Higher Percentage Of Fruit Set Research Articles

Effect of pollenizers on production and fruit characteristics of date palm(Phoenix dactylifera L.) cultivar Medjool in Mexico

Pollen from four date palm cultivars (Medjool, Zahidi, Khadrawy, and Deglet Noor) was selected to study the effect of pollenizers on Medjool female production and fruit characteristics. The study was conducted during the 2016 season in San Luis Rio Colorado, Mexico. Three bunches of each of the four selected female palms were pollinized by each source of pollen. Results were statistically analyzed using the ANOVA test. Set percentage and fruit characteristics showed a significant effect depending on the selected pollenizer. Bunches pollinized with the Zahidi cultivar had the highest fruit set percentage at 50.30%, while bunches pollinized with the Khadrawy cultivar had the lowest set percentage at 13.25%. However, bunches pollinized with Khadrawy had the highest total weight (25.73 g), the highest weight of pulp (23.98 g), and the highest length (5.33 cm). The lowest weight of fruit (21.73 g), lowest pulp (20.39 g), and lowest fruit length (4.97 cm) was obtained from bunches pollinized with the Zahidi cultivar. The highest total yield was obtained with Zahidi pollen at 64.55 kg, while the lowest total yield, 41.79 kg, was obtained with Deglet Noor pollen. Total soluble solids, bunch weight, and seed diameter did not show significant variation. The best pollenizers for the Medjool cultivar in terms of fruit set and quality characteristics are the Zahidi and Khadrawy varieties. This study allowed for the identification of fruit characteristics according to the pollenizer used. These results can be used to strategically reach high yields in Medjool date cultivar.

COMPARATIVE STUDY OF SOME SEMI-DRY ARABIAN DATE PALM CULTIVARS GROWN IN MOUNOFIA GOVERNORATE

This study was carried out through 2014 and 2015 to study the performance of four Arabian semi-dry date cultivars produced through tissue culture namely: Zahdi, Sakai, Medjool, and Khalas” grown in El-Khatatba region, Mounofia governorate, Egypt in comparison with the commercial semi-dry Sewy (as a local cultivar). The study involved the flowed assessed parameters, dates of the first and last spathe emergence and bursting, fruit set and fruit retention %, date of harvest, number of bunches/palm and average yield per palm, as well as physical and chemical properties of fruits. Emergence and bursting of spathe of Medjool and Khalasoccurred early, followed by “Sewy and “Zahdi while Sakaicv. came last. Harvesting of all tested cultivars was done on the first week of October. Regarding the yield, highest yield was obtained fromMadjool palms in comparison with other tested cvs. followed by “Sewy and “Zahdi while it was the lowest with Sakai and Khalas. Also, Sewy andMadjool palms produced the highest number of bunches /palm while the lowest number of bunches /palm was recorded by Sakai. With regard to fruit set and fruit retention % Medjool attained the highest percentage of fruit set and fruit retention% while “Khalas was the lowest cultivar in this respect. Concerning physical properties, data proved the superiority of Medjoolfruits in weight, dimensions and flesh/fruit weight% meanwhileSakai fruits were the opposite. As for chemical properties, moisture content in fruits was the highest in “Sakai fruits and lowest in Khalas. Data proved the superiority of Sakai and Madjool in T.S.S% and total sugars content. Results showed also that most of these sugars were reducing sugars. Regarding tannins content, the differences between tested cultivars did not reach the level of significance. General evaluation revealed that Madjoolcv. proved to be the superior in yield and fruit quality among all the studied cvs., followed by Sewy cultivar which ranked the second in both total score units of yield and fruit quality, while Khalas and Sakaicvs.had the lowest score in general evaluation due to receiving the lowest score units specified for yield. However, fruit quality of these cvs.was lower than of the standard cultivar (Sewy). In addition, seemed to be of great yield but fruit quality was less than that of “Sewycv. Thus, one can conclude thatMedjool and Sewy” cvs. proved to be the superior cvs. in yield and fruit quality. However Zahdi seemed to be of great yield but fruit quality was lower than the standard Sewy. On the other hand,Sakai cv. showed lower palm yield but fruit quality was reasonable for consumer, but, it was generally lower than of Sewy cultivar.

