Heritability of adventitious rooting of grapevine dormant canes

First online: 30 October 2012One of the most important viticultural characteristics of a grapevine rootstock is the ability to form roots on dormant lignified canes (rootstrike). North American species of Vitis are the primary source of germplasm for grapevine rootstocks and vary widely in their rate of rootstrike. Breeders have hybridized grape species in order to introgress traits to produce commercial rootstocks. A combination of 26 parents consisting of improved and wild accessions of Vitis spp. was used to generate 27 families. The percentage of rootstrike of dormant canes was observed over several years for 552 individuals. A logistic generalized linear mixed model (GLMM) method was used to estimate the narrow sense heritability (h 2) of rootstrike. Heritability was found to be moderate (h 2 = 0.307 ± 0.050). The model also estimated breeding values of all parents and progeny. A GLMM method can be used to estimate breeding values of germplasm to identify individuals with commercially acceptable rates of rootstrike with a defined probability of transmitting this trait to progeny. This is useful for the introgression of traits into potentially new commercial rootstocks. The pattern of normal distribution of rooting indicates that it is possible to identify individuals with good rootstrike from Vitis species that are generally considered to have low rootstrike. Selection of individuals with a higher breeding value will increase the efficiency of rootstock breeding.Brady P. Smith, Matthew S. Wheal, Tim H. Jones, Norma B. Morales and Peter R. Clingeleffe

The influence of grapevine rootstocks on scion growth and drought resistance

Grapes are a widely cultivated and economically important crop. Climate change is increasing the focus and investment on the development of more drought resistant varieties. However, markets often dictate specific grape varieties that can be grown and sold. Thus growers are increasingly interested in conferring particular traits of interest (e.g., drought tolerance) through grafting onto rootstocks. A major goal is to develop rootstocks that can influence scion growth and productivity under drought; particularly those that can increase water conservation through reducing the need for irrigation while ameliorating negative impacts on yields. Growers and scientists recognize that rootstocks have a profound influence on vine physiology (e.g., stomatal conductance, photosynthesis, water status), productivity (e.g., growth, fruit yields, fruit composition), and drought resistance. The challenge is to better understand the exact mechanisms through which rootstocks manifest these effects and thus build the knowledge necessary to drive the development of rootstocks with predictable effects on the scion. The aim of this review is to explore our current understanding of the mechanisms by which grapevine rootstocks influence scion growth and stress response; specifically focused on the integration of vine growth and productivity under water deficit

Improving water use efficiency of vineyards in semi-arid regions. A review

Water is critical for viticulture sustainability since grape production, quality and economic viability are largely dependent on water availability. The total water consumption of vineyards, 300 to 700 mm, is generally higher than the annual average precipitation in many viticultural areas, which induces a risk for sustainability of vineyards. Improving vineyard water use efficiency (WUE) is therefore crucial for a sustainable viticulture industry in semi-arid regions. Increased sustainability of water resources for vineyards can be achieved using both agronomical technology and cultivar selection. Here, we review advances in grapevine water use efficiency related to changes in agronomical practices and genetic improvements. Agronomical practices focus on increasing green water use by increasing soil water storage capacity, reducing direct soil water loss, or limiting early transpiration losses. Cover crops for semi-arid areas show a favorable effect, but careful management is needed to avoid excessive water consumption by the cover crop. Canopy management practices to reduce excessive water use are also analyzed. This is a genetic based review focused on identifying cultivars with higher WUE