The present paper had the purpose to ascertain the effects of different soil water tensions and different concentrations of boron on the bud fertility in grapevines cv. Italia, grown under a mixed system of pruning. The experiment was conducted in a commercial vineyard in the municipality of Petrolina, state of Pernambuco, Brazil. The experimental set-up was a randomized block design, in a factorial scheme 3x3: three indicative tensions for water recharge by irrigation (-30 kPa, -50 kPa and -70 kPa) and three boron concentrations (3%, 6% and 9%), with three replications and two plants per plot. The control did not receive boron applications and the soil moisture was maintained at field capacity (-10 kPa). The analyzed variables were bud fertility, relative chlorophyll index (CRI), and leaf area. The data were interpreted by means of analyses of variance and regression, and the models were chosen based on the significance of the regression coefficient (R²> 0.70). It was observed that the bud fertility showed a negative linear effect in keeping with the increase of soil water tension, decreasing from 31.88% (-30 kPa) to 23.66% (-70 kPa). However, the bud fertility of grapevines submitted to a water stress of -30 kPa was superior to the one at -10 kPa; boron at 3% resulted in the highest bud fertility rate when compared to the other treatments with boron; soil water stress at -30 kPa caused an economy in applied water of 35.4% when compared to the management at -10 kPa; the relative chlorophyll index increased linearly to the increase of soil water tension, and there was a greater expansion in the leaf area in plants submitted to irrigation management at field capacity.
Vitis vinifera (L.); production systems; matric potential