Interspecific Hybridization between Eggplant and Wild Relatives from Different Genepools

Wild relatives represent a source of variation for many traits of interest for eggplant (Solanum melongena) breeding, as well as for broadening the genetic base of this crop. However, interspecific hybridization with wild relatives has been barely used in eggplant breeding programs. As initiation of an introgression breeding program we performed 1424 interspecific hybridizations between six accessions of eggplant from the Occidental and Oriental groups and 19 accessions of 12 wild species from the primary (Solanum incanum and Solanum insanum), secondary (Solanum anguivi, Solanum dasyphyllum, Solanum lichtensteinii, Solanum linnaeanum, Solanum pyracanthos, Solanum tomentosum, and Solanum violaceum), and tertiary (Solanum elaeagnifolium, Solanum sisymbriifolium, and Solanum torvum) genepools. Fruit set, hybrid seed, and seed germination were obtained between Solanum melongena and all wild species of the primary and secondary genepools. The highest fruit set percentage and quantity of seeds per fruit were obtained with the two primary genepool species S. incanum and S. insanum as well as with some secondary genepool species, like S. anguivi, S. dasyphyllum, or S. lichtensteinii, although some differences among species were observed depending on the direction of the hybridization. For small-fruited wild species, the number of seeds per fruit was lower when using them as maternal parent. Regarding tertiary genepool species, fruit set was obtained only in interspecific hybridizations of eggplant with S. sisymbriifolium and S. torvum, although the fruit of the former were parthenocarpic. However, it was possible to rescue viable interspecific hybrids with S. torvum. In total we obtained 58 interspecific hybrid combinations (excluding reciprocals) between eggplant and wild relatives. Some differences were observed among S. melongena accessions in the degree of success of interspecific hybridization, so that the number of hybrid combinations obtained for each accession ranged between 7 (MEL2) and 16 (MEL1). Hybridity of putative interspecific hybrid plantlets was confirmed with a morphological trait (leaf prickliness) and 12 single nucleotide polymorphism markers. The results show that eggplant is amenable to interspecific hybridization with a large number of wild species, including tertiary genepool materials. These hybrid materials are the starting point for introgression breeding in eggplant and in some cases might also be useful as rootstocks for eggplant grafting.

The effect of three plant bioregulators on pollen germination, pollen tube growth and fruit set in almond [Prunus dulcis (Mill.) D.A. Webb] cvs. Non Pareil and Carmel

Background: In commercial almond [ Prunus dulcis (Mill.) D.A. Webb] orchards in Chile, the percentage of fruit set is low and commonly reaches 5-30%. As almond trees bloom during a cool period and also suffer from self-incompatibility, any factor that can improve pollination, pollen germination and pollen tube growth or extend the effective pollination period, such as the application of plant bioregulators (PBRs), should be beneficial for fruit production. Results: Three plant bioregulators (PBRs): brassinolide (BL), gibberellic acid (GA 3 ) and kinetin (KN) were evaluated for pollen germination and pollen tube growth in vitro , as well as for fruit set in almond cultivars Non Pareil and Carmel, in central Chile, during the 2013 and 2014 seasons. For pollen germination in vitro, the BL concentration of 10 mg L -1 had the highest value in Non Pareil (97.7%), after 4 h germination in 2014 growing season (the control was 90.9%). KN at a concentration of 50 µL L -1 induced the longest pollen tube growth of 1243.4 µm in Carmel after 8 h germination in 2013 (the control was 917.7 µm). In Non Pareil, the highest percentage of fruit set (31.0%) was achieved in 2014 by spraying during bloom at pink bud stage with KN at 50 µL L -1 (the control was 16.7%). Conclusions: A significant favorable effect of the tested PBRs was observed in pollen germination and pollen tube growth in vitro , as well as on fruit set in Non Pareil and Carmel almonds. Normal 0 21 false false false ES-CL X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif;}

