Genetic divergence in seedling trees of Persian walnut (Juglans regia L.) for various metric nut and kernel characters in Himachal Pradesh

The nature and magnitude of genetic divergence was assessed using non-hierarchical Euclidean cluster analysis in 229 seedling trees of Persian walnut growing naturally in four districts of Himachal Pradesh for 15 nut and kernel characters. Minimum and maximum values of coefficients of variability were recorded for nut width and kernel weight, respectively. All genotypes were grouped into 16 different clusters. The clustering pattern of walnut genotypes belonging to the same location revealed their distribution in more than one cluster showing non-parallelism between geographic and genetic diversity. Genotypes of clusters 5 and 8 were highly diverse from each other. Mean nut weight and kernel weight were highest in clusters 8 and 14, respectively. The highest mean kernel percentage and minimum shell thickness were observed in cluster 13. The highest mean value for fat was recorded in cluster 9 whereas cluster 3 had the maximum value of protein.     

Gas exchange and antioxidant response of sweet pepper to foliar urea spray as affected by ambient temperature

This paper analyses the effect of different air temperatures (10, 20 and 30 °C) on the response of sweet pepper plants (Capsicum annuum L. cv. Herminio) to foliar urea applications after growing plants for 20 day with and without nitrogen (N) applied to the growing substrate. Leaf CO₂ assimilation, chlorophyll fluorescence, root respiration, lipid peroxidation and antioxidative enzymes were analysed. Spraying plants with urea increased leaf CO₂ assimilation of N-deficient plants when applied at 20 or 30 °C, compared with non-sprayed plants. When plants were sprayed with urea at 10 °C chlorophyll fluorescence of leaves was similar to that of plants that were supplied with full N in the nutrient solution. Root respiration was not affected by urea sprays whilst leaf NO₃⁻ concentration was increased by urea but only when it was sprayed at 10 or 20 °C. Lipid peroxidation and ascorbate peroxidase in N-deficient plants were reduced significantly by urea sprays, especially when plants were sprayed at 20 °C with N-limitation in the growing substrate. This study shows that N-limitation in the growing substrate induces a temperature-dependant increase in the activities of antioxidant enzymes in leaves of pepper and applications of foliar urea can be optimised, when applied at the appropriate temperature, to partly replace the N supplied to the roots of sweet pepper.     

Rooting response of plum hardwood cuttings to IBA in relation to treatment duration and cutting moisture content

The rooting response of plum rootstock hardwood cuttings to 50, 500 and 5000 ppm IBA was influenced by the duration of treatment in the auxin solution, 18 min, 30 sec and 5 sec being needed to achieve similar levels of rooting at the respective concentrations.

A delay between collection and IBA treatment of cuttings, resulting in a partial water deficit, caused an increase in IBA uptake which was associated with increased rooting. For Myrobalan B a delay of 22 hours at 60 °F (15.5 °C) and 50% RH, leading to a 10% moisture loss, was optimal.     

Pollen germination as affected by pollen age in cherimoya

Cherimoya (Annona cherimola (Mill.)) is a subtropical fruit tree, which is cultivated in a good range of subtropical regions. In most of these areas the crop relies on hand pollination. However, following this practice, erratic fruit set is often produced, which could be related to problems in pollen handling. Indeed, very little is known of the time that the pollen remains viable and on which is the best stage to collect the anthers or pollen from the flower. The aim of this work is to evaluate pollen germinability prior and after anther dehiscence and also how the age of pollen affects pollen vigor, understood as speed of germination. Pollen samples at different times following anther dehiscence were germinated in vitro and in vivo. Pollen up to 90 min following dehiscence performed as well as freshly dehisced pollen. However, the pollen taken 120 min following dehiscence, showed a clear reduction in vigor and germinated much slower in vivo. To overcome this short pollen germinability, pollen was taken from anthers 30 and 5 h prior to natural anther dehiscence and compared with pollen taken at anther dehiscence and 20 h later. However, a reduction in germination rate was obtained in pollen taken prior to anther dehiscence. The narrow stage at which pollen can be collected together to its ephemeral germinability explains erratic results obtained following hand pollination in this crop and these results provide the clues for an adequate pollen handling.     

