Higher Percentage Of Fruit Set Research Articles

Yield parameters in young jojoba plants and their relation to actual yield in later years

A total of 30 jojoba clones, among them six already commercial clones and 24 newly selected ones were characterized in terms of yield parameters, chilling requirements and morphological traits. The aim was to supply farmers (from Israel and abroad) better yielding clones. Considerable variability was found among the clones in all the parameters. Some clones exhibited excellent vegetative traits related to yield potential, such as a high survival rate, rapid growth, extensive branching, high node density, while others exhibited outstanding reproductive traits, such as earliness, high flower density, high percentage of fruit set, high seed weight, and high wax content in the seed. The clones also differed in their wax composition. Plants began to yield 2 years after planting in the field, some having commercial yields as early as their third year. The best clones with respect to wax yield were Hazerim, Negev, BGU, Forti, and Gvati, all new clones not yet planted in commercial plantations. An attempt to relate yield parameters at the third year to wax yield at their sixth year was made. The height in the third year and the flower index, relative fruit set and seed weight were related to yield. The flowering pattern of all clones was followed up during the season 1993/94, which was characterized by a combination of cool night temperatures with warm days. This weather enabled the clones that broke dormancy to flower during the winter instead of spring. We were thus able to identify clones with different chilling requirement. In conclusion some very promising clones with high yields can be added to our commercial clones. Owing to the new information gathered on depth of dormancy and flowering pattern, clones can also be allocated to environments differing in climatic conditions.

A comparative study of the efficiency of bumble bees and an electric bee in pollinating unheated greenhouse tomatoes

SummaryThe efficiency of an electric bee in pollinating tomatoes grown in an unheated greenhouse was compared with that of bumble bees. Two years of experiments show that under the moderate climatic conditions of autumn and early winter, the two methods had similar effects on fruit set, seed number, fruit size and yield. Under more severe winter conditions, however, bumble bees were more efficient than the common agricultural practice of using the electric bee 2–3 times a week. Even in the presence of relatively low amounts of pollen grains per flower, a high percentage of fruit set was obtained by the bees. Under these adverse climatic conditions, flower vibration with the electric bee and with bumble bees achieved equal degrees of fruit set, only when the electric bee was operated every day. It may be concluded, therefore, that bumble bees are efficient pollinators as long as the flower organs are functional and a minimum number of pollen grains is available. For achieving similar pollination efficacy with an electric bee, one should adjust the frequency of its use according to the circumstances, with daily operation under unfavourable conditions.

PEGAMENTO DE FRUTOS DE LARANJEIRA `PERA' EM DIFERENTES ALTURAS NA COPA RELACIONADO AOS QUADRANTES GEOGRÁFICOS

Observou-se o pegamento de frutos de laranjeira `Pera' enxertada sobre limoeiro `Cravo' em relação aos quadrantes geográficos (Sudeste, Nordeste, Sudoeste e Noroeste) nos diferentes terços da copa (basal, mediano e apical) em cinco períodos de coleta. O trabalho foi conduzido em Piracicaba-SP, com localização 22º43'S, 43º38'W e 540 metros de altitude. O delineamento experimental foi em blocos ao acaso, considerando-se cada planta um bloco, no esquema fatorial 3x4x5, perfazendo um total de 300 sub-subparcelas. Os parâmetros avaliados foram o número de flores (1a coleta) e frutos (chumbinhos, nas quatro coletas subsequentes), analisando-se separadamente o 1º período e conjuntamente os demais. Os resultados permitiram observar uma diferença significativa a nível de 5% tanto para o número de flores em relação aos quadrantes, destacando-se o SE, como para a interação alturas x quadrantes, destacando-se o terço mediano dentro do referido quadrante que diferiu dos demais. Não foi detectada diferença significativa entre as alturas. Com relação a percentagem de chumbinhos, foi possível distinguir uma diferença significativa ao nível de 5% entre as alturas, os quadrantes e períodos, destacando-se o terço basal e o quadrante SO. A interação do quadrante dentro da altura e vice-versa, não apresentou diferença significativa, embora que no decorrer dos períodos, o comportamento tenha sido semelhante, independente do quadrante ou altura.

