Phenology,flowering and fruit-set performance of six recent pear cultivars of Nordic origin

ABSTRACT

Flowering performance and phenology of six new pear cultivars of Nordic origin were examined during a 12 year period. The seasonal timing of shoot growth and flower initiation were monitored in three years. The morphological floral stages of the flower bud formation process were examined for the cultivar ‘Celina’. Seven floral stages were identified and described. The date of full bloom varied between years as a function of the currently accumulated heat sum in early spring. Still, the earliness ranking of the cultivars was consistent across years for both flower initiation and blooming. The cultivars ‘Anna’ and ‘Ingeborg’ consistently initiated floral primordia 2–3 weeks earlier than ‘Celina’, ‘Clara Frijs’, ‘Fritjof’ and ‘Kristina’, and this was accompanied with 4–5 days earlier blooming in the following spring. The early flower initiation cultivars ‘Anna’ and ‘Ingeborg’ also had richer flowering than the late-blooming cultivars. ‘Fritjof’ was identified as a suitable pollinator for ‘Celina’ in the Nordic climate. Comparison of the flowering phenology of pear and apple cultivars showed that while the pears, on average, flowered a week ahead of the apples, they initiated flower primordia almost two weeks later, thus rendering the intervening period approximately three weeks longer in pear than in apple.     

Flowering phenology and the interrelations between phenological stages in apple trees (Malus domestica Borkh.) as influenced by the Nordic climate

In order to assess to what degree the ongoing global warming has affected flowering time of apple trees in the Nordic climate, we studied flowering phenology of trees in an orchard in Southern Norway. Correlation analysis of a 70-year (1946–2016) data series for flowering time of the cultivar ‘Gravenstein’ revealed a close relationship of the flowering phenophase with April–May heat accumulation (r?=??0.98). Over the last 50-year period, flowering was advanced by 16 days in response to the temperature rises. Similarly, on average for 12 cultivars of varying earliness, flowering was advanced by 9 days over the latest 30-year period (1986–2016). Furthermore, the interrelationship between various phenological stages and floral morphogenesis of the same cultivars in the years 2013 and 2014 was studied, and related to flower-bud formation. The different stages of floral morphogenesis were identified, presented and used as a basis for assessment of flower-bud development in serial dissections. Floral initiation in spurs of actively growing trees took place in late July, approx. 8 weeks after full bloom, whereas in extension shoots, initiation took place after growth cessation in August, approximately 2 weeks later. Decreasing temperatures in mid-August coincided with the cessation of growth and floral initiation in extension shoots, suggesting that the processes may be causally related. The results show that, in the Nordic climate, the period between blooming and initiation of new floral primordia is considerably shorter than in warmer climates, suggesting that the period is only marginally long for completion of shoot growth, and hence, timely floral initiation. This may be an important reason for the irregular flowering and frequent incidences of alternate bearing in apple trees in the cool Nordic climate. The presented information can be useful for determination of the correct timing of flower and fruit thinning to counterbalance biennial bearing.     

Performance of six European plum cultivars on four plum rootstocks growing in a northern climate

Abstract

The performances of the plum rootstocks Marianna GF 8-1, Pixy, and Wangenheim, compared with St. Julien A as a standard, for the cultivars ‘Avalon’, ‘Edda’, ‘Excalibur’, ‘Jubileum’, ‘Reeves’, and ‘Victoria’ were assessed in a field trial in western Norway at 60° North. Trees were planted in spring 1999; the plant material was one-year-old whips, spaced 2.0×4.5 m and formed with a central leader as free spindles. Tree vigour, yield, fruit size, fruit quality, and yield efficiency were evaluated for the seven subsequent years. Tree size was significantly affected by the rootstocks after seven years' growth. Wangenheim produced the smallest and St. Julien A and Pixy the largest trees as measured by trunk cross-sectional area, on average for the different cultivars. However, Pixy produced significant larger yields per tree for the cultivar ‘Reeves’ than did St. Julien A. ‘Edda’ gave the smallest yield and ‘Avalon the largest. Trees on Pixy were the most yield efficient for all cultivars with the exception of ‘Victoria’. The fruit sizes became little affected by the different rootstocks. ‘Edda’ and ‘Victoria’ produced the smallest fruits and ‘Excalibur’ and ‘Reeves’ the largest. Fruit quality characterized by the content of soluble solids was on average 16.1% and did not differ between trees on the various rootstocks. The cultivar ‘Avalon’ had the highest contents of soluble solids and ‘Reeves’ the lowest. The nutrient levels in the leaves were within the optimum range by the end of the seventh season. Trees on Marianna GF 8-1 had the highest nitrogen and magnesium leaf uptake. In conclusion, St. Julien A and Pixy were the most reliable semi-vigorous rootstocks which induced high yield efficiency and with favourable influences on fruit quality to the six European plum cultivars. Pixy is a good alternative to St. Julien A, with a lower vigour in trees, more precocity, and higher yield efficiency.     

