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.
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.
Muskmelon fruits were either dipped in or injected with 2-(4-chlorophenylthio-) triethylamine hydrochloride (CPTA) at half- and full-slip maturities prior to storage at various temperatures. Concentrations of 500, 1000, and 5000 ppm caused fruits to have more pink color and a higher ratio of red to yellow color than did those untreated. The greatest response to CPTA was in half-slip fruits. We believe that the pink color is associated with lycopene accumulation.
Flowering was induced in the sweetpotato cultivar, ‘Allgold’, by growing plants with a N level of 280 mg/1 in a peat moss-perlite medium. Plants grown with other factorial combinations of N and K failed to flower. Analyses of plants from treatment N2K0 prior to and after flowering showed these plants to contain the highest percentage of N, the lowest total sugars, and the lowest starch in both tops and roots as compared with plants that failed to flower.
Tomato seedlings of a selection from the plant introduction PI 244956 and the cultivar, ‘Floralou’, were grown for 5 weeks following cotyledon expansion under 2 different temperatures regimes, i.e., 42 to 56°F, and 68 to 80° and subsequently grown in the greenhouse at 68 to 80°. Plants of the PI selection grown at the 42 to 56° range as seedling bore more deformed fruits on the first and second clusters than those grown at 68 to 80°. The PI plants produced more deformed fruits in both temperature regimes than did ‘Floralou’ plants. Most fruits from ‘Floralou’ plants appeared normal regardless of seedling temperature. Flower buds from the first and second clusters of both warm and cold-treated plants were studied histologically. Buds with abnormal ovary development exhibited breakdown of tissue at the stylar base. Ovaries of such buds developed into abnormal fruits that were not marketable.
Cracking and scarring of pepper (Capsicum annuum L.) fruit are under genetic control in families having the cultivar Serrano Chili as the P1 parent. Fruit of `Serrano Chili' exhibited slight cuticle cracking or scarring, with no wall cracking, for an average rating of 2.2. Fruit cracking ratings of the P2 parents (`Anaheim Chili', `Red Cherry Small', and `Keystone Resistant Giant') were 1.0, 1.0, and 1.8, respectively, whereas ratings for F, (`Serrano Chili' × `Anaheim Chili'), F1(`Serrano Chili' × `Red Cherry Small'), and F, (`Serrano Chili' × `Keystone Resistant Giant') were 3.5, 2.8, and 3.5, respectively—an indication of overdominance. Cracking ratings in F2 and BCP2 populations were very similar and shifted toward the mean of the P2 parent within each family, while ratings in the BCP1 populations were similar to the F1 mean. Estimates of gene effects for cracking were mostly dominant, with some additive effects in `Serrano Chili' × `Anaheim Chili' and `Serrano Chili' × `Keystone Resistant Giant' families, and additive × additive epistasis in `Serrano Chili' `Keystone Resistant Giant'. Plants selected from segregating generations for either high and low scarring or high and low cracking produced progeny the following year with lower ratings than their respective mother's rating the previous year. Since cracking and scarring were significantly correlated with length, diameter, and length: diameter ratio of fruit in only a few generations and in segregating progeny of selected plants, fruit shape has minimal relationship to cracking and scarring.
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 18.104.22.168, 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'.
A three-year study was conducted with cucumber (Cucumis sativus L.), sweet corn (Zea mays L.), tomato (Lycopersicon esculentum Mill.) and pepper (Capsicum annuum L.) under no-tillage (NT) and conventional tillage (CT) systems. Plant stand of cucumber was less in NT than in CT in 1973 and 1974, but the tillage system had no effect on cucumber plant stand in 1975 when a cover crop was used. Plant stand of NT sweet corn was less than CT in 1973, but equal to that of CT in 1974 and 1975. Tillage system had no effect on survival of tomato and pepper plants. Total yields of NT cucumber were lower than CT in 1974 because of lower plant stand in NT than in CT plots. However, lower NT tomato yields in 1973 and 1974 and NT pepper yields in each of the 3 years was attributed to greater reinfestation and competition of weeds in NT than in CT plots. NT sweet corn yields were as good or better than CT yields. Nutrient uptake varied with cropping system and sampling time. Generally, CT crops had more nitrogen but less phosphorus than NT crops. Calcium was higher in CT cucumber plants early in the 1973 and 1974 seasons but less than that in NT plants at the last sampling dates in 1974 and 1975. The other crops were less consistent than cucumber in calcium uptake. Potassium varied with cropping system and sampling date, while magnesium was not affected by cropping systems.
Spring cabbage plants (Brassica oleracea L. Capitata group) grown by no-tillage culture yielded less than conventionally tilled plants when grown under the same N treatment and spacing. No-till yields could be compensated somewhat by increasing plant population and N, but head size was generally smaller than for conventionally tilled plants. Large head size was positively correlated with high N content of wrapper leaves in 3 of 4 years, while high Ca was associated with large plants or heads in 2 of 4 years.