Sweet-potato productivity as affected by recurrent use of vines as planting-material

Yield performances of apical shoot cuttings of sweet potato (Ipomoea batatas) obtained from crops raised 2 or 4 times recurrently through vines, were compared with those obtained from tubers. The recurrent use of vines as planting-material did not show any marked variation in market-grade tuber yield, but it significantly decreased vine yield and increased weevil infestation in tubers. Cultivars ‘Cross-4’, ‘RS-5’ differed significantly in performance     

Flower and corm development in gladiolus as affected by photoperiod

Gladiolus plants cultivar ‘Spick and Span’ were grown in winter under natural short day (SD) or under long day (LD), with 4 hours low intensity light at midnight. Growth of the various organs was followed by periodic sampling. SD promoted flower development and advanced anthesis but reduced the final size of the flower. LD increased weight and size of leaves and flowers.Initial growth of the corm was similar under both photoperiods, but while corm growth continued throughout the growing-period under SD, it was checked under LD when flowers were developed at an enhanced rate and until anthesis. At this stage, the allocation of assimilates was directed towards the flower sink and away from the corm sink.Final corm weight was also promoted by LD. This is interpreted as an indirect effect due to increased photosynthesis of the larger LD plants. In non-flowering plants raised from cormels, SD specifically promoted corm growth, although no competing flower sink was present.It is concluded that photoperiod affects growth and development of gladiolus in two ways: directly — by affecting the partitioning of assimilates between the flower or the corm; and indirectly — by affecting the total photosynthates available to the plants by influencing foliage size and the total growth period.     

应用响应面法优化鲜核桃低温贮藏保鲜工艺北大核心CSCD

【Objective】In order to prevent the loss of nutrients and prolong the shelf life of fresh walnut during storage, the best preservation conditions of low temperature storage for fresh walnut were optimized. 【Methods】In this experiment, the fresh fruits of Qingxiang were selected as the test materias. Under the conditions of cold storage [temperature: (-1±0.5)℃, relative humidity: 70%-80%], the walnut kernel moisture content, seed coat color difference, peel color conversion index, peel browning index, fruit cracking rate and decay rate were evaluated, and the comprehensive indexes were calculated according to Hassan method. Then, single factor experiments were conducted on the number of 1-methylcyclopropene (1-MCP) preservative bags, the thickness of polyethylene (PE) bags, and the number of holes on the bags. 1-MCP was directly put into the PE bag. The response surface design was used to optimize the best preservation process parameters with the comprehensive scores as the response value. Finally, according to the best preservation process parameters, the fresh walnut fruits of Qingxiang were kept fresh for 90 days, and the comprehensive quality evaluation and sensory quality level were determined according to the consulting survey results of consumers (18-45 years old). The changes of fresh walnut flavor during the preservation period were analyzed by principal component analysis.【Results】 The best technology of low-temperature storage for 5 kg fresh walnut fruits was 1 bag (0.625 g) of 1-MCP, 40 μm PE and 1 holes on the bag (hole diameter 5 mm;fresh keeping bag 400 mm × 600 mm. The theoretical comprehensive score was 94.48. From the perspectives of sensory and flavor evaluation, the sensory quality level and comprehensive quality evaluation of fresh walnut stored at low temperature for 90 days under the best technology were less than grade 2, the color difference of seed coat could not be distinguished by naked eyes, and the flavor basically did not change, which indicated that the best technology of this experiment had a good preservation effect on fresh walnut.【Conclusion】 The results showed that the best low-temperature storage technology for 5 kg the Qingxiang fresh walnut is 1 bag of 1-MCP, 40 μm PE and 1 hole on the bag. The results of this study would provide a basis for low temperature storage of fresh walnut. © 2021, Office of Journal of the Fruit Science. All right reserved.     

Sex expression in watermelon as affected by photoperiod and temperature

The effect of environmental factors on sex determination of flowers of watermelon (Citrullus lanatus) was studied under controlled conditions. Short days (8 h) and a day temperature of 27° C increased the tendency towards female flowers. Day length of 16 h and a day temperature of 32° C inhibited the development of female flowers.     

