Search Results
The segregation ratios for verticillium wilt resistance in PI 215699 suggests that verticillium wilt resistance is a quantitative trait. Additive and dominance genetic variance effects were studied. The F1, F2, F1 B Cr, and F1 B Cs, using the resistant parent (Pr) and the susceptible parent (Ps), PI 215699, and BG. 1668, respectively, were accomplished. The plants were grown in soil temperature tanks with a 25 ± 1C soil temperature, an inoculum level of 2000 microsclerotia of Verticillium dahliae Kleb. per gram of soil, and 18 hours of 250 umol·m-2 · s-1 light. The experiment consisted of four replications with 30 plants per replication for each generation. The seedlings were individually scored 70 days after sowing for an interaction phenotype score (IP) using a scale ranging from 1 to 9 in which 1 = no aerial symptoms and 9 = death. Means, variance, and standard deviations for the percentage of resistant plants (IP = 1) were calculated. A joint three-factor scaling test to estimate the parameters [mid-parent value (m), additive effects (d), and dominance effects (h)] revealed that the data did not fit a simple additive-dominance model. Epistasis was suspected to be present and a joint six-factor model was therefore tested. The joint six-factor model estimates m, d, h, and three epistatic interactions parameters [additive × additive (i), additive × dominance (j), and dominance × dominance (1)]. All epistatic interactions parameters were significant. These results indicate that additive and epistasis effects were involved in the genetic control of verticillium wilt resistance in PI 215699. Broad-sense and narrow-sense heritabilities for percentage of resistant plants in population PI 215699 were estimated to be 0.81 and 0.48 after 70 days of sowing, respectively.
Effect of combination and concentration of growth regulators on the regeneration of pepper plant from different explant tissues was studied. Seedlings were grown aseptically in 400 ml glass bottles containing MS agar medium at 26±2C under a 16 h·d-1 photoperiod (2000 lux, florescent lamps). Explants taken from 4 week-old seedlings were cultured under these conditions on 40 ml of MS agar (8 g·liter-1) medium containing 3 g·liter-1 sucrose in a 400 ml glass bottle. Primary and subsequent leaves attached to petiole regenerated better than cotyledon and hypocotyl. Among the combinations of different concentrations of cytokinin and auxin added in the medium, a combination of 5 μM IAA with either 10 μM zeatin or 10 μM BA gave the best regeneration. With these combinations, regeneration frequency of multiple shoots from the primary and subsequent leaves was greater than 70%. Regenerated shoots rooted readily in MS agar medium containing 3 g·liter-1 sucrose and 0.5 μM NAA.
Field research was conducted in Deerfield, Mass. to study the effects of different cover crop species seeded between plastic mulch on weed pressure and pepper yield. A complete fertilizer was applied before plastic was laid on Sept. 13, 1991. Two cover crop treatments were seeded Sept. 13, 1991: white clover (Trifolium repens) alone and hairy vetch (Vicia villosa) in combination with winter rye (Secale cereale). On May 27, 1992 the vetch and rye were mow-killed with the biomass left on the soil surface. Annual rye (Lolium multiflorum) was then seeded on the same day as the third cover crop treatment. The remaining two treatments were a weedy check and a hand-weeded check. Peppers were transplanted into the plastic on May 31. Both the annual rye and clover were mowed three times over the course of the experiment with the biomass left between the plastic mulch. The white clover and annual rye were much more competitive with weed species than the dead mulch of vetch and rye. The three cover crop treatments had pepper yields that were severely depressed compared to the hand-weeded treatment. Among the three cover crop treatments, only the annual rye yielded more peppers than the weedy check.
Physical characteristics [initial water content, surface area, surface area: volume (SA: V) ratio, cuticle weight, epicuticular wax content, and surface morphology] were examined to determine relationships between physical properties and water-loss `rate in pepper fruits. `Keystone', `NuMex R Naky', and `Santa Fe Grande' peppers, differing in physical characteristics, were stored at 8, 14, or 20C. Water-loss rate increased linearly with storage time at each temperature and was different for each cultivar. Water-loss rate was positively correlated with initial water content at 14 and 20C, SA: V ratio at all temperatures, and cuticle thickness at 14 and 20C. Water-loss rate was negatively correlated with surface area and epicuticular wax content at all temperatures. Stomata were absent on the fruit surface, and epicuticular wax was amorphous for each cultivar.
