Effects of biennial cropping and controlled shoot density on yield performance and fruit quality in red raspberry (Rubus idaeus L.)

Effects of annual versus biennial cropping with varying shoot densities on plant structure, berry yield and quality were studied in ‘Glen Ample’ raspberry over a period of four seasons (two cropping years). In the vegetative phase, primocane height and internode length were larger in the annual than in the biennial cropping system. These parameters as well as Botrytis infestation increased with increasing shoot density. In both cropping years, berry yields per unit area were about 20% higher in the biennial cropping system, whereas yields per shoot were not significantly different in the two systems. In both cropping systems, yields per shoot strongly declined with increasing shoot density, while yields per metre row increased slightly. Regardless of cropping system, yields per metre row did not increase with increasing shoot density beyond eight shoots per metre. The concentrations of dry matter, soluble solids, titratable acidity and ascorbic acid as well as the intensity of juice colour all declined with increasing shoot density. We conclude that under controlled shoot density conditions, there is little scope for biennial yield increases that fully compensates for the lost crops every second year. However, the system greatly facilitates berry harvest and eases plant disease pressure.     

高产优质耐割茴香新品种“德农1号”的选育

“德农1号”是从德州茴香原始群体中选择优良单株,经系统选育而成的高产、优质、耐割茴香新品种.全株绿色,株高41.3 cm,叶7片,叶长40.6 cm,叶柄长23.8 cm,叶距小;生长较快,耐密植,正常情况下播后45 d,即可收割,单茬产量1 500 kg/667m2左右,全年总产量7 000kg/667m2,全株可食率为94％;抽薹迟,香味浓,品质优,精油含量为17.3 mL/kg DW,维生素C含量为421.6 mg/kg;再生能力强,全年可连续收割5～6次;耐寒性强,可耐3℃以上低温.     

分株和遮荫对花叶芒生长的影响

 盆栽条件下研究了分株和遮荫对观赏植物花叶芒(Miscanthus sinensis‘Variegatus’) 生长的影响, 为种苗快速扩繁和应用配置提供技术依据。分株试验有4个处理, 初始分蘖数分别为2～3、5～6、10～12和20～23个/盆, 结果表明初始分蘖数对植株生长有明显影响, 分株生长6个月后, 植株的茎数、花序数、冠幅和地上生物量随初始分蘖数的增加而显著提高, 但对植株高度没有影响。初始分蘖数为20～23个/盆时, 繁殖系数最低, 仅为2.1, 而初始分蘖数为2～3个/盆时繁殖系数最高, 为6.7, 是前者的3.2倍。通过覆盖不同层数的黑色尼龙网形成了4个遮荫度, 分别为0, 25% , 50%和75%。遮荫度对花叶芒的生长有显著的影响, 25%~50%遮荫度下, 花叶芒的株高、茎数、花序数、地上和地下生物量以及叶绿素含量都显著高于全光照条件下的, 但遮荫度增加到75%时, 这些指标又明显降低, 由此得出25% ～50%的遮荫度适合花叶芒生长, 高于50%的遮荫度不利于其生长。     

The effect of planting date and plant density on nitrogen uptake and nitrogen harvest by Brussels sprouts

Summary

Single and combined effects of three planting dates and three plant densities on nitrogen uptake and nitrogen harvest by Brussels sprouts (Brassica olerácea var. gemmifera) were studied in field experiments. The total amount of nitrogen taken up by the crop at harvest ranged between 220 and 325 kg ha^–1. Although final crop dry matter decreased, total nitrogen uptake was not lower when planting was delayed. This resulted in increased nitrogen concentrations both in the total crop and in the harvested product. Forty to fifty per cent of the nitrogen taken up by the harvest was removed from the field with the product. Within the range of 2.7 to 4.4 plants per m², plant density had no effect on final nitrogen uptake nor on the amount of nitrogen harvested with the product. The results indicate that nitrogen fertilizer recommendations should take planting date into account, because with delayed planting less dry matter will be accumulated with a corresponding lower nitrogen requirement. There was no interaction of effects of planting date and plant density on nitrogen uptake.     