Midsummer copper sprays have no effect on ‘delicious’ apple fruit color grade or typiness

Recent reports suggested that multiple midsummer copper (Cu) sprays could improve the proportion of apple fruit (Malus × domestica Borkh.) being packed in the reddest market color grades. We conducted a three‐year field experiment in a low‐Cu orchard with a history of poor fruit coloring. We applied multiple mid‐summer sprays of Cu sulfate and basic Cu sulfate in 1994 and 1995 to ‘Bisbee Delicious’ and ‘Oregon Spur II Delicious’ apple trees. Plant tissue nutrient levels, fruit color grade, and fruit typiness were evaluated in the years of application and the following year. The Cu sprays increased leaf Cu in the years of application; however, leaf Cu in the Cu‐sprayed plots returned to or very near to background concentrations in the year after sprays were terminated. The Cu treatments did not increase the proportion of fruit in the reddest market color grades or influence five fruit typiness indices of either apple cultivar. Although midsummer Cu sprays may not enhance apple fruit red color or typiness, they may be useful for increasing overall tree Cu status, particularly for long‐season cultivars which are harvested too late for postharvest sprays to be effective.     

Net Photosynthesis of Schefflera arboricola Hayata Clones at Different CO2 Concentration and Photosynthetic Flux Densities

Tomato seedlings, cvs ‘Matador’ and ‘Revido’, were irrigated on alternate days with one of six solutions in which the EC was increased stepwise from 2 to 27 mS cm^?1 by the addition of NaCl to a standard complete nutrient solution. Plant height, leaf area and shoot fresh and dry weight were significantly reduced by increasing nutrient solution EC after 12 days of treatment. A significant interaction between cultivar and nutrient solution salinity was found for fresh and dry weights, the weight reduction with increasing salinity being greater for ‘Revido’ than for ‘Matador’. No interaction was found for plant height or leaf area. A greater reduction in fresh weight than in dry weight resulted in increased dry matter content with increasing salinity. Linear reductions in relative growth rate and rate of leaf initiation were found with increasing salinity. The number of leaves initiated prior to floral initiation was unaffected by nutrient solution salinity.     

Evaluation of Saskatoon berry (Amelanchier alnifolia Nutt.) cultivars for their polyphenol content, antioxidant properties, and storage stability

The polyphenol contents and antioxidant activities were assessed for 17 Saskatoon berry cultivars grown in Canada in fresh and stored fruits at -20 degrees C for 9 months. The Nelson cultivar was the richest in total polyphenol, anthocyanin, and procyanidin contents (801, 382, and 278 mg/100 g fresh weight, respectively). This cultivar was characterized also by the highest antioxidant potential measured with DPPH and ABTS radicals (2.8 and 5.0 mM/100 g FW, respectively). Cultivar-dependent changes in polyphenol content after freezer storage were observed. In the Lee 2 cultivar, significant increases in anthocyanin and flavonol contents occurred, while in the Lee 3 and Martin cultivars considerable decreases were observed. During the freezer storage, the antioxidant activity remained unchanged except for the Smokey which showed to be the most sensitive cultivar during storage. The Nelson and Lee 2 were the most stable cultivars during storage. The high polyphenol content and antioxidant activity of the Nelson cultivar and its good storage stability would make this cultivar the optimal material for fruit growers and food producers.     

