Search Results
Abstract
Seeds of jalapeno (Capsicum annuum L.) and tabasco (Capsicum frutescens L.) peppers were placed in aerated distilled water for 9.5 or 8 hr, respectively, or primed for 144 hr in aerated 3.0% or 2.75% KNO3 solutions, respectively. After treatment, seeds from each replication were placed on moist filter paper in Petri dishes for germination tests, in rolled paper towels for radicle and hypocotyl development tests, or in 70-ml incubation jars for 24-hr respiration studies. All tests were maintained at 25C. Jalapeno seed germination percentage was not affected by seed priming, but the mean rate of germination was increased. Jalapeno hypocotyl development was advanced at 7 and 14 days following seed priming. Compared to the soak controls, primed jalapeno seed respiration rates were greater at 0.15 and 0.45 hr following removal from incubation solution, but were no different thereafter. Tabasco seed germination percentage and rate were positively influenced by priming treatment, but seedling hypocotyl development was only advanced at 7 days following treatment. Primed tabasco seed respiration rates were depressed significantly relative to the soak control, suggesting that priming treatment inhibits some aspect of seed metabolism during germination. These data support earlier observations that seed priming is not useful in tabasco field stand establishment efforts.
Abstract
In the laboratory, gibberellic acid (GA3) applied to Tabasco pepper (Capsicum frutescens L.) seed at 1000 ppm for 48 hr and priming in 2.75% KNO3 for 144 hr significantly stimulated seed germination performance (a function of germination rate and percent germination). In the field, GA3-treated and primed seed treatments were direct-seeded or plug-mix planted and were evaluated for germination, emergence, and yield. In addition, a pregerminated plug-mix seed treatment and a transplanting treatment also were evaluated. Seed priming and GA3 treatment significantly decreased field emergence of both direct-seeded and plug-mix planted treatments. Seedling emergence percentages of untreated seed that was direct-seeded, and pregerminated seed that was planted in plug-mix were significantly higher than other treatments. Greatest stand percentage was observed in the pregerminated seed treatment. Mean rates of emergence increased in primed and pregerminated seed treatments. Total fruit yields of Tabasco were increased by transplanting or pregerminated seed treatments; red fruit yields were greater in pregerminated seed treatments.
Abstract
Field emergence of Tabasco pepper (Capsicum frutescens L.) often requires 10 to 14 days even under optimum conditions. Methods to increase and accelerate Tabasco seed germination were investigated. Seed were extracted from orange and red fruit harvested at 150, 195, and 240 days from transplanting. The influence of fruit maturity on seed germination performance was significant over all harvest times. Seed extracted from red fruit had a significantly greater germination rate and final germination percentage than seed from orange fruit. Germination performance of seed extracted from red fruit harvested 150 days after transplanting was superior to that of seed harvested from orange fruit and to seed harvested later in the growing season. Results indicate that Tabasco seed extracted from red fruit responds favorably to a period of dry after ripening. A 21-day period at 25°C appears to be optimum for improving germination percentage and rate.
Abstract
‘Redglobe’ peaches (Prunus persica (L.) Batsch) were grown under drip irrigation and no irrigation, with and without fumigation with 1,2–dibromo–3–chloropropane (DBCP). The irrigation treatments were 1) nonirrigated, 2) irrigated until harvest, 3) irrigated from harvest to dormancy, 4) irrigated all season. Fumigation increased trunk cross-sectional area by 18 cm2, and when postharvest water was applied the increase was 25 cm2 at the end of 1978. Irrigation increased marketable yields of fresh peaches from 3.6 to 7.4 MT/ha (62-150 bu/acre) in 1977. In 1978, fumigation did not increase yields unless preharvest water was applied; then, yields were increased from 12.1 to 17.2 MT/ha (232-357 bu/acre). Fumigation apparently increased water use as indicated by the increased rate of controlled water application. Fumigation reduced populations of Macroposthonia xenoplax (Raski) DeGrisse and Loof, from a range of 30-400 to a range of 1-30 nematodes/150 cm3 of soil.