Effects of development,temperature, and calcium hypochlorite treatment on in vitro germinability of Phalaenopsis seeds

There are no standardized procedures for sanitizing orchid seeds for propagation by tissue culture and there is insufficient information about the optimum stage of orchid seed development for best germination. Phalaenopsis amabilis flowers were hand-pollinated and fruits harvested 90, 105, and 120 d after pollination (DAP) for seed developmental analysis. Embryo cell number per seed was counted after staining with 4′-6-diamidino-2-phenylindole and viewing through a confocal microscope. Germination percentage and cell number per embryo increased from 14 to 61% and 41 to 66%, respectively, during fruit development from 90 to 120 DAP. Seeds from mature, browning (∼140 DAP) Phalaenopsis Sogo Lit-Angel and Phalaenopsis spp. breeding line 9450 seed pods failed to germinate until frozen at −196, −80, or −18 °C and thawed or chilled at 4 °C for 10 d. Germinability in 140 DAP seeds was correlated with cracked testa after freezing and thawing. P. amabilis seeds were treated with 0, 5, 10, or 15% calcium hypochlorite (CH) for 5, 10, or 15 min. Ninety six percent of untreated seeds from 90 DAP fruit produced protocorms within 40 d after sowing (DAS). Exposing seeds to 5% CH for 10 or 15 min decreased germination to 85 and 73%, respectively. Exposure to 10 or 15% CH for 5, 10, or 15 min produced seed germination percentages of less than 40%. Protocorms developed root hairs and shoot primordia by 50 DAS and an average of one leaf and root by 85 DAS after treatment with either 0 or 5% CH. Higher concentrations delayed or inhibited protocorm development. Green fruits 120 DAP produced the highest percentage of protocorms, while ∼140 DAP seeds from browning fruit were dormant but cold treatments increased germination.     

The effect of the time of taking side shoots on the regulation of fruit size in glasshouse-grown tomato crops

Summary

Young tomato plants were transferred to heated glasshouse compartments on 9 December at a density of 2.04 plants m-2 and grown as a conventional long-season tomato crop. Beginning in either the third, fifth, seventh or ninth week of the year, every other plant was allowed to retain one side shoot so as to increase the effective plant density to 3.06 plants m-2. Control crops were grown throughout at both the initial and the final densities. Two different patterns of taking the side shoots were tested in two sub-treatments: taking the required number of side shoots in four tranches over a period of six weeks was neither significantly better nor worse than taking them in two equal tranches, four weeks apart. The main effect of adding side shoots was to increase the number of fruit harvested per m-2, as compared with a control crop grown throughout at the initial density of 2.04 plants m-2. However, these additional fruit were not harvested until at least 80.d after the first side shoots had been allowed to grow. When side shoots were taken as early as week 3, a high proportion of the marketable fruit were in the preferred size (viz.47to57.mm in diameter, 50 to 90.g in weight, UK grade D) in all harvest periods. Thus, the additional side shoots enabled the crop to bear extra fruit and when the side shoots were taken early, the production of additional fruit coincided with the time when both the quantity of solar radiation incident per day and the concomitant assimilate production were increasing rapidly. Consequently, the supply of assimilates and the numbers of fruit available per m-2 were better matched for the purpose of continually producing fruit of one size. However, the presence of side shoots tended to reduce the number of marketable fruit carried on each truss. The addition of side shoots increased leaf area index and also significantly increased total fruit yield. The increased area of foliage served to shade more fruit from the heating effects of incident solar radiation and a smaller proportion of marketable fruit was downgraded to Class II in all side-shoot treatments. In general, the means of the four successive side-shoot treatments provided a graded series between those of the fixed low-density and the fixed high-density control treatments.     

