The effect of drought stress on the leaf relative water content and tuber yield of a half-sib family of ‘Katahdin’-derived potato cultivars

Drought tolerance in plants is a complex trait involving morphological, physiological, and biochemical mechanisms. Hundreds of genes underlie the response of plants to the stress. For crops, selecting cultivars that can produce economically significant yields under drought is a priority. Potato (Solanum tuberosum L.) is considered as drought sensitive crop, although cultivar-dependent differences in tolerance have been described. Cultivar ‘Katahdin’ possesses many appropriate characteristics and is widely used for breeding purposes worldwide; it also has enhanced tolerance to drought stress. In this study, we evaluated cv. ‘Katahdin’ and a half-sib family of 17 Katahdin-derived cultivars for leaf relative water content (RWC) and tuber yield under drought stress. The yields of cultivars ‘Wauseon’, ‘Katahdin’, ‘Magura’, ‘Calrose’, and ‘Cayuga’ did not significantly decline under drought stress. Among these five, Wauseon exhibited the lowest reduction in both tuber yield and relative water content under water shortage. The data showed that ‘Wauseon’ is the most attractive cultivar for studies of molecular and physiological processes under drought and for potato breeding due to low yield losses that correspond with high RWC values. This cultivar can serve as a reservoir of potentially useful genes to develop cultivars with enhanced tolerance to this abiotic stress.     

Effect of gamma irradiation on the physico-mechanical and chemical properties of potato (Solanum tuberosum L.), cv. ‘Kufri Sindhuri’, in non-refrigerated storage conditions

The effects of γ-irradiation doses, 0.04, 0.08, 0.12 and 1 kGy, applied at two different postharvest times (5 and 30 days after harvest), were studied on the textural behaviour (puncture force, shear force, work done to puncture and shear, cohesiveness and gumminess), microstructure, reducing sugar, total sugar and tuber losses of potato (Solanum tuberosum L.), cv. ‘Kufri Sindhuri’, during storage at 22 °C (RH: 85–90%). The lowest dose (0.04 kGy) was sufficient to inhibit sprouting in potatoes exposed on day 5 but not in the tubers exposed on day 30. The irradiated, non-sprouted potatoes maintained their appearance during storage. Potatoes irradiated early appeared more sensitive to radiation-induced damage, resulting in excessive loss of tubers at 1 kGy but low doses (up to 0.12 kGy) did not increase the susceptibility of the tubers to rotting. No significant differences between reducing sugar and total sugar contents of the control and low dose irradiated tubers were observed after 120 d. High dose (1 kGy) induced blackening of the bud tissue, increased rotting percentage and poor textural quality. Increasing low doses (up to 0.12 kGy) progressively reduced the textural deterioration in the tubers during storage. The scanning electron micrographs of potatoes irradiated with 0.08–0.12 kGy showed intact cells with rigid cell walls, accounting for the higher textural values registered by the samples. Among the two treatment timings, ‘K. Sindhuri’ irradiated early after harvest (i.e., on day 5) with 0.08–0.12 kGy doses retained higher textural parameters compared to those irradiated after a delay (day 30). The study showed the potential effect of γ-irradiation for enhancing the storage life of potatoes in non-refrigerated storage.     

The effect of modified atmospheres on the rate of firmness change of ‘Hayward’ kiwifruit

Gas exchange rates and softening of kiwifruit (Actinidia deliciosa (A Chev) Liang et Ferguson cv Hayward) were measured during two seasons under a range of modified atmosphere (MA) conditions (0–21 kPa O₂, 0–5 kPa CO₂) at 0–10 °C to characterise their functional relationship. The kinetics of gas exchange and softening were the same for the two seasons studied.CO₂ partial pressures delayed softening but did not inhibit the rate of gas exchange. Lowering the O₂ levels to near 0 kPa did not inhibit softening completely, suggesting that the rate of softening was driven by energy provided by both oxidative and fermentative processes.An integrated modelling approach was used to link the rate of softening to the rate of gas exchange explaining 88% of the effect of MA on both the rate of gas exchange and fruit softening. Shelf life simulations showed that during storage at 0 °C, lowering O₂ or raising CO₂ gave a substantial benefit towards extending shelf life. At temperatures higher than 3 °C, the additional effect of MA was already limited.     