Abstract
Application of limestone to a Cahaba sandy loam increased exchangeable soil Ca and decreased extractable soil Al and Mn. Leaf tissue composition of ‘Calhoun Gray’ and ‘Dixielee’ watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] was significantly influenced by soil pH. Increased levels of limestone significantly increased tissue Ca and reduced tissue Al and Mn concentrations. High soil acidity was closely associated with high tissue Mn in both cultivars. Tissue Al levels were not as sharply reduced by increasing soil pH as were tissue Mn levels. Tissue Al influences on yield were not significant in either cultivar at any soil pH. In nonlimed plots, ‘Calhoun Gray’ tissue Mn was highly correlated with depressed crop yield, while ‘Dixielee’ produced no marketable fruit at soil pH 5.0. Foliar Mn toxicity symptoms were observed on the 2 cultivars at soil pH 5.0. Maximum watermelon yield was obtained at soil pH 6.0 on plots that received 112 kg N/ha.
Abstract
Nitrogen rate and in-row plant spacing significantly influenced yields of mechanically harvested red Tabasco (Capsicum frutescens L.) pepper. Red pepper yields increased with an increase in N rate from 0 to 112 kg N/ha, and a decrease in in-row plant spacing from 81 to 10 cm. The percentage of machine harvested red pepper in relation to green and orange fruit removal was enhanced with 20 cm in-row spaced plants. Tabasco plant height increased with an increase in N rate from 0 to 112 kg N/ha, while plant diameter decreased with a decrease in in-row spacing from 81 to 10 cm. Conventionally spaced (81 cm in-row spacing) Tabasco plants were damaged substantially more during mechanical harvesting than 10 cm in-row spaced plants. Early season leaf-petiole tissue N concentrations had higher correlations with red pepper yields than did late season tissue N concentrations. Multiple harvests of red Tabasco pepper with a flail-type machine produced yields similar to those obtained with hand harvesting.
Abstract
Three cucumber (Cucumis sativus L.) populations were evaluated to determine the effects of several seed harvesting and handling procedures on seed quality. Fruit maturity at seed harvest, fermentation duration in seed extraction, seed storage time, and germination temperature all significantly influenced germination percentage and rate. About 30% of the observed variation in germination percentage was due to interactions between handling factors rather than to main effects of factors. Although germination in excess of 90% was observed for some combinations of factors with as little as 28 days of fruit maturity (post-pollination), the advantages of greater seed maturity at harvest were evident for rate of germination and tolerance to long fermentation times. Positive responses to short fermentation durations (≤4 days) occasionally were observed, but longer fermentation durations were markedly deleterious under some conditions. Six months of seed storage were effective in improving germination of seed at 15° and 20°C, but had little effect on germination at 25°. The 3 cucumber populations were markedly different in response to some seed handling factors.
Abstract
Priming seed of ‘Jalapeno M’ jalapeno pepper (Capsicum annuum L.) and ‘McIlhenny Select’ tabasco pepper (Capsicum frutescens L.) in 3% KNO3 for 144 hours and –4 bar polyethylene glycol-6000 (PEG) for 120 hours enhanced germination rates, tested at 5° to 35°C. Seed priming stimulated jalapeno germination at 5°, but had no effect on tabasco when temperatures were less than 15°. Surface drying seed following priming retarded germination rate of both peppers over all temperatures as compared to primed seed not surface dried. Primed pepper seed performance in media under suboptimal temperatures (10° and 15°) was significantly less than that observed on filter paper. In the greenhouse, KNO3-primed jalapeno seed had significantly earlier germination and accelerated vegetative seedling development. Priming in PEG appeared to retard jalapeno vegetative seedling development.
Abstract
‘Redglobe’ peaches [Prunus persica (L.) Batsch] were grown under drip irrigation. Applications of NH4NO3 through the irrigation system were compared with broadcast applications. Soil pH, where NH4NO3 was applied through the irrigation system, decreased in the top 30 cm from 6.2 to 3.7 pH in the zone wetted by emitters that had been in place for 2 years, and from 6.2 to 4.5 pH in the zone where emitters had been in place for 6 months. Aluminum concentration in wetted zones increased from 0.01 to 1.45 meq/100 g of soil after 2 years and from 0.02 to 0.73 meq/100 g of soil after 6 months of NH4NO3 application through drip irrigation. Soil Ca and Mg concentrations were reduced in both wetted zones, but the greatest decrease occurred in the 2-year emitter site. The addition of NH4NO3 in the irrigation water substantially reduced root growth in the vicinity of the emitters, irrigation water application, and fruit yield, because of the high A1 concentration in the wetted zone.