Research

Filter results

Research

• 17

  Dec
  Lighting in Ranunculus

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 7/1/2009

  תיאור מלא The production of geophyte crops in Israel has increased in recent years and benefits from a seasonal marketing advantage. Following a survey of a number of bulb and corm cut-flower crops, which was conducted by Central and North Arava R&D, it became clear that it is possible to move up the flowering and harvest season relative to that in other regions of the country, yielding positive results that have transformed geophytes into an additional crop in the portfolio of flower crops produced in the Arava. Taking advantage of, and adapting existing cropping infrastructure, such as greenhouses, soil-less culture, and supplemental heating and lighting, has allowed geophytes to become a worthwhile alternative to declining large-scale crops. In work we performed in ranunculus, we found that increasing day-length led to slightly earlier flowering and encouraged the production of longer stems, but adversely affected flower quality and quantity. The ‘Elegance’ cultivars were brought into commercial production as cultivars possessing economical potential, despite their late-ripening flowers. In work that was conducted at the Yair Research Station in the Arava over a period of three growing seasons (2005/6 through 2007/8), we examined the effect of 16 hours of daylight (achieved through the use of supplemental lighting during night-time hours) on the flowering of ranunculus, specifically ‘Elegance’ cultivars. Ranunculus was planted in the ground and in tuff at the end of October, with a planting density of 20 corms per m2. Supplemental lighting was first supplied approximately one month after planting. We found that the cyclical lighting regimen of two weeks of supplemental lighting and two weeks without supplemental lighting, under natural (winter) day-length conditions, caused earlier flowering with minimal damage to flower quantity or quality. Additionally, we found that supplemental lighting with fluorescent bulbs was not as effective as supplemental lighting with incandescent bulbs.

  שפה English
  מחבר Maayan Plaves Kitron, Avi Osherovitz, Keren Elbaz, Dorit Hashmonai, Iris Yedidya, Gidon Luria, Amnon Navon, Yair Nishri
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 7/1/2009
  תאריך עדכון 7/1/2009

  OPEN
• 17

  Dec
  Lisianthus shading

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 7/1/2009

  תיאור מלא Lisianthus production in Israel is primarily directed to the winter and spring, which is when European lisianthus production is reduced and prices are high. For this reason, there is an interest in transplanting young plants as early in the season as possible (until October), while air temperatures are still high. This causes a significant delay in the development of the plants and delayed flowering, which is problematic. In order to facilitate the establishment of the transplanted plants and decrease the temperature around the crop, growers shade production plots from the time that the plants are transplanted. The shading material is left in place for different periods of time, the durations of which have been determined empirically. To date, there have been no in-depth investigations into the effects of shading on quality and yield of lisianthus in the Arava. The primary goals of this investigation were: (1) to test the effects of shade treatments on the development of lisianthus plants, particularly on the timing of differentiation for flowering, the timing of flowering and flower quality; and (2) to set up a system to chart the biochemical factors that contribute to flowering in lisianthus. The study was conducted at the Yair Research Station in the Arava during the 2004/5, 2005/6, 2006/7 and 2007/8 growing seasons. In the first year of the research, we saw that heavy shading negatively affected both the quality and quantity of flowering branches in the cultivar ‘Echo White’. In this season, the shading was in place for long periods of time; the plants spent 58 days under a 75% shade net. In the second season, we shortened the periods of time that the plants were shaded, and found that the best treatments were those in which the plants spent five weeks under a 50% shade net or three weeks under a 75% shade net. In this season, the tested cultivar was ‘Mariachi White’. The actual shading treatments ranged from 67 to 88%. In the third year, we examined a combination of different shading treatments and transplanting dates. None of the shading periods exceeded five weeks. In terms of transplanting dates, for two cultivars, the development of plants transplanted on September 28 was generally one week faster than that of plants transplanted on October 16. Shading delayed differentiation to flowering in all of the cultivars. The amount of amylin was noticeably reduced in all of the plants, indicating that lisianthus plants are dependent on the constant supply of assimilates from the process of photosynthesis.
  In the fourth year, we transplanted plants without any shade and, only after differentiation, spread 90% shade nets, which were left in place for three weeks. From the results of the fourth year’s experiment, we learned that shading after differentiation also has a negative effect on the amount of flowering branches available for harvest, as well as the timing of the harvest of the first crop wave.

  שפה English
  מחבר Maayan Plaves Kitron, Avi Osherovitz, Keren Elbaz, Dorit Hashmonai, Amnon Navon, Yair Nishri, Michelle Zakai, Maya Lugasi, Rivka Ophir
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 7/1/2009
  תאריך עדכון 7/1/2009

  OPEN
• 17

  Dec
  Ranunculus vernalization in the Arava

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 18/1/2009

  תיאור מלא Geophytes production in Israel has increased over the past several years, thanks to a relative marketing advantage during periods in which competing nations have not been active in this market. Following tests of a number of corms and bulbs of flower crops conducted by R&D Central and North Arava, it became clear that taking advantage of and adopting sophisticated cropping infrastructure for geophyte crops, such as the use of greenhouses, growing the plants in trays instead of in the ground, and supplemental heating and lighting, makes it possible to move up the flowering and harvest seasons, relative to other parts of the country, to produce positive results. These results have transformed geophytes in the Arava into an additional crop in the portfolio of local flower crops and a worthwhile alternative to least profitable large-scale crops. When Ranunculus crops, specifically Elegance cultivars, were first brought into commercial production, they were thought to hold great economic potential, despite their late-ripening flowers. In work that was conducted at the Yair Research Station in the Arava over three growing seasons (2005/6, 2006/7, 2007/8), we tested the effects of different vernalization treatments on the timing of flowering. These treatments were: standard vernalization (4ºC for 4 weeks and 9ºC for 1 week), Italian vernalization (gradual cooling of the corms to 13ºC for 1 week, 9ºC for an additional week, followed by 4ºC for one week and gradual warming) and transplanting into seed trays. Despite the fact that we had anticipated that transplanting into trays might be advantageous, this treatment was no better than regular transplanting. Standard vernalization led to early flowering, as well as the production of a larger quantity of flowers. Transplanting into trays could be advantageous in situations in which the planting area could not be prepared in time, or when the goal is to transplant earlier than is customary. In this situation, it is important that the young plants be sufficiently hardy before they are taken from the ground, and it is also important to take into account the likelihood of establishment problems among a portion of the transplanted plants.

  שפה English
  מלות מפתח NURIT
  מחבר Maayan Plaves Kitron, Keren Elbaz, Avi Osherovitz, Dorit Hashmonai, Iris Yedidya, Gidon Luria, Amnon Navon
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 18/1/2009
  תאריך עדכון 14/3/2012

  OPEN
• 18

  Dec
  Digitalis Arava

  Flowers

  by Maayan Plaves Kitron

  תאריך עדכון 14/3/2008

  תיאור מלא In the introduction of the plant species Digitalis purpurea taken place at Yair station in the Arava Valley during two seasons between 2005 and 2007, it has been observed that the possibility exists to cultivate it as a cutting flower. In a comparison among varieties, Lavender was found to be of the highest growth rate and of the largest yield, followed by Krim and Rose, as the least one. The best planting time was at the beginning of September. Lopping treatments brought about an increase in the number of flowers per unit area, however, they reduced the quality of the flowers. Gibberellins' treatments applied to lopped plants decreased flower quality further.

  שפה English
  מחבר Maayan P. Kitron, Keren Elbaz, Avi Oshrowits, Dudu Elkayam, Amnon Navon, Eitan Shlomo
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 14/3/2008
  תאריך עדכון 14/3/2008

  OPEN