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To estimate the effect of treatments or cultural practices over fruit dimensions on peach, such as fresh and dry weight and equatorial and polar diameters (FW, DW, ED and PD, respectively), the use of destructive samples are frequent. These variables are generally not included, due to the time-consuming and research costs involved. With the purpose to determine in situ the FW and DW of fruit of seedling peach trees, two cubic regression models (CRM) were fitted with 1241 and 1119 field observations of FW, DW, and ED. To determine DW, fruits were cut off immediately and dried at 70C for 24-h. These measurements were taken during growing season of 1984 and 1985. At 2-week intervals, 12 samples were collected each year. Each sample consisted in harvesting randomly five fruits and around the middle part of trees. The CRM were fitted taking the mean of five fruits. FW and DW were used as dependent variables, while ED as independent variable. To validate both models, during the growing season of 1985, 11 samples (five fruits per sample) were taken again from other trees. The real and predicted values of FW and DW were analyzed by a linear regression model (IRM), to know the grade of adjustment between them. The CRM of both variables had significant fit (r 2 = 0.975 and 0.941 for FW and DW, respectively). In contrast, the highest variation coefficient was observed in DW (29.14%), compared with FW (13.4%). In both cubic models, error mean square was the lowest compared to other models. The linear relation between real and predicted values ha values of r 2 = 0.983 and 0.941 for FW and DW, respectively; while the variation coefficients were 9.59% (FW) and 17.32% (DW). The CRM's can be used in future seedling peach experimental works, to predict fruit weight after full bloom until harvest.
Cactus pear (Opuntia spp.) is an important Mexican fruit crop cultivated extensively (about 51,000 ha) in the semiarid highlands of Mexico. Fruit exports have increased in the last decade, but to fulfill these markets, fruit size must be enhanced. However, current hand thinning reduces yield, thus making it uneconomical for growers. The objective was to evaluate two reproductive bud (RB) thinning protocols in an effort to increase export fruit size without depressing cactus pear yield. Two experiments were conducted during the 2004 growing season with two cactus pear types: Cristalina (Opuntia albicarpa) and Rojo liso (Opuntia ficus-indica). In the first experiment, the treatments were no thinning (control) or keeping 4, 8, or 12 RBs per cladode. In the second experiment, the treatments were no thinning (control), thinning every other bud along the cladode, and thinning two of every three buds along the cladode. In the first experiment, yield of Cristalina was reduced by 10.4% and 51.8% when eight or four RBs per cladode were retained, respectively. Mean fruit weight of Cristalina decreased with the most severe thinning treatment. Yield of Rojo liso was reduced when four RBs were retained per cladode. In the second experiment, yield of both cactus pear types was unaffected by the thinning treatments. Therefore, we recommend thinning every other bud along the cladode because it does not reduce yield and tends to improve marketable fruit in both cactus pear types. However, this thinning alternative should be tested in other commercial cactus pear types if growers are interested in export markets.
Quality and storability of ‘Pacific Rose™’ apple grown under partial rootzone drying (PRD) were studied over 2 years. The treatments were commercial irrigation (CI) and PRD, which were applied by watering one side of the tree row throughout the season (Expt. 1) or by alternating irrigation between two sides of the tree row when volumetric soil water content ranged between 0.18 and 0.22 m3·m−3 (Expt. 2). The PRD and CI fruit had similar quality attributes at harvest and after storage except that the former had lower weight loss during storage in Exp. 1 and a lower firmness after storage in Exp. 2. Compared with CI, PRD saved water by 0.15 mega liters per hectare in Exp. 1 and by 0.14 mega liters per hectare in Exp. 2. We recommend PRD for humid environments similar to ours.