The energized water, Bio Green Water (BG water) was manufactured through a series of processes: tap water, purification, adding catalysts, spectra energy imprinting, filtering, BG water. BG water was supplied at four times at 3-week interval to the bench soil of green peppers (`Nokwang') in the plastic film house. BG water-treated green pepper showed the reduced plant highs compared to the control, although there were no difference in the number of nodes and leaves between the BG water treatment and the control. This was attributed to shorter internode length by the treatment. The BG water treatment significantly increased fruit weight, length, and diameter and decreased abnormally curved fruit. The treatment also increased harvested fruit numbers and yields outstandingly. Postharvest, the green peppers harvested from the treated plants were not changed in green color; however, fruit in the control were gradually discolored to dark brown.
Hot pepper is the most important vegetable in Korea in terms of both acreage and product value. Morphogenic response in tissue culture of hot pepper varied greatly with explant source and growth regulators. Somatic enbryogenesis, which we believe had not been reported yet, was only induced from 5-month-old callus derived from anther culture. Embryogenic callus was solely observed in the MS medium supplemented with 2 mg/l of NAA and 2 mg/l of BA. Better somatic embryogenesis and plant regeneration was observed on hormone free medium. Adventitious organogenesis was well induced from both hypocotyl and cotyledon. Polarity of explant for shoot regeneration was observed. Success rate of regeneration has been continuously improved mainly due to combinations of growth regulators. The best combination so far was 2 mg/l of zeatin and 1 mg/l of IAA, resulting in 92% of regeneration from cotyledon explant.
Based on anatomical investigations, temperature effect on the rate of plant and flower primordium differentiation were determined. Flower primordium differentiation of bell pepper was divided into 10 stages from a vegetative shoot apex to a fully developed flower bud according to ontogenic changes of the shoot apex. Both the physiological age as determined by leaf number and the flower primordium differentiation were significantly hastened by the high temperature of 30*C day and 15*C night. The flower primordium differentiation was highly correlated with the physiological age and the relationship was independent of temperature. The result showed that carpels were initiated between the sixth and seventh leaf stage and were fused with each other and with developing placentae after the eighth leaf reaching 1 cm long.
A replicated greenhouse study was conducted to confirm the availability of resistance to western Rower thrips in pepper germplasm. Host-plant resistance ratings confirmed earlier observations that there is a considerable amount of variability within pepper germplasm for reaction to F. occidentalis. Plants of `Keystone Resistant Giant', `Yolo Wonder L', `Mississippi Nemaheart', `Sweet Banana', and `California Wonder' were resistant to the insect and exhibited only mild symptoms of damage. Plants of `Carolina Cayenne', `Santaka', and `Bohemian Chili', however, exhibited the symptoms of severe thrips damage, i.e., poorly expanded, deformed, and distorted leaves; greatly shortened internodes; and severe chlorosis. The resistance to F. occidentalis in pepper appears to be due to tolerance mechanisms, not antixenosis (nonpreference) or antibiosis mechanisms. Thrips-resistant cultivars could be used as a cornerstone in an integrated pest management program for greenhouse pepper production.
Three Korean cultivars, Pungkak, Kalmi, and Subi, were crossed with PI 201234, which has resistance to P. capsici. A backcross breeding program was initiated to incorporate the Phytophthora resistance into the Korean cultivars, but the level of resistance decreased as the backcross round increased. Highly resistant plants occurred frequently in the BC1F2 populations but were rare in the BC2F1 populations. Resistant plants selected in BC1F3 populations had nearly enough recovery of the growth and fruit characteristics of the Korean recurrent parents. Crosses were made between resistant selections in each BC1F2 population. The F1 hybrids showed a considerably increased level of resistance.