EFFECT OF DRIP IRRIGATION REGIMES AND FERTIGATION LEVELS ON YIELD AND QUALITY OF MANGO CULTIVAR 'ALPHONSO' UNDER ULTRA HIGH DENSITY PLANTING

A field experiment for drip irrigation regimes and fertigation levels in mango in four-year-old trees of ‘Alphonso’ mango was conducted. There were three irrigation regimes in main plots namely I1 (16 L day-1 plant-1), I2 (20 L day-1 plant-1) and I3 (24 L day-1 plant-1) and four fertigation levels in subplots viz., F1 (50% RDF), F2 (75% RDF), F3 (100% RDF) and F4 (125% RDF) replicated three times in a split plot design. The results of the experiment revealed that among the irrigation treatments I3 – 24 L day-1 plant-1 – recorded the highest percentage of fruit set, fruit weight, number of fruits per tree, fruit yield per tree and quality characters like, TSS, ascorbic acid, sugar, carotenoids were also the highest in the same treatment. On comparison of sub plot treatments, percentage of fruit set, fruit weight, number of fruits per tree, fruit yield per tree were recorded by the application of 100% RDF (F3) through fertigation. In the interaction effect, application of 100% recommended dose of fertilizers (120:75:100 g NPK/tree/year) along with 24 L day-1 plant-1 has resulted in the improvement of all beneficial parameters leading to enhanced yield and quality of mango cultivar ‘Alphonso’ under ultra high density planting.

Efeito da intensidade de poda na produção e qualidade de frutos de pessegueiro

O presente estudo teve como objetivo avaliar o comportamento vegetativo e produtivo de pessegueiros quando submetidos a variações na intensidade de desponte dos ramos durante a poda de frutificação. Foram utilizadas plantas de duas cultivares, Riograndense e Leonense, e três intensidades de poda, poda curta (retirada de 2/3 do comprimento do ramo), poda longa (retirada de 1/3 do ramo) e poda sem desponte (manutenção dos ramos íntegros). De acordo com os resultados, as plantas de 'Riograndense' apresentaram frutos com maior diâmetro, já as de 'Leonense' apresentaram maior percentual de frutificação efetiva (40,91 %), firmeza de polpa (7,70 kgf), sólidos solúveis (11,12 ºbrix) e número médio de frutos por planta (70,11). A poda denominada poda curta proporcionou maior diâmetro de frutos e maior volume de massa fresca retirada da poda em verde (3.193,75 g.planta-1). A interação 'Riograndense' e poda curta proporcionou maior percentual de frutos colhidos (91,02 %), maior massa média de frutos (141,62 g) e maior volume de massa fresca na poda de frutificação (3.188,14 g.planta-1), já a maior produtividade foi obtida em plantas de 'Riograndense', que receberam poda sem desponte (10,82 t.ha-1). Os diferentes tipos de poda influenciam no desenvolvimento das plantas, afetando o número de flores e frutos. Nas condições em que o experimento foi conduzido, podemos concluir que características como frutificação efetiva, firmeza de polpa e sólidos solúveis não são alteradas pelos diferentes tipos de poda, já as variáveis relacionadas à produtividade estão intimamente relacionadas com as variações de intensidade de poda de ramos.