Fertilization of rabbiteye blueberries grown on a typic paleudult soil

A 6 year field study comparing the effects of 5 fertilizer sources applied at 4 levels to 3 rabbiteye blueberry (Vaccinium ashei Reade) cultivars was established on a Typic paleudult soil in southern Misssssippi. Fertilizer sources had little influence on plant height, vigor, chlorosis, or fruit yield. The first year, ‘Tifblue’ was lowest in vigor and fruit yield, but after 4 growing seasons, had the highest plant height and fruit yields. Chlorosis symptoms were more prevalent at the highest fertilization rate, in the cultivar ‘Woodard’, and with Ca(NO₃)₂ fertilizer. During the first 5 years, fruit yields increased as fertilization levels increased from 0 to 5.9 g N/plant but additional fertilization did not influence yields There were no differences in plant vigor due to cultivars but the highest rate of fertilization decreased vigor. The cultivar X fertilization rate interaction was significant for plant height in 1983 and for fruit yields in 1984 and 1985. ‘Delite’ and ‘Woodard’ plant height increased while height of ‘Tifblue’ decreased as fertilization rates increased from the 0 to 5.9 g N/plant levels; higher rates decreased plant height in all cultivars. In 1984 and 1985 fruit yields of ‘Woodard’ and ‘Delite’ were not influenced by fertilization but yields of ‘Tifblue’ indicated a negative response to increasing fertilizer levels.     

Influence of root restriction on two cultivars of summer squash (Cucurbita pepo L.)

Variable root restricting conditions were imposed on summer squash (Cucurbita pepo L.) cultivars ‘Senator’ and Dixie’ using container sizes of 0.35, 2.00, and 7.60 liters. Nondestructive and destructive plant sampling were conducted to evaluate leaf area production, dry weight accumulation and partitioning, crop growth rate and net assimilation rate, and flower and fruit development. Within 10 days after transplanting (DAT), ‘Senator’ exhibited declining leaf area production under increased root restriction, and within 17 DAT leaf area was diminished for both cultivars under increased root restricting conditions. Dry weight accumulation in leaves, stems, roots, and fruit was reduced for both cultivars over time and level of root restriction severity. There was a tendency for greater vegetative growth reductions with ‘Senator’ than with ‘Dixie’ at comparable levels of root restriction. Root‐to‐shoot ratio, timing and duration of flowering, and sex of flowers were not significantly impacted by root restriction level or cultivar. Fruit dry weight was greatest for Dixie’ early on, but by 28 DAT, total fruit dry weight produced did not differ for the cultivars except under the most severe root restricting conditions. Fruit dry weight production was limited for both cultivars as container volume became smaller.     

Dry Matter and Nutrient Partitioning of Selected Pineapple Cultivars Grown on Mineral and Tropical Peat Soils

The pineapple cultivars ‘Moris’ (Queen cultivar), ‘N‐36’ (‘Sarawak’ × ‘Gandul’ hybrid), ‘Gandul’ (Singapore Spanish cultivars), and ‘Josapine’ (‘Singapore Spanish’ × ‘Smooth Cayenne’ hybrid) are mostly grown on peat soils in Malaysia, whereas ‘Sarawak’ (‘Smooth Cayenne’ cultivar) is more commonly grown on mineral soils. To obtain good yields of fruit of high quality, it is important to understand the differences in nutrient requirements for these cultivars in the different soils in which they are grown. Therefore, the objectives of the study were to determine the biomass and nutrient partitioning of the different pineapple cultivars and to determine the plant variables affecting fruit yield and quality. Plants of each of the pineapple cultivars were randomly sampled from different locations of the major pineapple‐growing areas in Malaysia. Only plants having A‐grade fruit of marketable quality at harvest were selected. The cultivars and respective field sites were as follows: ‘Sarawak,’ Bukit Tandak farm, Kelantan (5° 55.274′ N, 102° 00.608′ E); ‘Moris,’ ‘N‐36,’ and ‘Gandul,’ Peninsula Pineapple Plantations, Simpang Renggam, Johor (1° 49.909′ N, 103° 14.053′ E); and ‘Josapine,’ Goh Swee Eng Pineapple Farm, Simpang Renggam, Johor (1° 48.441′ N, 103° 11.935′ E). Plants were partitioned into roots, stem, leaves, peduncle, fruit, and crown, and fresh and dry weights were recorded. Total biomasses for the different cultivars were 733.46 ± 22.83 g for ‘Gandul,’ 842.34 ± 43.26 g for ‘N‐36,’ 927.38 ± 53.10 g for ‘Moris,’ 434.77 ± 16.82 g for ‘Josapine,’ and 2446.94 ± 156.00 g for ‘Sarawak.’ Leaves accounted for the greatest proportion of dry matter (48.5%), followed by fruit (22.9%) and stem (21.6%), and a smaller proportion (1.2–2.5%) was roots, peduncle, and crown. The proportions of the dry‐matter accumulation in leaves and stem for the cultivars were 53.5 ± 0.7 and 16.7 ± 0.9% for ‘Gandul’; 45.1 ± 0.5 and 17.7 ± 0.7% for ‘N‐36’; 51.9 ± 1.6 and 16.8 ± 0.6% for ‘Moris’; 56.5 ± 1.0 and 12.0 ± 0.9% for ‘Josapine’; and 54.2 ± 5.1 and 27.7 ± 4.4% for ‘Sarawak.’ The proportion of the macro‐ and micronutrients in pineapple parts differed widely between cultivars. Potassium (K) showed the greatest proportion (7.96 ± 0.6 to 29.73 ± 1.17%) in leaves and (4.46 ± 0.70 to 9.35 ± 0.28%) in fruit followed by nitrogen (N) and phosphorus (P) with lower proportions. Most pineapple cultivars grown showed variation in nutrient‐use efficiency (NUE) with respect to the elements measured with values of <1.0 g dry matter g^?1 nutrient. The NUE values of >1.0 g dry matter g^?1 nutrient were observed for magnesium (Mg) in ‘Gandul’ and ‘N‐36’ and for calcium (Ca) and copper (Cu) in ‘N‐36.’ Total nutrient accumulation in the plant components differed approximately according to their cultivar origins (‘Smooth Cayenne,’ ‘Queen,’ ‘Singapore Spanish’). It is interesting that the results for the ‘Singapore Spanish’ × ‘Smooth Cayenne’ hybrid Josapine were more similar to the ‘Singapore Spanish’ cultivars than being between the parents. Partitioning of biomass and nutrients in pineapple provides a means to categorize them and makes it possible to use a cultivar‐based fertilization program.     

