Effect of harvest time on the storage performance of carrot

Summary

Storage loss may adversely affect a considerable proportion of the carrot yield taken to the store. The present study aimed to determine the optimum harvest time to minimize storage losses. Experiments with two cultivars (Fontana F₁ and Panther F₁) were performed at an experimental site and on farms for three years. Delaying harvest decreased storage losses which mainly comprised spoilage due to storage diseases. Infections by the two major pathogens, Mycocentrospora acerina and Botrytis cinerea, were reduced towards the end of the harvest period. No further improvement in storability was observed after early October, but storage losses did not increase with a later harvest in most cases. Changes in storability were generally not related to weather conditions at or prior to harvest. Only the continuous frost at the very end of October in one season impaired storage quality.     

Effect of overhead shading on yield and fruit quality of kiwifruit (Actinidia deliciosa)

Summary

Kiwifruit vines (cv. Hayward) were shaded from early spring until fruit harvest at levels of 100% (control), 70% or 45% full sun. Although shoot growth during the early part of the season was not significantly affected by the shading, the percentage bud burst was reduced and the time of full bloom appeared to be slightly delayed. The mean fresh weight of individual fruits was significantly reduced by shading, and fruit on shaded vines reached commercial harvest maturity of 6.2% soluble solids two to three days later than those on unshaded vines. During cool storage, fruit from vines grown under 45% full sun were slightly but consistently less firm and had lower soluble solids concentrations than unshaded fruit. No differences in the starch or total sugar contents were found between shaded or unshaded fruit, either at harvest or after cool storage. Shading vines did not affect either the colour (HunterLab values) or the chlorophyll concentration of fruit. Possible implications of these results for commercial orchards are discussed.     

Leaf-to-fruit ratio affects water and dry-matter content of mango fruit

Summary

Changes in water and dry-matter content of developing mango fruit (Mangifera indica L. ‘Lirfa’) were investigated over a single season in Réunion Island, along with the effects of leaf:fruit ratio (10, 25, 50, 100 and 150 leaves per fruit on girdled branches). As the fruit developed, about 8–13% of fruit water weight was in the peel compared with 78–86% in the pulp and 6–9% in the stone. When the data were expressed on a dry-weight basis, 12–20% was in the peel, 60–70% was in the pulp and 18–20% in the stone. At harvest, larger fruit, on treatment 100, had a higher proportion of weight in the pulp. Good relationships between water and dry weight of each fruit component were found, regardless of the treatment. They showed that the rate of water accumulation decreased when the dry weight increased and that the dry-matter content increased as the fruit developed as well. Increasing leaf:fruit ratio to 100 leaves per fruit improved fruit yield by 300 g and pulp dry-matter content by 6%, for a total of 550 g and 20% at harvest. Fruit quality as estimated by pulp dry-matter content could be calculated easily during the changes in fruit weight over the season. Moreover, this indicator could be useful to assess the maturity of mango fruit.     

Development and assessment of F1 hybrids in Romanesco cauliflower

Summary

In a trial of Romanesco cauliflower inbred lines, hybrids and controls, differences between mean performance of hybrids and their mid-parents demonstrated heterosis, with F₁ hybrids producing larger curds on larger plants with earlier maturity in most crosses. In F₁ hybrids, the small increases in curd depth, together with reduction in looseness and the overall slight improvement in curd quality, were attributed to the ability to harvest hybrid curds at earlier maturity than their inbred parents. The ability to increase the marketable yield is a prime benefit of F₁ hybrids in Romanesco cauliflowers. An effect of early test crossing was to improve seed production, both in inbred lines and hybrids. With a wider diversity of inbred lines, early testing generally would be advantageous and would also provide an opportunity to screen for inbred lines with strong self incompatibility as potential F₁ parents.     

Effect of harvest date and applied ABA on polyphenol oxidase levels in avocado (Persea americana Mill.) fruit

Summary

‘Fuerte’ avocado fruits from five harvest dates, which spanned the normal packing season, were infused with different amounts of ABA from zero to 550 ng per gram fresh mass of fruit. After ripening at 21°C, the fruits were analysed for PPO activity and residual ABA. Both ABA and harvest date affected PPO activity, with the greater effect being time of harvest. The later the harvest date and the higher the level of infused ABA, the greater was the effect on PPO activity. Early in the season the infused ABA had no effect upon PPO activity. This study has shown that ‘Fuerte’ fruit with the best potential for long distance transport are those harvested soon after minimum legal maturity. If fruits must be hung (tree stored) after maturity, they should be stressed as little as possible.     