Effect of plant density and macronutrient nutrition on Delphinium shoot cultures

The effect of shoot density on the uptake of macronutrients from MS medium and growth rates of Delphinium shoot tissue cultures was determined. Multiplication rates and uptake of phosphate, nitrate and sugar per shoot increased with decreasing shoot density. Increasing the concentration of total nutrients significantly increased both fresh weight gain and multiplication rate at the high plant density (15 shoots 50 ml'1 medium) usually used for micropropagation. However, increasing the phosphate concentration (phosphate being the nutrient most rapidly depleted in the medium) resulted in higher fresh weight only, while the multiplication rates of shoots remained similar.     

In vitro micropropagation of the ornamental prickly pear cactus Opuntia lanigera Salm–Dyck and effects of sprayed GA3 after transplantation to ex vitro conditions

We established the conditions to micropropagate the ornamental prickly pear cactus Opuntia lanigera Salm–Dyck through axillary shoot development from isolated areoles. For the shoot proliferation stage different explant orientation (vertical and horizontal), type of cytokinin (BA, DAP and K), and concentrations (0, 1.25, 2,5, 5.0 and 7.5 mg/L) were evaluated. Media [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco cultures. Phys. Plant. 15, 473–497: 50 and 100%], and carbohydrate concentration (0.25, 0.5, 0.75 and 1.0%) were studied to optimize individual shoot growth and elongation. Following micropropagation and plantlet acclimatization, the effects of GA₃ on plant growth were determined by spraying a series of increasing concentrations (0, 150, 300 and 450 ppm). A reliable and efficient protocol of micropropagation was established for this particular plant species. The greatest propagation ratio (shoot proliferation) was obtained when explants were cultured in vertical orientation (4.975 shoots per explant) as compared to horizontal position (3.692 shoots per explant). The addition of BA to the media resulted in increased shoot number per explant (8) in comparison to K and DA, which produced only 2 shoots in average. However, after 42 days of culture, significantly higher shoot length was obtained with DAP (14 mm) compared to K and BA (4 mm). After the shoot proliferation stage, an elongation subculture was performed prior rooting in which shoot growth was enhanced when crowns of shoots were cultured in 50% of basal salt formulation of Murashige and Skoog (1962) and low sucrose concentration (2.5 and 5%). Exogenous application of GA₃ after plantlet acclimatization on glasshouse conditions increased spine-hair (developed from areoles in young plants) length as part of short-term effects. However, significantly higher values were obtained in plantlets treated with 300 ppm of GA₃ when compared with the rest of the treatments. At the end of the study, the most important long-term effect produced by GA₃ was the suppression of total shoot growth. The micropropagation protocol described here and the conditions to grow the plants through fertigation plus the application of GA₃ that induced changes in the phenotype may be used in commercial exploitations to regenerate 12,500 plantelts in average after 12 months of culture and produce healthy plants with better ornamental characteristics and higher commercial value.     

华晶七号小果型无籽西瓜配套栽培技术研究

为了探索适合华晶七号小果型无籽西瓜的优质高效栽培技术,进行育苗期、栽培密度、整枝方式等方面的试验研究。结果表明,华晶七号的最佳播期日光温室早春栽培于12月中旬育苗,翌年1月下旬或者2月初移栽,3月上中旬授粉,4月中旬开始采收。塑料大棚早春栽培于元月初育苗,2月中下旬移栽,3月下旬至4月上旬授粉,5月上旬开始采收;栽植密度和整枝方式2000株/667m2、双蔓整枝;留果节位在第2、3朵雌花。     

微生物菌肥对大棚辣椒生长及产量的影响

摘要：为研究微生物菌肥在辣椒上的应用效果，在大棚辣椒育苗期至生长期施用3种不同微生物菌 剂，研究其对辣椒生长势、产量、品质、抗病性等指标的影响。结果表明：微生物菌肥处理（苗期施用 根际益生生根菌50 g/盘，幼苗出圃前至采收期使用根际益生菌II号1 000～1 200倍液喷雾9次，缓苗期至采 收期每667 m2 每次使用根际益生菌IIII号60 g，随灌溉水灌根10次）可提高辣椒生长势，增强抗病性；与对 照相比，微生物菌肥处理的辣椒开花、结果较早，采收期延长了10 d，单果质量、667 m2 产量和效益及果 实还原性糖含量分别提高16.4%、10.6%、35.37%、57.7%，且均达显著差异水平。     