昼夜连续照射LED红蓝光对不同品种生菜生长和品质的影响

为探究生菜对全生长期连续光照的响应及品种差异性,在密闭式植物工厂内,以LED红蓝光为光源研究了水培条件下常规光照（12h/12h,NL）与连续光照（24h/0h,CL）对5种生菜生长和品质的影响。结果表明：与常规光照（NL）处理相比,连续光照（CL）处理显著提高了除“大卫”外其它4种生菜的地上部鲜重,其中“绿罗”生菜增加幅度最高。生长初期连续光照（CL）处理下5种生菜叶片叶绿素含量显著高于常规光照（NL）处理,但在生长后期,5种生菜两个处理下的叶绿素含量均无显著差异。与常规光照处理相比,连续光照处理显著提高了5种生菜可溶性糖、总酚和类黄酮含量,以及其中2种紫叶生菜的花青素含量。除“绿罗”外,其它4个品种连续光照处理下的抗坏血酸总量均略有或显著升高,其中主要提高了还原型抗坏血酸的含量,对脱氢抗坏血酸含量的影响不显著。总之,全生长期连续光照能显著提高生菜的产量,促进可溶性糖和抗氧化物质合成;5个品种生菜对连续光照的适应性存在差异,其中“绿罗”的适应性最强;全生长期连续光照运用于植物工厂生菜生产对提高产量和品质的潜力较大。     

Effect of saline irrigation on the biomass yield,and the protein,nitrogen, phosphorus,and potassium composition of alfalfa in a pot experiment

During 1994–1995, field experiments were conducted in six apple orchards located in the southwest of Finland (the mainland and the Åland Islands). The cultivars were ‘Melba’, ‘Raike’, ‘Red Atlas’, ‘Lobo’, ‘Aroma’, and ‘Åkero’. Fruit samples were picked at about one week before commercial maturity and stored for three to six months at 2 to 4°C and 85–95% relative humidity. During storage the percentage of physiological disorders was visually recorded. Fruit nitrogen (N) and calcium (Ca), firmness, diameter, juice titratable acidity (TA), and soluble solids concentrations (SSC) were determined at harvest. Nitrogen and Ca in the soil and leaves collected during fruit development were determined. The ranges in fruit N were 296–624 and Ca 27–68 mg kg^‐1 fresh weight, and in the leaves N 15–23 and Ca 9–19 g kg^‐1 dry matter. The N/Ca ratio was 5 and 16 and 0.9 and 2.3 in fruit and leaves, respectively. There was more variation between years in N and Ca contents of leaves than that of fruit. Other fruit quality characteristics varied between seasons and cultivars. Leaf N correlated positively with fruit diameter and negatively with fruit dry matter. The incidence of physiological disorders on apples after three month storage was 2 to 13% and after six months 10 to 95%. Fruit with Ca content below 45 mg kg^‐1 fresh weight were susceptible to bitter pit ('Aroma’ and ‘Åkero') and Jonathan spot ('Red Atlas'). The cultivar ‘Melba’ was susceptible to bruising damages and ‘Raike’ and ‘Red Atlas’ were affected more with internal breakdown and core browning.     

