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- Author or Editor: Dean E. Knavel x
- HortScience x
A short-internode mutant of `Mainstream' muskmelon (Cucumis melo L.), designated Main Dwarf, was crossed with 13 normal and six short-internode cultivars or breeding lines. Regardless of whether Main Dwarf was crossed with a normal or short-internode line, the F1 family was normal for internode length. From crosses of Main Dwarf with normal lines, the F2 families segregated in a 3 normal: 1 short-internode ratio and the families from backcrosses to Main Dwarf segregated 1 normal: 1 short internode. Crosses of Main Dwarf with short-internode lines produced F2 families that segregated in a 9 normal: 7 short internode ratio and families from backcrosses to Main Dwarf that segregated 1 normal: 1 short internode. The segregation data from crosses of Main Dwarf with normal lines indicate that Main Dwarf has a recessive gene that conditions short internode. The segregation data from crosses of Main Dwarf with short-internode lines (five conditioned by si-1 and one conditioned by si-2) indicate that the recessive gene for short internode in Main Dwarf is not allelic to si-1 or si-2. The gene for short internodes in Main Dwarf is designated si-3.
Plant spacing or population studies with normal internode-length `Calypso' and short-internode Ky Littleleaf (Ky-LL), both gynoecious-flowering, in 6-row beds for once-over harvest in 1987, 1988, and 1989 showed that increasing spacing increased leaf area per plant, but had no effect on leaf area, fruit number, and total fruit weight in Grades 1, 2, and 3 per growing area. `Calypso' plants had more leaf area than Ky-LL, but both had similar number and weight of fruit. The best spacing for `Calypso' and Ky-LL was 15 × 21.5 cm for an average of 28.5 plants/m2 (283,570/ha). Ark Littleleaf (ARK-LL), a monoecious-flowering normal-internode length genotype, had more leaves and greater leaf area than `Calypso' and KY-LL plants. Increasing bed spacing of Ark-LL plants from 30 × 30 to 30 × 45 cm increased leaf area, fruit number and fruit weight per plant, but not per growing area. For fruit number and weight in Grades 1, 2, and 3, the best row spacing of Ark-LL plants was a single row of 15 cm or a 30 × 30 cm double row with fruit weight of 25,500 and 27,000 kg/ha, respectively. Data for the three plant types in various row spacings to be conducted in 1990 will be presented.
Abstract
Foliage dry weight for a fall turnip (Brassica rapa L. Rapifera group) crop grown in plowed no-till (NT) plots that previously contained a cover crop of hairy vetch (Vicia villosa Roth.) (NT + V) was greater for plants grown in plots that were previously treated with N at 0 and 56 kg·ha−1 than with 112 kg·ha−1. There were significant linear effects of N rates on fresh root and dry foliage weights of turnip plants in plots that had not contained vetch (NT − V), but not for plants in NT + V plots. About 64 and 48 kg·ha−1 of N were recovered by turnip plants grown in NT + V plots that were previously treated with N at 0 and 56 kg·ha−1, respectively. The previous tillage treatments had no effect on turnip root yield.
Abstract
Clipped pepper (Capsicum annuum L.) transplants produced as well as control plants, but out-yielded plants sprayed with butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide). Clipping increased branching and fruiting sites. Solution-culture studies showed fresh weight of clipped plants to be similar to that of daminozide-treated plants, but root and shoot growth of treated plants was less than that of control plants. The different growth responses affected N and Ca absorption.
Abstract
Plants of bibb lettuce (Lactuca sativa var. capitata L.) were grown in greenhouses from January 6 to March 20 at 2 temperature regimes, one involving a –1°C minimum and the other a 10° minimum. On a whole head basis, only N was influenced by temperature; plants grown at the lower temperature contained more N. Youngest leaves contained most of the N and P, while the oldest contained most of the absorbed K, Ca and Mg. Plants grown at the lower temperature contained more N in the youngest leaves and more K in the oldest leaves. Ca levels were highest in oldest leaves of plants grown at the higher temperature. Trimming off the oldest, cold-injured leaves removed approximately 84% of the total Ca present in the plants.