Effects of storage length and flowering stage of pollen influence its viability, fruit set and fruit quality in ‘Red’ and ‘Lessard Thai’ sugar apple (Annona squamosa) and ‘Gefner’ atemoya (A. cherimola × A. squamosa)

The fruit set of commercial Annonaceae pollinated by natural pollinators is generally insufficient to produce commercially acceptable yields. In addition, several studies have reported that both the pollen source and age affect the potential percent fruit set of sugar apple and atemoya. Annona flowers are hermaphrodite; however, the female part mature before the male, which is known as dichogamy of the protogynous type. The objectives of the present study were to determine the effect of pollen storage duration on pollen viability; the percent fruit set by hand pollination of ‘Red’ sugar apple, ‘Lessard Thai’ green sugar apple and ‘Gefner’ atemoya; and resulting fruit characteristics as a result of pollen source in South Florida. Hand pollination and in vitro pollen germination tests were arranged in a 3×5 factorial design, with three cultivars, five treatments, and five replicates per treatment. The percentage of in vitro pollen germination was the highest for ‘Red’ sugar apple pollen (26.5%) collected from male stage flowers and for pollen collected from female stage flowers collected late afternoon and germinated 18h later (23%). Percent pollen germination was higher for ‘Lessard Thai’ (∼33%) than for ‘Red’ sugar apple and pollen storage for up to 24h was not significantly different than male stage pollen used immediately and pollen collected from female stage flowers and used 18h later. ‘Gefner’ atemoya pollen did not germinate when pollen grains were collected from male stage flowers and when using female stage flowers collected late afternoon and stored for 72h. Fruit set and fruit quality varied significantly as a result of pollen storage treatments. Hand pollination promoted high percentages of fruit set, greater than 80% when female stage flowers were collected late afternoon and hand pollination performed 18h after collection. Fruit harvested as a result of the various pollen storage treatments varied significantly in weight, diameter, and the number of seeds per fruit. The pollen from ‘Lessard Thai’ sugar apple and ‘Gefner’ atemoya may be stored up to 24 and 48h, respectively.

Pistil starch reserves at anthesis correlate with final flower fate in avocado (Persea americana).

A common observation in different plant species is a massive abscission of flowers and fruitlets even after adequate pollination, but little is known as to the reason for this drop. Previous research has shown the importance of nutritive reserves accumulated in the flower on fertilization success and initial fruit development but direct evidence has been elusive. Avocado (Persea americana) is an extreme case of a species with a very low fruit to flower ratio. In this work, the implications of starch content in the avocado flower on the subsequent fruit set are explored. Firstly, starch content in individual ovaries was analysed from two populations of flowers with a different fruit set capacity showing that the flowers from the population that resulted in a higher percentage of fruit set contained significantly more starch. Secondly, in a different set of flowers, the style of each flower was excised one day after pollination, once the pollen tubes had reached the base of the style, and individually fixed for starch content analysis under the microscope once the fate of its corresponding ovary (that remained in the tree) was known. A high variability in starch content in the style was found among flowers, with some flowers having starch content up to 1,000 times higher than others, and the flowers that successfully developed into fruits presented significantly higher starch content in the style at anthesis than those that abscised. The relationship between starch content in the ovary and the capacity of set of the flower together with the correlation found between the starch content in the style and the fate of the ovary support the hypothesis that the carbohydrate reserves accumulated in the flower at anthesis are related to subsequent abscission or retention of the developing fruit.

Effects of foliar application with compost tea and filtrate biogas slurry liquid on yield and fruit quality of Washington navel orange (Citrus sinenesis Osbeck) trees