Yield of iron‐sprayed and non‐sprayed strawberry cultivars grown on high ph calcareous soil

Abstract

Iron (Fe) deficiency chlorosis (FeDC) results in extensive reduction in yield of strawberry (Fragaria x ananassa Duch.) grown on high pH calcareous soils. Three cultivars differing in response to FeDC were grown on a high pH (8.2) calcareous soil (25.4% calcium carbonate equivalent in surface 20 cm) in the field (Choueifat, coastal area of Lebanon) to determine the effects of FeDC on fruit yield of cultivars sprayed with FeEDDHA [ferric ethylene‐diiminobis (2‐hydroxyphenyl) acetate]. The unsprayed plots were used as a control. No significant interaction (P<0.05) between cultivars x FeEDDHA spray treatment, and no significant differences (P<0.05) between one and two FeEDDHA spray(s)/week treatment was noted for visual FeDC, fruit number, and fruit yield. Sprayed cultivars once a week produced higher yields than unsprayed ones; overall increases were 33% (13% for ‘Motto’, 30% for ‘Chandler’, and 56% for ‘Douglas'). Even though only slight FeDC was noted on the ‘Motto’ cultivar receiving no Fe EDDHA spray, fruit yields were increased when sprayed with FeEDDHA. However, significant increases in yield for ‘Chandler’ and ‘Douglas’ cultivars with severe FeDC ratings were rioted when sprayed with FeEDDHA.     

MYCORRHIZAL INFLUENCE ON FRUIT YIELD AND MINERAL CONTENT OF TOMATO GROWN UNDER SALT STRESS

Tomato (Lycopersicon esculentum Mill.) yields are known to decrease for plants grown in saline soils. This study was conducted to determine the effects of arbuscular mycorrhizal fungi (AMF) inoculation on fruit yield and mineral content of salt-tolerant and salt-sensitive tomato cultivars grown with varied levels of salt. NaCl and CaCl₂were added to soil in the irrigation water in equal molar ratios to give EC_e values of 1.4 (nonstressed) and 4.9 dS m^?1 (salt stressed). Plants were grown in a greenhouse using unsterilized, low phosphorus (P) (silty clay) soil-sand mix. Mycorrhizal root colonization occurred whether cultivars were salt stressed or nonstressed, but the extent of AMF root colonization was higher in AMF inoculated than uninoculated plants. The salt tolerant cultivar ‘Pello’ generally had higher AMF root colonization than the salt sensitive cultivar ‘Marriha’. Shoot dry matter (DM) yield, fruit fresh yield, and AMF colonization were higher for plants grown under nonstressed than for plants grown under salt stressed conditions. Shoot DM and fruit fresh yields were higher in AMF inoculated than uninoculated plants grown with or without salt stress. Pello generally had higher fruit fresh yield per plant and fruit weight than Marriha, but these differences were only significant for fruit weight in unioculated plants grown under salt stressed conditions. The enhancement in fruit fresh yield due to AMF inoculation was 26 and 23% under nonstressed and 28 and 46% under salt stressed treatments for Pello and Marriha, respectively. For both cultivars, fruit contents of P, potassium (K), zinc (Zn), copper (Cu), and iron (Fe) were higher in AMF inoculated compared with uninoculated plants grown under nonstressed and salt stressed conditions. Fruit Na concentrations were lower in AMF inoculated than uninoculated plants grown under salt stressed conditions. The enhancement in P, K, Zn, Cu, and Fe acquisition due to AMF inoculation was more pronounced in Marriha than in Pello cultivar under salt stressed conditions. The results of this study indicated that AMF inoculated plants had greater tolerance to salt stress than unioculated plants.     

