Author: Rivka Offenbach

Rivka Offenbach

Ms. MSc. Agr. Research in vegetables, including organic farming. The main vegetable crops are pepper, tomato, eggplant, melon and watermelon. The research focuses in crops grown under partial controlled environmental conditions, such as greenhouses, net-houses and walking tunnels. We study the sustainable production under combined stress conditions (climate, salinity and water drought), efficient use of water and new crops cultivation.

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Recent Publications
  • 14
    years
    ago
    Evaluation of pepper rootstock lines 2007/8
    Vegetables

    תאריך עדכון 14/1/2009

    תיאור מלא The decreased use of chemical soil treatments, the decreased variety of chemicals applied, increased nematode damage and a lack of nematode-resistant cultivars have all increased the need for appropriate rootstock lines for commercial production of conventional and organic pepper. In an experiment that was conducted during the 2007/8 growing season in screen-houses in the organic section of the Yair Research Station (Arava region), we tested new rootstock lines, in comparison with the veteran rootstock line, 23, in an effort to identify pepper rootstock lines that exhibit vigorous vegetative growth under different growing conditions. In particular, we evaluated the performance of the plants in the presence of salinity, low winter temperatures, diseases and soil pests (nematodes). We examined the following new rootstock lines: Capital, 72001 and 72002. During the growing season, the plants from cultivars 7158 and Vergasa that had been grafted onto rootstock line 23 produced many side branches. These branches were removed at a late date, which damaged the yields of these graft combinations and this rootstock line. Overall, ungrafted 7158 yielded 8.9 kg/m2, as compared to the 7.7 kg/m2 produced by 7158 grafted onto rootstock line 23. The difference in these yields is due to the side branches mentioned above. A similar negative yield effect was observed for plants in which ‘Vergasa’ was grafted onto rootstock line 23. These grafted plants yielded 7.4 kg/m2, as compared to the 8.0 kg/m2 produced by ungrafted ‘Vergasa’ plants. The quantities of fruit suitable for export and the percentages of the total crop that were suitable for export were also similar. Grafts of 7158 onto the rootstock lines 72001 and 72002 produced overall yields of 8.4-8.6 kg/m2, similar to the yield of the ungrafted 7158 plants (8.9 kg/m2). The combination of 7158 grafted onto ‘Capital’ rootstock produced an overall yield that was less than 7.4 kg/m2. The results involving export quality were similar.

    In light of the problems that arose as a result of the rapid sprouting of side branches in rootstock line 23, it is difficult to make any conclusions regarding the grafts of 7158 and ‘Vergasa’ onto this control veteran rootstock line. Of the three new rootstock lines that were evaluated (Capital, 72001 and 72002), the lines 72001 and 72002 both performed well. We recommend continued evaluation of these two rootstock lines, in comparison with the outstanding control rootstock from previous years, 23. Following transplanting, it is important to diligently remove side branches as they are produced by the rootstock line. We recommend future evaluations of new rootstock lines with high levels of resistance to viruses, including resistance to the TSWV virus. It is important that the rootstock line and graft have similar virus resistance profiles, to prevent the collapse of grafted plants as a result of incompatible resistances, a phenomenon that is found in tomato grafts.

    שפה English
    מלות מפתח Grafted Capsicum
    מחבר Rivka Offenbach, Ariel Yafe, Israel Tzabari, Yoram Zvieli, Dudu Elkayam, Svetlana Gugiu,Rami Golan
    שנה 2008
    שייכות yzvieli
    תאריך יצירה 14/1/2009
    תאריך עדכון 14/3/2012

  • 14
    years
    ago
    Effect of the Use of Tomato Transplants from a Nursery in Sussiya on Early Fruit setting 2007-8
    Vegetables

    תאריך עדכון 16/1/2009

    תיאור מלא The marketing period for exported tomato is short, from November until April. Growers usually transplant beginning in September, when the weather is warm and not conducive to fruit setting (average air temperature above 35ºC). Transplanting during this period is problematic because conditions for fruit setting (for the fruit intended for export) begin to prevail in mid-October. Early transplanting can lead to problems with fruit setting, and these plants are also exposed to a number of different pests which are very active during this period, particularly the virus vector whitefly and mites. In organic production systems, hormones can not be sprayed and the majority of the growing areas (for both the organic and conventional crop) are not equipped with cooling systems. During this short marketing season, the export crop is small and its profitability has declined from year to year.
    During the summer of 2006/7 season, a project was begun to evaluate the possibility of earlier transplanting in the Syro-African Rift Valley. This research found that earlier transplanting was only successful in structures that were physically cooled using a fan and pad evaporative cooling system. In light of this finding, a decision was made to evaluate the possibility of later transplanting of slightly older tomato plants at a later date. Fruit setting would be induced in the nursery under cooler conditions, prior to transplanting, to ensure the continuous setting of quality fruit and decreased production costs.

