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• 17

  Dec
  Mycorrhiza pepper stress Yair Arava 2007-8

  Vegetables

  by Shabtai Cohen

  תאריך עדכון 18/1/2009

  This report sums experiment of growing sweet pepper (Capsicum annuum L. cv Celica) while studying the effects of the plants being Mycorrhizal with Glomus intraradices or not at two levels of fertilization and three levels of irrigation. The motivation is to improve growing and irrigation management based on findings that show improved water and nutrients uptake by Mycorrhizal plants in general and G. intraradices in particular. The experiment took place during 2007/8 agricultural season in a greenhouse at Yair Experimental Station in the Arava Valley.
  The studied three levels of irrigation were 50, 75 and 100% relative to the recommended amount by the extension service that is based on evaporation "A" pan data and a crop factor that changes according to the growing stages. The fertilization treatments were the recommended doze that is actually in practice and low in phosphorous. There were two separate treatments with the two different fertilization levels, each contained four replicas of the six possible combinations of irrigation levels (50, 75 and 100%) and the plants being Mycorrhizal or not (Mycorrhizae treatment hereafter). The dependent and measured variables were total yield and the percentage of export out of the total yield. These data were collected throughout the harvesting season, in this report we relate only to the accumulated data at the end of the growing season. Analysis of variance (ANOVA) was done while fitting a general linear model (GLM) to the data: The effect of the fertilization treatment was statistically significant – the recommended fertilization treatment is better than the low phosphorous one. In the low phosphorous treatment, there was not a significant effect to the irrigation level, however, the yield from Mycorrhizal plants was significantly higher than the non Mycorrhizal ones. In the recommended fertilization treatment, both irrigation level and the Mycorrhiza had a significant effect – higher yields were obtained at the 100% irrigation treatment and the Mycorrhizal plants. No interaction was found between the irrigation levels and the Mycorrhizae – one factor cannot compensate for the other one. Another interesting observation was the larger variability in the low phosphorous treatments.
  On the economic side, it seems that the farmer who grows 4.5 hectares of pepper can increase the income by 315,000 NIS in return to a 6,750 NIS investment of adding Mycorrhizae to the plants.

  שפה English
  מחבר Shabtai Cohen, Rivka Offenbach, Shimon Pivonia, Rami Golan, Yoram Zvieli, Yoram Kapulnik, Uri Yermiyaho, Alon Ben-Gal
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 18/1/2009
  תאריך עדכון 18/1/2009

  OPEN
• 17

  Dec
  Vine storage pepper Arava 2007/8

  Postharvest, Vegetables

  by Rami Golan

  תאריך עדכון 24/1/2009

  תיאור מלא During the commercial cropping season, and particularly in the middle of the season, growers may choose to shade their pepper greenhouses using black shade nets, in order to delay the pepper harvest. There are two main reasons to delay the pepper harvest. The harvest may be delayed in response to low prices at harvest-time or a shortage of workers to harvest the produce. For these reasons, the frequency of pepper harvests may vary. Fruit may be harvested once a week, or left on the vine for 2-3 weeks after it is ready to be harvested. This means that sometimes, particularly in late February and early March, fruit may remain on the vine for a long time after it has ripened. During this period, there are increased complaints about fruit quality from buyers, particularly concerning short shelf-life, old fruit and rotten fruit, to the point that, in some years, export is discontinued during this period due to complaints about fruit quality. In an experiment that was conducted in a net-house at the Yair Research Station during the 2007/8 growing season, we examined the effects of delayed harvest and vine storage over different periods, together with the effects of shading on fruit quality at harvest and shelf-life. For this experiment, we transplanted (20 August 2007) cultivars Copla (Soli) and 7182 (Zeraim). Between 29 October 2007 and 22 November 2007, we marked unripe fruits in the study area (approximately 80 unripe fruits per treatment). On 15 December 2007, we covered half of the experimental area with shade netting. The marked fruits were re-marked when they changed color and 70% of the red fruit was defined as ready to harvest. Harvesting began on 21 February 2008. The harvests were arranged according to the number of days that the fruit was stored on the vine (0 = on-time harvest, or delays of 8, 13, 21, or 28 days). The harvested fruit was sorted and stored under conditions designed to simulate those surrounding fruit sent for export. This fruit was stored for 17 days at 7ºC and 96% humidity, and then for another three days at 20ºC. The fruit was then examined once again to determine its level of quality. The harvesting of fruit for this experiment ended on 13 April 2008.
  The results of this experiment show that shading influences the time at which the fruit change color, and leads to the production of smaller fruits and fruits that have fewer cracks at harvest. Vine storage and delayed harvesting of pepper led to increased proportions of fruits that were old on the day of harvest, in all of the cultivars. The fruit that was stored on the vine for 7-10 days without any shading did not appear marketable following the storage period. The shading effect varied by cultivar. Fruit from the cultivars Copla and 7182 could be stored on the vine for two weeks and still reach buyers in marketable condition. In contrast, 100% of the fruits of 7158 that were stored for a similar period appeared old when they were harvested.

