Bouquet, A.

Chabbert, A.-M.

Danglot, Y.

English

JKI Open Journal Systems (Julius Kühn-Institut)

Tissue and cell culrure In vitro selection for tolerance to magnesium deficiency in grapevine rootstocks A. BouQcET, A·M. CH.->.BBERT, Y. DANGLOT Station de Recherehes Viticoles , CentreINRAde Mompellier, Domaine du Chapitre, F-347 50 Villeneuve les Maguelonne, France 445 S u m m a r y : Same grapevine rootstocks ( 44-53 Malegue. Fercal) are known as very susceptible to magnesium deficiency, whether it is induced by low Ievel of magnesium in the soil, panicularly in acidic soils or, more generally, by high Ievels of potassium fenilization in soils nonnally provided with magnesium. So, their cultivation is strongly hindered in many vineyards, despite their other interesting culrural characteristics: very high chlorosis resistance for Fercal, drought tolerance, low vigor and beneficial effects on wine qualiry for 44-53 Malegue. In 1'itro tissue culrure offers new prospects to solve this problem. In order to select somaclonal variants of these rootstocks exhibiting a lower Ievel of susceptibiliry to magnesium def1ciency, we compared the results of in vitro tests made on different varieties known as tolerant or susceptible to magnesium deficiency \vith the behavior of these varieties in the vinevard. The varieties chosen were 44-5.3 Malegue and Fercal (susceptible), 41 Band 140 Ruggeri (tolerant). Plants were grown for 2 months on culrure media with different concentrations of magnesium and potassium. Tissues of samples constiruted of the foliar system (leaf blades, petioles and stems) of 6-15 plams (100-300 mg of dry matter) were extracted by HCI 0.1 N (10 ml for 100 mg of dry matter) and ions K-, MC and Ca- we~e assayed by flame spectrophotometry. An initialexperimentwas perfonned using one-node microcuttings and mieregrafrings (seien: Vitis vinifera cv. Syrah) grown on a half-strength Murashige and Skoog medium with three Ievels of potassium and magnesium fenilization. It shows that the uptake of magnesium by vitroplants grown on this medium is not suitable to characterize the differences in susceptibility of rootstock varieties to magnesium deficiency. Fercal was more susceptible than 41 B (difference slightly signiiicant, P = 0.05), 44-53 Malegue appeared curiously moretolerant than 140 Ruggeri, but the difference was not significant. The effect of grafring was not significant and there was· no interaction between variery and grafting. A secend experiment was perfonned using one·node microcuttings grown on a Galzy medium (modified Knoop 1 12), with a low content in magnesium and increasing Ievels of potassium fenilization (0, 500, 7 50 and 1000 mg/1 ofKNO,J. It showed that the uptake ofmagnesium was significantly (P < 0.01) higher in 140 Ruggeri and 41 B than in Fercal and 44-53 Malegue. The inhibitory effect of increasing Ievels ofK' on the absorption of Mg- was clearly demonstrated. Somatic embryos of 44-53 Malegue were obtained by anther culture and selected in conditions of magnesium deficiency: After four sub-cultures in liquid medium, 3 7 embryos were retained from which 4 genninated and developed into plants. Attempts to obtain somatic embryos by anther culrure were unsuccessful with the variety Fercal. 3 selected somaplants of 44-53 Malegue (S , S and S ) were compared to an unselected somaplant (T) and the original clone (Cl. 120). After micropiopägation' of the somaclones, one-node microcuttings an°d micrograftings (scion: Viris 1'inifera cv. Cot) were grown on Galzy medium with reduced Ievel of magnesium and rwo Ievels ofpotassium fenilization (0 and 1000 mg/1 KNO ). There were no signif1cant differences in the uptake of potassium and calcium between clone and somaclone~. With low potassium fenilization, the uptake of magnesium by somaclone S was significantly lower (P < 0.01 ). With high potassium fenilization, somaclone S and clone 120 were signiti'cantlv lower than the other somaclones S , S and T. So, there is evidence of somaclonal variation, but it is po;sible that the occurrence ofthis variatidn is'not link~d to the selection pressure applied in 1'itro. The amplirude of this variation is small and its srability and expression need to be confurned in the vineyard. So far. the somaplants have been acclimated in the greenhause and will be planred next year in the field for funher investigations. K e y w o r d s: magnesium, potassium, .calcium, deficiency, tolerance, rootstock, tissue culture, somaclonal variation, test, selection. · The detailed resulrs will be published elsewhere. 

In vitro selection for tolerance to magnesium deficiency in grapevine rootstocks

https://ojs.openagrar.de/index.php/VITIS/article/download/5539/5298

In vitro selection for tolerance to magnesium deficiency in grapevine rootstocks

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