Late blight and virus host-plant resistances,crossing ability and glycoalkaloids in Nordic potato germplasm*

Old potato cultivars from the Nordic Genetic Resource Center (NordGen) and advanced breeding clones from the Swedish University of Agricultural Sciences (SLU) were evaluated for susceptibility to Potato Virus Y (PVY) and Potato Leafroll Virus (PLRV), foliar and tuber resistance to late blight – caused by Phytophthora infestans – as well as for glycoalkaloid content and crossing ability. Enzyme-Linked Immunosorbant Assay (ELISA) tests were used for PVY and PLRV screening during two years that were characterized by intensive virus incidence and severity in the field, while foliar and tuber resistances to late blight were assessed under artificial inoculation with an aggressive Swedish isolate of P. infestans. Hybrid seeds were obtained by crossing cultivars such as ‘Kiva’, ‘Sarpo Mira’, ‘Rosamunda’ and ‘Superb’ with SLU advanced breeding clones and a selected clone of Solanum tuberosum Group Andigena. Some cultivars (‘Hårek’, ‘Sarpo Mira’) and breeding clones (04-2662, 04-2085) with late blight resistance did not show virus infection. The α-solanin and α-chaconin contents of some of the old Nordic potato cultivars and breeding clones were similar to the known Dutch table cultivar ‘Bintje’ after 3 years of testing. This research allows identification of promising Nordic potato cultivars and SLU breeding clones for further use in developing germplasm aiming at organic and conventional farming systems.     

Powdery mildew resistance of Nordic spring wheat cultivars grown in Estonia

Abstract

A group of spring wheat cultivars originating from Sweden, Finland, Norway, Germany, and the Netherlands was analysed for powdery mildew resistance. Using functional molecular markers, two alleles of the major resistance gene Pm3 were detected among the cultivars under the study. One of the alleles, Pm3d, was detected in the resistant cultivars ‘Vinjett’, ‘SW Estrad’, and ‘Zebra’, and in ‘Tjalve’, a cultivar of earlier release susceptible to the local population of powdery mildew. The second allele of Pm3 detected in the analysed group of cultivars was the allele Pm3f, rarely used in Europe. It was identified in the resistant cultivars ‘Satu’, ‘Helle’, and in the moderatively resistant cultivar ‘Mahti’. Pm3f was found to be effective against the local population of powdery mildew in Estonia, while Pm3d provided no protective effect. Besides the Pm3d allele on chromosome 1A, monosomic analysis of the cultivar ‘Vinjett’,which is almost immune to powdery mildew, identified two additional loci on chromosomes 5D and 7D, respectively, presumably responsible for the high resistance in this cultivar. In contrast to the earlier cultivars, six recently released cultivars (‘Vinjett’, ‘SW Estrad’, ‘Zebra’, ‘Satu’, ‘Helle’, ‘Meri’) demonstrated a high resistance to the powdery mildew fungus Blumeria graminis DC. f. sp. tritici both in the field and seedling tests, showing that the genetic basis of powdery mildew resistance in Nordic spring wheat has been improved noticeably in the last ten years.     

Optimizing seed crops of common bent (Agrostis capillaris) by sowing rate

Abstract

As part of a project to stimulate Norwegian seed production of common bent (syn. browntop, US: colonial bentgrass, Agrostis capillaris L. syn. A.tenuis Sibth.) field trials comparing sowing rates of 2.5, 5.0, 7.5 or 10 kg ha^?1 were conducted at Landvik, south-east Norway, (58°N) from 1989 to 1994. Three trials were laid out of the forage cultivar ‘Leikvin’ and three trials of the lawn cultivar ‘Nor’, each trial being harvested for three consecutive years. While the average per cent ground cover in spring increased from 87% at 2.5 kg ha^?1 to 94–96% at 7.5 kg ha^?1, seed yields decreased with increasing sowing rate in both cultivars. On average for all harvests, quadrupling the sowing rate from 2.5 to 10 kg ha^?1 reduced seed yield by 9% in ‘Leikvin’ and 15% in ‘Nor’, the stronger effect probably being associated with a greater competition between tillers in the lawn cultivar. Seed yield reductions with increasing sowing rate showed no relationship with crop age, but were less accentuated for crops undersown in spring wheat in a dry year than for crops established without cover crop in years with ample rainfall in early summer. Increasing sowing rates reduced plant height and panicle number in ‘Nor’, but had no effect on seed weight or germination in any of the cultivars. It is concluded that seed crops of common bent should be established with a sowing rate of 2–5 kg ha^?1, with the lowest rate in lawn cultivars, under ideal seedbed conditions and when seed crops are sown without cover crop.     