Stabilization of pH in solid-matrix hydroponic systems

2-[N-morpholino]ethanesulfonic acid (MES) buffer or Amberlite DP-1 (cation-exchange resin beads) were used to stabilize substrate pH of passive-wicking, solid-matrix hydroponic systems in which small canopies of Brassica napus L. (CrGC 5-2, genome : ACaacc) were grown to maturity. Two concentrations of MES (5 or 10 mM) were included in Hoagland 1 nutrient solution. Alternatively, resin beads were incorporated into the 2 vermiculite : 1 perlite (v/v) growth medium at 6% or 12% of total substrate volume. Both strategies stabilized pH without toxic side effects on plants. Average seed yield rates for all four pH stabilization treatments (13.3 to 16.9 g m-2 day-1) were about double that of the control (8.2 g m-2 day-1), for which there was no attempt to buffer substrate pH. Both the highest canopy seed yield rate (16.9 g m-2 day-1) and the highest shoot harvest index (19.5%) occurred with the 6% resin bead treatment, even though the 10 mM MES and 12% bead treatments maintained pH within the narrowest limits. The pH stabilization methods tested did not significantly affect seed oil and protein contents.     

The effect of nitrogen,volume of media,plant density and module shape on the growth of asparagus seedlings

There were three experiments in which the seedlings were raised in media contained in plastic cells. In Experiment 1, 150 or 200 mg l^?1 N were applied in factorial combination with cell volumes of 20, 32 or 50 cm³, There were 6 successional harvests. All cells were 7.5 cm deep and cylindrical in shape. Experiment 2 compared these 3 cell volumes at densities of 983, 1532 or 2440 plants per m². Cell diameters restricted the 50-cm³ cell to the 983, and the 32-cm³ cell to the 983 and 1532 plants per m² densities. 200 mg l^?1 N increased shoot growth, but not root growth. This increase in shoot growth was not considered advantageous. Seedling growth increased with increases in cell volume, but there were no responses to changes in plant density. Experiment 3 compared a cell having an inverted pyramid shape with a cylinder. The cylinder, despite holding 20% less media, produced the larger seedlings.     

Early leaf harvest reduces yield but not protein concentration of cowpea seeds

Five greenhouse-grown cowpea [Vigna unguiculata (L.) Walp] cultivars were tested in a generalized random complete-block design to determine the effect of early leaf harvest on dry weight and protein concentration of plant parts at maturity. The most recent, fully expanded leaves on each branch from one group of plants were harvested at 5 and 7 weeks after planting. On the other groups of plants, no early leaf harvest was performed. Dry weight and protein concentration (dry weight basis) were determined for leaves, stems, and seeds at maturity and for leaves harvested early. Weight and protein concentration of seeds, leaves, and stems differed significantly between cultivars; protein concentration of leaves harvested at 5 or 7 weeks did not. Dry weight of leaves harvested at 5 vs. 7 weeks did not differ significantly, but leaf protein concentration was significantly higher at 5 weeks compared to 7 weeks. Across all cultivars, early leaf harvest had no significant effect on leaf or stem weight per plant at maturity. However, there was a significant decrease in seed weight when leaves were harvested early. Results suggest that even limited leaf harvest at 5 and 7 weeks has detrimental effects on yield, but not on protein concentration, of cowpea seeds harvested at maturity.     

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.     

