effects on mycelial growth of C. gloeosporioides in vitro. CH and AL coatings alone or in combination with thyme oil [3:1 v/v], either as preventative or curative treatments in comparison with commercial treatment (prochloraz, 0.05%) and untreated control were evaluated on incidence and severity (lesion diameter) of anthracnose in vivo. Preventative CH + thyme oil treatments significantly reduced the severity of anthracnose (8.9 mm) compared to thyme oil (12.7 mm), AL + TO (14.4 mm), CH (17.8 mm), AL (20.6 mm), PZ (18.3 mm) and untreated samples (34.8 mm). As curative method, the CH + thyme oil combination also reduced the severity of anthracnose by at least 4 mm compared to the other treatments. The total phenols, polyphenol oxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities, firmness and flesh colour were also determined. Results showed an increase in peroxidase, phenylalanine ammonia-lyase, β-1,3-glucanase, chitinase, catalase and superoxide dismutase activities and total phenolics with reduced loss of firmness and flesh colour following CH + thyme oil treatments. This investigation recommends CH + thyme oil [3:1 v/v] combination treatment as a suitable alternative to the currently adopted prochloraz applications in controlling anthracnose disease in avocado fruit during storage.     

Effects of kaolin-based particle film to control Ceratitis capitata (Diptera: Tephritidae) infestations and postharvest decay in citrus and stone fruit

Ceratitis capitata (Wiedemann) is a major pest of fruit crops due to its wide host range and distribution. The objectives of this study were to evaluate the effectiveness of Surround WP, a kaolin-based particle film, as an alternative to synthetic insecticides to control medfly infestations and postharvest decay in citrus and stone fruit. No-choice, choice and half-choice laboratory experiments with citrus fruit, nectarines and peaches showed a significant reduction of medfly punctures and landings on kaolin-treated fruit. The total loss at harvest in satsumas sprayed with Surround WP (17%) was significantly lower than in those untreated (57%) or treated with trichlorfon (68%). In 2004, the yield loss at harvest in peaches and nectarines treated with Surround WP was not different compared to fruit sprayed with fenthion and trichlorfon, while in 2005 Surround WP was significantly more effective than insecticides in reducing the incidence of damaged fruit. Citrus and stone fruit treated with Surround WP showed a lower incidence of postharvest decay than control and insecticide-treated fruit. The present study shows for the first time the lower incidence of postharvest decay in fruit protected with Surround WP, which represents a suitable alternative to conventional insecticides in integrated and traditionally managed orchards.     

纸片型1-MCP对杨桃果实采后病害的抑制与抗病相关酶的诱导

研究纸片型1-MCP(1-甲基环丙烯)处理对采后‘香蜜’甜杨桃果实病害指数、抗病相关酶活性和总酚含量的影响。采后杨桃果实用0(对照)和0.6μL/L的纸片型1-MCP处理12 h后,在(15±1)℃下贮藏。贮藏期间定期测定果实病害指数、果实抗病相关酶如几丁质酶(CHI)、β-1,3-葡聚糖酶(GLU)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)和过氧化物酶(POD)活性及总酚含量的变化。结果显示:与对照果实相比,纸片型1-MCP处理能有效降低杨桃果实病害指数,提高CHI、GLU、PAL、PPO和POD的活性,保持较高的总酚含量。表明纸片型1-MCP对抑制杨桃果实采后病害的发生与抗病相关酶活性的升高及酚类物质的合成有关。     

Molecular mapping of QTLs for gluten strength as measured by sedimentation volume and mixograph in durum wheat (Triticum turgidum L. ssp durum)

Quantitative trait loci (QTLs) responsible for gluten strength measured by SDS-sedimentation volume (SV), mixograph and grain protein content (GPC) were located on the molecular linkage map of a durum wheat recombinant inbred line population. QSv.macs-1B.1 flanked by Xgwm550–Glu-B3 was the most consistent QTL for SV identified in all the environments. The same QTL was also associated with mixograph peak energy, peak time and total energy. The Glu-B1 locus was at the center of another QTL responsible for SV, while, Glu-B2 influenced SV as well as mixograph peak energy and peak time. Apart from glutenin coding loci, QTLs influencing mixing parameters and GPC were located in three other marker intervals Xwmc48.2–Xpsp3030 (4B), Xgwm573–Xbarc231.1 (7A) and Xgwm46–Xgwm540.1 (7B). A total of 26 main effect QTLs and 10 digenic epistatic interactions (QQ) for quality traits were distributed over 11 chromosomes. Out of these, seven main effect QTLs and three QQ interactions were involved in interactions with environments (QE, QQE). The results indicated that along with chromosome 1B, chromosomes 4B, 7A and 7B are also important for improvement of gluten strength and GPC in durum wheat.     

A study on soil solarization and combined with fumigant application to control Phytophthora crown blight (Phytophthora capsici Leonian) on peppers in the East Mediterranean region of Turkey

Field trials conducted in the pepper growing area ( çel/Turkey) showed that solarization alone and combined with a reduced dose of methyl bromide (40 g/m²), were effective in controlling crown blight disease caused by Phytophthora capsici. Solarization was achieved by covering plots with a clear polyethylene sheet, 0.03 mm thick for 8 weeks. The temperature reached 47 °C and 35 °C at 5 cm and 30 cm soil depth, respectively, an average of 3–8 °C higher than those at equivalent depths in the untreated plots. The average incidence of the disease in solarization plus a reduced dose of methyl bromide, the recommended dose of methyl bromide, solarized and untreated plots in 1991 and 1992 were 17.6 and 13.3%; 20.8 and 16.8%; 24.1 and 19.7%; 39.8 and 42.9%, respectively. All treatments significantly reduced disease incidence.