Fruit thinning in ‘Conference’ pear grown under deficit irrigation: Implications for fruit quality at harvest and after cold storage

Fruit thinning in pear is feasible for mitigation of water stress effects. However, it is not well known how fruit quality at harvest and after cold storage is affected by pre-harvest water stress. Even less is known about the effects of fruit thinning on quality under these circumstances. To elucidate these, we applied deficit irrigation (DI) and fruit thinning treatments to ‘Conference’ pear over the growing seasons of 2008 and 2009. At the onset of Stage II (80 and 67 days before harvest in 2008 and 2009, respectively), two irrigation treatments were applied: full irrigation (FI) and DI. FI trees received 100% of crop evapotranspiration (ETc). DI trees received no irrigation during the first three weeks of Stage II to induce water stress, but then received 20% of ETc to ensure tree survival. From bud-break until the onset of Stage II and during post-harvest, FI and DI trees received 100% of ETc. Each irrigation treatment received two thinning levels: no thinning leaving commercial crop load (∼180 fruits tree⁻¹), and hand-thinning at the onset of Stage II leaving a light crop load (∼85 fruits tree⁻¹). Under commercial crop loads, DI trees were moderately water-stressed and this had some positive effects on fruit quality. DI increased fruit firmness (FF), soluble solids concentrations (SSC) and acidity at harvest while no changes were observed in fruit maturity (based on ethylene production). Differences in FF and acidity at harvest between FI and DI fruit were maintained during cold storage. DI also reduced fruit weight loss during storage. But fruit size was reduced under DI. Fruit thinning under DI resulted in better fruit composition with no detrimental effect on fresh-market yield compared to un-thinned fruit. Fruit size at harvest and SSC values after five months of cold storage were higher in fruit from thinned trees than fruit from un-thinned trees. Fruit thinning increased fruit ethylene production, indicating advanced maturity. This may lead to earlier harvest which is desirable in years with impending drought. Fruit thinning is therefore a useful technique to enhance pear marketability under water shortage.     

Preliminary studies on the use of (2RS, 3RS)-paclobutrazol for fruitlet thinning and growth control of ‘Conference’ pear

Summary

Single foliar sprays of paclobutrazol (PP333) at 300, 1000 or 3000 mg H applied at three different stages from full bloom to petal-fall in a year of average initial sets . and fruit size were equally effective in thinning ‘Conference’ pear, increasing the proportion of large fruits at harvest, but decreasing their absolute numbers. Sprays applied nine days after petal-fall reduced initial sets less effectively and, applied 21 days after petal-fall, were ineffective. Thinning was completed within 25 days after petal-fall. Shoot extension was initially retarded at all three concentrations, but later increased, so that the total growth made during the season was not reduced. Single foliar sprays at 300 or 1000 mg l^?1 applied at 70% full bloom in a year of heavy set and small fruit size increased the numbers of large fruits in the >55 mm size category by 66% and decreased those of fruits <55 mm by a similar amount. The increase in the yield of fruits >55 mm and decrease of unsaleable <45 mm fruits was equivalent to about 3 and 2 t ha^?1 respectively from a total average yield of about 17.5 t ha^?1. In the same experiment, similar sprays counteracted the stimulation in the production of small fruits by sprays of gibberellic acid (GA) applied on the same day, but did not increase the harvest of large fruits. Sprays of paclobutrazol at 30 or 100 mg l^?1 applied two weeks after petal-fall and then on three successive occasions at two-week intervals inhibited total extension growth per shoot during the season without affecting initial or final sets, fruit size or flower bud production. Single sprays applied at 100 mg l?1 in July reduced total extension per shoot almost as effectively as the repeated sprays. For more effective control of ‘Conference’ shoot growth, paclobutrazol may have to be sprayed later in the season than commercially recommended. Applied as a blossom thinner, paclobutrazol may increase the yield of large fruits only in years of heavy set and small fruit size, requiring that applications be delayed until set can be judged.     

