Simple trait measurements across rootstock genotypes indicates performance as field grown, grafted vines

Abstract

CSIRO rootstock breeding aims to provide industry with enhanced material to meet challenges associated with the Australian environment, future climate scenarios (high temperatures, limited water supply and drought) and soil-borne pests (phylloxera and root knot nematodes).  In this study, analysis of results from three long term field trials with Shiraz grafted on genotypes from a single family involving Vitis cineria, V. champini, V. riparia and V. rupestris has shown that vine performance and fruit composition can be linked to simple traits, measured on field grown ungrafted seedlings or as ungrafted or grafted nursery grown plants. The field trials included full irrigation and deficit irrigation in a hot climate and supplementary irrigation in cooler region. The simple traits linked to vine performance in these trials included pruning weight and canopy condition after 1 or 2 seasons without irrigation and canopy height of field grown seedling vines; and for vines grown in a high density nursery shoot length, pruning weight, leaf transpiration efficiency, conductance, leaf temperature and ICP mineral element analysis of dried petioles. Across the 3 trials, significant multilinear regressions which included the measured traits accounted for a significant proportion of the variation across the rootstock genotypes including TSS (75%), malate (68%), pruning weight (66%), yeast assimilable nitrogen (62%), titratable acidity (51%), pH (38%), bunch number (38%), bunch weight (38%), tartrate (34%), berry weight (29%), anthocyanin (25%) and yield (25%). The results indicate that measurement of simple traits may provide tools for early screening of rootstock genotypes without establishment of large field trials. Together, the use of molecular markers for discrete traits combined with simple trait measurement tools provide breeders with a rapid evaluation system to breed new rootstocks.