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.     

Soilless systems as an alternative to wild strawberry (Fragaria vesca L.) traditional open-field cultivation in marginal lands of the Tuscan Apennines to enhance crop yield and producers’ income

Yield and quality of wild strawberry (Fragaria vesca L.) cultivars ‘Regina delle Valli’ and ‘Alpine’ cultivated in soil, as the traditional production system, and in soilless (both in open air and protected environments), as an innovative and sustainable production system, were investigated in a marginal and inner area of the Pistoiese Apennine Mountains during two production seasons. An earlier marketable production was obtained in soilless culture, but total marketable yield was higher from plants grown in a traditional open-field environment. Fruits obtained from the protected soilless system were larger, but developed some mildew, had some visual defects, and revealed a reduced skin chroma index, flesh firmness, and total soluble solids content compared to fruits harvested from plants grown under direct sunlight, while no significant differences were observed in total titratable acidity and pH between growing systems. ‘Alpine’ was more suited to soilless protected cultivation, with a much higher yield compared to ‘Regina delle Valli’. Physicochemical properties of berries were not affected by the cultivar, but fruit quality changed with plant age and seasonal crop cycle. ‘Alpine’ fruits gained a greater sensorial preference, both in traditional soil and soilless culture.     

Effect of temperature on bulb growth capacity and sensitivity to summer sprouting in Lilium longiflorum Thunb.

The production of Lilium longiflorum bulbs in The Netherlands, with its cool climate, has been a problem because of unsatisfactory bulb growth and the risk of premature sprouting of the daughter bulbs (summer sprouting). To investigate the possibilities of breeding a type of L. longiflorum that can be grown under cool climatic conditions, a collection of 27 L. longiflorum cultivars from Japan, The Netherlands and the United States was tested, together with two Asiatic hybrids and a L. speciosum cultivar, under low phytotron temperatures (10, 14, 17°C) and in field experiments.‘Mount Everest’, ‘Saeki’, ‘Indian Summer’ and ‘White American’ were among the best L. longiflorum cultivars, with less than 20% summer sprouting and good bulb production. This was in contrast to ‘Hinomoto’, ‘Ace’ and some American introductions, which showed more than 60% summer sprouting and low bulb production. The lower the phytotron temperature, the more summer sprouting occurred. The differences observed between the cultivars in the field experiments were in agreement with those observed in the phytotron. The genetic variation proved large enough to start a breeding program for L. longiflorum adapted to cool climate conditions.     

Berry yields of two Finnish sea buckthorn cultivars under organic farming methods

Summary

The effects of different organic farming methods on berry production by two Finnish sea buckthorn (Hippophae rhamnoides L. ssp. rhamnoides) cultivars, ‘Terhi’ and ‘Tytti’, were studied in field experiments over 4 years at Merikarvia, western Finland. Four organic fertilisers, five mulches, and two land contours were used. Two experiments were conducted. In the first, fertilisation experiment, the fully-crossed effects of four different fertilisers and two land contours were tested for both cultivars. In the second, mulch experiment, the fully-crossed effects of five different mulches and two land contours were tested for the cultivar ‘Tytti’. Some sea buckthorn bushes produced a small number of berries in the second growing season. According to the three-way interactions, the effect of fertiliser on yield depended on the land contour in ‘Terhi’, but not in ‘Tytti’. Apatite increased yields in bushes grown on flat land. Yields increased in the third and fourth growing seasons, when ‘Terhi’ produced larger berries and yields than ‘Tytti’. ‘Terhi’ had a higher yield on ridged beds than on flat land. Berry size was larger on ridged beds compared to flat land in both cultivars. The effect of mulch depended on the land contour in the second and fourth growing seasons. In the second growing season, straw mulch increased berry production on the flat land compared to the other mulches. In the fourth growing season, a plastic mulch increased yields compared to organic mulches. The results of this experiment provide information on ways to improve sea buckthorn berry yields when organic farming methods are used.     