Breeding of ‘Manten-Kirari’, a non-bitter and trace-rutinosidase variety of Tartary buckwheat (Fagopyrum tataricum Gaertn.)

Here, we developed a new Tartary buckwheat cultivar ‘Manten-Kirari’, whose flour contains only trace amounts of rutinosidase and lacked bitterness. The trace-rutinosidase breeding line ‘f3g-162’ (seed parent), which was obtained from a Nepalese genetic resource, was crossed with ‘Hokkai T8’ (pollen parent), the leading variety in Japan, to improve its agronomic characteristics. The obtained progeny were subjected to performance test. ‘Manten-Kirari’ had no detectable rutinosidase isozymes in an in-gel detection assay and only 1/266 of the rutinosidase activity of ‘Hokkai T8’. Dough prepared from ‘Manten-Kirari’ flour contained almost no hydrolyzed rutin, even 6 h after the addition of water, whereas the rutin in ‘Hokkai T8’ dough was completely hydrolyzed within 10 min. In a sensory evaluation of the flour from the two varieties, nearly all panelists detected strong bitterness in ‘Hokkai T8’, whereas no panelists reported bitterness in ‘Manten-Kirari’. This is the first report to describe the breeding of a Tartary buckwheat cultivar with reduced rutin hydrolysis and no bitterness in the prepared flour. Notably, the agronomic characteristics of ‘Manten-Kirari’ were similar to those of ‘Hokkai T8’, which is the leading variety in Japan. Based on these characteristics, ‘Manten-Kirari’ is a promising for preparing non-bitter, rutin-rich foods.     

Effect of minimal processing on bioactive compounds and antioxidant activity of fresh-cut ‘Kent’ mango (Mangifera indica L.)

The influence of dipping in ascorbic acid, citric acid and calcium chloride (AA + CA + CaCl₂) solution and storage time on color, bioactive compounds content and antioxidant activity of fresh-cut mango ‘Kent’ stored at 5 °C was evaluated. The treated mangoes showed better color retention during storage than control mangoes. The dipping treatments with AA + CA + CaCl₂ significantly increased the vitamin C values compared with untreated mango cubes. β-Carotene was not affected by dipping treatments and vitamin E showed a significant decline over storage time for both treated and untreated mango cubes. However, higher vitamin E values were found in treated mangoes. Dipped cubes had higher antioxidant activity measured as TEAC and %RSA than controls. In general, addition of ascorbic acid as an anti-browning agent not only retarded quality loss of fresh-cut mango cubes but also promoted significant increases in antioxidant activity in comparison with control samples.     

The effect of temperature on fruit set,seed set and seed germination in ‘Sonia’ × ‘Hadley’ hybrid Tea-rose crosses

Summary The effect of temperature on fruit set, seed set and seed germination was studied in Sonia × Hadley Hybrid Tea-rose crosses. Sonia mother bushes were grown at constant temperatures (10, 14, 18, 22, 26°C) in the greenhouses of the phytotron until fruit ripening. Fruit set, fruit weight and number of seeds increased as temperature was higher. Optimum temperatures were found for days to fruit ripening (18°C), seed germination (22°C) and number of seedlings per pollinated flower (22°C). Fruit weight and number of seeds were positively correlated. For crossing and the subsequent growing of seed-bearing plants 22°C was the most favourable temperature. Effects of temperature on pollen tube growth, fertilization and seed germination are discussed.     

