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  • Author or Editor: A.R. Bonanno x
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Abstract

Three row covers (spunbonded polyester, double-slitted, and perforated polyethylene) used in combination with clear polyethylene mulch and trickle irrigation for muskmelon (Cucumis melo L.) production in 1985 and 1986, increased soil (5-cm depth) minimum and maximum temperatures and air (15-cm height) maximum temperatures compared to clear mulch alone. Increased minimum air temperatures resulted from the use of all row covers in 1985. All row covers enhanced earliness in both years. However, in 1985, there were no total marketable yield differences; in 1986, total marketable yield was greater with the spunbonded and double-slitted row covers than with the no row cover treatment. Within row cover treatment, the use of the perforated row cover in 1986 resulted in lower total marketable yields than with the spunbonded row cover. Excessive air temperatures with the perforated row cover may have resulted in reduced marketable yield. Lower minimum air temperatures in 1986 may have resulted in lower yields than in 1985.

Open Access

Seeds of `Golden Delicious' apple (Malus domestic a Borkh.) were exposed to constant and alternating chilling temperatures. Germination was reduced in seeds treated with 4/11, 4/13, and 4/15 C for 16/8 h, respectively, compared to those treated at a constant temperature (4 C). The 4 C reached 100 % germination after 1600 h, the 4/11 C after 1864 h, and the 4/13 C after 1973 h at 4 c. The 4/15 C never reached complete germination even after 2200 at 4 C. The predominant fatty acids during stratification at constant and alternating temperatures were palmitic, oleic, and linoleic acids. Stearic acid was found at a lower level. Arachidic and behenic acids were only found in constant temperature treatment. There were no significant changes in fatty acid content during stratification at constant and alternating temperatures except that the 4/11 C treatment increased levels of palmitic, oleic, and linoleic acids.

Free access

The ability of two cryoprotectants to protect tomato and pepper transplants during frost and freeze conditions was evaluated in Clayton, NC. A commercially available cryoprotectant (50% propylene block copolymer of polyoxyethylene, 50% propylene glycol, tradename FrostFree) was evaluated during 4 spring and 3 fall seasons. An antitranspirant (96% di-1-p-Menthene, i.e. Pinolene, a terpenic polymer, 4% inert, tradename VaporGard) was evaluated for 2 spring and 1 fall season. Protection from these products was not observed under the field conditions experience? Yield differences were not observed between the treated and untreated plants. With several days of cool weather preconditioning, transplants survived air temperatures of -2.0 to -1.0 C with no damage. However, with no preconditioning, damage occurred at -1.0 C without the formation of frost. At -3.5 C all plants, both treated and untreated, died. Both crops were stunted and delayed by periods of cold temperatures even when no freezing temperatures were experienced.

Free access