Production of high yielding red raspberry long canes in a Northern climate

Techniques for the production of raspberry long canes with high yield potential were studied on a research station and in two commercial nurseries in South Norway. Potted ‘Glen Ample’ plants were grown in the open and in polyethylene greenhouses during two seasons in order to optimize cultural practices. Dates of propagation and transfer to the production sites were varied. Following cold storage from December to early June, the canes were tipped (cut) at 160 cm height and grown in open plastic tunnels in the fruiting season for the evaluation of growth and yield performance. Remarkable berry yields of 1.5–3.8 kg per plant (cane) were regularly achieved. When grown in the open, later starts than June 1 (June 15 and July 1) successively reduced yields. On the other hand, an earlier start involves risks of growth cessation due to low spring temperature. When grown in greenhouses, high yields were still possible when plants were transferred from propagation conditions as late as July 1, although optimal yields of nearly 4 kg per plant were obtained with transfer on June 15. In a year with unusually high summer temperatures, the yields of canes produced in the open and in greenhouses did not vary significantly, whereas in the second year with normal summer temperatures, canes produced in greenhouses consistently out-yielded those produced in the open by about 1 kg per cane. Regression analyses revealed that high yields were associated with fruiting cane architecture traits such as cane height, number and length of laterals, and a low proportion of dormant buds. The single most important component was lateral length which alone accounted for 82% of the yield variation. Since lateral lengths increased from the shoot tip towards the base, cane heights in excess of 2 m are required for the attainment of top yields as the uppermost nodes with short and low-yielding laterals then can be eliminated by tipping.     

Ergebnisse des Naumburg-Pillnitzer Birnenunterlagenzuchtprogrammes

The aims of the German pear rootstock breeding programme were to improve the propagation ability, dwarfism, resistance to biotic and abiotic damage, sufficient anchorage, positive influence on yield and fruit quality of the cultivars, and free of suckers and burr knots. Results were collected from long-term randomised trials and from field tests in farms under different production conditions. Approximately 6000 seedlings of cross combinations between different wild species and wild species with known pear cultivars were grown. Finally, seven clones were selected (Pi-BU 1 to 7). The new Pillnitz pear rootstocks are moderately to easily propagated in stoolbeds, are more frost resistant against winter frost than quince rootstocks, and the growing capacity is intermediate between quince and seedling. The rootstocks are easy to propagate from green cuttings and in vitro. Pomological testing with ‘Clapps Favourite’ was done under a minimal pruning regime to evaluate the cropping potential. Compatibility with several cultivars was satisfactory. Promising clones were quickly multiplied using in vitro propagation for test plants. The original propagation material for multiplication at nurseries was never multiplied in vitro. More results are needed. To achieve this a trial commenced in Germany in 2002 to test the new pear rootstocks Pi-BU 2 and Pi-BU 3 together with the new rootstocks Pyrodwarf from Germany, S 1 from Poland, and Fox 11 from Italy using three cultivars at nine sites.     

Yields and the extent and causes of damage in cauliflower,bulb onion,and carrot grown under organic or conventional regimes

Summary

The effects of organic vs. conventional growing practices on yield, pest attacks, N uptake, and NO₃^– contents of three vegetable crops were examined. A range of cultivars of cauliflower (Brassica oleracea L. cv. Botrytis), bulb onion (Allium cepa L.), and carrot (Daucus carota L.) were grown organically and conventionally in a sandy-loam soil. Ranking of cultivars according to yield and susceptibility towards insect attack and fungal disease was similar in the two systems. Yields of cauliflower and onion were 20% and 45% higher, respectively, when grown conventionally. No differences in carrot yields and discard rates were observed between the two systems. Generally, the reasons for discarding varied between the two systems. In organically grown cauliflower, damage by slugs was the main reason for discarding, with 9% discarded, while hollow stem was more prevalent in conventionally grown cauliflowers, where 7% was discarded. No statistically significant differences were found between discard rates or causes in bulb onions grown organically or conventionally. Conventionally grown carrots were significantly more damaged by carrot root fly with 5% of carrots discarded, even though the flies were also present in the organic system. In contrast, more carrots with morphological defects were seen in the organic system, where 29% were discarded. The lower yields in organically grown vegetables can be explained mainly by the management practices specific to the organic system that are designed to facilitate weed and pest management. In addition, inadequate early nutrient supply provides a possible explanation for the lower yields in organically grown cauliflowers and onions, as well as the lower planting density of onions.     

