Critical irrigation threshold and cranberry yield components
Yield components are useful for characterizing the impact of crop management parameters on cranberry yield and are known to be influenced by irrigation management. This study was conducted to evaluate the potential contribution of cranberry yield components to maximizing yield, and the influence of the soil water tension threshold used to initiate irrigation (SWTI) on those components. During the 2011 and 2012 growing seasons, tensiometers were installed at three production sites in Quebec to test SWTI values ranging from 5.5 to 10.0kPa. Sites were cropped to cranberries to evaluate the impact of these irrigation treatments on yield components. The four most important cranberry yield components related to final yields were, in order of importance, the number of marketable berries per quadrat (BM/Q), the number of uprights per quadrat (U/Q), the number of marketable berries per upright (BM/U), and the marketable fruit set (BM/F). Significant reductions in BM/Q, BM/U and BM/F were observed when SWTI varied from 8.5 to 10.0kPa while a reduction in U/Q was associated with a SWTI of 5.5kPa. A SWTI ranging from 7.0 to 8.0kPa significantly improved the principal yield components.
Impact of potassium sulfate salinity on growth and development of cranberry plants subjected to overhead and subirrigation1
Abstract: New recommendations in cranberry production suggest reducing overhead irrigation and the use of subirrigation as an alternative irrigation method, two strategies suspected to increase the risk of salt buildup in soil. Because very little is known about cranberry tolerance to salinity, this study was conducted to determine if deficit irrigation and subirrigation could cause salinity issues and affect plant yield. In a greenhouse, cranberry plants were submitted to eight different treatments combination from two irrigation methods (overhead irrigation and subirrigation) and four salinity levels created by increasing amounts of applied K2SO4 (125 (control), 2500, 5000, and 7500 kg K2O ha-1). Irrigation methods showed no significant difference in measured electrical conductivity of soil solution (ECss). Meanwhile, growth and yield parameters decreased significantly with soil salinity in both irrigation treatments, and an average ECss of 3.2 dS m-1 during flowering caused a 22% drop in relative photosynthetic rate and a 56% decrease in yield when compared with the control. Cranberry seems to be salt sensitive, and further work should investigate ECss levels under different field and irrigation practices to make sure that it does not reach critical levels.
New Sweet-Tasting C21-Pregnane Glycosides from Pericarps of Myriopteron extensum.
Ten novel C21 pregnane glycosides, extensumside C-L (1-10), were isolated as highly sweet-tasting substances from the edible pericarps of Myriopteron extensum (Wight) K. Schum by sensory-guided fractionation and purification. Their structures were determined through 1D and 2D NMR, such as HSQC, HMBC, 1H-1H COSY, HSQC-TOCSY, and ROESY, as well as other spectroscopic analysis combined with chemical evidence. These compounds shared the same aglycone, 3β,16α-dihydroxy-pregn-5-en-20-one, and contained the deoxysugar chain and the glucose chain which were linked to C-3 and C-16 of the aglycone, respectively. The sweetness potency was evaluated by a human sensory panel test and preliminary structure-taste relationship was discussed. The sweetness intensities of these compounds are between 50 and 400 times greater than that of sucrose. Furthermore, quantitation analyses of compounds 1, 3, 4, and 6 in different parts of M. extensum indicated that the concentrations of these sweet components in the pericarps are obviously higher than those in stems and roots.