An Evaluation of Blueberry Cultivars Grown in Plastic Tunnels in Douglas County,Oregon

Abstract

Growing fruits and vegetables in plastic tunnels is known to accelerate maturity and protect quality. There are several studies on highbush blueberry (Vaccinium corymbosum) that demonstrate the ability of row covers to advance or delay crop maturity depending on how they are manipulated. Accelerating or delaying harvest time can prove to be very lucrative for producers. However, before producers start putting plastic tunnels over their crops it is important to know how blueberry cultivars will behave when grown under plastic. Six cultivars of southern highbush blueberry and eight cultivars of northern highbush blueberry were grown in a high hoop plastic tunnel for two seasons. Blueberry plants were grown under plastic from February 1 until their harvest was completed each year. After harvest, the plastic covering over the hoops was removed to help the blueberry plants develop fruit buds and meet winter chill requirements. On February 1 the plastic covering was returned to the high hoop tunnel after chilling requirements were met. As expected, fruit maturity dates were 1-3 weeks earlier for all the highbush blueberries grown inside the tunnel versus the same cultivars grown outside. The difference in maturity dates between cultivars grown under plastic and outside did change from one year to the next because of variation in the weather. Despite potential for poor pollination of blueberries in plastic tunnels, yields were significantly enhanced for four cultivars when grown under plastic tunnels. ‘Toro’, ‘Nui’, ‘Legacy’, and ‘Misty’ showed yield gains ranging from 1 to 4 times when grown under a plastic tunnel. Seed numbers per fruit were not significantly impacted by growing plants inside our tunnel.     

干椒新品种湘干椒1号(湘椒3号)的选育

湘 干椒１ 号是 利用亚洲 蔬菜研究 与发展 中心干椒 材料的 多代 自交 系９５ １ 为母 本,湖南地方 干椒品 种的优良 自交系８００１ 为父 本育成 的干 椒一 代杂 种。植 株 生长 势强 ,果 实细 羊 角形,商品性 好,品质 佳;中晚 熟,从定植 到采收 红椒约７０ ｄ（ 天） , 平均 每６６７ ｍ ２ 产干 椒３５０ ｋｇ , 极显 著地比对照 皇椒１ 号增 产;耐旱, 耐热,抗病 性强。     

Post-Harvest Studies on Autumn-Drilled Bulb Onions. The Effect of Harvest Date,Conditioning Treatments and Field Drying on Skin Quality and on Storage Performance

Overwintered onion cvs Express Yellow and Senshyu Semi-globe Yellow were harvested at 80% foliar fall-over (early June) and two and four weeks later, in 1975 and 1976. Plants were conditioned for one (1975) or two weeks (1976) at 20°C, 70% RH or 30°C,60% RH or field dried, and then stored at ambient temperature. Measurements of fresh weight loss during the first six weeks after harvest in 1976 indicated that drying was slow and was incomplete after 14 days conditioning at 30°C. Skin staining and splitting generally increased with delay in harvest date. Skin colour improved with delay in harvest date and with conditioning at 20°C. Wastage due to both rotting and sprouting during storage was generally lower when plants from the first two harvest dates were conditioned at 30°C. These bulbs are likely to be useful for long-term storage as total wastage levels of only 20% were reached in both cultivars after 3-5 months storage. Good field drying of the bulbs could not be consistently obtained and consequently storage performance was more variable than for bulbs conditioned at 20 °C and 30 °C before storage.     

Site and fruit maturity influence on the quality of European plum in organic production

Information available on the role of site and fruit maturity in the quality of European plums in organic production has not been studied to date. European plum cv. ‘Green Gage’ grown in organic production was harvested in order to study the effect of site and fruit maturity on fruit quality. At harvest, significant differences were found in fruit weight, colour, firmness and TSS between harvest dates, whereas significant differences were found in fruit weight, colour, firmness and fruit Ca content between sites. Differences remained during storage. Fruit weight loss during storage was affected by site. Fruit with high Ca content showed higher firmness both at harvest and during storage. Harvest moment should not be chosen according to date, since differences between sites at the same date have been found. Firmness and colour parameters a* and h° would be useful to distinguish maturity at harvest between different sites and harvest dates. Linear regression between h° and firmness at harvest would allow the use of the h° colour parameter as a non-destructive measurement to distinguish maturity. Organic orchards should keep a minimum level of Ca in order to assure a slower fruit softening during storage.     

Combinations of GA3 and AVG delay fruit maturation,increase fruit size and improve storage life of `Feicheng' peaches

