The Influence of Phosphorus Availability, Scion, and Rootstock on Grapevine Shoot Growth, Leaf Area, and Petiole Phosphorus Concentration

Abstract

Cabernet Sauvignon (CS) and Chenin blanc (Cb) scions on Freedom, AxR#1, St. George, and 110R rootstocks were grown under conditions of sufficient (+P) and deficient (-P) soil phosphorous availability. Shoot length, shoot dry weight, leaf area, and petiole P concentration were lower for -P compared to +P vines. Cb vines had larger leaves and more leaf area than CS vines and the leaf area of Cb vines was less inhibited by exposure to -P than was CS vines. Vines on Freedom had longer shoots, greater shoot biomass, and greater leaf area than vines on other rootstocks regardless of P availability. Under +P vines on St. George produced less shoot dry weight than vines on Freedom, but more than vines on 110R. However, the shoot dry weight and leaf area of vines on St. George was greatly inhibited by -P and vines on St. George appeared to not use P efficiently for growth under these conditions. Vines on 110R produced the least amount of shoot growth and leaf area among the rootstocks under +P, but were also the least inhibited by -P conditions. The shoot dry weight and leaf area of vines on AxR#1 was intermediate between vines on Freedom and vines on St. George and 110R, and were inhibited by -P slightly less than St. George. Freedom and 110R are more suitable for low P soils than St. George and AxR#1.