核桃种质资源研究进展

核桃是世界范围内的重要果树,无论面积和产量在各类干果中居首位。种质资源是核桃品种选育的基础,对国内外核桃种质资源研究工作进行了全面综述,包括国内外种质资源研究现状、分类和利用现状、品种类型适应性研究等方面,并对美国国家种质资源圃收集及利用情况进行了介绍。提出在今后的核桃种质资源研究工作中,应充分发挥我国资源丰富的优势,加强和利用不同特异类型及生物技术开展核桃的种质资源研究。     

The impact of within-row spacing on the productivity of glasshouse roses grown in two planting systems

Summary

Stem yield and quality of roses for cut flower production were evaluated. The plants were grown in two planting systems as an alternative to the traditional ``vase-shaped'' system. In the trellised system, two cultivars of Rosa hybrida (cvs Gabrielle and Kardinal) were planted in a commercial glasshouse in 3.m sections of bed. Within-row spacing was varied to give 6–16 plants m<sup>–2</sup>. After a three-month establishment phase the basal shoots were bent to an angle of 308 above horizontal and restrained with a trellis wire. Flowering shoots sprouting from axillary buds along a basal shoot were harvested at their lowest node, minimizing branching. Compared with ``vase-shaped'' rose plants at the same density, trellised roses produced 24% more basal shoots, 46% more flowering shoots (cv. Gabrielle) and approximately 46% less blind shoots per plant over five months. Phenotypic variation was greater in cv. Gabrielle than in cv. Kardinal in response to within-row spacing, as indicated by the number of basal shoots formed. Within-row spacing, over the range explored, did not affect the number of flowering shoots per basal shoot. Trellising rose plants increased stem yield and quality, but production over the long-term requires further investigation. The single shoot planting system contained a mixed population of single-stemmed rose plants of Rosa hybrida (cvs Gabrielle and Gerdo). It was grown in a field over a range of within-row spacings to give 20–105 plants m^–2. Over three harvests, increasing the number of plants by 10 plants m^–2 reduced the proportion of flowering shoots by 4.4%. Expressed on a unit area basis, a five-fold increase in plants m^–2 produced a three-fold increase in stem production.     

我国薹用不结球白菜主栽品种现状及育种趋势

薹用不结球白菜(薹菜)以菜心、红菜薹为代表,起源于中国,在岭南和长江流域有悠久的栽培历史,近年来以迟菜心、秋香828、中薹1号为代表的专业薹菜的选育及推广带动了新型薹菜品种的发展,未来丰产、优质和抗性仍然是新品种选育的3大主题,但能够满足周年供应、满足规模化种植、适应机械化种植采收的品种将更受欢迎.薹菜将向专业化、优质...     

Options for Management of Fusarium Wilt of Strawberry in California

ABSTRACT

The emergence of Fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae, as a problem for strawberry production in California has been associated with delivery of fumigants to beds through drip-lines rather than flat-fumigation of an entire field. Our research shows that bed fumigation fails to eliminate propagules of the Fusarium wilt pathogen, which remain particularly abundant in bed shoulders at a depth of 30 cm. Controlled environment studies confirmed that inoculum at this depth could cause disease. Screening of currently grown strawberry cultivars documented a wide range of susceptibilities to Fusarium wilt, with some being highly resistant.     