Sixteen-year-old navel orange trees at a private orchard located in Kafer El-Sheikh Governorate, Egypt, were used in this study. Compost tea (CT) and filtrate biogas slurry liquid (FLB) were applied at two different concentrations (50% and 100%); control trees were sprayed with water. Trees treated with CT at 100% were the highest in yield, fruit weight, and vitamin C, whereas the highest percentage of fruit set, fruit number, and soluble solid content (SSC), lowest fruit drop, and highest reducing and total sugars were in trees treated with 100% FLB. Concentrations at 50% for both foliar application (CT and FLB) improved yield and fruit characteristics than control treatment. Generally, using a foliar application of compost tea and filtrate biogas slurry liquid at (100%) treatments as food nutrients could be recommended to improve the yield and fruit quality of navel orange fruits under the current study conditions. Implications: Consequently from the previously mentioned results, it was clear the great role of compost tea (CT) and filtrate biogas slurry liquid (FLB) as two sources of foliar application of organic fertilization for Washington navel orange grown in a clay loamy soil, as they are indispensable for improvement of the nutritional status of the navel orange trees and production of maximum yield and quality of orange, as well as minimizing the cost of production and in turn increasing the income of orange orchard. So, it should be recommended the superiority of application of FLB and CT, especially 100%, which gave the best results in yield and physical and chemical characteristics of navel orange fruits.

Pollen and seed fertility of three functional male-sterile lines of eggplant with the wild Solanum cytoplasms

To find out the possibilities of propagation by selfing and production of pure lines through anther culture, pollen fertility and seed fertility were investigated in three functional male-sterile lines of eggplant developed by continuous backcross method using wild Solanum species Solanum kurzii, Solanum violaceum and Solanum virginianum as a cytoplasm donor and Solanum melongena ‘Uttara’ as a nucleus donor. Pollen fertility was assessed by pollen stainability in acetocarmine, in Lugol's solution and in vitro germination rate of pollen at three different stages of pollen maturation, such as, 2 days before anthesis, at anthesis and 2 days after anthesis. Pollen stainability with acetocarmine and in vitro germination rate of pollen in all three stages of pollen maturation were comparatively lower in the male-sterile lines. Pollen stainability with Lugol's solution revealed that, the low pollen fertility of the male-sterile lines would be caused by incomplete degradation of starch during pollen maturation. The male-sterile lines showed high percentage of fruit set with large number of seeds in the fruits obtained from selfing. Our results confirm that, it is possible to propagate the male-sterile lines by selfing and to produce pure male-sterile lines through anther culture.

Preliminary evaluation of pollen quality, fertility relations and fruit set of selected sour cherry cultivars in polish conditions

Preliminary experiments were carried out in spring 2006. The percentage of fruit set of 'Schattenmorelle IR-2', 'Koral', 'Debreceni Bötermö', 'újfefértói Fürtos' and 'Karneol' was higher after open pollination compared with self-pollination. The cultivar Vowi had an inconsiderably higher percentage of fruit set after self-pollination compared with open pollination. The percentage of fruit set in 'Debreceni Bötermö' and 'újfehértói Fürtos' was about 25 % higher after pollination by 'Schattenmorelle IR-2' and 'Koral' compared with the percentage of fruit set after cross - pollination of both cultivars with each other. In general, they did not appear to be good pollinators with each other. The highest quality of pollen was observed for the following cultivars: 'Schattenmorelle IR-2', 'Koral' and Vowi and the lowest result was obtained in 'újfehértói Fürtos'. The highest yield was given by the following cultivars: Vowi, Schattenmorelle IR-2 and Koral.

Initial Growth and Yield of Skeena, Kordia and Ferrovia Sweet Cherry Varieties on Gisela 5 Rootstock

Evaluation and testing rootstocks for sweet cherry and combinations variety / rootstock began long time ago and the goal was to find those solutions that respond better to the specific climatic and soil conditions in terms of adaptability, precocity, productivity and constancy in the fructification of the varieties in the high-density orchard system. This work addresses to these issues by assessing the behavior of the modern sweet cherry varieties 'Skeena', 'Kordia' and 'Ferrovia' grafted on dwarfing rootstock Gisela 5. The trial has been set up in 2009 and it has placed in Pitesti Maracineni area. The trial includes lot of trees planted at a distance of 4 x 2 meter row and plant distance, high density orchard of 1250 trees with drip irrigation system and individual support for trees and trellis. Observations and measurements made on the growth and fructification particularities of these sweet cherry varieties on rootstock Gisela 5 had revealed 'Kordia' as the most vigorously cultivar comparatively to the other two varieties in terms of increased growth of TCSA and total annual tree growth, the weakest being 'Ferrovia' variety. This variety formed the highest number of spur branches per tree and had the highest percentage of fruit set which lead to the obtaining of a higher yield per tree and per unit area.