早熟梨不同整形方式研究

通过开展不同整形方式研究,结果表明:梨幼树不同树形对侧枝生长、树冠形成的影响不同,因此在开花结果早晚、前期产量、效益方面差异较大。以折叠式扇形和Y字形整形提高早期产量效果最为显著。在每667m2栽植110株左右的密度情况下,常常采用折叠式扇形的树形;在栽植密度大于110株/667m2的情况下,采用Y字形树形;栽植密度小于40株/667m2以下的早熟梨采用疏散分层形的树形。根据不同整形方式的方差分析,得出丰产树形结构指标:在栽培密度110株/667m2的条件下,‘翠冠’梨产量控制在3000～4000kg/667m2,枝量30000～40000枝/667m2,一般每20～25cm着生1个结果枝,叶面积系数2.5～3.2,果距保持20～25cm,留果量12000～16000个/667m2,叶果比25～30:1,枝果比2～2.5:1,中短果枝占85%～90%,单株负荷27.5～37.5kg。     

Cell wall metabolism of pear fruit on the tree after 2,4-DP treatment

Summary

The effect of 2,4-dichlorophenoxy-propionic acid (2,4-DP) on fruit ripening on the tree was investigated in `La France' pears (Pyrus communis L.). Forty-five ppm, 2,4-DP solution was applied at 159 d after full bloom (DAFB), which was optimum harvest date for `La France' pears. They were compared with fruit harvested at 159 DAFB and placed in a controlled room with a 208C and 90% r.h. After harvest, the fruit firmness decreased dramatically 13 d after harvest (DAH). In 2,4±DP treatment, the levels decreased gradually 13 d after treatment (172 DAFB). In the untreated control, the levels also showed a slight decrease with time. Final ethylene concentration was almost the same in harvested and 2,4-DP treated fruit, but lower in the untreated control. In each treatment, water-soluble polyuronide (WSP) concentrations increased with time and hexametaphosphate-soluble polyuronide (HMP) and HCl-soluble polyuronide (HP) concentrations decreased. WSP concentration increased rapidly 20 DAH in harvested fruit and 194 DAFB in 2,4-DP treatment. Harvested and 2,4-DP treated fruit reached the edible condition on 17 DAH and 194 DAFB, respectively. Pectinesterase (PE) activity increased slightly with time for all treatments, showing no significant difference between treatments. Polygalacturonase (PG) activity increased gradually in all cases, being higher in 2,4-DP treated fruit than in control fruit left on the tree. These results suggest that 2,4-DP treatment before harvest induces pear fruit softening. This implies that 2,4-DP may be used as a replacement for low-temperature storage to promote the ripening, and good quality ripe fruit with buttery and juicy texture may be harvested on the tree.     

Plant productivity in controlled environments

To assess the cost and area/volume requirements of a farm in a space station or Lunar or Martian base, a few laboratories in the United States, the Soviet Union, France, and Japan are studying optimum controlled environments for the production of selected crops. Temperature, light, photoperiod, CO2, humidity, the root-zone environment, and cultivars are the primary factors being manipulated to increase yields and harvest index. Our best wheat yields on a time basis (24 g m-2 day-1 of edible biomass) are five times good field yields and twice the world record. Similar yields have been obtained in other laboratories with potatoes and lettuce; soybeans are also promising. These figures suggest that approximately 30 m2 under continuous production could support an astronaut with sufficient protein and about 2800 kcal day-1. Scientists under Iosif Gitelzon in Krasnoyarsk, Siberia, have lived in a closed system for up to 5 months, producing 80% of their own food. Thirty square meters for crops were allotted to each of the two men taking part in the experiment. A functional controlled-environment life-support system (CELSS) will require the refined application of several disciplines: controlled-environment agriculture, food preparation, waste disposal, and control-systems technology, to list only the broadest categories. It has seemed intuitively evident that ways could be found to prepare food, regenerate plant nutrients from wastes, and even control and integrate several subsystems of a CELSS. But could sufficient food be produced in the limited areas and with the limited energy that might be available? Clearly, detailed studies of food production were necessary.     