Influence of environmental conditions on the quality attributes and shelf life of ‘Goldfinger’ bananas

‘Goldfinger’ bananas (Musa accuminata, FHIA-01) were harvested, held for 14–22 d at five temperatures and a constant relative humidity (RH) or at five RHs and a constant temperature and evaluated for quality attributes. The objectives of this work were to: (1) create quality curves for bananas stored at chilling and non-chilling temperatures; (2) create quality curves for bananas stored at a non-chilling temperatures and different RHs; (3) identify which sensory quality attribute limits the shelf life and marketability of bananas when stored at chilling and non-chilling temperatures or at different RHs; and (4) correlate subjective sensory attributes with quantitative quality measurements. Results from this study showed that temperature had a more significant impact on the quality of banana than RH. Bananas stored at temperatures higher than 10 °C were yellower and softer but had lower starch and higher soluble solids and total sugar content than those stored at lower temperatures. When stored at 2, 5 and 10 °C, bananas developed chilling injury (CI) and abnormal ripening when transferred to 20 °C. The most remarkable impact of RH on banana quality was on weight loss, which was significantly higher in fruit held below 80% RH than in fruit held in 87 or 92% RH. CI was the first sensory quality attribute to reach the limit of acceptability in fruit stored at 2, 5 and 10 °C, whereas color changes and softening limited the shelf life of bananas stored at 15 and 20 °C. Changes in color and/or softening were the two main sensory attributes that limited the shelf life of bananas stored at different RHs. Overall, for maximum quality and shelf life bananas should be stored at or above 15 °C and 92% RH. Finally, sensory attributes can be used to estimate peel color, pulp softening and sweetness, while SSC can be used as a reliable and simple method to estimate the total sugar content of bananas stored at different temperatures or different RHs.     

Use of equilibrium modified atmosphere packaging for preservation of ‘San Antonio’ and ‘Banane’ breba crops (Ficus carica L.)

The purpose of this work was to study the effect of equilibrium modified atmosphere packaging on the stability of ‘San Antonio’ and ‘Banane’ breba fruit during postharvest cold storage by the use of three different microperforated films (1/50 mm, 1/30 mm, and 1/10 mm; ø = 100 μm). Gas composition in the wraps, weight loss, % disorder, and microbial counts were monitored during cold storage for 21 days. The tested microperforated films allowed the extension of cold storage time for brebas, minimizing weight loss and delaying the disorders due to fungal proliferation, especially M50 (1/50 mm). Total soluble solids (TSS), titratable acidity (TA), pH, firmness, and sensory quality were also evaluated. Among the tested microperforated films, M50 showed the best performance in terms of delaying physicochemical senescence processes of fruit. The breba cultivar had an important impact on the extension of cold storage. For ‘San Antonio’ and ‘Banane’ cultivars packaged with microperforated M50, the optimal time of cold storage was 14 and 21 days, respectively.     

Effects of repeated 1-methylcyclopropene (1-MCP) treatments on ripening and superficial scald of ‘Cortland’ and ‘Delicious’ apples

Postharvest 1-MCP can maintain fruit quality and inhibit development of superficial scald, a physiological storage disorder found in apple fruit, but the extent of the inhibition can vary by cultivar. In this study, we investigated whether multiple applications of 1-MCP, which are now permitted by a label modification of the commercial 1-MCP product, SmartFresh™, might improve scald control. ‘Cortland’ and ‘Delicious’ apples were untreated, treated on the day of harvest with the antioxidant inhibitor of scald, diphenylamine (DPA), or with 1 μL L⁻¹ 1-MCP at different intervals after harvest. Treatment times (days) were 1, 4, 7, 1 + 4, 4 + 7, 1 + 4 + 7, 7 + 14, 7 + 28, 7 + 42, and 7 + 84. Internal ethylene concentrations (IECs), flesh firmness, and accumulations of α-farnesene and conjugated trienols (CTols) were measured at harvest, at the time of treatment, and at intervals during air storage at 0.5 °C for up to 36 weeks. Scald was completely inhibited by DPA and all 1-MCP treatments in ‘Delicious’. However, effective control of scald in ‘Cortland’ was obtained with 1-MCP treatments within the first 4 days of harvest, either alone or in combination. Scald control with delayed 1-MCP treatments resulted in poorer scald control that was comparable to that obtained with DPA. IECs and α-farnesene accumulation were similar in untreated and DPA treated fruit, but inhibited by 1-MCP. However, differences among 1-MCP treatments became more evident with increasing storage periods. Inhibition of IECs and α-farnesene accumulation was greater in fruit treated on days 1, 4, 1 + 4, 4 + 7, 1 + 4 + 7, than on day 7 alone. A second application of 1-MCP on day 14 to fruit treated on day 7 increased inhibition of IECs, α-farnesene and CTol accumulations, but increasing delays before the second 1-MCP treatment resulted in progressively less inhibition of these factors. Similar effects of treatment on IECs, α-farnesene and CTol accumulations were found for both cultivars, even though no scald was detected in treated ‘Delicious’ apples. The results indicate that initial 1-MCP treatments should be applied to faster ripening cultivars such as ‘Cortland’ within a few days of harvest.     

