Search Results
Abstract
Naphthaleneacetic acid (NAA) thinning sprays applied at appropriate intervals and dosage levels to 3 apple cultivars, verified the existence of a critical stage during which developing fruitlets were maximally sensitive. Average fruit diameter accurately identified NAA-sensitivity, but the index varied among cultivars. Polynomial regression analyses revealed a direct relationship between diameters of individual fruit samples and thinning response for each experimental unit. NAA-induced fruit abscission was usually maximal 2 to 3 days prior to the onset of cytokinesis in the endosperm. Cell wall formation did not invariably signify an end to the induction of significant abscission.
Abstract
Succinic acid-2,2-dimethylhydrazide (SADH) applied one 01 two consecutive seasons for preharvest drop control did not significantly reduce response of ‘McIntosh’ apples to chemical thinning treatments the following year, and increased dosage of thinning chemicals was not warranted. Pronounced reductions in size of mature fruit the following season induced as a carryover effect of SADH, emphasized the need for chemical thinning. Combinations of carbaryl (Sevin) and naphthaleneacetic acid (NAA) generally enhanced size of SADH inhibited fruit, whereas high levels of NAA failed.
Abstract
Three cultivars of peach (Prunus persica (L.) Batsch) were grown for 9 years at 3 different densities under 3 training systems. Those spaced at 1157 and 868 trees/ha were mechanically summer pruned annually to predetermined forms; trees spaced at 397 trees/ha were pruned conventionally. While yields during the first few years reflected tree density, the cumulative yield gap among treatments narrowed annually beginning in the 6th growing season. The usually lower production from mature trees spaced at 1157 and 868 trees/ha was attributed in part to non-selective, summer hedging. The effectiveness of various pest control chemicals did not differ among treatments.
Abstract
Effects of annual mechanical summer shearing on growth and productivity of six European plum cultivars (Prunus domestica L.) were studied. The cultivars were grown for 15 years on three clonal plum rootstocks and trained to modified leader system. The annual summer shearing reduced growth, yield, and yield efficiency index but did not affect mean fruit weight compared to the trees dormant-pruned annually and trained to modified leader system. Trees that were annually dormant-pruned from 1974 to 1984 yielded similarly when grown on ‘Brompton’ (P. domestica L.) and ‘St. Julien A’ (P. insititia Bailey) and ‘Myrobalan B’ (P. cerasifera Ehrh.). Yields of ‘Verity’ and ‘Valor’ were higher than ‘Iroquois’ and ‘Italian’, which had the lowest cumulative yield. ‘Bluebell’, ‘Stanley’, and ‘Valor’ had intermediate yields. Mean fruit weight was the same for all rootstocks trained to modified leader systems, but, after 7 consecutive years of shearing, pooled mean fruit weight from trees on ‘Myrobalan B’ was smaller than that of other roots. Trees with ‘Myrobalan B’ root were larger than trees grown on ‘Brompton’ and ‘St. Julien A’.
Abstract
‘Veeglo’ is an attractive, high quality peach (Prunus persica (L.) Batsch) that matures during the last week in August, 9 days after ‘Redhaven’. Assessments indicate typical, moderate susceptibility to perennial canker (Leucostoma spp.) and moderate resistance to bacterial spot (Xanthomonas pruni (E.F. Smith) Dows.). ‘Veeglo’ was introduced to satisfy the requirement for a high quality fresh market or home preserving peach maturing between Redhaven and Loring, and adapted to climatic conditions in southern Ontario, Canada.