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D.A. Raworth and S.J. Clements

Red raspberry (Rubus idaeus L. cv. Willamette) primocanes were artificially defoliated to various degrees and at two dates in each of 2 years to simulate defoliation caused by the twospotted spider mite (Tetranychus urticae Koch). The effect on primocane diameter, lateral length, yield and four yield components was determined. When defoliation occurred evenly along the length of the primocanes, and all floricanes and excess primocanes were removed in early Aug. 1989, yield was reduced 26% at 25%, 50%, and 75% defoliation and 55% at 100% defoliation compared with nondefoliated controls. The number of canes per stool, number of fruit per lateral, and weight per fruit were reduced when defoliation occurred earlier, in August rather than September, but the number of laterals per cane increased with early defoliation. The effect of increasing defoliation on plant growth and yield was generally nonlinear. When defoliation occurred in sections along the lower 2 m of all primocanes, and all floricanes and excess primocanes were removed in Nov. 1992, no significant differences in yield or three yield components were detected. The effects of primocane defoliation are not necessarily predictable, so T. urticae should be controlled before mite-induced defoliation occurs.

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S.S. Miller, R.W. McNew, B.H. Barritt, L. Berkett, S.K. Brown, J.A. Cline, J.M. Clements, W.P. Cowgill, R.M. Crassweller, M.E. Garcia, D.W. Greene, G.M. Greene, C.R. Hampson, I. Merwin, D.D. Miller, R.E. Moran, C.R. Rom, T.R. Roper, J.R. Schupp, and E. Stover

Cultivar and planting site are two factors that often receive minimal attention, but can have a significant impact on the quality of apple (Malus ×domestica) produced. A regional project, NE-183 The Multidisciplinary Evaluation of New Apple Cultivars, was initiated in 1995 to systematically evaluate 20 newer apple cultivars on Malling.9 (M.9) rootstock across 19 sites in North America. This paper describes the effect of cultivar and site on fruit quality and sensory attributes at a number of the planting sites for the 1998 through 2000 growing seasons. Fruit quality attributes measured included fruit weight, length: diameter ratio, soluble solids concentration (SSC), titratable acidity (TA), flesh firmness, red overcolor, and russet. Fruit sensory characteristics rated included crispness, sweetness, and juiciness, based on a unipolar intensity scale (where 1 = least and 5 = most), and acidity, flavor, attractiveness, and desirability based on a bipolar hedonic scale (where 1 = dislike and 5 = like extremely). All fruit quality and sensory variables measured were affected by cultivar. The two-way interaction of cultivar and planting site was significant for all response variables except SSC, TA, russet, crispness, and sweetness ratings. The SSC: TA ratio was strongly correlated with sweetness and acidity sensory rating, but was weakly correlated with flavor rating. The results demonstrate that no one cultivar is ideally suited for all planting sites and no planting site is ideal for maximizing the quality of all apple cultivars.