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- Author or Editor: E.P. Miller x
Three experiments were conducted in north-central Florida to determine the effects of fall defoliation on flower bud initiation and yield of southern highbush (SHB) blueberry (Vaccinium corymbosum hybrid). In 1998, randomly selected upright shoots of mature, field-grown `Misty' and `Sharpblue' plants were hand-defoliated at monthly intervals beginning 4 Sept. and ending 7 Dec. In 1999, a similar study was conducted using different plants of the same cultivars. Representative shoots were defoliated at monthly intervals beginning 14 Sept. and ending 15 Dec. Additional shoots were also partially defoliated by removing the distal two-thirds of each leaf at monthly intervals from 15 Oct. through 15 Dec. In a third experiment, 2-year-old container-grown `Star' SHB plants were completely defoliated at monthly intervals beginning 13 Sept. and ending 15 Dec. In each experiment, control shoots, or plants ('Star'), were not defoliated. Although there were differences among cultivars and years, all cultivars tested demonstrated negative effects on reproductive growth and development from September and October defoliations. For `Sharpblue', reduced fruit yield from early fall defoliation appeared to be due to fewer fruit set per flower bud. However, for `Misty', reduced fruit yield from early fall defoliation was the result of large reductions in flower bud numbers as well as fewer fruit set per flower bud. September and October defoliations of `Star' reduced yields or delayed fruit ripening. Collectively, these experiments demonstrate the importance of maintaining healthy foliage through October in the lower southeastern United States for adequate flower bud initiation and high yields of SHB blueberry the following spring.
Growth and yield of ‘Misty’ and ‘Star’ southern highbush blueberry (Vaccinium corymbosum hybrid) plants that were grown in pine bark culture were evaluated under several rates of granular or liquid fertilizers. Granular fertilizer resulted in larger canopy volumes and slightly greater annual fruit yield than liquid fertilizer. In 2003 and 2004, canopy growth increased linearly as fertilizer rate increased up to the highest rate tested [81 g nitrogen (N), 11.8 g phosphorus (P), and 44.6 g potassium (K) per plant per year]. Similarly, a positive relationship was found for fruit yield and fertilizer rate during all 3 years. Berry yield was positively correlated with canopy size, and there was no relationship between fertilizer rate and berry yield per canopy volume, indicating that yield and canopy volume increased proportionally with increased fertilizer rate. Mean ‘Star’ berry weight was greater for granular fertilizer treatments than for liquid fertilizer treatments, but mean berry weight of ‘Misty’ was unaffected by fertilizer form. At the end of the experiment, visual examination of eight plants excavated by hand indicated that root systems of blueberry plants were primarily located in the pine bark layer with very few roots penetrating into the underlying soil. Limited water and nutrient holding capacities of pine bark, coupled with frequent irrigations to the shallow root systems in pine bark culture, probably resulted in considerable nutrient leaching and a high fertilizer requirement.
In 1998, representative canes of mature, field-grown, `Misty' and `Sharpblue' southern highbush blueberry were hand-defoliated on 4 Sept., 2 Oct., 6 Nov., 7 Dec., or not defoliated. The experiment was repeated in 1999. Randomized complete-block designs with 11 (1998) or 10 (1999) replications were used. The early defoliation treatments (4 Sept. and 2 Oct.) resulted in reduced flower bud number per unit length of cane for `Misty', but not for `Sharpblue', when compared with later defoliation treatments or controls. A similar response to early defoliation was found both years for both cultivars. The later defoliation treatments (6 Nov. and 7 Dec.) had no significant effect on flower bud number compared to controls. Early defoliation had a negative effect on flower bud development for both cultivars. Flower buds that developed on canes defoliated on 4 Sept. or on 2 Oct. had smaller diameters than flower buds on canes defoliated on 6 Nov., 7 Dec., or on non-defoliated canes. Fruit fresh weight per unit cane length was less for the September and October defoliation treatments than for the December defoliation treatment or controls. These results support the need for summer pruning and a effective summer spray program to control leaf spot diseases that often result in early fall defoliation of southern highbush blueberries grown in the southeastern United States.
