determining fruit set, embryo death, seed number, and development and fruit growth are needed as well as evaluation of the maternal and paternal influences. In the present study, the effect of all possible pollination combinations among the cultivars Ascolana
Daniela Farinelli, Pierluigi Pierantozzi, and Assunta Maria Palese
Bernadine C. Strik and Amanda J. Vance
–19 mm), and large (>19 mm) diameter, and 10 berries from each size category were individually weighed and frozen for later analysis of seed number. Seeds were separated from skin and pulp and prepared for counting using the procedure published by
Sarah K. Taber and James W. Olmstead
. Supporting this association between seed number and fruit size and development period are cases where interspecific crosses have been compared with crosses that were either self- or cross-pollinated. Aalders and Hall (1961) found reduced seed set in lowbush
W.J. Bramlage, S.A. Weis, and D.W. Greene
In a population of `Delicious' apples (Malus domestica Borkh.) with varying seed number at harvest, fruit size and Ca concentration in fruit increased with seed number. Neither K nor Mg concentration in fruit was related to seed number. In another population of `McIntosh' apples from 50 commercial orchard blocks, the percentage of fruit that developed senescent breakdown, a Ca-deficiency disorder, decreased linearly as seed number per fruit increased. Low seed number is probably a factor contributing to Ca deficiency in apple fruit.
Rogério Ritzinger and Paul M. Lyrene
Open-pollinated southern highbush (V. corymbosum L. hybrids) and F1 (southern highbush × V. simulatum Small) hybrid blueberry seedlings were compared for fertility in a high-density nursery in Gainesville, Fla. Most of the pollen sources in the field were tetraploid southern highbush seedlings. Berries were collected from 100 southern highbush seedlings and from 100 seedlings from southern highbush × V. simulatum crosses. The seeds were extracted and dried on a laboratory bench for several days before weighing. No significant differences were found in seed mass/berry between the two types of seedlings. Although the F1 interspecific hybrids averaged slightly lower in seed mass per berry, this was due to the smaller size of their well-developed seeds, not to poor seed development. The estimated number of well-developed seeds per berry was 35.4 and 39.1 for southern highbush blueberries and their F1 hybrids with V. simulatum, respectively. These results indicate that reduced fertility should not be a problem in using V. simulatum to breed southern highbush blueberries.
Daniel L. Ward, Richard P. Marini, and Ross E. Byers
Preharvest fruit drop of apple [Malu×domestica (L.) Borkh.] can cause significant crop losses, but factors controlling date of individual fruit drop are unknown. In three types of experiments, we investigated the relationships among seed number/fruit, fruit weight, and day of year of drop. By shading in mid-May and stigma excision before bloom, we induced variability in seed number. Dropped fruit were weighed, and their seeds were counted daily from late August until all fruit had dropped. Nontreated trees were studied similarly. Regression analyses were used to assess relationships among day of drop, fruit weight, and seed number/fruit. Substantial variation in day of drop of individual fruit was not explained by seed number of the fruit in these experiments with `Smoothee Golden Delicious', `Redchief Delicious', and `Commander York'.
Fahrettin Goktepe and Harrison Hughes*
The watermelon cv. Crimson Sweet was transformed with the copper inducible isopentenyl transferase, the rate-limiting step in cytokinin biosynthesis, gene via Agrobacterium tumafaciences (LBA4404). Transformed (ipt) and nontransformed plants were regenerated from tissue culture and clonally propagated by the rooting of leaf node cuttings. Twelve plants of each were grown in 1-gal. pots. Once the plants initiated new growth both transgenic plants and wild type plants were sprayed with one of four different concentrations (0, 5, 10, & 50 μm) of CuSO4. The experimental unit was a single plant with three replicates. The growth rate, number of leaves, flowers, lateral shoots, and chlorophyll content were measured weekly for five weeks. Treated transgenic plants had greater numbers of leaves, flowers and lateral branches as well as higher chlorophyll levels. Pollen viability was examined in all treatments with no differences among treatments. Plants of both types were self pollinated to generate seeds. Female flowers were bagged before opening and then selfed. Selfed flowers were bagged for at least two days. The fruits were grown for eight to ten weeks with support. Once they reached maturity, fruits were harvested and fruit shape, flesh color, brix, number of normal seeds, number of colored but empty seeds and number of white seeds were recorded. Significant differences were observed only in seed number between wild type and transgenic (both treated and nontreated,) watermelon fruits. The number of seeds in transgenic watermelon plants treated with CuSO4 was reduced to about 5% to 7% of wild type plants. Transgenic plants which received no CuSO4 had approximately 33% to 50% of the seed of wild type.