Abstract
Several muskmelon (Cucumis melo L.) cultivars of short-internode or bush-type plants are available, but none have attained commercial prominence. Ky-P7 is a homozygous short-internode inbred that is resistant to all races of powdery mildew (Spaerotheca fuligenea Schlecht., Poll.) in Kentucky, and has value as either a cultivar or as a parent in the development of F1 hybrids.
Plants of Main Dwarf, a short-internode mutant of the normal-internode `Mainstream' muskmelon (Cucumis melo L.), have shorter internodes, fewer nodes, less total vine length, less total dry weight, smaller leaves, increased chlorophyll concentrations, increased specific leaf dry weight, and increased ribulose-1, 5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39, rubisco) activity per unit leaf area than `Mainstream' plants. Main Dwarf plants produce an equal number of fruit as `Mainstream' plants but are only half their size. Many of the plant and fruit characteristics for F1(Main Dwarf × `Mainstream') are similar to those of `Mainstream', except for greater leaf chlorophyll and rubisco activity per unit leaf area. The F1 (`Mainstream' × Main Dwarf) produced fewer and lower weight fruit than its reciprocal, F1 (Main Dwarf × `Mainstream').
Plant growth and yield of broccoli (`Green Comet'), and cauliflower (`Majestic', `Snow Crown') cultivars were evaluated by no-tillage (NT) and conventional tillage (CT) in the fall 1987 with NH4NO3 applied dry or through the trickle line. Total plant dry weight, plant stand, average head weight and number of heads harvested were not affected by tillage system. `Snow Crown' plants had less of the following leaf area, dry weight, plant stand, number of heads harvested, and total head weight, than `Majestic', especially in NT where NH4NO3 applied dry. In the greenhouse, cauliflower cultivars had similar leaf area, leaf dry weight, and mot dry weight at 30, 45, and 60 days after growing in sand culture while broccoli cultivars had similar leaf area, leaf dry weight, and mot dry weight after 35, 50, and 65 days. Generally, nutrient uptake was similar at each sampling date for cultivars within crops. Cultivars had similar leaf water and osmotic potentials when grown for 2 weeks in modified growth chambers at either 23.9 or 29.4 C day, and 18.3 C night. These plants were then root-pruned and grown in sand culture for 3 weeks. Leaf area, mot dry weight, and plant dry weight was greeter for `Majestic' than for `Snow Crown' and `Olympus'.
Abstract
Killing Sudan grass (Sorghum vulgare var. sudanense) at a 30-cm height with glyphosate and leaving the residue on the soil surface reduced the number of marketable heads, head weight, and total yield of fall transplanted ‘Market Prize’ cabbage (Brassica oleracea L., Capitata Group). The total plant weight and weight of heads where the cover crop was killed at a 15-cm height were equal to those of conventional culture. Killing the grass at different heights also affected the concentration and distribution of N, K, and Ca in leaf petioles, leaf laminae, and the core of the matured plant. There were positive correlations of head weight with N in the petioles of wrapper leaves, laminae of inner leaves, and core and with Ca in the laminae of the oldest leaves, wrapper leaves, inner head leaves, and core. Sidedressing with N increased head weight, marketable yield, and N concentration in all plant parts analyzed. The response to Ca(N03)2 was similar to that of NH4NO3. Chemical names used: N-(phosphonomethyl) glycine (glyphosate).
Abstract
A two-year study of popcorn cultivars grown by no-tillage (NT) and conventional tillage (CT) systems indicated that popcorn can be produced successfully by NT. Plant populations, plant heights, ear lengths, and ear weights were generally greater for NT than for CT. Popping expansion of NT corn, except for ‘Snow Puff’, a white kernel cultivar, was equal to that of CT. The use of either NH4NO3 or Ca(NO3)2 at 56 kg N/ha in 1981 and 84 kg N/ha from NH4NO3 in 1982 produced the highest yields. Increasing N to 140 kg/ha decreased yields of ‘Snow Puff’ in CT. The N levels had no effect on popping quality.