INFLUENCE OF DIFFERENT RATES OF PHOSPHORUS ON GROWTH,YIELD AND PHOSPHORUS USE EFFICIENCY IN TWO WHEAT CULTIVARS

To study the influence of different rates of phosphorus (P) on growth and yield of wheat, experiments were conducted at NIAB, Faisalabad, Pakistan under natural conditions. Results indicated that the P requirement of wheat at early growth was higher and adequate available P in the growth medium helped to attain relatively higher growth rate and resulted in higher grain yield. The two wheat cultivars when subjected to different rates of P application showed that the cultivar ‘MH-97’ was more responsive than ‘Pasban-90’ that attributed to its higher P translocation efficiency from roots to tops. The two cultivars also showed differential yield response when grown under field condition. At optimum nitrogen (N): P ratio of 1.5:1, the cultivar ‘MH-97’ gave 31.5% while cultivar ‘Pasban-90’ gave a maximum response of 25.9% over their respective N alone application. Contrarily, at the wider NP ratio of 3:1, yield response of cultivar ‘MH-97’ was 26.5% while that of cultivar ‘Pasban-90’ was only to the extent of 2.2%, thereby indicating a much wider difference in their yield response pattern. Thus, choosing an appropriate cultivar for a particular rate of fertilizer application would be more rewarding in terms of yield and profitability.     

Origin and history of old cucurbit cultivars in Israel and the sources of several internationally important market types

Over the past century, Israel was a focal point for the improvement of local cucurbit landraces and introduction of cucurbit germplasm. Some improved open-pollinated cucurbit cultivars developed in Israel became established as market types of considerable economic importance far beyond its borders. The origin and history of these cultivars is not widely known and therefore the purpose of the present work was to collect and compare the records relevant to the development of these cultivars, and to describe them more fully. The four economically most important cultivars originated through mass-selection by amateur breeders and were named after their respective farming communities. The ‘Bet Alfa’ cucumber (Cucumis sativus) was selected from a local landrace and introduced in 1936. The ‘Malali’ watermelon (Citrullus lanatus) originated as a rogue in a local landrace and was commercialized around 1940. The ‘Ananas Yoqne‘am’ melon (Cucumis melo) was selected from a local landrace and commercialized around 1950. The ‘Ha‘Ogen’ melon was selected from a cultivar introduced from Hungary and commercialized in the 1950s. The outstanding fruit quality of these four cultivars resulted in their widespread planting in Israel and neighboring countries. Moreover, the quality of the cucumber and melon cultivars inspired successive improvements, notably introgression of disease resistance and development of hybrids, by Israeli breeder-geneticists. The ever-increasing demand for their high-quality fruits established as international market types the Bet Alfa cucumber, the Ananas Yoqne‘am melon, and the Ha‘Ogen melon and its derivative, the Galia melon, and each is intensively bred today by local and multinational seed companies.     

Growth and phosphorus accumulation in tomato cultivars 1

Abstract

The distribution patterns of dry matter and P in field‐grown tomato ‘Campbell‐37’, ‘Knox’, and ‘Tipton’, (Lvcopersicon esculentum mill), were determined from 25 days after emergence to harvest. Dry weight accumulation was about the same for the 3 cultivars up to 55 days after plant emergence. From 55 to 75 days, ‘Knox’ accumulated more total plant dry weight than either ‘Tipton’ or ‘Campbell‐37’, largely due to an accelerated fruit accumulation rate during this period. In the 75 to 105 day interval, dry weight accumulation by ‘Knox’ was less than ‘Campbell‐37’ or ‘Tipton’. Fruit accumulation, as indicated by fruit number increase, was during the 45 to 75 day period for ‘Knox’, the 55 to 75 day period for ‘Tipton’, and the 55 to 85 day period for ‘Campbell‐37’. ‘Knox’ and ‘Tipton’ had a faster fruit ripening rate than ‘Campbell‐37’. The total ripe fruit yields, for single and multiple harvests, were 36.7% and 28.6% respectively, higher in ‘Campbell‐37’ than in ‘Knox’. Phosphorus concentration of stem, leaf, and cluster tissues decreased over the season for the 3 cultivars. Phosphorus concentrations of leaves decreased from 0.49% to 0.16% as plant development progressed from seedling stage to ripe fruit harvest. Phosphorus in the vegetative portion of the tomato plant at final harvest represented only about 10% of the total P accumulated. The plant efficiency with respect to P accumulation decreased from an early stage of plant development as the relative growth rate of the plant declined.