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Qiryat Shemona, Israel

Zahavi T.,Ministry of Agriculture | Sharon R.,Northern Research and Development | Sapir G.,Northern Research and Development | Mawassi M.,Israel Agricultural Research Organization | And 2 more authors.
Australian Journal of Grape and Wine Research

Background and Aims: Grapevine yellows caused by different phytoplasma strains share common epidemiological and horticultural characteristics. The aim of this study was to determine the implications of the disease epidemiology for growers. Methods and Results: Cabernet Sauvignon and Chardonnay blocks were mapped annually for disease symptoms, and new infections and vine recovery were assessed. We measured yield and pruning weight of healthy, symptomatic and recovered vines, as well as the presence of phytoplasma particles in leaves, shoots and roots. We show a high remission rate in Cabernet Sauvignon vines infected with Stolbur phytoplasma and a low rate in Chardonnay. One year after symptom remission, vines of both cultivars had yields significantly higher than that of symptomatic ones, and after two years the yield of Cabernet Sauvignon vines did not differ from that of healthy vines. Vine vigour remained low for at least two years. Phytoplasma particles were found in all the symptomatic vines, in only one of 12 recovered vines, and were absent in healthy vines. Conclusions: A high rate of recovery from phytoplasma was recorded in Cabernet Sauvignon and a lower rate in Chardonnay, coupled with good yield performance in recovered vines. Significance of the Study: We do not recommend uprooting diseased vines as most vines recover from the disease and return to normal production. © 2013 Australian Society of Viticulture and Oenology Inc. Source

Golodets C.,Tel Aviv University | Sternberg M.,Tel Aviv University | Kigel J.,Hebrew University of Jerusalem | Boeken B.,Ben - Gurion University of the Negev | And 3 more authors.
Climatic Change

Climate change is predicted to alter the rainfall regime in the Eastern Mediterranean Basin: total annual rainfall will decrease, while seasonal and inter-annual variation in rainfall will increase. Such changes in the rainfall regime could potentially lead to large-scale changes in aboveground net primary productivity (ANPP) in the region. We conducted a data-driven evaluation of herbaceous ANPP along an entire regional rainfall gradient, from desert (90 mm MAR [Mean Annual Rainfall]) to Mesic-Mediterranean (780 mm MAR) ecosystems, using the largest database ever collated for herbaceous ANPP in Israel, with the aim of predicting consequences of climate change for rangeland productivity. This research revealed that herbaceous ANPP increases with increasing rainfall along the gradient, but strong dependence on rainfall was only apparent within dry sites. Rain Use Efficiency peaks at mid-gradient in Mediterranean sites without woody vegetation (560 and 610 mm MAR). Inter-annual coefficients of variation in rainfall and herbaceous ANPP decrease along the rainfall gradient up to ca. 500 mm MAR. Climate change is more likely to affect herbaceous ANPP of rangelands in the arid end of the rainfall gradient, requiring adaptation of rangeland management, while ANPP of rangelands in more mesic ecosystems is less responsive to variation in rainfall. We conclude that herbaceous ANPP in most Mediterranean rangelands is less vulnerable to climate change than generally predicted. © 2013 Springer Science+Business Media Dordrecht. Source

Golodets C.,Tel Aviv University | Sternberg M.,Tel Aviv University | Kigel J.,Hebrew University of Jerusalem | Boeken B.,Ben - Gurion University of the Negev | And 3 more authors.

Climate change is expected to reduce annual precipitation by 20 % and increase its standard deviation by 20 % in the eastern Mediterranean. We have examined how these changes may affect herbaceous aboveground net primary production (ANPP) and its inter-annual coefficient of variation (CV) in natural rangelands along a desert—Mediterranean precipitation gradient, at five sites representing arid, semi-arid, and Mediterranean-type ecosystems, respectively, all showing positive linear relationships between herbaceous ANPP and annual precipitation. Scenarios of reduced annual precipitation and increased inter-annual precipitation variability were defined by manipulating mean annual precipitation (MAP) and its standard deviation. We simulated precipitation and calculated ANPP using current ANPP–precipitation relationships. Our model predicts that reduced precipitation will strongly reduce ANPP in arid and semi-arid sites. Moreover, the effect of reduced precipitation on the CV of ANPP along the entire gradient may be modified by changes in inter-annual variability in MAP. Reduced precipitation combined with increased precipitation variability was the scenario most relevant to the wet end of the gradient, due to the increased likelihood for both dry and rainy years. In contrast, the scenario most relevant to the arid end of the gradient combined reduced precipitation with decreased precipitation variability, due to the strong effect on mean ANPP. All scenarios increased variability of ANPP along the entire gradient. However, the higher sensitivity of vegetation at arid and semi-arid sites (i.e., lower forage production) to future changes in the precipitation regime emphasizes the need to adapt grazing management in these ecosystems to secure their long-term viability as sustainable rangelands. © 2015, Springer-Verlag Berlin Heidelberg. Source

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