Assessment of tissue culture-derived ‘Gala’ and ‘Royal Gala’ apples (Malus × domestica Borkh.) for somaclonal variation

To assess somaclonal variation, ‘Gala’ and ‘Royal Gala’ trees obtained via axillary and adventitious bud formation were compared ex vitro to conventionally grafted trees. In general, tissue culture-derived trees were relatively erect in comparison to grafted trees. Their branch angles were narrower than those of grafted trees. All trees that flowered had pink blossoms. There were no obvious differences in flowering time or in floral morphology. Most of the seven-year-old grafted control trees produced more fruits than either axillary or regenerated trees. Although there were differences in the range of fruit color between ‘Royal Gala’ and ‘Gala’ apples in both the control and tissue culture-derived plants (the fruits of ‘Royal Gala’ were darker red and more striped than those of ‘Gala’) and also in the degree of pigmentation from tree-to-tree, none of the variation exceeded that observed among apples harvested from an individual ‘Royal Gala’ or ‘Gala’ control tree for either the plants derived from axillary buds or adventitiously. Since both ‘Gala’ and ‘Royal Gala’ axillary buds showed very little somaclonal variation for the morphological and reproductive traits we studied, it appears that tissue culture may be a useful way to propagate these cultivars. This revised version was published online in August 2006 with corrections to the Cover Date.     

Effects of Sucrose Concentration on the Bulblet Formation and Growth of ‘Acheng’Garlic in vitro

以MS为基本培养基，用地方品种阿城紫皮大蒜茎尖为外植体进行离体培养试验。结果表明，随蔗糖浓度的提高，大蒜试管微鳞茎形成被促进，而鳞茎发生数呈下降趋势；蔗糖浓度在30，60，90 g/L时，鳞茎发生数无显著差异，但均与120 g/L蔗糖处理下的鳞茎发生数间存在极显著差异；此外，各个处理条件下形成的平均鳞茎直径与鳞茎鲜重间均存在着极显著差异，90g/L处理效果最佳。     

Influence of the combination of different atmospheres on diphenylamine,folpet and imazalil content in cold-stored ‘Pink Lady®’ apples

‘Pink Lady^®’ apples were harvested at commercial maturity, treated with three different agrochemical products, and stored at 1 °C under either air or controlled atmosphere conditions (2 kPa O₂ + 2 kPa CO₂ and 1 kPa O₂ + 1 kPa CO₂) for 13 and 27 weeks, followed by 4 weeks storage in air at 1 °C. Diphenylamine, folpet and imazalil contents in both the skin and flesh were simultaneously determined after cold storage plus simulated marketing periods of 1 and 7 d at 20 °C. After 27 weeks plus 7 d, diphenylamine and folpet levels in apple skin were lower for fruit stored in low O₂ (2 kPa) or air than for those kept under ultra-low O₂ (1 kPa). An additional storage period of 4 weeks in air reduced diphenylamine and folpet contents in whole apples stored for 13 weeks in the low O₂ controlled atmosphere. For imazalil, the same result was obtained in apple skins stored for 27 weeks under an ultra-low O₂ controlled atmosphere. Differences in diphenylamine and folpet contents were found for skin and flesh samples throughout the simulated marketing period, but there were observable differences in imazalil contents only for flesh samples.     

