In tomato, Ve is implicated in race-specific resistance to infection by

Crop development rates, yields and production economics for muskmelon (Cucumis melo), pepper (Capsicum annuum) and tomato (Lycopersicon lycopersicum) grown in high tunnels [4.3 m wid × 2.5 m high × 29 m long (14 × 8 × 96 ft)] were compared to standard low tunnels over several cropping seasons in a temperate production area. The polyethylene-covered high tunnels protect several rows of crop for the duration of the cropping season. Air temperatures in the high tunnels were controlled by raising the sides of the tunnel. Low tunnels cover only a single row and must be removed soon after the crop is established to prevent overcrowding or overheating. When the low tunnels were in place, rates of accumulation of growing-degree days (GDDs) and early crop growth were comparable in the two tunnel systems. However, once the low tunnels were removed, the accumulation of GDDs in the high tunnels exceeded the standard system. The crops in the high tunnels matured 1 to 2 weeks earlier and produced substantially greater fruit yields before frost than in the low tunnel treatments. The high tunnels provided little frost protection and were of limited utility for extension of the growing season. The high tunnels were much more costly to purchase and construct than the low tunnels but were durable enough to be used for multiple cropping seasons. Based on wholesale commodity prices, it would take 2 to 5 years for the enhanced gross returns obtained with the high tunnels to cover their higher capital costs.

Evaluation of biodegradable mulches for production of warm-season vegetable crops. Can. J. Plant Sci. 90: 737Á743. While plastic soil mulches are widely used in vegetable crop production, removal and disposal of these plastics at the end of the growing season is costly and environmentally unsound. This trial assessed the field performance of several colors of corn-starch-based biodegradable mulches for the production of warm season vegetable crops (sweet corn, zucchini, cantaloupe, pepper and eggplant) over three cropping seasons in Saskatchewan. The clear and wavelength selective types of mulch most commonly produced beneficial effects on the rate of crop development and yields. This may be attributed to these mulch types enhancing soil temperatures, especially early in the growing season. There were no appreciable differences in the soil temperatures or crop growth and yield responses on the biodegradable mulches as compared with the same color of standard low-density polyethylene mulch. The biodegradable mulches were easy to apply and were readily incorporated into the soil at the end of the growing season. Although the clear and to a lesser extent the wavelength selective forms of biodegradable mulch tended to break down well before the end of the growing season, this early failure did not negatively impact the performance of any of the crops tested, as long as supplemental weed control was provided. Supplemental weed control would be more important for slow-growing, erect crops like peppers and eggplants than for the more robust and sprawling crops like corn and melons. Although the biodegradable mulches are more expensive than the corresponding standard polyethylene-based plastics, this added cost is more than offset by the costs to remove and dispose of the standard plastic mulches.Key words: Sweet corn, pepper, zucchini, eggplant, cantaloupe, Biotelo Waterer, D. 2010. É valuation d'un paillis biode´gradable pour les cultures maraıˆche`res de la saison chaude. Can. J. Plant Sci. 90: 737Á743. Si l'on utilise abondamment les paillis de plastique pour le maraıˆchage, leur retrait et leur e´limination a`la fin de la pe´riode ve´ge´tative couˆtent cher, et l'environnement en subit les conse´quences. L'essai devait servir a`e´valuer la performance sur le terrain d'un paillis en fe´cule de maı¨s biode´gradable de couleur varie´e pour la production de fruits et de le´gumes de la belle saison (maı¨s sucre´, courgette, melon brode´, poivron, aubergine), durant trois pe´riodes de production, en Saskatchewan. Le paillis translucide et ceux se´lectionnant une longueur d'onde ont des effets be´ne´fiques sur la rapidite´du de´veloppement et sur le rendement des cultures. On l'attribue au fait que ces paillis haussent la tempe´rature du sol, surtout au de´but de la pe´riode ve´ge´tative. On ne note aucun e´cart appre´ciable entre la tempe´rature du sol ou la croissance et le rendement des cultures obtenus avec le paillis biode´gradable et le paillis ordinaire de meˆme couleur, en polye´thyle`ne de faible densite´. Le pai...