Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: A.K. Carter x
Clear All Modify Search
Authors: and

Chile (Capsicum annuum L.) seeds sown in July for fall transplants in the greenhouse often yield poor stands due to thermoinhibition. To determine cultivar response to high temperature, five jalapeno cultivars and one cayenne cultivar used commercially in Florida and New Mexico were tested. Two seedlots of `Cayenne, Large Red Thick', `Ole', `Jalapeno M', `Mitla', and `Tam Veracruz', and one seedlot of `Ebano' were evaluated on a thermogradient table at a temperature range of 20, 25, 30, 35, and 40°C. Percent germination, mean daily germination, and germination performance index were calculated. Additional seeds were soaked for 24 hours at 25, 30, 35, and 40°C. The exudate was then measured for electrical conductivity and glucose equivalents as an indication of seed leakage. All cultivars exhibited thermoinhibition, but the critical temperature of onset varied among cultivars. `Ebano' had the highest germination performance index across all temperatures among the six cultivars. At 40°C, however, no cultivar exceeded 4.0% germination. There was significant variation in germination performance between seedlots of some cultivars. The electrical conductivity and the number of glucose equivalents leached from the seed varied among cultivars, but did not correlate with decreased germination. Thermoinhibition in chile is probably due to factors other than those associated with membrane leakage.

Free access

Thermoinhibition has been observed in chile (Capsicum annuum L.) transplants grown in greenhouses in southern climates. Hormones have been used successfully as a treatment for thermoinhibition in other vegetable crops. This experiment examined the effects of Ethrel and Release as treatments to improve germination in chile seeds germinated at a supraoptimal temperature. Seeds of `Jalapeno M' were soaked in solutions of Ethrel at 1.75, 3.0, 7.0, or 10.5 mM concentration or Release at 0.50, 1.0, 2.0, or 3.0 mM concentration, or 16 different combinations of the two growth regulators. The seeds were soaked in the treatment solutions for 40 hours at 25°C. A H2O-soaked and a non-soaked control were also included. Afterwards, the seeds were rinsed, dried, then germinated in 25°C or 40°C incubators. At 25°C, all treatments reached 98% germination or better after 10 days, indicating that none of the treatments were detrimental to germination. At 40C, germination percentages amongtreatments ranged from 0% for the nonsoaked control to 90% for a Release–Ethrel combination. Generally, the combination treatments resulted in germination percentages higher than either Ethrel or Release used alone. Results of these tests in petri dishes indicate the possibility of growth regulators being used to overcome thermoinhibition in chile. A greenhouse study is underway.

Free access

Twenty-eight seedlots of Capsicum annuum from several commercial seed companies were tested for tolerance to low temperatures. Each cultivar was tested three times at 25, 20, and 15°C in laboratory incubators. It was observed that while high germination percentages (r85%) and fast germination rates were found in several seedlots, the relationship was not strongly linked to type of chile, age of seed, or treatment temperature. Of the 28 seedlots, 14 came from companies which are in the top 10% in volume and sales. The other 14 seedlots were from smaller companies. Seventy-one percent of the seedlots with germination at r85% came from the top ten companies. Ninety-two percent of the seedlots with s85% came from small companies. To further test this finding, we randomly choose six seedlots from a small company and 6 seedlots from a small company. There was a clear delineation in germabiltiy between the small company and the large company. Our results indicate a trend that could have a negative impact on some chile seed markets. Electrical conductivity (EC) is commonly used to detect membrane leakage in seeds. Chile seed from 12 seedlots (6 from the large company and 6 from the small company) were soaked 18 hours at 25 and 5°C. There was a negative correlation (r 2 = 0.76) between the 15°C germination at 40 days and the EC. It is important to determine why membrane leakage varies in seedlots from different companies and whether the leakage is due to phenotypic or cultural factors, or due to management practices within the company.

Free access