套袋对果实品质影响的研究进展

综述国内外水果果实套袋栽培概况;套袋对果实贮藏品质、果实着色、果面光洁度、果实大小、病虫危害、农药残留、可溶性固形物和可滴定酸含量及果实硬度的影响等方面的研究进展。     

Nutrient shift in Parthenocissus tricuspidata seedling in response to soil water stress

A climate-controlled greenhouse experiment was conducted to determine the influence of soil water stress on the nutrient status of a climbing plant, Parthenocissus tricuspidata (Sieb.et Zucc) Planch. The results showed that water stress constrained N uptake more than P and K uptake in P. tricuspidata. Soil water supply significantly affected N efficiency ratio, but had no effect on P and K efficiency ratios. P. tricuspidata had low K concentration (<10 mg g⁻¹) in all its plant tissues, which allowed the plant to limit its stomatal opening and reduce its water loss. The study revealed that P. tricuspidata is able to adjust biomass distribution, nutrient uptake and nutrient use efficiency in response to soil water stress and that nutrient management for this plant under water stress should focus on N more than on P and K.     

不同浓度的IBA对猕猴桃组培苗生根的影响

用不同浓度的IBA诱导猕猴组培苗生根。结果表明：把组培苗直接接种于IBA浓度为0．7mg/L的生根培养中，不仅存活率高，而且诱导生根效果最好，单株生根数量及根总长均高于其余浓度。     

Chlorophyll fluorescence as affected by some superficial defects in stored apples

Summary

Chlorophyll fluorescence, skin coloration and surface contour were measured for apple (Malus domestica Borkh.) fruit with and without common storage and handling surface defects. Defects included C0₂ injury in ‘Empire’, bitter pit in ‘Jonagold’, superficial scald in ‘Cortland’, ‘Law Rome’, ‘Gala’ and ‘Red Delicious’ and bruising in ‘Cortland’. Measurements were made along a transect established on the fruit surface. The fluorescence parameters, minimal fluorescence (Fo), maximal fluorescence (Fm) and photochemical efficiency (Fv/Fm, where Fv = Fm - Fo) were relatively similar around the circumference of undamaged control fruit. Skin colour was not found to influence chlorophyll fluorescence. With the exception of bruises, there were marked changes in fluorescence in the areas where surface disorders or damage had developed. C02 injury and bitter pit reduced Fv/Fm, whereas superficial scald did not. However, scald symptoms were accompanied by a reduction in Fo and Fm. The reduction in Fo and Fm became more marked as scald symptoms intensified during post-storage holding at 22°C. Chlorophyll fluorescence may have some potential for sorting fruit having superficial defects.     

Flower-bud formation and shoot growth in apple as affected by temperature

Under controlled conditions, 3-year old ‘Golden Delicious’ and ‘Cox's Orange Pippin’ trees were exposed to 2 temperatures (high: 24° and low: 17° or 19° C) in various treatments in a 4-month period starting at full bloom. In general, shoot growth was reduced at the low temperature. For ‘Golden Delicious’ flowering did not respond to the various treatments; in ‘Cox's Orange Pippin’ it was stimulated at the low temperature.A rise in temperature from 17° to 24° C seven weeks before harvest, given to ‘Cox's Orange Pippin’ trees kept at 17° C from full bloom, reduced flower-bud formation and stimulated growth. A similar temperature increase applied to trees maintained at 24° C for 4–5 weeks after full bloom favoured flower-bud formation, but did not affect growth.The inhibitory effect of the high temperature on flowering is discussed in terms of an increase of the plastochron under the influence of gibberellins produced by the growing shoot tips.     

Growth of Rhododendron cultivars as affected by temperature and light

Summary

The purpose of this study was to investigate the adaptation of four Rhododendron cultivars to contrasting light and temperature conditions. Two evergreen rhododendron cultivars and two deciduous azaleas were grown for 112 d under short day (14 h) and long day (20 h) photoperiods combined with temperatures of 15 and 24°C. Additionally, these cultivars were compared for daylength extension at 24°C/long day under two irradiation treatments (incandescent lamps and fluorescent tubular lamps). The number of flushes of growth increased with increasing photoperiod and temperature in both evergreen cultivars and in R. canadense; azalea #89132 made only one flush in all treatments. In the evergreen cultivars the number of leaves per shoot in the first flush did not differ significantly between treatments, indicating that this character was predetermined by conditions during bud development. The number of leaves in later flushes increased with increasing photoperiod and temperature. The elongation growth of most flushes was also enhanced by longer photoperiod and higher temperature. High irradiation during photoperiodic extension further enhanced the growth. Azalea #89132 made more flower buds under high than low irradiation. The two evergreen cultivars differed in their growth habit. ‘Pohjola’s Daughter’ tended to continue growth in long days or at very high temperatures, and is thus predicted to thrive best in a maritime or semi-maritime cool climate. ‘Helsinki University’ responded to short daylength by ceasing growth regardless of temperature, and could be expected to perform successfully also in continental climates at latitudes around 45° N. R. canadense seemed to do best in a cool climate, but azalea #89132 should in time acclimatize in all kinds of climates within the limits of this study.     