    The present work was conducted at the Yair Research Station during the 2007/8 season. When young tomato plants (cv. Shiran and Meital – Hazera Co.) from different cohorts from the Sussiya nursery in the Hebron Mountains, where temperatures are lower than those in the Arava, were transplanted into organic greenhouse plots 15 days later than usual (25 Sept. 2007. vs. 10 Sept.), there was no difference between the yields of the two cultivars. For cv. Meital, the overall yield and the yield of clusters for export were greater for the 45-day-old plants that were transplanted on 25 September than for the standard plants that were transplanted earlier. The plants transplanted at the later date produced fruits that were lighter (weight of individual fruits) than those of the plants transplanted at the earlier date. Early fruit setting, which allowed for a harvest in December, was only observed in the regular plants transplanted at the later date, and was less significant for the plants that were transplanted when they were 45 or more days old than for the control. There was no advantage to transplanting 60-day-old plants instead of 45-day-old plants. For 45-day-old transplants of cv. Meital, the overall yield for the later transplanting date was greater than the overall yield for the earlier transplanting date. However, the yields of clusters for export were similar for the two planting dates. No early fruit setting was observed for the second transplanting date.

    Delaying the transplanting of slightly older tomato plants raised in Sussiya (cv. Shiran and Meital) by 15 days did not lead to a significantly earlier harvest, had no negative effects on overall yield or yield quality and led to increased yields when the transplanted plants were 45 days old. There was no advantage to transplanting 60-day-old plants instead of 45-day-old plants.

    שפה English
    מחבר Rivka Offenbach, Ariel Yafe, Yoram Zvieli, Rami Golan, Israel Tzabari
    שנה 2009
    שייכות yzvieli
    תאריך יצירה 16/1/2009
    תאריך עדכון 14/3/2012

  • 14
    years
    ago
    Use of of a Fan and Pad Evaporative Cooling System
    Vegetables

    Use of a Fan and Pad Evaporative Cooling System

    תחום או ענף אגרוטכנולוגיה; ירקות

    תאריך עדכון 24/1/2009

    A fan and pad evaporative cooling system based on sprinklers and black shading nets was evaluated during the 2007/8 growing season (third season) in a greenhouse planted with pepper at the Zohar Research Station in Sodom Valley. A cooling system made of four nets, which were tightly bound together with the weave facing outward to slow the falling water and increase the cooling efficiency, was installed in the greenhouse. In this experiment, pepper plants (cultivars Celica, 7187, Copla, Sairus, 35131 and 117) were transplanted in the greenhouse on 15 August 2007. Pole trellising was used. Harvesting began on 25 November 2007. There was significant early-fruit setting of export-quality fruit under the conditions prevailing in Sodom Valley. The red cultivars, Celica, 7187 and Sairus, yielded 2.4 kg/m2 of export-quality fruit in November and December. The yellow, early cultivar 117 yielded 3.5 kg/m2 of export-quality fruit. Of the red cultivars, cv. Copla excelled in the production of fruit that was suitable for export even after a storage period. The quality of the fruit produced by cv. Sairus was particularly low, with an overall quality score of 0.5 as compared to the other red cultivars. The yellow cultivar 117 scored very well in terms of fruit quality following storage. The transplanting date used in this study was particularly early (15 August), as compared to the standard local practice. Local pepper crops are generally transplanted into walk-in tunnels during the first and second weeks of September, with the first harvest taking place in late December or early January. These results indicate the potential that a fan and pad evaporative cooling system made of sprinklers and nets holds for those interested in early transplanting in Sodom Valley and marketing fruit beginning in November, as is standard for the central Arava.

    שפה English
    מחבר Rivka Offenbach, Ami Maduel, Yoram Zvieli, Israel Tzabari, Rami Golan, Yitzhak Askira
    שנה 2008
    שייכות yzvieli
    תאריך יצירה 24/1/2009
    תאריך עדכון 9/2/2012

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