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- Author or Editor: Dean E. Knavel 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.
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.
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.
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.
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.
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.
A short-internode (SI) muskmelon line was compared with a normal-internode (NI) cultivar in four seasons for growth and yield differences. Vines of both plant types were divided into leaves, petioles, and stems at 58, 72, and 86 days of age. Leaf dry weight and leaf area were generally the same for both plant types early in growth. NI plants had greater leaf and stem dry weights and leaf area at 72 days; however, only stem dry weights differed at 86 days. The leaf : stem and leaf area : leaf dry weight ratios were always greater for SI than for NI plants, but NI plants produced twice the number and weight of fruit as SI plants. Mean fruit weight for SI plants was slightly smaller than fruits of NI plants. Doubling the population of SI plants by either spacing plants 0.45 m within the row or planting two per hill reduced fruit number and total fruit weight per plant. Highest total fruit weight was obtained by spacing SI plants 0.90 m apart in a triangular fashion within double rows spaced 0.30 m apart on a mulch row. SI plants contained less K and more Mg in leaves and less N and Ca but more K in stems than NI plants. Both plant types had similar Mg levels in stems at each sampling. There were significant year effects and internode type × year interactions for fruit number, fruit weight, and elemental concentrations.
Short-internode (SI) muskmelon (Cucumis melo L.) genotypes Ky-P7 (si-1 gene for SI) and Main Dwarf (si-3 gene for SI) were compared with the normal-internode (NI) cultivar Mainstream at various plant spacings or planting densities over 3 years. SI `Honey Bush' (si-1 gene for SI) and `Bush Star' (si-1 gene for SI) were included in 2 years. At double the population, SI plants (si gene type) produced ≈35% fewer fruit than `Mainstream' plants grown at one-half the population density. Spacing generally had no effect on average fruit weight, but increasing plant density of SI genotypes decreased the number of fruit per plant. Generally, doubling the density reduced leaf area and total plant dry weight, but had minimal effect on the amount of shaded leaf area. Ky-P7, `Honey Bush', and `Bush Star' plants had more leaf shading than `Mainstream' and Main Dwarf plants.
Pepper transplants grown with 240 or 300g N/m3 were the tallest, and subsequently the highest yielding when grown to maturity with 155 kg/ha soil N. At 100, 210 or 265 kg N/ha, transplants grown for 6 weeks with N level of 300g/m3 were the highest yielding. The optimum level of leaf N for 6 week-old transplants is approximately 3.7% dry wt.
Plants of the ‘Allgold’ sweetpotato were grown for 60 days with 3 levels of N and K in a peat-perlite medium to determine the influence of these nutrients on plant development early in the stage of root enlargement. Dry vine and fresh root weights were highly correlated, with high N and medium K resulting in the largest vine and root weights. The numbers of roots were influenced more by K than by N, but the size of roots was influenced more by N than by K. The addition of N without K was responsible for long roots, and the addition of K reduced root length at all N levels.