Management of Radopholus similis and Helicotylenchus multicinctus in Ratoon Banana Grown under High Density Planting Systems

Cultivation of banana in modified high density planting systems with more crop cycles is widely followed in Gujarath, Kerala, and Tamil Nadu states of India due to its higher productivity and lower cost of production. In this system, three suckers were planted in a pit spaced at 1.8 × 3.6 m accommodating 1542 mats or 4626 plants/ha. Nematode pests remain a threat to this modified system of banana cultivation especially in ratoon cycles. Investigations were undertaken in ratoon banana grown under a high density planting system on effect of cartap hydrochloride 4G, carbofuran 3G, Glomus mosseae, Pseudomonas fluorescens, Sunhemp, Coriander, Marigold, and neem cake on control mixed populations of burrowing nematode, Radopholus similis, and spiral nematode, Helicotylenchus multicinctus. Application of cartap hydrochloride @ 20 g/mat twice at the time of ratooning followed by 4 months later gave greater control of R. similis and H. multicinctus in soil and root with lesser damage in root and corm than untreated plants. The banana plants in this treatment were taller with a larger number of leaves and thicker pseudostem girth resulting in 33.4–37.3% more bunch yield than other treatments including control. The effect of cartap hydrochloride at 20 g/mat was similar at higher dose (40 g/mat) but significantly superior than 10 g/mat dose. Carbofuran 3 G @ 80 g/mat twice, Neem cake @ 250 g/mat twice and growing Marigold around the basin and incorporating before flowering were the next best treatments on nematode control and growth promotion. The P. fluorescens and G. mosseae applied were not established well and caused lesser nematode control in ratoon banana grown under high density planting system. Hence application of cartap hydrochloride @ 20 g/mat or neem cake @ 250 g/mat or growing Marigold around the basin and incorporating before flowering could rectify the damage caused by R. similis and H. multicinctus in ratoon banana crops growing under a high density planting system.     

Effect of photoperiod on flower bud initiation and development in myoga (Zingiber mioga Roscoe)

Selection of suitable production locations in Australia and New Zealand for production of myoga (Zingiber mioga Roscoe) has been limited by lack of information on climatic influences on flowering. This study focused on photoperiod as potential production sites within Australia differ considerably in daylength due to the geographical range. The two cultivars available in Australia (Inferior and Superior) were examined in this trial due to previously observed differences in vegetative and reproductive development.Plants grown under long-day conditions (16 h) and short-day conditions (8 h) with a night break produced flower buds, while those under short-day conditions (8 h) did not. The failure of plants under short-day conditions to produce flower buds was due to abortion of developing floral primordia rather than a failure to initiate inflorescences. It was concluded that for flower development in myoga a qualitative long-day requirement must be satisfied, but that flower initiation was day-neutral.Short-day conditions resulted in abortion of flower primordia, premature senescence of foliage and reduced foliage dry weight in both cultivars. Early senescence and low flower bud yield of the Inferior cultivar, but not the Superior cultivar have been observed in crop evaluation trials in Southern Australia and New Zealand. Differences in critical photoperiod between the two cultivars may explain this observation and therefore photoperiodic requirements may be an important consideration in site and planting date selection for different cultivars.     

硅对甜瓜早熟性及光合特性的影响*

 在水培条件下, 以不同熟性甜瓜品种为材料, 研究了适度低温条件下, 营养液中硅对甜瓜生长、光合作用以及早熟性的影响。结果表明, 供硅处理可以增加植株根冠比, 提高地上部与地下部硅含量。与缺硅植株相比, 施硅可以明显地提高两个品种叶绿素含量, 不同程度地增强光合速率, 降低蒸腾速率。使得甜瓜品种&#1048578; Starship 开花期提前, 坐果节位降低,化果率明显下降, 从而显著地提高早期产量。     

Effects of irrigation frequency and scheduling on fruit production and radial fruit cracking in greenhouse tomatoes in soil beds and in a soil-less medium in bags