  שפה English
  מחבר Rami Golan, Svetlana Gugiu, Katrina Krijova, Rivka Offenbach, Yoram Zvieli, Israel Tzabari, Dudu Elkayam, Eli Falik, Yoni Elkind
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 24/1/2009
  תאריך עדכון 9/2/2012

  OPEN
• 17

  Dec
  Pepper day heating Zohar 2007-8

  Vegetables

  by Shabtai Cohen

  תאריך עדכון 24/1/2009

  תיאור מלא In a study conducted at the Zohar Research Station (Sodom Valley), pepper production inside a greenhouse that was warmed during the day, by closing the sides of the greenhouse to trap the heat inside so that the temperature approached 28ºC, was compared with pepper production in a plastic-covered greenhouse with open sides. In previous seasons of this experiment, a positive yield effect was observed in greenhouses in which day-time heating was used. In a continuation of this study, an experiment was conducted in the 2007/8 growing season in two greenhouses. The control greenhouse was continuously ventilated; its sides were left open for the entire cropping season. The treatment greenhouse (day-time heating) was connected to a climate control system (Eldar), which maintained the prescribed temperature by opening and closing the sides of the greenhouse in response to the temperature. The defined temperature thresholds were as follows: sides were closed at 27ºC and opened at 30ºC. Within the framework of the experiment, two pepper cultivars, Celica (Efal) and 7158 (Zeraim Gedera) were transplanted (4 Sept. 2007) into the ground and perlite sleeves (calculated stand = 3.3 plants/m2). Spanish trellising was used. As the crop developed, the plants were maintained according to current standard practices for indoor pepper in the Arava. At the end of the experiment, we did not find that the heating treatment had any positive effect, and this treatment was associated with decreased yield of export-quality fruit. Throughout this experiment, cv. 7158 yielded more than cv. Celica. Apparently, the temperatures in the day-time heating treatment were not high enough to induce the expected positive yield effect. The results collected from this year of the study contradict those collected in earlier years. This is apparently due to exceptionally low temperatures both outdoors and in the day-time heating treatment.

  שפה English
  מחבר Shabtai Cohen, Rivka Offenbach, Ami Madual, Israel Tzabari, Yoram Zvieli, Rami Golan, Eviater Itiel
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 24/1/2009
  תאריך עדכון 14/3/2012

  OPEN
• 17

  Dec
  Evaluation of day time heating of Pepper

  Vegetables

  by Shabtai Cohen

  תאריך עדכון 24/1/2009

  תיאור מלא This experiment was conducted in the context of a four-season experiment at the Yair Research Station that evaluated the effects of day-time heating and night-time heating on pepper (Capsicum annuum) yield and quality. In all of the experiments conducted at the Yair Research Station, no advantage was associated with day-time heating, and intense day-time heating (approx. 35ºC) caused a significant decrease in yield. In contrast, at the Zohar Research Station, heating was found to have a positive effect. (Spanish trellising was used at the Zohar Research Station.) Our assumption for this year’s experiment was that crop yield would be limited by the amount of foliage on the plant, based on an inverse relationship between fruit-setting capacity and the amount of foliage on the plant, following the use of Dutch trellising to limit the amount of foliage. This experiment was conducted using Spanish trellising, in which there is almost no pruning.
  The experiment was conducted at the Yair Research Station, Arava, in four greenhouses that each had an area of 340 m2. In each greenhouse, we transplanted (4 Sept. 2007) pepper plants of the cultivars Celica and 7158, with four replicates of each cultivar. Two of the four greenhouses were heated to a minimum night-time temperature of 12ºC. During the day, an average temperature of 28ºC was maintained in these greenhouses. The third greenhouse was not heated at night, but the day-time temperature in this greenhouse was kept at 28ºC. The fourth greenhouse served as a control. This greenhouse was not heated and its sides were not closed. The temperature in the fourth greenhouse was determined by the prevailing environmental conditions.
  Day-time and night-time heating treatments (minimum 12ºC) did not contribute to the production of high-quality yield in either of the cultivars, in comparison to day-time heating alone. The yield quality of cv. 7158 was not affected by any of the treatments and (for this cultivar) there was no difference between the results of the heated treatments and those of the control. However, an effect on overall yield was observed and day-time and night-time heating had positive yield effects. For cv. Celica, there were no differences between the yields of the heated treatments, but the control treatment yielded significantly less (in terms of overall yield and export-quality yield) than the heated treatments. This significant difference can be attributed to an unusually cold January. The results of this experiment suggest that there are highly significant differences between the responses of different cultivars to heating treatments, and additional cultivars should be evaluated in this context.

  שפה English
  מחבר Shabtai Cohen, Avi Osherovitz, Rivka Offenbach, Yoram Zvieli, Eviatar Itiel
  שנה 2009
  שייכות yzvieli
  תאריך יצירה 24/1/2009
  תאריך עדכון 9/2/2012

  OPEN