加盟WTO对山东果品生产的影响及对策

根据山东省果品生产及贸易现状，分析了我国加入WTO后，山东省果品的优势及带来的冲击和问题，提出了山东省果品产业发展的对策。     

Greenhouse gas flux in a temperate grassland as affected by landform and disturbance

Much of the remaining native rangelands in Canada are topographically complex. The flux of greenhouse gases (GHGs) in rangelands of hummocky terrain has not been adequately studied, leaving a gap in the national GHG sources and sinks budget. The objectives of this study were to determine the effects of topography and mowing on carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) flux and to correlate these fluxes to abiotic and biotic factors. GHG flux was studied on six landform elements, including north-facing concave and, south-facing concave and convex, upland and depressions, in the Northern Mixedgrass Prairie of Canada over 2 years with mowing being imposed in early spring. GHG fluxes showed strong temporal variations, ranging from 3.0 to 40.4 kg CO₂–C ha^?1 d^?1, 0.1 to 2.6 g N₂O–N ha^?1 d^?1, and ?0.25 to ?0.01 g CH₄–C ha^?1 d^?1. GHG fluxes responded to changes in soil water and soil temperature across the landscape. The largest production of CO₂ was recorded in depression mainly due to its more favourable soil water conditions. Mowing enhanced CO₂ flux more than CH₄ and N₂O fluxes. Dominant plant species varied among the six landform elements, but using plant community type as the direct indicator for GHG emissions in grasslands may not always be reliable when precipitation is low. The net emissions of GHGs from Saskatchewan rangeland was relatively low, but the potential to increase emissions through changes in land management could be high. Our results suggest that in the Mixedgrass Prairie, best management practices for maintaining grassland health such as moderate grazing may also reduce GHG emissions.     

不同处理方法对套袋红富士苹果外观质量的影响

试验表明，富士苹果套袋前喷施50％轮纹宁可湿性粉剂600倍液，对提高苹果外观质量有较好效果，可以显著降低烂果率，改善着色，减少果锈和果面裂纹。果袋以小林双层果袋和山东省果树研究所生产的双层果袋效果最好。套袋时间以6月上旬最为适宜。     

Yield and quality of carrots as affected by soil moisture and N-fertilization

Summary

High yield and quality are important factors for growers of carrots (Daucus carota L.). The objective of this study was to determine optimum soil moisture and N-fertilization to maximize carrot yield and external quality (i.e. the quantity of split and forked roots). The experiment was carried out in a microplot field installation with three levels of soil moisture (75, 50 and 25 vol% available field capacity (AFC)) on a sandy and a loamy soil over the last 16 and 11 weeks of the cropping period, respectively. Two movable roofs covered with polyethylene foil were used to maintain the three soil moisture levels, which were measured in all combinations with two levels of nitrogen fertilization (0 and 150 kg N ha^-1). The highest total yields were reached at both soil types at 75 vol% AFC and 150 kg N ha^-1. The quantity of forked carrots was more affected by reduced soil moisture on the sandy soil than on the loamy soil. The mass fraction of split roots increased with increasing soil moisture on both soil types and a significant interaction was calculated between soil type and fertilization. The mass of split roots on the sandy soil was significantly increased by fertilization.     

涂凡士林防止核桃幼树（苗）冻旱抽条的研究

连续两年以当年播种幼苗、嫁接新梢为试材，11月上旬核桃落叶后，在其上均匀涂抹凡士林，进行防冻旱抽条试验，结果表明：经凡士林处理的一年生播种幼苗、接芽新梢与埋土处理的防抽条效果相近，抽条指数分别为2.8%、2.7%和2.3%，三者差异不显著；而不做任何处理的一年生播种幼苗的抽条指数为74.8%，表明涂抹凡士林能有效地防止核桃幼树发生冻旱抽条。