John C. Neilsen and Frank G. Dennis Jr.
Chan and Cain (Proc. ASHS 91:63-68, 1967) demonstrated that seeded apple fruits inhibited flowering, whereas seedless ones did not. `Spencer Seedless' spurs bearing seeded or seedless fruits were defruited at various times after anthesis in 1989-1991 and fruit weight, seed number and bourse shoot length recorded, as well as repeat bloom. Similar defruiting treatments were also applied to entire `Paulared (all seeded fruits) trees in 1991 and 1992. In all years spurs bearing seedless fruits flowered the following year, regardless of defruiting time, shoot length or fruit weight per spur. Flowering of spurs bearing seeded fruits decreased as defruiting was delayed. In all years over 90% of spurs bearing fruits containing a total of 5 seeds or less flowered, whereas 90% of those with more than 5 seeds remained vegetative. Flowering was not correlated with shoot length or fruit weight. Bearing spurs of `Paulared' flowered when whole trees were defruited within 60 days after anthesis, but flowering was greatly inhibited when fruits were left on for 97 and 74 days in 1991 and 1992, respectively.
Douglas Nichols, Charles Embree, John Cline, and Hak-Yoon Ju
To determine the effect of blossom and fruitlet thinners on crop load, fruit weight, seed development during the year of treatment, and the subsequent year effect on return bloom, fruit weight and yield, a field trial using the biennial apple cultivar `Northern Spy' (Malus × domestica Borkh.) was established. Treatments applied at full bloom included ATS (ammonium thiosulphate) [12% (w/v) nitrogen, 26% (w/v) S]; TD [15.9% (w/v) diacarboxylic acid, 5.5% (w/v) dimethylalkylamine salt (Endothal)] and SCY [57% (w/v) pelargonic acid (Scythe)]. At 18 days after full bloom (DAFB), oil treatments [98% (w/v) mineral oil (Superior “70” oil)] were applied with S [480 g·L-1 a.i. carbaryl (Sevin XLR)] and without as a means of increasing the efficacy of S. BA [19 g·L-1 a.i. 6-benzyladenine/1.9 g·L-1 a.i. gibberellins 4+7 (Accel)]; S; and/or SA [100% (w/w) 2-hydroxybenzoic acid (salicylic acid)], were also applied in a factorial arrangement on the same day. Fruit abscission was significantly increased the year of treatment with BA, S, BA + S, BA + SA, S + SA, BA + S + SA, oil, and S + oil. Average fruit weight was enhanced by S, BA + S, BA + SA, S + SA, BA + S + SA, and S + oil although in the latter treatment the crop load was very low. Only treatments that included BA reduced the number of fully developed seeds per fruit and seed number per trunk cross-sectional area (TCA) and increased return bloom. Defining the number of fully developed seeds per tree coupled with crop load is proposed as a predictor of return bloom in `Northern Spy'.
Ashley K. Brantley, James D. Spiers, Andrew B. Thompson, James A. Pitts, J. Raymond Kessler Jr., Amy N. Wright, and Elina D. Coneva
, as kiwifruit size is positively correlated with seed number ( Ferguson, 1991 ). A. deliciosa fruit can have more than 1200 seeds per fruit, whereas A. chinensis ‘Hort16A’ was reported to contain up to ≈700 seeds per fruit ( Goodwin et al., 2013