The effects on yield and radial fruit cracking of 2 media (soil in beds and soil-less medium in bags) and 2 drip-irrigation frequencies (once and 4 times daily) were determined for 4 greenhouse tomato (Lycopersicum esculentum L. Mill.) cultivars. For plants grown in soil-less medium, 2 tensiometer-controlled, drip-irrigation scheduling methods were compared. ‘Michigan’—‘Ohio’ hybrid fruit cracked significantly more than the 3 remaining cultivars, but did not differ in production of total and No. 1 fruit. The amount and severity of fruit cracking was least from the soil-less, bag-cultured plants. Total mean fruit weight was greatest from soil-grown plants. Although no differences in cracking occurred in the fruit from soil-less, bag-cultured plants, those whose irrigation was based on soil-less medium tensiometer readings produced lower total mean fruit weight than those whose irrigation was based on soil tensiometer readings. Number and weight of defective fruit was lowest from plants grown in soil-less medium and whose irrigation was based on soil tensiometer readings, and greatest from soil-grown plants. Fruit cracking was reduced by increasing the irrigation frequency from 1 to 4 times daily.     

The effect of split-root salinity stress on tomato leaf expansion,fruit yield and quality

Summary

A crop-scale experiment between March and October 2000 investigated the effects of split-root salinity stress and rooting volume on the expansion of leaves, fruit yield and quality in two standard round fruited cultivars of tomato (Lycopersicon esculentumMill) Solairo and Espero, grown in rockwool. To implement the treatments, a split-root method was utilized whereby different levels of salinity (expressed as EC), adjusted by the addition of NaCl, was administered to two halves of a root system. The split-root high EC (2.8/8.0 dS m^–1) treatment enhanced fruit quality by increasing the concentrations of sugar, acid, total soluble solids and reducing the incidence of visual defects such as uneven ripening and gold-spot. Split-root high EC did however reduce leaf area that corresponded with low K concentration in the leaf tissue. The split-root method utilized doubled the rooting volume compared with the standard single rockwool slab, but this extra rooting capacity had no detectable effect on leaf expansion, yield or fruit quality. Although there was little impact on yield for ten weeks after the imposition of the high EC split-root treatment, mean reductions in weekly yield occurred thereafter and were of the order of 9 and 13% for ‘Solairo’ and ‘Espero’ respectively through to the end of the experiment. The fall in yield was due, in part, to a decrease in fruit size. Whilst water uptake was reduced it was unclear how the effects on leaf growth and fruit yield were mediated in the shoot. Possible processes that coordinate responses to root-zone salinity stress are discussed. The potential use of the split-root system in commercial production is considered.     

Effects of suboptimal low temperature on yield,fruit appearance and quality in muskmelon (Cucumis melo L.) cultivars

Summary

The effects of suboptimal low temperature were investigated on an array of yield, fruit appearance and fruit quality characters in 23 cultivars of melon, Cucumis melo L. The cultivars were grown in two temperature regimes: (I) a heated greenhouse (T1) with temperatures similar to those used in commercial cultivation in the winter in Israel; and (ii) an unheated greenhouse (T2) that had significantly lower night temperatures than T1. Significant differences were found among the cultivars in all characters. Plants from T2 showed an extended fruiting period, more fruits and higher total yield but smaller and lighter fruits than in T1. Fruits from T2 also had significantly more netting and higher amounts of total soluble sugars (TSS), sucrose and fructose than fruits from T1. Hybrid cultivars showed significantly higher electrical conductivity (EC), pH, acidity, TSS, sucrose, fructose and total sugars than open pollinated cultivars. Three trends were found among the characters in respect to the performance of the cultivars between T1 and T2: (a) most cultivars had significantly higher amounts in T2 than T1 (fruit/plant, yield/plant and fructose); (b) only cultivars with amounts below the pooled mean in T1 had higher amounts in T2 (percent dry weight, sucrose, TSS and total sugars); (c) no trend was found between T1 and T2 (mean fruit weight, pH, EC, glucose). Suboptimal low temperatures, when used appropriately, can aid in improving fruit quality.     

Relationship between light,fruit and leaf mineral content with albinism incidence in strawberry (Fragaria x ananassa Duch.)