Crop load effects on floral quality in olive

Alternate bearing in olive is largely determined by flowering load. In order to know if there are differences in floral quality related to flower load, and if these differences reinforce or alleviate the alternate-bearing tendency, we compared pistil abortion, floral sink strength and fruit set between “on” and “off” ‘Manzanillo’ olive trees. ‘Manzanillo’ trees with light flowering showed a higher percentage of pistillate inflorescences, higher dry weight and nitrogen content of the flower, and a higher percentage of fruit set. The tree with the lightest flower load had greater ovule longevity than the tree with the heaviest flower load, although differences were not found in the incidence of undeveloped embryo sacs. The results suggest partial compensation of the alternate habit by enhancement of female floral quality and an increase in fruit set when low levels of flowering occur.

MOISTURE STRESS AND HORMONAL INFLUENCE ON THE FLOWERING BEHAVIOUR AND YIELD OF GROUNDNUT (ARACHIS HYPOGAEA )

Field experiment conducted at Hebbal, Bangalore, on TMV-2 groundnut during 1976 and 1977 summer seasons, to study the effect of moisture stress and hormonal influence indicated that the total flowers produced in plants stressed between 30 10 45 days from sowing did not differ significantly from the regularly irrigated plots. The pod yield in stressed plots reduced by 4.7 per cent compared to normally irrigated crop with a yield of 3533.5 kg/ha. The flower primordial initiation and the first flower opening were noticed 14 and 24 days after sowing respectively. The first flush of flowers produced before 45th day from sowing dried up and did not form gynophores in stressed plants. However, a higher percentage of fruit set from the second flush compensated for yield differences in both seasons. NAA spray of 25 ppm at any stage of growth did not influence the total flower production as well as yield significantly in stressed and regularly irrigated plots.

Cytokinins of the Developing Mango Fruit

The cytokinin activity has been isolated and identified from extracts of immature mango (Mangifera indica L.) seeds. The structures of zeatin, zeatin riboside, and N(6)-(Delta(2)-isopentenyl)adenine riboside were confirmed on the basis of their chromatographic behavior and mass spectra of trimethylsilyl derivatives. Both trans and cis isomers of zeatin and zeatin riboside were also identified by the retention times of high performance liquid chromatography. In addition, an unidentified compound appeared to be a cytokinin glucoside.The concentration of cytokinins in the panicle and pulp of mango reached a maximum 5 to 10 days after full bloom and decreased rapidly thereafter. The cytokinin level in the seed remained high until the 28th day after full bloom. The quantity of cytokinins in pulp per fruit increased from the 10th day after full bloom, the maximum being attained around the 50th day after full bloom. Similarly, the amount of cytokinins per seed increased from the 10th day after full bloom, reaching a peak on the 40th day and decreasing gradually thereafter.A high percentage of fruit set in mango was persistently maintained by supplying 6-benzylaminopurine (1.5 x 10(3) micromolar) onto the panicle at the anthesis stage and by supplying gibberellic acid (7.2 x 10(2) micromolar) and naphthalene acetamide (3.1 x 10 micromolar) at the young fruit stage.

Effect of Subfreezing Temperature on the Viability of Persian Walnut Pollen1

Abstract Viability of walnut, Juglans regia L., pollen was not diminished by storage at subfreezing temperature, as previously indicated. Pollen stored 20 days at −19°C effected high percentages of fruit set in the orchard in 1969. Fruit set of the bagged flowers was relatively low in 1970, but the set effected by pollen stored a year at −19°C was not significantly different from that effected by fresh pollen. Laboratory tests indicated less than 1% germination for both freshly dehisced and stored pollen, and were unreliable for indicating the ability of walnut pollen to effect fertilization.

Studies on the efficiency of artificial pollination in fruit growing

1. During a period of 1958-1960, a series of experiments was carried out with various kinds of chemicals such as plant growth regulators, vitamins, amino acids, organic acids and inorganic substances, in order to examine their stimulating effect on the pollen germination of pears, apples and persimmons on the artificial media. A similar experiment was also conducted on the stigmas of pears and apples grown in the field.2. Of these substances tested, tartaric acid, oxalic acid and glutamic acid (sodium salt) were the most effective in promoting the pollen germination. Particularly, in the artificial pollination, a high percentage of fruit set was obtained in either case, when the pollens of pears suspended in the sodium of glutamic acid solution were sprayed on the stigmas, or when the flowers of apples were treated with the sodium of glutamic acid solution soon after the blooming prior to the pollination.3. From the standpoint of practical application, it was very convenient for us that glutamic acid could be used in a wider range of concentrations giving no injury to plants, as compared with the other effective chemicals examined in these experiments.