Effect of modified atmosphere packaging and storage temperature on volatile composition and postharvest life of minimally-processed pomegranate arils (cvs. ‘Acco’ and ‘Herskawitz’)

This study investigated the effects of passive modified atmosphere packaging (MAP), storage temperature (5, 10 and 15 °C) and duration of 14 days on the postharvest quality attributes, compositional change in flavour attributes and microbiological quality of minimally processed pomegranate arils (Punica granatum L.), cvs ‘Acco’ and ‘Herskawitz’. Volatile compounds were extracted via headspace solid phase micro-extraction (HS-SPME) and analyzed by gas chromatography–mass spectrometry (GC–MS). A total of 17 and 18 volatiles were detected and identified in the headspace of pomegranate juices of ‘Acco’ and ‘Herskawitz’, respectively. Based on the physicochemical attributes and microbial evaluation, the postharvest life of MA-packaged ‘Acco’ and ‘Herskawitz’ was limited to 10 days due to fungal growth ≥2 log CFU g⁻¹ at 5 °C. However, the concentration (%) and compositional changes in volatile compounds indicated that the flavour/aroma life (7 days) was shorter than the postharvest shelf-life based on appearance and other physicochemical (10 days) for both cultivars.     

α-Tomatine and other steroidal glycoalkaloids in fruits of tomato lines resistant to the glasshouse whitefly (Trialeurodes vaporariorum Westw.)

Summary The total steroidal alkaloid compositions of the mature-harvested fruits of the tomato cultivar Allround (Lycopersicon esculentum), of the species L. hirsutum glabratum, resistant to the glasshouse whitefly (Trialeurodes vaporariorum), and of four resistant lines were determined by capillary gas chromatography. The contents of -tomatine in the red-ripe fruits of Allround and in those of the lines were low (5 mg/kg fresh weight). The green-mature fruits of the wild species had a high content (3390 mg/kg fresh weight) of -tomatine. The total alkaloid profiles of Allround and of the lines were similar. Comparison of flame ionisation detector response with thermoionic detector response indicated that in addition to tomatidine, the aglycone of -tomatine, a small amount of one other steroidal alkaloid might be present in Allround and in the lines. The wild species contained five compounds which possibly are steroidal alkaloids.The safety level of -tomatine in tomatoes is discussed. It was concluded that, in respect of the glycoalkaloids of the mature-harvested fruits, the resistant tomato breeding lines are as safe for human cosumption as the standard cultivar.     

The effect of the ‘Golden Promise’ dwarfing gene on partial resistance to leaf rust and powdery mildew in spring barley

Summary F₂-plant progenies, derived from seven crosses between susceptible erectoides breeding lines and conventional, nutans breeding lines with partial resistance to leaf rust incited by Puccinia hordei Otth., derived from Vada x Cebada Capa, were examined in a field and a glasshouse experiment. In the field experiment, the nutans plant progenies generally were more resistant to leaf rust and powdery mildew than the erectoides progenies. In the glasshouse experiment, the components of partial resistance to leaf rust of six erectoides and six nutans progenies derived from one cross were studied. The nutans progenies generally had lower infection frequencies than erectoides progenies with a similar infection level in the field experiment. The variation for leaf rust and powdery mildew infection in the field was similar for the nutans and erectoides progenies. This suggests that erectoides lines with a fairly high level of partial resistance to leaf rust and powdery mildew can be selected from these populations.     

Effect of gamma irradiation on the physico-chemical and visual properties of mango (Mangifera indica L.), cv. ‘Dushehri’ and ‘Fazli’ stored at 20 °C

