Variation in chloride accumulation in hybrids and backcrosses of Vitis berlandieri and Vitis vinifera under glasshouse conditions

Abstract

Two glasshouse trials were conducted to examine vineyard data which suggested that the action of a single dominant gene is responsible for low chloride concentrations in petioles of vines of Vitis berlandieri and V. berlandieri x V. vinifera hybrids. Both trials employed a nutrient solution technique with NaCl at a concentration of 25 m M . To an extent, the data from the trials indicated a single gene for Cl - exclusion derived from Vitis berlandieri . There was a marked segregation for high and low petiole Cl - concentrations in one pair of backcross families, MF77-13 ( V. berlandieri x Sultana) x Biancone or Koshu Sanjaku. However, the other pair of backcrosses investigated, MF78-01 ( V. berlandieri x Sultana) x Biancone or Koshu Sanjaku, did not segregate in a 1:1 ratio expected from vineyard data. This result is discussed in terms of possible incorrect classification in the vineyard due to variations in rootzone salinities and/or the action of genes derived from V. vinifera parents which may have modified the phenotypic expression of a major gene. While there was little evidence for genotypic differences in shoot Cl - concentrations being affected by genotypic differences in vine vigor, there were exceptions which raised the question of whether initial vine size affects the expression of a major gene for Cl - exclusion in short-term glasshouse trials. For example, two F1 hybrids, MF77-13 ( V. berlandieri x Sultana) and MU21-91 ( V. berlandieri x Biancone), had high petiole Cl - concentrations contrary to the assumption of a dominant gene for Cl - exclusion derived from V. berlandieri . Both of these genotypes were less vigorous than others, and it is possible that as young vines they were less tolerant of NaCl than more vigorous vines. As a result, they accumulated greater petiole Cl - concentrations than expected. The ratio of genotypic to phenotypic variance was greater for backcross families than for F1 hybrids ( V. berlandieri x V. vinifera ), which supported a segregation of a major dominant gene in the backcross generation.