Summary

Different concentrations of aminoethoxyvinylglycine (AVG) and gibberellic acid (GA₃) and their combinations, applied at two stages of fruit growth, were evaluated for prolonging the marketing season of `Feicheng' peaches. GA<sub>3</sub> applied at the end of pit hardening, or AVG applied two weeks before commercial harvest, inhibited fruit maturation on the tree, delayed harvest and reduced flesh browning after cold storage in a concentration-dependent manner. A synergistic effect was found when both GA<sub>3</sub> and AVG were used, with the combination of 100 or 150.mg l<sup>±1</sup> GA<sub>3</sub>, applied at the end of pit hardening, and 100 mg l<sup>±1</sup> AVG, applied two weeks before harvest giving the best results. These combinations retarded the change in ground colour, loss of firmness, and reduction in acidity by 2±3 weeks. Since harvest was prolonged by 2±3 weeks, soluble solids content (SSC) in fruit increased compared with the control (harvested earlier). Fruit size was significantly greater on treated trees compared with the controls when fruit set was controlled to the same level by hand thinning. After four weeks of storage and 4.d at 208C, 83% of control fruit developed tissue browning, but only 5% of AVG + GA<sub>3</sub>-treated fruit developed browning after six weeks of storage and 4 d at 208C. Thus, the marketing season of `Feicheng' peaches was prolonged by at least four weeks by 100 or 150 mg l^±1 of GA₃ and 100 mg l^±1 of AVG. Fruit treated with 150 mg l^±1 GA₃ plus 100 to 150 mg l^±1 AVG showed similar results but failed to ripen properly after cold storage.     

The effect of thermal environment,planting date and crown size on growth,development and yield of Fragaria × ananassa Duch. cv. Elsanta

Summary

The effects of environmental conditions, planting date and crown size on the timing, intensity and duration of cropping in the strawberry Fragaria × ananassa cv. Elsanta were investigated. Temperature was positively correlated with the rate of progress to fruiting whereas crown size had no effect. The first fruit reached harvest maturity after an estimated 891 day-degrees had elapsed above a base temperature of 2.9°C for waiting bed plants and 831 day-degrees above a base temperature of 2.4°C for cold stored plants. Temperature was negatively correlated with total yield, berry number and average berry weight for both waiting bed and cold stored plants of different crown sizes. Yield, berry number and average berry weight were positively correlated with crown size. The effect of temperature on the yield components appeared to be due to its effect on vegetative growth of the plants: canopy development was more limited at warmer temperatures. These results can be used to generate models to predict the effect of growth environment on cropping in strawberry.     

The effects of pre-harvest dehydration on the composition of once-over harvested sweet paprika

When paprika fruits (Capsicum annuum L.) were allowed to dry in the sun, on the plant itself, before harvest, there was a considerable increase in the dry matter content of the subsequently harvested fruit, along with a decrease in the total fresh yield. The dry matter yield did not vary during the drying period, but the colour intensity of the fruit increased continuously. Early cessation of irrigation accelerated the drying rate and intensified fruit colour, but lowered the total dry matter yield.Removal of seeds, placenta parts and stalk after harvest increased fruit colour intensity but lowered yields.Leaving fruit to dry in the sun before harvest resulted in a considerable saving in transport and storage volume, as well in the amount of energy required otherwise to dry the fruit in the dehydration plant. It also opens up possibilities of once-over mechanized harvesting of high quality fruit.     

遵椒系列品种辣椒单果质量变化规律、校正系数及折干率研究

本研究以遵椒系列品种为材料,探索其单果质量变化规律、常规测产校正系数和折干率。结果表明:①从8月上旬始收期开始,每晚收1d,遵椒1号单果鲜质量会下降0.1534g,单果干质量会下降0.0132g;遵椒2号单果鲜质量会下降0.0905g,单果干质量会下降0.0157g;遵椒3号单果鲜质量会下降0.0882g,单果干质量的变化不会随采收期的推迟而显著下降。②由于遵椒系列品种前期营养充足,病虫害轻,单果质量较大,商品率高,而后期长势渐衰,病虫害加重,商品率下降,单果质量变小,从而导致常规测产产量与实际采收量相差较大,常规测产产量乘上校正系数才能得出接近于实际的产量,通过试验,遵椒1号的校正系数为0.4782、遵椒3号的校正系数为0.541、遵椒3号的校正系数为0.629。③遵椒系列品种辣椒折干率基本遵循前期低后期高的规律,遵椒1号平均为23.81%,遵椒2号平均为25.23%,遵椒3号平均为25.82%。     

厚皮甜瓜新品种红星的选育

红星是以自交系0801为母本,以金20-1为父本配制而成的中早熟厚皮甜瓜一代杂种,全生育期75～90 d（天）,果实发育期33～35 d（天）,植株长势中等,抗逆性强,田间表现高抗霜霉病,中抗蔓枯病,抗白粉病。果实高圆形,果皮光滑、亮黄色;果肉红色,肉厚4.0～4.5 cm,肉质脆甜,可溶性固形物含量15.5 %以上,平均单果质量2.0 kg,保护地适宜栽培密度为2 000株·（667 m²）^-1,每667 m²产量4 000 kg左右。适宜在华北及条件适宜的保护地栽培。     