Performance of Prunus rootstocks for apricot in Mediterranean conditions

The influence of five rootstocks (Evrica, Krymsk ® 86, Torinel, PAC 00-08 and PADAC 01-47) on flowering, fruit set, trunk cross-sectional area, yield efficiency and fruit quality parameters of apricot cultivars ( Prunus armeniaca L.) grown in a Mediterranean agro-climatic environment was evaluated. The five rootstocks were grafted with ‘E-101’ and ‘E-404’ apricot cvs., and established in an experimental orchard in the Region of Murcia (South-eastern of Spain) in 2004. Rootstock had no significant influence on the number of flowers but affected fruit set. Evrica, PAC 00-08 and PADAC 01-47, induced a higher percentage of fruit set on the apricot cultivar ‘E-101’. The greatest TCSA was exhibited with Torinel, Evrica and PADAC 01-47. The yield efficiency was significantly greater on PADAC 01-47, because of its higher yield and cumulative production compared with the other rootstocks. Thus, differences in precocity among rootstocks became evident, PADAC 01-47 being the most efficient rootstock for the first bearing years. The fruit quality traits were also significantly affected by rootstocks. In the case of ‘E-101’, the highest fruit weight was induced by Evrica, Krymsk ® 86 and Torinel. In relation to fruit size, the smallest equatorial, suture and polar diameters were produced by fruit on PADAC 01-47 for both cultivars. The highest firmness was induced by PAC 00-08 for ‘E-101’, while in ‘E-404’ the highest firmness was induced by PADAC 01-47. The colour of fruit was also affected by the rootstock. The brightest coloured skin (high L* values) was found on Evrica, PADAC 01-47, Torinel and Krymsk ® 86. The fruit weight was positively correlated with pulp yield and negatively correlated with TCSA. According to these results, higher fruit quality was found on PADAC 01-47 and Evrica.

COMPARATIVE STUDIES ON SIX POMEGRANATE CULTIVARS UNDER BENI – SUEF GOVERNORATE CONDITIONS

The present study was carried out for the comparison of six pomegranate cultivars namely: Manfalouty, Nab El-Gamal, Wardy, Araby, Badr and Tahrir grown at the experimental farm of the Hort. Res. Instit., station at Seds, Beni- Suef Governorate of middle Egypt region during the two growing seasons of 2007 and 2008.The present study included the different polymorphism variances as ; vegetative growth, flowering, yield, fruit quality and rooting ability of the six pomegranate cultivars. In this respect, Manfalouty and Tahrir cultivars were superior in most of vegetative growth characteristics. On the other hand, Badr cv. had the lowest values in most of these growth characteristics. The highest percentage of perfect flowers / tree was recorded for Araby and Tahrir cvs. and the lowest one was for Nab El-Gamal cultivar. Manfalouty and Wardy cvs. gave higher percentage of fruit set while Badr cultivar recorded the lowest values. Moreover, Nab El-Gamal and Manfalouty exhibited the highest yield (kg / tree), fruit weight, length, diameter & volume and juice volume while Badr cv. gave the least ones. The highest percentage of fruit grain was in Tahrir cultivar. As for fruit juice chemical characteristics (total acidity; total soluble sugars; vitamin (c); ascorbic acid; total anthocyanin and tannins), in general, the best cultivars were Manfalouty, Nab El-Gamal, Wardy and Tahrir. Cuttings of Badr and Tahrir cultivars gave the highest rooting percentage with tallest root while Nab El-Gamal had the highest number of roots in both experimental seasons. It is worthy to mention that, it can be recommended with Nab El-Gamal, Manfalouty, Wardy and Tahrir cultivars ( the yield more than 30 kg/tree) to be planted in Beni-Suef Governorate representing the Middle Egypt region and are preferable than Badr and Araby pomegranate cultivars.

