A base population of high specific gravity clones was established from a diploid hybrid population of Solarium tuberosum Group Phureja and Solarium tuberosum Group Stenotomum previously adapted to the long-day growing conditions in North Carolina. This base population was subjected to two 2-year cycles of recurrent selection. During each cycle, selections in the field were made on the basis of tuber smoothness, shape, and size. Tubers from unselected clones were bulked by plots. Tuber specific gravity was determined for the selected and unselected (bulk) clones. Tuber specific gravity was significantly greater in the selected than in the unselected clones in each cycle of selection.
K.G. Haynes and F.L. Haynes
H.L. Bhardwaj, A.S. Bhagsari, and K.G. Haynes
Two experiments, each with 100 (Solanum tuberosum L.) genotypes, were planted to compare fall-planted (August 22, 1988) crop with spring-planted (March 14, 1989) crop and to identify high yielding genotypes for each planting. Significant variation for tuber yield, 90-100 days after planting, was observed in both experiments. The mean yield of spring planting (25.8 Mg/ha with a range of 9.8 to 49.5 Mg/ha) was significantly higher than mean yield of fall-planting (18.2 Mg/ha with a range of 8.5 to 30.2 Mg/ha). The five highest yielding genotypes in fall planting were: B-0245-15, B-0175-2, B-0242-2, Kennebec, and Norchip whereas the five highest yielding genotypes in spring planting were: B-0180-36, B-9792-88, B-0179-17, B9988-7, and Belchip.
An additional split-split-plot experiment with 4 replications was initiated March 14, 1989 to identify optimum rate of N fertilizer and spacing within rows. This experiment consisted of three Nitrogen levels (0, 125, and 250 kg/ha), three genotypes (Atlantic, Kennebec, and La Rouge), and two spacings between plants (10 and 20 cm). All plots received 120 kg P and 170 kg K/ha. Data showed that N rates of 125 Kg/ha and 250 kg/ha gave identical tuber yields (50 Mg/ha). Closer spacing of 10 cm within rows resulted in significantly higher tuber yield (46 Mg/ha) as compared to 20 cm spacing (33 Mg/ha).
S.B. Sterrett, K.G. Haynes, and C.P. Savage Jr.
Sixteen broccoli (Brassica oleareacea var. italica) cultivars were evaluated for yield, head maturity, and quality attributes in the fall of 1997. `Liberty', `Sabre', `Barbados', and `XPH12211' were dropped after 1997 because of poor yield, coarse stems with severely shortened internodes, or lack of seed availability. Thus, three new cultivars, `Nomad', `Sussex', and `XPH12212', were included in the 1998 trial. Head yield was generally higher in 1998 than in the cooler and drier 1997. In each year, cultivars were ranked into early and main season based on yield over sequential harvest dates. Only `Windsor' was rated as a main-season cultivar in 1997, but an early-season cultivar in 1998. Cluster analyses were then used to group cultivars within year and season by head quality attributes. Based upon these analyses, `Captain' is recommended for early production because of favorable head quality and moderately high yield potential. After 2 years of tests, none of the main-season cultivars could be recommended. `Arcadia', `Decathlon', and `Windsor' were either too late or inconsistent in maturity. Yield was low for `Excelsior' and `Arcadia'. Head quality of `Laguna' and `XPH12212' was poor or inconsistent. In the 1998 trial, `Nomad' and `Sussex' warranted additional evaluation because of improved yield, head and stem diameter and head quality.
H.L. Bhardwaj, A.S. Bhagsari, and K.G. Haynes
Three experiments, each with 100 potato (Solanum tuberosum L.) genotypes, were conducted using triple lattice designs from 1988-1989. The use of lattice designs did not improve the efficiency of these experiments over randomized complete blocks. The phenotypic stability of tuber yields of 91 genotypes, common to three experiments, was measured by regression of genotype means over environmental means. Regression coefficients indicated that 60 days after planting (DAP), genotypes adapted to high yielding environments (b > 1), had significantly higher tubers/plant, leaf area index, and yield/plant, as compared to genotypes suited to low-yielding environments. At final harvest, approximately 100 DAP, genotypes specifically adapted to high yielding environments had significantly higher tubers/plant and yield/plant than genotypes adapted to low yielding environments (b < 1). Green Mountain, Kennebec, and Norchip were adapted to high-yielding environments whereas La Chipper, Ontario, and Superior were adapted to low-yielding environments.