The effect of paclobutrazol injected into the soil on vegetative growth and yield of Vitis vinifera L., cv. Thompson Seedless

Summary

Grapevines, cv. Thompson Seedless were treated with the plant growth regulator paclobutrazol in the spring of 1984. The treatments consisted of four soil application rates (including a zero control) of paclobutrazol on two phenological dates (budbreak and bloom). Vegetative growth, as measured by pruning weight, vine yield and fruit maturity characteristics, were determined in 1984 and in the next three growing seasons. There was no significant difference in vine yield between treatments at harvest in 1984; however, the fruit of vines receiving paclobutrazol at budbreak had accumulated less sugar at that time. Paclobutrazol application significantly (P < 0.01 ) reduced pruning weights in 1984 for all vines receiving paclobutrazol. Only the highest rate of paclobutrazol significantly reduced pruning weights in 1985. The number of clusters per vine and yield were significantly less for the treated vines than for the control ones in 1985 and 1986. Pruning weights in 1986 and yield in 1987 showed no significant differences between treatments. The results indicate that a single soil application of paclobutrazol was effective in reducing vegetative growth of Thompson Seedless grapevines for a period of two years if the rate of application was greater than 1.1 kg a. i. ha^-1. However, the adverse effect of this growth regulator on vine yield indicate that it would be of little practical use when applied via the soil to this seedless cultivar.     

西瓜新品种‘抗病948’

 ‘抗病948’为早中熟、优质、丰产西瓜新品种。该品种高抗西瓜枯萎病, 兼抗西瓜蔓枯病和炭疽病。果实高圆型, 单瓜质量5～8 kg, 开花至成熟约33 d, 果肉中心可溶性固形物含量13%以上, 瓤色浓粉红, 肉质细嫩松脆, 品质佳。产量45 t/hm² 以上, 适合苏、浙、沪、皖多阴雨地区小拱棚覆盖或露地栽培。     

Regulated deficit irrigation effects on yield,nut quality and water-use efficiency of mature pistachio trees

Summary

Regulated deficit irrigation (RDI) was evaluated on deep rooted, mature pistachio trees grown under high evaporative demand in the low rainfall southern San Joaquin Valley of California. The focus of this work was to assess the impact of deficit irrigation during various parts of the season with the goal of determining which period was most stress tolerant in terms of nut production. Pistachio nuts have a unique fruit growth pattern in which rapid kernel growth does not begin until about six weeks after full shell size has been attained. Our hypothesis was that irrigation could be reduced during this period with limited negative effects on production. The season was divided into three preharvest periods: leafout to full shell expansion (Stage 1), full shell expansion to the onset of rapid kernel growth (Stage 2), and rapid kernel growth to harvest (Stage 3). Water deprivation during Stage 1 applied 7.2% less water than the near-fully irrigated Control without any yield loss, based on mean values for the last “on” and “off” alternate bearing years of this study. Shell splitting (endocarp dehiscence) at harvest (a positive impact) was significantly higher (10.4% relative to the Control) but this was offset by a nut weight reduced by 9.4%. Stage 3 water deprivation (53% less applied water than the Control) significantly reduced nut size, shell splitting, mechanical nut removal by tree shaking, and yield, while increasing kernel blanking and abortion. Postharvest water deprivation (5.0% less applied water than the Control) had no significant negative effects on yield components. Six irrigation regimes that applied water at various rates were used to investigate Stage 2 behaviour. While there were no significant differences in yield components among these regimes, the best production occurred with deficit irrigation during Stage 2 at 50% of near-potential ETc during Stage 2 and 25% of near-potential ETc after harvest. This RDI regime saved about 180 mm of water (23.2% of the Control) and water use efficiency was significantly higher (4.69 versus 3.61 kg marketable fruit per mm water, for this RDI regime and the Control, respectively). We believe RDI during Stage 2 and postharvest is a viable irrigation strategy to save water while maintaining top yields of high quality pistachio nuts. Further work is needed to determine if the improved shell splitting harvest that occurred with Stage 1 stress can be exploited to improve grower profits.     

早熟加工番茄新品种屯河8号的选育

屯河8号是利用美国引进加工番茄品种分离选育的自交系N-375和N-47配制的早熟加工番茄一代杂种。该品种为自封顶类型,生长势强,果实长圆形,鲜红色,平均单果质量85 g,可溶性固形物含量 54 %,番茄红素含量136 mg·kg-1,从播种至始收94 d（天）左右,早熟,每667 m2产量6 000~7 000 kg,可作为早熟育苗移栽或直播品种栽培。