A study was conducted in strawberry to establish a relationship between shading, mineral nutrient of leaves and fruits with albinism incidence. Plants grown under shade produced albino fruits in higher proportion than those grown in open fields. Similarly, plants under shade produced smaller sized fruits and have lower fruit yield. Among cultivars, Etna had highest incidence of albinism (49.6%) and Sweet Charlie the lowest (14.4%). Dry matter content (%), concentration of five major nutrients, viz. N, P, K, Ca, Mg, S and N:Ca and K:Ca nutrient ratios did not differ significantly in the leaves of plants producing normal or albino fruits. However, in contrast, the concentration of K was notably higher (1.97 mg g⁻¹ fresh tissue weight) and that of Ca was lower (0.098 mg g⁻¹ fresh tissue weight) in albino fruits than normal ones. Consequently, the ratios of N:Ca (11.34) and K:Ca (20.08) were higher in albino fruits than normal ones. Cultivars also differed widely in respect to dry matter (%), mineral content and nutrient ratios. Thus, it appears that lower light intensity favours the development of albinism in strawberry, and it seems that calcium is not the basic cause of albinism, but increased vigour associated with overuse of N and K might be positively associated with it.     

Characterization for yield, fruit quality, and molecular profiles of lemon genotypes tolerant to ‘mal secco’ disease

‘Mal secco’ is a serious disease of lemon and other citrus species, reduces lemon production, and limits the use of susceptible cultivars especially in the Mediterranean countries, against which there is no effective management system to control the disease. The objective of this study was to determine yield efficiency, tree and fruit characters, and molecular profiles of the selected promising genotypes in lemon breeding program to develop ‘mal secco’ tolerant lemon cultivars. After 4 years of evaluation, ‘Tuzcu 894’, a progeny of ‘Finike Yerli Yuvarlak’ and ‘Kutdiken’, was designated as promising genotype with high yield, fruit weight, juice content and low seed number contrary to ‘Kutdiken’ as control. ‘Tuzcu 8911’ was suitable for dense planting having the highest yield in CV. In addition, these two promising genotypes survived after many years being subjected to artificial and natural P. tracheiphila infections and harsh winter temperatures, which were attractive to the citrus industry. Molecular analysis, as assessed with 11 inter-simple sequence repeats (ISSR) primers, indicated that ‘Tuzcu 09 Aklimon’ and its selections, ‘Tuzcu 896’, ‘Tuzcu 897’ and ‘Tuzcu 898’, were distinct from the other genotypes with similarity value of 0.82. Genetic variation among the other lemon genotypes was low and some of the genotypes were identical. It was concluded that variations in the agronomical characters are mainly due to mutations.     

Evaluating variability of root size system and its constitutive traits in hot pepper (Capsicum annum L.) under water stress

The importance of root size system has long been recognized as crucial to cope with drought conditions. This investigation was conducted to: (i) evaluate the variability in root size system of hot pepper at maturity; (ii) estimate the effect of root size system on yield under drought conditions; and (iii) effect of water stress on xylem vessel development and total xylem cross-sectional area in roots of hot pepper cultivars. Twelve diverse hot pepper cultivars were grown in wooden boxes with two different water treatments, normal and in 50% water application as water deficit condition. Mean primary root length (PRL) showed a significant positive correlation with final fruit yield at normal as well as stressed condition. Total dry mass of fruit was reduced by 34.7% in drought treatments (DI) compared to full watered treatment (FI). At harvest, water-stressed plants had 21% lower root dry weight mass but higher root:shoot ratio other than FI. PRL, lateral root density, total xylem area per root cross-section showed a significant positive relationship with fruit yield. Also, lateral root density was higher in cultivars with higher xylem density, particularly in tolerant cultivars. Lateral root density (r = 0.847, P < 0.001) and total xylem cross-sectional area in root (r = 0.926, P < 0.001) were tightly related with total biomass production. The importance of root traits contributing to withstand drought in hot pepper is discussed.