Use of the bioagent Bacillus subtilis to break dormancy of buds in table grape, Flame seedless, under organic farming condition [ READ ]
Sarah A. El-Kaed, Wafai Z. A. Mikhail, Maisa L. Abd-El-Moneim and Amira Sh. Soliman
Table grape is considered one of the most important fruit crops, either for local consumption, or for exportation. In subtropical countries such as Egypt, there is no adequate winter chilling to stimulate bud burst. Farmers, especially those aim to export their grape fruits, familiarized to use chemical treatment with Dormex (hydrogen cyanamide 2-5%) to break bud dormancy. According to European organic regulation EC. 834/2007 and 889/2008, Annex I and II dormex is not allowed. The present work offers biological method that could be replaced to Dormex in organic farms. Bacillus subtilis (three isolates) were selected from micro flora of dormant buds according to their efficacy in cellulose decomposition. Selected purified and identified B.subtilis isolates were used to determine their effect on grape bud brust compared with Dormex 2%. Data obtained showed that using these bacterial isolates either as single isolate or as a mixture contains two isolates at different concentrations led to significant increase in number of burst buds compared with control treatment (water). Data also showed that positive correlation between concentrations of the bacterial cell /ml and efficacy of the treatment was detected. Data also indicated that the different isolates as single or as a mixture varied in their effect. In this respect, the mixture of B2 + B3 (60 X 106 c.f.u) caused the highest effect whereas the lowest effect was noticed when B. subtilis isolate B2 was used alone at concentration of 20 X 10 6 c.f.u / ml. Moreover, using of bacterial suspension as spray resulted in low effect compared with using the same suspension as brushing using soft brush. Repeating treatment every week for 2 or 3 times led to increase of the number of burst buds compared with using only one application
Sarah A. El-Kaed, Wafai Z. A. Mikhail, Maisa L. Abd-El-Moneim and Amira Sh. Soliman
Table grape is considered one of the most important fruit crops, either for local consumption, or for exportation. In subtropical countries such as Egypt, there is no adequate winter chilling to stimulate bud burst. Farmers, especially those aim to export their grape fruits, familiarized to use chemical treatment with Dormex (hydrogen cyanamide 2-5%) to break bud dormancy. According to European organic regulation EC. 834/2007 and 889/2008, Annex I and II dormex is not allowed. The present work offers biological method that could be replaced to Dormex in organic farms. Bacillus subtilis (three isolates) were selected from micro flora of dormant buds according to their efficacy in cellulose decomposition. Selected purified and identified B.subtilis isolates were used to determine their effect on grape bud brust compared with Dormex 2%. Data obtained showed that using these bacterial isolates either as single isolate or as a mixture contains two isolates at different concentrations led to significant increase in number of burst buds compared with control treatment (water). Data also showed that positive correlation between concentrations of the bacterial cell /ml and efficacy of the treatment was detected. Data also indicated that the different isolates as single or as a mixture varied in their effect. In this respect, the mixture of B2 + B3 (60 X 106 c.f.u) caused the highest effect whereas the lowest effect was noticed when B. subtilis isolate B2 was used alone at concentration of 20 X 10 6 c.f.u / ml. Moreover, using of bacterial suspension as spray resulted in low effect compared with using the same suspension as brushing using soft brush. Repeating treatment every week for 2 or 3 times led to increase of the number of burst buds compared with using only one application
