The effect of irrigation and canopy management on selected vegetative growth and reproductive parameters of Vitis vinifera L. cv. Shiraz in the Breede River Valley

[摘要] ENGLISH ABSTRACT:The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation The objective of the study was to determine combined effects of irrigation and canopy management practices on grapevine water status, growth, yield and juice characteristics. The field study was carried out with Shiraz/110R grapevines in the Breede River Valley. Grapevines were drip irrigated at 30%, 60% and 90% plant available water (PAW) depletion, respectively. For each PAW level, grapevines had (i) suckered, vertical shoot positioned (VSP), (ii) non-suckered, VSP and (iii) sprawling canopies. Treatments were replicated three times in a randomised block design and applied during the 2011/12 and 2012/13 seasons. Irrigation applied at low PAW depletion levels, i.e. high frequency irrigation, required substantially higher irrigation volumes compared to high depletion levels, i.e. low frequency irrigation. Low frequency irrigation increased grapevine water constraints compared to high frequency irrigation. Sprawling canopy grapevines experienced more water constraints than VSP grapevines. Grapevines irrigated at 90% PAW depletion experienced strong water constraints. Low frequency irrigation seemed to accelerate berry ripening compared to high frequencies, probably due to smaller berries and lower yields. Sprawling canopies consistently enhanced berry ripening due to more sunlight interception by the leaves. Berry ripening of VSP grapevines was slower, but inconsistent between seasons. Level of PAW depletion and canopy management practice did not affect number of leaves per primary shoot. Low frequency irrigation reduced number of leaves per secondary shoot. Leaf number per shoot contributed more to total leaf area than leaf size. Level of PAW depletion did not affect number of shoots per grapevine. Suckering reduced number of shoots per grapevine. Low frequency irrigation reduced total leaf area per grapevine compared to high frequency irrigation. Effects of canopy management practice were more pronounced in the case of high frequency irrigation compared to low frequency irrigation. At pruning, primary cane length was not affected by level of PAW depletion or canopy management practice. Secondary cane mass and diameter were not affected by canopy management practice. Multiple linear regression showed that cane mass was a function of cane length and diameter. Low frequency irrigation reduced berry mass compared to high frequency irrigation, irrespective of canopy management practice. However, at harvest there was no difference in berry mass between 30% and 60% PAW depletion. Low irrigation.

[发布机构] Stellenbosch University