Morphology,yield and quality of ashwagandha (Withania somnifera L. Dunal) roots and its cultivation economics as influenced by tillage depth and plant population density

Summary

Ashwagandha (Withania somnifera L. Dunal; Solanaceae) is being cultivated around the world mainly for its root which has rejuvenative properties. Field experiments during 1999–2001 under semi-arid tropical conditions of Hyderabad, India studied the effect of tillage depths (15 and 30 cm) and plant population densities (20, 40, 60 and 80 plants m^–2) on root morphology, yield and quality and cultivation economics of ashwagandha. Preparatory tillage to 30 cm depth in combination with a density of 60 plants m^–2 gave the highest root yield of 1.2 t ha^–1 which was 50% higher than that following 15 cm tillage depth and the same density. This is attributed to the favourable effect of the former treatment leading to 33, 37 and 21% increases in plant height, number of branches per plant and shoot biomass yield, respectively. Further, this treatment produced most (68%) best quality root pieces. Main root length, length of lateral roots and diameter of lateral roots were significantly increased, while the diameter of main root and the number of laterals decreased. Furthermore, increase in plant density from 20–80 plants m^–2 increased production of best quality roots from 42% to 59% under shallow tillage and from 53% to 71% of root yield under deep tillage. The implications of change in root morphology are discussed in the light of production of different grades of roots, their market preferences and economics. Deep tillage was equally advantageous for seed production, but plant population density for maximum seed yield (211 kg ha^–1) was lower at 40 than at 60 plants m^–2 for maximum root yield. Maximum gross and net returns and benefit-cost ratio occurred following the highest root yield.     

The influence of planting date,sucker selection and density on yield and crop-timing of bananas (cultivar ‘Williams’) in the Eastern Transvaal

In the subtropical banana-growing areas of South Africa, there is a pronounced and consistent tendency for fruit to be oversupplied in the spring (September–November) and undersupplied in the autumn (March–May). Under identical soil, planting material and general management conditions, a crop-timing trial with ‘Williams’ banana was established at Burgershall Research Station, Eastern Transvaal, to compare the effects of planting date (September, December, March), time of first sucker selection (5 and 10 months after planting) and density (1666 and 1250 plants ha⁻¹) on yield and harvest season over 3 crop cycles.Cumulating the yield/ha/annum for the plant crop and first ratoon cycles, there was a small but significant decrease (4%) as planting date was delayed from September to December, and a larger significant reduction in yield (18%) with delay from December to March planting. While cumulative yield/ha/annum for plant crop plus first ratoon increased significantly (19%) at the higher density of 1666 plants ha⁻¹, no differences occurred as a result of sucker selection treatment.March-planted bananas were harvested during the undesirable spring period, and this effect was largely carried over into the first ratoon and second ratoon cycles. December planting was optimal and September planting intermediate from a crop-timing viewpoint. Cumulating all 3 crop cycles, 50% of the total bunch harvest could be timed during the autumn from December planting at a density of 1666 plants ha⁻¹. From September planting, the proportion of autumn-harvested fruit could also be increased by delaying the selection of the first ratoon sucker until at least 10 months after planting. Results demonstrated the in-field potential for overcoming the natural banana shortage in South Africa during autumn.     

Greenhouse tomato limited cluster production systems: crop management practices affect yield

Limited-cluster production systems may be a useful strategy to increase crop production and profitability for the greenhouse tomato (Lycopersicon esculentum Mill). In this study, using an ebb-and-flood hydroponics system, we modified plant architecture and spacing and determined the effects on fruit yield and harvest index at two light levels. Single-cluster plants pruned to allow two leaves above the cluster had 25% higher fruit yields than did plants pruned directly above the cluster; this was due to an increase in fruit weight, not fruit number. Both fruit yield and harvest index were greater for all single-cluster plants at the higher light level because of increases in both fruit weight and fruit number. Fruit yield for two-cluster plants was 30% to 40% higher than for single-cluster plants, and there was little difference in the dates or length of the harvest period. Fruit yield for three-cluster plants was not significantly different from that of two-cluster plants; moreover, the harvest period was delayed by 5 days. Plant density (5.5, 7.4, 9.2 plants/m2) affected fruit yield/plant, but not fruit yield/unit area. Given the higher costs for materials and labor associated with higher plant densities, a two-cluster crop at 5.5 plants/m2 with two leaves above the cluster was the best of the production system strategies tested.