Immunolocalization and quantification of IAA after self- and free-pollination in Olea europaea L.

Abstract In order to characterise the self-compatibility in ‘Pisa 9’, that is an improved clone of cultivar Leccino ( Olea europaea L.), biological, histological and biochemical analyses were carried out. Observations were also focused on ‘Pendolino’, the main pollinator for Italian cultivars considered as being self-incompatible. After self-pollination, in ‘Pisa 9’ the majority of the pollen tubes reached the distal part of the style, entered the ovule leading to a high fruit-set percentage. These same processes were also noted in the Pendolino cultivar, though in a lesser degree. The indole acetic acid (IAA) concentration and its immunocytochemical localization were determined in pollinated flowers after self- and free-pollination and in unpollinated flowers. In both cultivars the highest IAA levels and signal intensity were observed in free-pollinated pistils, whereas after self-pollination a different behaviour emerged. In ‘Pendolino’ the immunostaining was not uniformly distributed and stopped at the style level. This finding sustained the low percentage of fruit-set obtained in the cultivar. In ‘Pisa 9’ the auxin distribution was similar to the free-pollinated pistils where the immunolocalization staining reached the ovary. The correspondence between the IAA signal in the ovary and the high percentage of fruit-set in ‘Pisa 9’ self-pollinated pistils, confirms the role of this hormone in the induction and regulation of the fertilisation process.

Evaluation of the effectiveness of Armothin for chemical peach thinning

This study was designed to test Armothin as a candidate for chemical peach thinning. Fruit set on ‘Andross’ trees sprayed with 3% Armothin was lower than on those sprayed with 1.5% Armothin. Both 3 and 1.5% Armothin resulted in less fruit set than in the untreated control. The rootstock used did not influence the effectiveness of Armothin. However, when treated with 3% Armothin, the number and proportion of fruit set in the cultivar ‘Flavour Crest’ was much higher than that set in the cultivar ‘May Crest’. The highest percentage of fruit set per annual shoot ranged from 10 to 40% on ‘Katerina’ trees treated with 3% Armothin, whereas the range was 60–80% on the untreated control.

The influence of girdling on flower type, number, inflorescence density, fruit set, and yields in three different olive cultivars (Barnea, Picual, and Souri)

The influence of girdling on flower type and number, inflorescence density, and fruit set in 3 different olive cultivars (Barnea, Picual, and Souri) under intensive growing conditions using saline irrigation water was studied for 3 years. The density of inflorescences on the branches was not affected by girdling in any of the 3 cultivars during any of the 3 consecutive years studied. Also, no clear relation between the number of flowers and girdling was found in any of the 3 cultivars tested. The percentage of perfect flowers on the girdled scaffolds of cvv. Barnea and Picual increased significantly, except for Picual in 2002 where no differences were observed. However, no such difference between the non-girdled and girdled scaffolds was observed in cv. Souri. Comparison of fruit set on non-girdled and girdled scaffolds showed a similar and generally positive response to the treatment in the examined cultivars. However, in the third year of the study, no significant difference between the non-girdled and girdled scaffolds was observed. A significantly higher yield of the girdled trees was measured in the 3 cultivars during the first year after the winter girdling. Due to the young age of the trees the effect of girdling on yield was not further recorded. Fruit size on the girdled scaffolds was smaller than those from the non-girdled ones, as a consequence a higher percentage of fruit set was observed on the first ones. The results presented in this study point to different varietal responses of olive trees to girdling. However, this might also be due to the young age of the trees in this study as well as the peculiar agronomic condition of the trees.

