Abstract

Experiment was carried out throughout two successive seasons of 2016 and 2017 on Flame Seedless, Ruby Seedless and Thompson Seedless grapevines grown at the Experimental Orchard of Assiut University, Faculty of Agriculture. The aim of this study was to assess the impacts of abscisic acid (ABA), cluster thinning and their combinations with GA3 on yield weight of three important grape cultivars grown under hot region. Data revealed that, the application of abscisic acid (ABA) increased yield weight (kg/vine), while cluster thinning decreased it. During the 1st season of study (2016), all individual ABA treatments and ABA at 400 ppm combined with GA3 at 10 ppm significantly increased yield weight (kg/vine) comparing with the control treatment. As a result of ABA treatments at 200, 400 and 600 ppm and ABA at 400 ppm plus GA3 at 10 ppm, the yield was increased by 15.5%, 10.5%, 9.8% and 9.2%, respectively. During the 2nd season of study (2017), only ABA at 600 ppm treatment significantly surpassed the control treatment with an increment percentage of 20.5%.  The rest of treatments either had no effect or reduced the yield weight comparing with the control. On the other side, cluster thinning by removing 30% of the total clusters that the vine bearing significantly reduced the yield weight (kg/vine) during the two studied seasons. As a result of such treatment, the yield was reduced by 37.2% and 39.2% in 2016 and 2017 seasons, respectively.

Keywords

grape; Vitis vinifera; ABA; Cluster thinning; yield

The predatory mites, Neoseiulus longispinosus (Evans) and N. womersleyi (Schicha) (Phytoseiidae) are two morphologically close species. Although they can be mainly separated by the length of the dorsal seta S5, misidentifications may occur. The present study investigated various strains of the two closely related species collected from Japan, Taiwan and/or Thailand using a combination of morphological and molecular data. We described and illustrated the adults and immature stages. We also sequenced the 28S region of nuclear ribosomal DNA to determine whether these strains represent different species. The two species could be clearly separated based on the length of seta S5 and the ratio of setae Z5/S5. In a 28S tree, the examined strains also formed separate clades with 100% bootstrap values. We conclude that a combination of different methods is often necessary to precisely distinguish these closely related taxa.

The objective of  this study was to determine the plant density  that result in the best marketable yields and gross crop value per fedan of onion Giza 6 cv. that grown   by sets .Sets were grown at the Experimental Farm of the Faculty of Agriculture, Assuit University, Assuit on September 13 and 15 in 2007/2008 and 2008/2009 seasons, respectively. Sets were grown on rows of 3.5 m long and 50 cm wide. Three rows were included each plot. Sets were grown at 4, 6 and 8 cm between plants (175,116 and 87 plants when sets grown on two sides of row and  262,175and131 plants when sets grown on three sides of row). Results showed  that  , plants gave the smallest bulb diameter when sets were grown at 4 cm space(high density) .The largest space between plants (low density) ,the highest value for both percentage of bolters and doubles were. The highest value of marketable yield was obtained when sets grown at 4 and 6 cm (262 and 175 plants/ row) and on 3 sides per row .Maximum economic returns occurred at higher plant populations.  High incidence of double onions was closely related to low onion plant population. Doubles clearly decreased with increased plant density. Wide plant spacing reduced onion bulb yield, but it significantly increased individual bulb weight and bulb diameter.

Field experiment were carried out on the clay soil of the Experimental Farm, Faculty of Agriculture, Assiut University,Assiut in two consecutive  winter seasons 2007-2008 and 2008 -2009.The aim of this investigation was to study the effects of three planting dates and three seeding rates in cv. Giza 6 on yield and quality of onion sets un- der Assiut conditions. The obtained results indicated that the onion plants. Average bulb diameter increased significantly with earlier planting compared with later planting. Lower seeding rate gave significantly the biggest average bulb diameter. The authenticity bulb was obtained from planting on December 1st in the second sampling date (105 days).However, no true bulb was obtained from any planting date in the first sampling date (75 days)in both seasons. Lower seed rate (30 kg/feddan) significantly gave the truth bulb in both seasons.

The experiments of this study were conducted to investigate the effect of magnetized water and two other chemical substances that are kown as Agro promotor1 (substance No.48) and Agro promotor2 (substance No.50) on growth, yield and chemical composition of onion variety Giza 6.  These substances were obtained from Cairo University. Result revealed that growth parameters, yield and its component and chemical contents increased with using both of magnetic water and Agro promotor1 (substance No.48) at concentration of 3 ml/l comparing with control (untreated) treatment. Using magnetized water and Agro promotor1 (substance No.48) at concentration of 3 ml/l induced positive significant effect on plant height and weight, number of leaves/plant and bulb diameter as well as significantly improved neck and bulb diameters, bulb weight, total soluble soiled, total yield and marketable yield percentage than plants of control treatment which showed an increase in percentage of bolters, in both season. In general, it might be concluded that application of each of magnetized water and Agro promotor1 (substance No.48) treatments proved to be good technology to enhance growth, yield and quality when compare with untreated treatment. The marketable yield was increased by 30% as compared with control treatment by using magnetized water and increased by 22-235% when substance No.48 at concentration of 3 ml/l was used. The increase in total yield ranged from 12-15.4% when using magnetized water and was 14-15.4% when substance No.48 at concentration of 3 ml/l compared with control treatment. This study recommends using magnetized water to obtain the highest marketable yield and the lowest percentage of bolters. In case of magnetized water un-available, Agro promotor1 (substance No.48) at concentration of 3 ml/l can be applied.