C.M. Hutchinson, J.M. White, K.G. Haynes, D.M. Gergela, P.A. Solano, and C.S. Lippi
Potato (Solanum tuberosum) is an important agricultural crop for Florida. From 1996 to 2000, the winter and spring potato crop was grown on an average of 15,782.7 ha (39,000 acres) and valued at $117 million. Variety evaluation and selection is an important tool to improve production efficiency and increase the competitiveness of Florida growers. A red-skinned potato variety evaluation was conducted in northeastern Florida in 2002. The experimental design was a 4 (site) × 5 (variety) factorial with four replications at each site. The four sites were the University of Florida's Plant Science Research and Extension Unit and three local commercial farms. Potato varieties in the trial were `Red LaSoda', `LaRouge', B0984-1, B1145-2, and B1758-3. Marketable tuber yields were 36.3, 35.6, 30.2, 20.3, and 21.4 t·ha-1 (324, 318, 269, 181, and 191 cwt/acre) respectively, with tuber yields of the two named varieties significantly higher than the numbered entries. Specific gravity ranged from 1.060 (`Red LaSoda') to 1.070 (B0984-1). There were no significant differences among entries for total cull weight or the incidence of hollow heart, brown rot, or corky ringspot. However, a higher percentage of B0984-1 tubers showed symptoms of internal heat necrosis than all other varieties. Potato varieties ranked from lowest to highest in overall appearance were `LaRouge', `Red LaSoda', B1758-3, B0984-1, and B1145-2. Higher appearance ratings in the numbered entries were attributed to darkerred skin color, rounder tuber shape, and shallower eyes compared to `Red LaSoda' and `LaRouge'. `Red LaSoda' and `LaRouge' will continue to be recommended as the standard redskinned potato varieties for Florida. However, B0984-1 and B1145-2 had desirable characteristics and should be planted in larger plantings to further evaluate quality and production characteristics.
C.M. Hutchinson, J.M. White, D.M. Gergela, P.A. Solano, K.G. Haynes, R. Wenrich, and C.S. Lippi
Potato (Solanum tuberosum) is a high value crop in Florida. It consistently ranks in the top five valued vegetable crops produced in the state. The identification of new potato varieties that improve production efficiency is an imperative because of constantly evolving market and production demands. A chip potato variety evaluation experiment was conducted in northeast Florida in 2002 to compare the production characteristics of industry standards to advanced selections. The potato varieties evaluated in this experiment were bred specifically for processing by the potato chip industry. The experimental design was a four (site) by five (variety) factorial with four replications at each site. The sites were the University of Florida's research farm in Hastings, FL and three commercial farms in the surrounding area. Potato varieties were two seed sources of `Atlantic', as well as, `Snowden', B0564-8, and B0766-3. Marketable yield for each variety was 39.4, 33.4, 38.4, 33.6, and 33.6 t·ha-1 (351, 298, 343, 300, and 300 cwt/acre), respectively. Total yield of B0564-8 was statistically equivalent to an `Atlantic' standard at all four locations and similar to `Snowden' at three of four locations. Specific gravity of B0564-8 and B0766-3 was significantly lower than that of `Atlantic' from both sources but within acceptable range for chip potatoes. B0564-8 tubers had the highest overall appearance ratings and the most consistent size and shape. B0564-8 and B0766-3 tubers had a significantly lower percentage of hollow heart and internal heat necrosis than `Atlantic' tubers. This resulted in overall better chip ratings for the numbered entries compared to `Atlantic' tubers. A potential fit for B0564-8 and B0766-3 in northeastern Florida production may be as a late season chip variety when the potential for the development of internal heat necrosis increases.