Influence of flower bud density, flower bud drop and fruit set on apricot productivity

Flower bud density, flower bud drop and fruit set were studied for nine apricot cultivars in order to understand the influence of these variables on apricot biology and productivity. Cultivars in southern Spain were chosen as representatives of different flowering times and productivity. Results indicate differences among cultivars in the studied parameters. Low flower bud production, high flower bud drop and low fruit set were often recorded in mid- to late flowering cultivars. These traits subsequently led to poor yields. Early blooming varieties, which are frequently good producers, generally showed the highest flower bud density, medium flower bud drop and high percentage of fruit set. The influence of the cultivar was more determinant than the seasonal effect on fruit yield. This information should be useful to breeders for choosing the best parents for productivity.

Effects of Repeat Annual Applications of Dichlobenil on Weed Populations and Yield Components of Cranberry

To address grower concerns that repeated use of dichlobenil could negatively affect cranberry productivity, field studies were conducted at two commercial farms in either high weed density (HW) or low weed density (LW) areas. Data from 4 yr of repeat annual applications of 0, 1.8, and 4.5 kg ai/ha dichlobenil indicated minimal negative impact on cranberry vines. Herbicide application did not affect upright productivity, leaf biomass production, percent fruit set, or other yield parameters adversely; in addition, no improvement in these parameters was noted. Although the interaction of herbicide application with weed density on cranberry root length varied with sampling date, no consistent trend (adverse or positive) was seen. The presence of weeds, rather than herbicide application, was the important determinant of yield. Vines in LW areas produced more marketable fruit and had higher percentage of fruit set than vines growing in HW areas. Repeat annual applications of dichlobenil on commercial cranberry beds may be considered as part of a viable integrated weed management program with no adverse effect on crop growth or yield.

604 Interspecific Hybridization between Euvitis and Muscadinia Grape Species

The grape belongs to the genus Vitis L., which are divided into two subgenera, Euvitis Planch. and Muscadinia Planch. The Euvitis has 50 to 70 species, in which V. vinifera L. is a predominant species with hundreds of known commercial cultivars grown world wide. The Muscadinia (muscadine grapes) consists of only two to three species predominated by V. rotundifolia and only commercially cultivated in the southeastern United States. V. rotundifolia is known by its multiple resistance to almost all grape diseases and insects found on the Euvitis species, while the latter possesses good fruit characteristics that do not exist in muscadines. Attempts to produce rotundifolia-vinifera hybrids to combine good fruit quality and disease resistance of both into F1 hybrids have been made by grape breeders for many years. Limited success was reported when the V. vinifera was used as seed parents. This research extended the interspecific crosses beyond V. vinifera into other Euvitis species. Among the Euvitis species, A. aestivalis, V. cinerea, V. champinii, V. labrusca, V. monticola, V. nesbittiana, V. riparia, V. rupestris, V. thunbergii, V. quinguangularis, all with pistillate flowers, were used as female parents pollinated with V. rotundifolia pollen. Eight out of the 10 cross combinations except V. cinerea and V. thunbergii set fruits. However, most of the Euvitis-rotundifolia crosses had extremely low fruits set (<1% of pollinated flowers). The only exception was V. labrusca cv. Woodruff, which had very high percentage of fruit set (70%). Interestingly, the fruits of V. labrusca cv. Woodruff × rotundifolia were pathonocarpic that had only half size of regular fruits set from open pollination with pollen sources from other Euvitis species. In the reciprocal crosses, three pistillate V. rotundifolia cultivars, `Fry', `Higgins', `Jumbo', were used as female pollinated by pollen from Euvitis species. Limited fruit sets were found from the crosses of V. rotundifolia × V. shuttleworthii, V. cordifolia, V. rupestris, V. Piasezkii, V. quinquagularis. Results from this study indicated that hybridization between Euvitis and muscadinia species is indeed very difficult but it is possible, and some Euvitis species are cross more compatible with V. rotundifolia than the others.