The effect of γ-irradiation doses (0.3, 0.5, 0.7, 1.0, 6.0, 10.0 kGy) on different physico-chemical and visual properties of two Indian cultivars of mango, cv. ‘Dushehri’ and ‘Fazli’ was observed during storage at 20 °C for the evaluation of delayed ripening and extension of shelf-life. Visually all the irradiated fruit showed greener peel and lighter pulp throughout the storage, however, radiation injuries were present in ‘Dushehri’ treated with 6–10 kGy and in ‘Fazli’ with 1–10 kGy. Loss of fruit due to rotting was less in the irradiated samples, treated up to 1 kGy of both the cultivars. Irradiated fruit of both the cultivars at high doses (6–10 kGy) showed increased sugar content from 0 d, however, all the treated fruit registered a slower rate of increase of sugars with storage compared to the respective controls and those treated with the lower doses of 0.5 and 0.7 kGy attained peak sugar concentration later. Significant (p ≤ 0.05) textural deterioration could be detected immediately after irradiation, in ‘Dushehri’ at doses ≥1 kGy and in ‘Fazli’ at doses ≥0.7 kGy. However, low dose treated fruit (0.3–1 kGy) of both the cultivars softened at a considerably slower rate during storage and registered significantly greater fruit firmness (compression strength) throughout the storage period. Similarly, ‘Dushehri’ treated with 0.3–0.7 kGy and Fazli treated with 0.7 kGy registered significantly greater flesh firmness (shear strength). ‘Dushehri’ treated with 0.3–1 kGy and ‘Fazli’ with 0.5–1 kGy also registered significantly harder and tougher peel, as determined by puncture test, throughout the storage. Scanning electron microscopy (SEM) performed on 3rd and 2nd d of storage of ‘Dushehri’ and ‘Fazli’ respectively, revealed microstructural breakdown at and above 1 kGy in both cultivars. Cell separation could be observed in ‘Fazli’ even at 0.7 kGy. SEM also revealed that the control fruit were in a more advanced stage of ripening than the low dose treated fruit. The study showed the feasibility of low dose γ-irradiation on ‘Dushehri’ (0.3–0.7 kGy) and ‘Fazli’ (0.5 and 0.7 kGy) that induced useful delay in ripening and extension of shelf-life by a minimum of 3 and 4 d, respectively.     

Effect of diniconazole on the growth and taking roots after transplanting of Sesamum indicum ‘Baekseol’ plug seedlings

Journal of Crop Science and Biotechnology - Sesamum indicum ‘Baekseol’ plug seedlings were treated with the fungicide diniconazole as a growth retardant in comparison to paclobutrazole....     

Effectiveness of 1-MCP treatments on ‘Bartlett’ pears as influenced by the cooling method and the bin material

Wooden bin-stored ‘Bartlett’ pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled (FAC) and immediately treated or not with 1-methylcyclopropene (1-MCP) for 24 h. 1-MCP gas concentrations used were 0, 0.3 or 0.6 μL L^?1 (called 0, 0.3 and 0.6, respectively). Fruit were subsequently kept at 20 °C for 20 d or stored at ?0.5 °C and 95% RH for 60, 90, 120 or 150 d. After cold storage, fruit were kept at 20 °C for up to 16 d for further ripening. In another experiment, pears stored in wooden bins (W) or plastic bins (P) were all hydrocooled, treated or not with 0.5 μL L^?1 1-MCP (called 0.5 and 0, respectively), stored at ?0.5 °C and 95% RH for 0, 30, 60, 90 or 120 d, and transferred to 20 °C for further ripening. In FAC pears, increasing 1-MCP concentrations usually resulted in delayed increases in ethylene production and lower ethylene production rates, as well as delayed softening. In contrast, HC-0.3 pear firmness did not differ from that of HC-0 fruit after cold storage. Generally, HC-0.3 pears displayed higher ethylene production and lower firmness values than FAC-0.3 pears after a 7-d exposure to 20 °C, regardless the length of cold storage. FAC-0.6 pears always showed lower ethylene production rates and higher flesh firmness values than HC-0.6 fruit. Soluble solids concentration was not consistently affected by 1-MCP. FAC-0.3 and HC-0.6 fruit showed higher titratable acidity values than HC-0 fruit after 0, 60, 120 and 150 d of cold storage plus 7 d at 20 °C. Effectiveness of 1-MCP treatments on HC pears was influenced by the bin material; P-0.5 pears were firmer than W-0.5 pears after 7 d at 20 °C, regardless the length of the cold storage. HC-0.5 fruit exposed to ?0.5 °C for 90 d reached eating quality (firmness ≤23 N) by day 7 if placed in W, and by day 21 when stored in P. Results and previous evidence suggest that wet wooden bin material may represent a major though unpredictable source of 1-MCP sorption that could bind a significant percentage of the 1-MCP applied. When used at relatively low doses 1-MCP partial removal by wet wooden bins can compromise the application effectiveness for controlling ethylene action.