Field-grown `Misty', `Star', and `Southmoon' southern highbush, and `Climax' rabbiteye blueberry plants were sprayed to drip with 0, 7.7 and 15.4 g·L–1 concentrations of hydrogen cyanamide in north central Florida on 17 Dec. 1997 and 6 Jan. 1998. Plants were dormant with slightly swollen flower buds (stage 2) at the times of applications. The extent and earliness of vegetative budbreak were increased by both hydrogen cyanamide sprays. Hydrogen cyanamide also increased mean fruit fresh weights and reduced fruit development periods for `Misty', `Southmoon' and `Climax' but not for `Star'. Yield response to hydrogen cyanamide was variable among cultivars. Fruit yields of `Misty' and `Climax' increased slightly by 7.7 g·L–1 sprays and decreased significantly by 15.4 g·L–1 sprays. In that case, increased fruit yields appeared to be the result of greater mean fruit fresh weights while reduced yields resulted from significant flower bud thinning that occurred at the highest spray concentration. Both hydrogen cyanamide spray concentrations increased fruit yield for `Southmoon' and decreased fruit yield for `Star' when compared to controls. Spray date had no effect on fruit yield and little effect on fruit development period. Hydrogen cyanamide has potential for increasing fruit quality and earliness of some blueberry cultivars that are grown in the lower southeastern United States.
Known populations (0, 269, 538, and 1075/ha) of pine voles (Microtus pinetorum LeConte) were maintained in wire mesh-enclosed blocks of ‘McIntosh’/M26 apple trees (Malus domestica Borkh.) for 2 years. There was little effect of the voles the 1st year, but the 2nd year the highest population was associated with the death of one tree; severe reductions in growth, yield, and fruit size; and a dramatic reduction in the value of the crop. Neither the low nor the medium population affected yield significantly, but there was a reduction in vegetative growth in the medium population plot in the 2nd year.
`Nellie White' Easter lilies were grown under two day/night temperature regimes, a positive differential temperature (+DIF) of 15.5C night / 21C day temperature or a negative differential temperature (-DIF) of 19.4C night / 14.4C day temperature. At anthesis the plants were divided into 15 leaf-node segments, starting from the plant base (nodal position 0-15). The segments were further subdivided into leaf, stem and flower tissue parts, with fresh and dry weights being recorded, and tissue being analyzed for NH4-N, P, K, Ca, Mg, Na, Cu, B, Fe, Mn, and Zn.
Of the elements studied, only P content was statistically different at the DIF treatment × nodal position × tissue type interaction. Total 1eaf P per segment was higher in the -DIF plants, with the concentration increasing from 0.19 mg at nodal position O-15 up to the 1.34 mg at nodal position 46-60, compared to 0.16 and 0.76 mg, respectively, for the +DIF plants. There were also significant differences at the DIF treatment × tissue type, with -DIF leaf tissue having a higher total content of P, K, Mg, Ca, Na and B, while Cu was lower, than the +DIF leaf tissue. Results indicate that the distribution of nutrients in Easter lily plants are affected by growing temperature regimes.
The development of a high yielding, pink root-resistant [Pyrenochaeta terrestris (Hansen) Gorenz, Walker, and Larson], mild, sweet, shortday onion (Allium cepa L.) with improved shipping quality was the objective for the onion breeding program in the Texas Agricultural Experiment Station. ‘Texas Grano 1015Y’ (TG1015Y) is a very mild and sweet cultivar with those quality characteristics.
The development of a high yielding, pink root resistant, medium length storage shortday onion (Allium cepa L.) with improved shipping quality and maturing slightly later than ‘Texas Early Grano 502’ (TEG502) was the objective in the development of this cultivar. ‘Texas Grano 1025Y’ (TG1025Y) extends the South Texas onion season by 7 to 10 days beyond the ‘TEG502’ maturity season.
The development of a late maturing, high yielding, pink root resistant shortday onion (Allium cepa L.) with improved shipping quality was the objective for introduction of this cultivar.
The development of a late maturing, high yielding, disease resistant shortday onion (Allium cepa L.) with improved shipping quality and medium length storage characteristics was the objective leading to selection and increase of this cultivar.