EFFECT OF 3 CHERRY ROOTSTOCKS ON THE YIELD AND FRUITING OF 4 SWEET CHERRY (PRUNUS-AVIUM L) VARIETIES

Three cherry rootstocks were evaluated at Lenswood, South Australia, for their effect on yield and quality of fruit from 4 sweet cherry (Prunus avium L.) varieties. There were no significant differences in total fruit yield, individual fruit weight, proportion of rain-split fruit, or fruit diameter between the seedling Mazzard (P. avium), Mahaleb (P. mahaleb) and Stockton Morello (P. cerasus) rootstocks, with varieties Venus, Stella, Sam and Merton Bigarreau, over 5 years. Yields for rootstocks and varieties followed similar trends over time. In particular, a large reduction in yield occurred in 1988, after a mild winter and unsatisfactory chilling at Lenswood. Although the difference was not statistically significant, Stockton Morello tended to produce fruit of lower weight and smaller diameter than the other rootstocks. In 1989, Stockton Morello produced fruit with a mean weight of 8.9 g, Mazzard 9.68 g, and Mahaleb 9.41 g. The percentages of fruit with a diameter > 25 mm were 65, 68 and 51, for Mazzard, Mahaleb and Stockton Morello in the same year. Mahaleb was associated with a greater proportion of rain-split fruit in each year. In 1989, 31% of the total yield of fruit from varieties on Mahaleb was rain-split, compared to 23% on Mazzard and 22% on Stockton Morello. Mean fruit yields in 1989 were about 14 kg/tree for Mahaleb, 11 kg for Mazzard and and 12 kg for Stockton Morello; a similar trend occurred in other years. Of the varieties, Sam had least rain-split damage each year, the greatest proportion being 7% in 1987. Venus, an earlier maturing variety, was associated with most rain-split fruit and resulted in 46% damaged fruit in 1989.